We are grateful to the Deutsche Forschungsgemeinschaft (DFG) for financial support, and we thank Dr. Daniel Werner for helpful discussions.

CAUTION! Please consult all relevant material safety data sheets (MSDS) before use. Several of the chemicals used in these syntheses are acutely toxic, pyrophoric, and carcinogenic. Nanomaterials may have additional hazards compared to their bulk counterpart. Please use all appropriate safety practices when performing a reaction, including the use of engineering controls (fume hood and glovebox) and personal protective equipment (safety glasses, gloves, lab coat, full length pants, and closed-toe shoes). Portions of the following procedures involve standard air-free Schlenk techniques. The co-condensation apparatus applied contains a 20 kW high-frequency generator. People with a cardiac pacemaker can have strictly no admittance. Gaseous HCl is highly corrosive. Store in a well-ventilated place or in a fume hood. Liquid nitrogen and dry ice are extremely cold substances; special gloves must be used to prevent frostbite.
1. Preliminary Work
<ol>
	<li>Setup of the graphite reactor
	<ol>
		<li>Take five reaction chambers, one terminal ring, one hollow graphite tube topped with a quartz glass tube, and two 0.7 mm graphite rods. Fill all five reaction chambers with elemental tin (pieces), in total 6 g. Stack the reaction chambers over the terminal ring, each of them twisted by 30&#176;, and fix the stack with the graphite rod. Ensure that the rod is not longer than the stack.</li>
		<li>Insert the stack into the graphite tube so that the holes of the terminal ring fit with the holes in the graphite tube. Fix the setup with a second graphite rod. Ensure that the rod is not longer than the diameter of the tube. Weigh the whole setup with a scale and note the value to determine the amount of tin consumed during the reaction.</li>
	</ol>
	</li>
	<li>Preparing the solvent mixture 
	NOTE: Toluene must be pre-dried over sodium/benzophenone and distilled. Tributylphosphine must be vacuum-distilled prior to use.
	<ol>
		<li>Attach a 200 ml Schlenk tube with a glassy stopcock to a lab Schlenk-line. Evacuate and purge the system with inert gas three times. Flame heat the evacuated Schlenk tube after the first evacuation cycle. 
		NOTE: Use either dry nitrogen or dry argon as inert gas.</li>
		<li>Fill with 180 ml of toluene and 20 ml of tributylphosphine. Mix the solvents by manually shaking the flask. 
		NOTE: Tributylphosphine reacts with paper towels. Do not wipe drops of tributylphosphine with paper.</li>
		<li>Cool the mixture with dry ice for at least 20 min and degas the mixture by slightly evaporating and shaking the cold flask. Close the valve under vacuum and let the mixture heat to room temperature. 
		NOTE: The mixture can evaporate violently, which can be avoided by continuously shaking the flask.</li>
	</ol>
	</li>
</ol>
2. Set up the Co-condensation Apparatus
<ol>
	<li>Reaction
	<ol>
		<li>Place the graphite reactor inside the copper induction coil and pass the quartz tube through the central hole of the top copper sheet, placed above the induction coil. Fix the quartz tube to the gas supply with a gasket and a screw nut. Check the position of the reactor inside the coil. Ensure that the reactor protrudes from the coil by 5 &#177; 0.5 mm. 
		NOTE: The copper induction coil is the central portion of the co-condensation apparatus. The coil is flush with cooling water and is connected to a high-frequency generator. Thus, the graphite tube will be heated inductively. To get reproducible conditions, the position of the graphite tube inside the coil is crucial. It should be located in the center of the coil&#39;s cavity, with 5 &#177; 0.5 mm protruding out the bottom.</li>
		<li>Connect the cooling shield to the water pins of the connector with the screw nuts. Fix the cooling shield at the other side with a screw. Test the water-tightness of the cooling cycle by opening the water tap for 30 sec. 
		NOTE: Due to the high voltage inside, there must be no direct metal-metal contact to prevent bypasses or electric arcs, especially at the top copper sheet. If there are contacts, change the position of the copper sheet with a stick. If this is not possible, remove all the components and restart from 2.1.1.</li>
		<li>Fix the fiber optics of the pyrometer (temperature control) to the holder at the copper shield with a screw. Put a quartz glass in the holder at the optics to prevent contamination of the optical system by chemicals like SnCl.</li>
		<li>Fix the solvent vapor diffuser with a screw nut. Be sure that the diffuser is centered under the cavity of the copper shield. Re-check that the graphite reactor is still in the center of the induction coil, and that there is no contact of the coil to the top copper sheet.</li>
		<li>Mount the Schlenk vessel, for solvent evaporation, onto the valve, which is connected via a steel tube to the vapor diffuser. Attach the prepared solvent mixture flask to the Schlenk vessel. Add a hemispherical heating mantle to the evaporating Schlenk vessel.</li>
		<li>Connect the long steel cannula to the apparatus with a screw nut. Close the outer tail with a small round-bottom flask. Place a magnetic stir bar (10 cm) inside the big stainless steel vessel, put the gasket into the cavity of the plane flange, and connect the vessel to the co-condensation apparatus.</li>
	</ol>
	</li>
	<li>Gas supply
	<ol>
		<li>Connect an HCl-containing glass vessel to a small steel tube and then to a four-point adapter. 
		NOTE: The HCl pressure inside the glass vessel must be below 1 atm so that the differential pressure manometer can work.</li>
		<li>Close the rear exit of the four-point adaptor with a blind flange. Connect the differential pressure manometer to the front exit and set up a valve at the top exit. Connect a fine-needle valve to the valve at the top exit of the four-point adapter. Then, use a long steel tube to connect the gas supply part to the co-condensation apparatus. 
		NOTE: Instead of a fine-needle valve, a mass flow controller can be used.</li>
	</ol>
	</li>
	<li>Further preparatory work
	<ol>
		<li>Connect the double-walled steel dewar bucket to the vacuum pump and evacuate the double-walled space for at least 30 min. 
		NOTE: This step can also be done during the setup of the reaction part of the co-condensation apparatus.</li>
		<li>Evacuate the whole co-condensation apparatus with a rotary vane pump to a final pressure of 10-2 mbar, which takes 60 min.</li>
		<li>After reaching the final pressure, preheat the oil diffusion pump. Switch on the cooling water cycle and evacuate the oil diffusion pump with the rotary vane pump during heating. 
		NOTE: During this time the apparatus stays under static vacuum until the diffusion pump is heated. This takes at least 45 min.</li>
		<li>Evacuate the apparatus with the pre-heated diffusion pump overnight to reach the final pressure of about 8 x 10-6 mbar the next morning.</li>
	</ol>
	</li>
</ol>
3. Co-condensation Reaction
<ol>
	<li>Setting up the reaction
	<ol>
		<li>Fill the cooling trap of the diffusion pump with 4 L of liquid nitrogen. Switch on the cooling water cycle of the high-frequency generator by opening the water tap. Then, switch on the high-frequency generator.</li>
		<li>Slowly pre-heat the graphite reactor by increasing the output power of the high-frequency generator manually, in incremental steps of 0.1 to 0.5 kW, until the reaction temperature is around 1,300 &#176;C. 
		NOTE: The temperature is monitored with the optical pyrometer and should not be higher than 1,300 &#176;C. In normal cases, this procedure needs approximately 30 min, and the final temperature is achieved at 3.5 kV. During the process, the stainless steel vessel also gets warm.</li>
		<li>Adjust the value of the generator to 1.0 kV to cool down the reactor. Fill the steel dewar with about 30 L liquid nitrogen. Lift the dewar with a lifting platform so that the reaction vessel is placed within the dewar. Add more liquid nitrogen to the steel dewar to reach the final level of liquid nitrogen. 
		NOTE: In the following steps, the level of liquid nitrogen should always be at the upper third of the stainless steel vessel.</li>
	</ol>
	</li>
	<li>Performing the reaction
	<ol>
		<li>Evaporate the solvent dropwise. Fix the drop rate so that all solvent is used during the reaction (4 hr). Switch on the hemispherical heating mantle on the lowest level to maintain evaporation.</li>
		<li>Close the fine-needle and the gas valve. Open the HCl vessel. Ensure that the displayed voltage at the differential pressure manometer is higher than 1,600 mV. If this is not the case, apply low pressure at the second connection of the manometer by connecting an evacuated vessel to the outer connection of the manometer. Write down the displayed starting value.</li>
		<li>Heat the graphite reactor to the final temperature of 1,300 &#176;C by adjusting the value of the generator to 3.5 kV. Open the gas valve. Slowly open the fine-needle valve to let in the reaction gas (HCl) with a constant rate of 8 mV/min. Check the rate at least every 10 min and write down the measured values. 
		NOTE: The control of a constant gas flow rate is absolutely necessary for a reproducible reaction. If a mass flow controller is used, the flow rate can be controlled via a computer program. Otherwise, the control can be done by noting the decreasing values of the differential pressure manometer during the gas inlet. The rate should be within 7-8 mV/min, and the reaction is finished when the displayed value is decreased by 1,600 mV, which is equal to 40 mmol of HCl consumed. 
		NOTE: When the reaction is running, hydrogen gas is produced, which can be monitored by the increase in pressure inside the apparatus from about 8 x 10-6 mbar to around 4 x 10-5 mbar.</li>
		<li>Put 2 L of liquid nitrogen in the dewar approximately every 10 min so that the level of liquid nitrogen is always at the upper third of the stainless steel vessel. This process will take 4 hr.</li>
		<li>After the value of the differential manometer is decreased by 1,600 mV, close the gas valve. Then, introduce the remaining HCl gas that is within the gas supply part by slowly opening the fine-needle valve. Wait until the pressure in the apparatus gets lower than 4 x 10-5 mbar and then switch off the high-frequency generator and let in the remaining solvent mixture if necessary.</li>
		<li>Change the liquid nitrogen-filled steel dewar to an insulated bucket placed on a magnetic stirrer. Disconnect the oil diffusion pump by closing the main valve and flush the apparatus with dry nitrogen (5.0) to a pressure around 1 atm (rough barometer). Add ~5 kg of fine, powdered dry ice into the bucket so that the stainless steel vessel will be cooled from outside and switch on the magnetic stirrer.</li>
		<li>Wait until the magnetic stirrer rotates freely. This indicates that the reaction mixture is molten. Let the solution stir for at least 45 min. 
		NOTE: During the heating process, the pressure increases and might get higher than 1.2 atm, which can be seen at the rough barometer. The overpressure can be released via the valve in the round-bottom flask at the long press cannula.</li>
		<li>Switch off the stirrer. Change the round bottom flask at the press cannula to a double valve Schlenk tube while still cooling with dry ice under constant flow of nitrogen. Fix the height of the press cannula so that it touches the bottom of the stainless steel vessel.</li>
		<li>Push out the Sn(I)Cl solution with slight overpressure by opening the valves at the double valve Schlenk tube. 
		NOTE: The solution should be deep red, dark brown to black, when concentrated.</li>
	</ol>
	</li>
	<li>Determine the quality of the solution
	<ol>
		<li>Halide titration 
		Take 2 ml of the solution and dissolve it in 20 ml of diluted nitric acid. Add 1 ml of 30% H2O2 and stir for 10 min. Perform a potentiometric titration of AgNO3 against the calomel electrode. 
		NOTE: The concentration of the halide should be ~0.2 M.</li>
		<li>Take the graphite tube and weigh it to determine the amount of consumed tin, which should be in between 4 g and 4.8 g. 
		NOTE: In normal cases, the amount of reacted tin is lower than the amount of the halide inside the solution, due to the side reaction: 
		Sn + 2 HCl&#160;&#8594; SnCl2 
		NOTE: This reaction takes place in small amounts, but it will not decrease the quality of the solution and the ability of the disproportionation reaction to form tin cluster species. A tin:c ratio of 1:1.2 is in the normal range.</li>
	</ol>
	</li>
</ol>
4. Synthesis of Sn10(Hyp)42-
<ol>
	<li>Preliminary work
	<ol>
		<li>Place 2 g (4.4 mmol) of LiHyp &#8226; 3 THF, prepared according to the literature24 and a small magnetic stir bar into a Schlenk tube in a glovebox.</li>
		<li>Prepare a 2-propanol/dry ice cooling bath at -78 &#176;C. Do not use a cryostat.</li>
		<li>Place the Schlenk vessel inside the cooling bath and place both on a magnetic stirrer.</li>
	</ol>
	</li>
	<li>Reaction
	<ol>
		<li>Add 20 ml of a 0.2 M SnCl solution to the cooled Schlenk vessel containing 2 g (4.4 mmol) of LiHyp &#8226; 3 THF via a steel or Teflon cannula. Switch on the magnetic stirrer. Let the reaction run and slowly warm it up to room temperature within 3 hr. Observe the color of the reaction solution change to dark brown. 
		NOTE: If the concentration of the solution is not 0.2 M, adjust the added volume so that 4 mmol of halide are applied (e.g., 40 ml of a 0.1 M solution).</li>
	</ol>
	</li>
	<li>Work-up procedure
	<ol>
		<li>Stop the stirrer and allow all insoluble precipitate inside the Schlenk tube to settle. Decant the black solution into another Schlenk vessel. 
		NOTE: In most cases, during the decantation process, it is useful to check the precipitate with a lamp to ensure complete transformation of the supernatant. The non-soluble precipitate LiCl can be identified as a grey solid at the bottom.</li>
		<li>Add 0.2 ml of TMEDA (TMEDA = N,N,N&#39;,N&#39;-tetramethylethylenediamine) to the mixture and allow it to stand overnight. Black, tetrahedral crystals grow in the solution. Upon isolation, identify the crystals via proton NMR as Li2(tmeda)4Sn10Hyp423. 
		NOTE: Over time, the mother liquor produces more crystals of the product. Hence, storing the mother liquor for at least one month is recommended to increase the yield. Concentration of the mother liquor also might be helpful to initiate further crystallization.</li>
		<li>To obtain crystals for X-ray crystal structure analysis, recrystallize the cluster in the following way: Dissolve 150 mg of Li2(tmeda)4Sn10Hyp4 at -40 &#176;C in 15 ml of absolute THF. Add in 1 ml of 12-crown-4 (5 g in 25 ml toluene) to the mixture. The solution should be dark green and must be stored at -30 &#176;C, as the cluster is not stable in THF at room temperature.</li>
		<li>After one day, obtain large blocks of Li2(12-crown-4)4Sn10Hyp4(140 mg). Use one of the single crystals for structural analysis (Figure 9) using X-ray crystallography23.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Goesmann, H., Feldmann, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoparticulate+Functional+Materials.">Nanoparticulate Functional Materials.</a> Angew. Chem. Int. Ed. 49, 1362-1395 (2010).</li><li>Purath, A., K&#246;ppe, R., Schn&#246;ckel, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=[Al7{N(SiMe3)2}6]-:+A+first+step+towards+aluminum+metal+formation+by+disproportionation.">[Al7{N(SiMe3)2}6]-: A first step towards aluminum metal formation by disproportionation.</a> Angew. Chem. Int. Ed. 38, 2926-2927 (1999).</li><li>Schn&#246;ckel, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metalloid+Al-+and+Ga-clusters:+a+novel+dimension+in+organometallic+chemistry+linking+the+molecular+and+the+solid-state+areas?.">Metalloid Al- and Ga-clusters: a novel dimension in organometallic chemistry linking the molecular and the solid-state areas?.</a> Dalton Trans. , 3131-3136 (2005).</li><li>Hu, K. -. J., Plant, S. R., Ellis, P. R., Brown, C. M., Bishop, P. T., Palmer, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atomic+Resolution+Observation+of+a+Size-Dependent+Change+in+the+Ripening+Modes+of+Mass-Selected+Au+Nanoclusters+Involved+in+CO+Oxidation.">Atomic Resolution Observation of a Size-Dependent Change in the Ripening Modes of Mass-Selected Au Nanoclusters Involved in CO Oxidation.</a> J. Am. Chem. Soc. 137 (48), 15161-15168 (2015).</li><li>Schno&#776;ckel, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structures+and+Properties+of+Metalloid+Al+and+Ga+Clusters+Open+Our+Eyes+to+the+Diversity+and+Complexity+of+Fundamental+Chemical+and+Physical+Processes+during+Formation+and+Dissolution+of+Metals.">Structures and Properties of Metalloid Al and Ga Clusters Open Our Eyes to the Diversity and Complexity of Fundamental Chemical and Physical Processes during Formation and Dissolution of Metals.</a> Chem. Rev. 110, 4125-4163 (2010).</li><li>Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metalloid+Cluster+Compounds+of+Germanium:+Novel+Structural+Motives+on+the+Way+to+Elemental+Germanium!.">Metalloid Cluster Compounds of Germanium: Novel Structural Motives on the Way to Elemental Germanium!.</a> New J. Chem. 34, 2079 (2010).</li><li>Schrenk, C., Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metalloid+Sn+clusters:+properties+and+the+novel+synthesis+via+a+disproportionation+reaction+of+a+monohalide.">Metalloid Sn clusters: properties and the novel synthesis via a disproportionation reaction of a monohalide.</a> Rev. Inorg. Chem. 34, 93-118 (2014).</li><li>Jin, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atomically+precise+metal+nanoclusters:+stable+sizes+and+optical+properties.">Atomically precise metal nanoclusters: stable sizes and optical properties.</a> Nanoscale. 7, 1549-1565 (2015).</li><li>Schnepf, A., Dehnen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metalloid.">Metalloid.</a> Clusters in Structure and Bonding - Clusters - Contemporary Insight in Structure and Bonding. , (2016).</li><li>Brynda, M., Herber, R., Hitchcock, P. B., Lappert, M. F., Nowik, I., Power, P. P., Protchenko, A. V., Ruzicka, A., Steiner, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Higher-Nuclearity+Group+14+Metalloid+Clusters:+[Sn9{Sn(NRR')}6].">Higher-Nuclearity Group 14 Metalloid Clusters: [Sn9{Sn(NRR')}6].</a> Angew. Chem. Int. Ed. 45, 4333-4337 (2006).</li><li>Klinkhammer, K. W., Xiong, Y., Yao, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+lead+clusters+-+from+unexpected+discovery+to+rational+synthesis.">Molecular lead clusters - from unexpected discovery to rational synthesis.</a> Angew. Chem. Int. Ed. 43, 6202-6204 (2004).</li><li>Richards, A. F., Brynda, M., Olmstead, M. M., Power, P. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+Ge5R4(R+=+CH(SiMe3)2,+C6H3-2,6-Mes2):+Germanium+Clusters+of+a+New+Structural+Type+with+Singlet+Biradical.">Characterization of Ge5R4(R = CH(SiMe3)2, C6H3-2,6-Mes2): Germanium Clusters of a New Structural Type with Singlet Biradical.</a> Organometallics. 23, 2841-2844 (2004).</li><li>Desireddy, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastable+silver+nanoparticles.">Ultrastable silver nanoparticles.</a> Nature. 501, 399-402 (2013).</li><li>Jadzinsky, P. D., Calero, G., Ackerson, C. J., Bushnell, D. A., Kornberg, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+a+Thiol+Monolayer-Protected+Gold+Nanoparticle+at+1.1+&#197;+Resolution.">Structure of a Thiol Monolayer-Protected Gold Nanoparticle at 1.1 &#197; Resolution.</a> Science. , 430-433 (2007).</li><li>Schnepf, A., Schn&#246;ckel, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metalloid+aluminum+and+gallium+clusters:+Element+modifications+on+the+molecular+scale?.">Metalloid aluminum and gallium clusters: Element modifications on the molecular scale?.</a> Angew. Chem., Int. Ed. 41, 3532-3554 (2002).</li><li>Ecker, A., Weckert, E., Schn&#246;ckel, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+structural+characterization+of+an+Al77+cluster.">Synthesis and structural characterization of an Al77 cluster.</a> Nature. 387, 379-381 (1997).</li><li>Schnepf, A., Schn&#246;ckel, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+structure+of+a+Ga84R204-+cluster-a+link+between+metalloid+clusters+and+fullerenes?.">Synthesis and structure of a Ga84R204- cluster-a link between metalloid clusters and fullerenes?.</a> Angew. Chem. Int. Ed. 40, 712-715 (2001).</li><li>Schrenk, C., K&#246;ppe, R., Schellenberg, I., P&#246;ttgen, R., Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+tin(I)bromide.+A+novel+binary+halide+for+synthetic+chemistry.">Synthesis of tin(I)bromide. A novel binary halide for synthetic chemistry.</a> Z. Anorg. Allg. Chem. 635, 1541-1548 (2009).</li><li>Schnepf, A., K&#246;ppe, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthese+von+Germanium(I)bromid.+Ein+erster+Schritt+zu+neuen+Clusterverbindungen+des+Germaniums?.">Synthese von Germanium(I)bromid. Ein erster Schritt zu neuen Clusterverbindungen des Germaniums?.</a> Z. Anorg. Allg. Chem. 628, 2914-2918 (2002).</li><li>Uhlemann, F., K&#246;ppe, R., Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+metastable+Si(II)X2solutions+(X+=+F,+Cl).+A+Novel+Binary+Halide+for+Synthesis.">Synthesis of metastable Si(II)X2solutions (X = F, Cl). A Novel Binary Halide for Synthesis.</a> Z. Anorg. Allg. Chem. 640, 1658-1664 (2014).</li><li>Schenk, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Formal+Combination+of+Three+Singlet+Biradicaloid+Entities+to+a+Singlet+Hexaradicaloid+Metalloid+Ge14[Si(SiMe3)3]5Li3(THF)6Cluster.">The Formal Combination of Three Singlet Biradicaloid Entities to a Singlet Hexaradicaloid Metalloid Ge14[Si(SiMe3)3]5Li3(THF)6Cluster.</a> J. Am. Chem. Soc. 133, 2518-2524 (2011).</li><li>Schrenk, C., Schellenberg, I., P&#246;ttgen, R., Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+formation+of+a+metalloid+Sn10[Si(SiMe3)3]6cluster+compound+and+its+relation+to+the+&#945;&#8596;&#946;+tin+phase+transition.">The formation of a metalloid Sn10[Si(SiMe3)3]6cluster compound and its relation to the &#945;&#8596;&#946; tin phase transition.</a> Dalton Trans. 39, 1872-1876 (2010).</li><li>Schrenk, C., Winter, F., P&#246;ttgen, R., Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term={Sn10[Si(SiMe3)3]4}2-+:+A+high+reactive+metalloid+tin+cluster+with+an+open+ligand+shell+for+further+applications.">{Sn10[Si(SiMe3)3]4}2- : A high reactive metalloid tin cluster with an open ligand shell for further applications.</a> Chem. Eur. J. 21, 2992-2997 (2015).</li><li>Gutekunst, G., Brook, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tris(trimethylsilyl)silyllithium.3+THF:+a+stable+crystalline+silyllithium+reagent.">Tris(trimethylsilyl)silyllithium.3 THF: a stable crystalline silyllithium reagent.</a> J. Organomet. Chem. 225, 1-3 (1982).</li><li>Timms, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Techniques+of+Preparative+Cryochemistry.">Techniques of Preparative Cryochemistry.</a> Cryochemistry. , 61-136 (1976).</li><li>Schrenk, C., Gerke, B., P&#246;ttgen, R., Clayborne, A., Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactions+with+a+Metalloid+Tin+Cluster+{Sn10[Si(SiMe3)3]4}2-:+Ligand+Elimination+versus+Coordination+Chemistry.">Reactions with a Metalloid Tin Cluster {Sn10[Si(SiMe3)3]4}2-: Ligand Elimination versus Coordination Chemistry.</a> Chemistry. 21, 8222-8228 (2015).</li><li>Schnepf, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemistry+Applying+Metalloid+Tin+Clusters.">Chemistry Applying Metalloid Tin Clusters.</a> Phosphorus, Sulfur and Silicon and the Related Elements. 191, 662-664 (2016).</li></ol>

The authors do not declare any conflicts of interest.

By applying the preparative co-condensation technique (Figure 1)25, novel materials based on molecules like SnBr are obtained. Due to the high flexibility in temperature, pressure, metal, and reactive gas, a large variety of metastable solutions of high reactive species can be synthesized. For example, subhalides of silicon and germanium are already obtained in this way. However, finding the right conditions to obtain a metastable solution for further synthesis is not trivial, and the solution...

Due to recent progress in the field of nanotechnology, the nanoscale size range between molecules and&#160;the solid state became more and more important and is the focus of various research efforts1. Research with nanoscaled compounds is especially of interest for metals or semimetals, as drastic changes take place during the transformation from small molecular species (e.g., oxides, halides: non-conducting; e.g., AlCl3, AuCl3, GeO2, etc.) to metalloid clusters2 of the general formulae MnRm (n&#62;m; M = metal such as Al, Au, Sn, etc.; R = ligand such as S-C6H4-COOH, N(SiMe3)2, etc.), to the final bulk elemental phase (metal: conducting; semimetal: semiconducting; e.g., elemental Al, Au, or Ge)3.
The synthesis of a definite molecular nanoscaled compound is challenging due to its metastable character. Many synthetic procedures give metal nanoparticles with a certain size distribution4, meaning a mixture of metalloid cluster compounds of different sizes. Consequently, to establish a basis for a structure-property relationship of nanoscaled materials, synthetic procedures must be developed to access definite nanoscaled molecular compounds. These definite molecular compounds (metalloid clusters in the case of metals5,6,7,8) will shed light on the complexity and the fundamental principles of deceptively simple chemistry, such as the dissolution and the formation of metals9.
One synthetic route to access metalloid clusters of various metals starts from the reduction of stable precursors that are reduced to form a metalloid cluster, mostly in low yield (e.g., metalloid group 14 clusters like Sn15(DippNSiMe3)6 (Dipp = 2,6-iPr2-C6H3)10, Pb10(Hyp)6 (Hyp = Si(SiMe3)3)11, or Ge5(CH(SiMe3)2)412). Additionally, an increasing number of metalloid clusters of coinage metals are synthesized via the reduction of precursors in the presence of a trapping ligand like [Ag44(p-MBA)30]4- (p-MBA = p-mercaptobenzoic acid)13 and Au102(p-MBA)4414. Beside the synthetic route of applying the reductive dehalogenation, Schn&#246;ckel et al. introduced a synthetic route to metalloid group 13 clusters by applying the disproportionation reaction of highly reactive metastable monohalides of the corresponding element (e.g., 3AlCl &#8594; 2Al + AlCl3).
The synthesis of the needed monohalides is thereby performed via a preparative co-condensation technique, where at high temperatures, gas-phase molecules of AlX and GaX (X = Cl, Br, I) are synthesized and afterwards trapped in a matrix of frozen solvents (Figure 1)15. This technique thus gives access to novel reagents, opening the way to novel areas of chemistry (e.g., starting from the metastable monohalides, metalloid clusters with diameters in the nanometer range like [Al77(N(SiMe3)2)20]2- or [Ga84(N(SiMe3)2)20]4- could be obtained)16,17.
The synthetic route via the disproportionation reaction is thus the most productive, leading to clusters with diameters in the nanometer range. However, this synthetic route is only possible if a metastable subhalide is at hand that disproportionates at low temperatures (normally far below 0 &#176;C). Again, in the case of group 14, monohalides are needed, as the subvalent dihalides MX2 (M = Ge, Sn, Pb) are too stable and disproportionate at temperatures well above 100 &#176;C. The synthesis of metastable group 14 monohalide solutions is possible via the preparative co-condensation technique. However, group 14 monohalides are obtained at much higher temperatures with respect to the group 13 monohalides, which are readily available as gas phase species at 1,000 &#176;C. Hence, SnBr is obtained in maximum yield at 1,250 &#176;C18, whereas GeBr19, as well as SiCl220, are obtained at even higher temperatures, up to 1,600 &#176;C. The monohalides are &#34;trapped&#34; via a preparative co-condensation technique (Figure 1), leading to metastable monohalide solutions. Starting from these metastable solutions, we were recently able to synthesize a variety of novel metalloid group 14 cluster compounds of germanium and tin, namely [Li(thf)2]3[Ge14(Hyp)5] (Hyp = Si(SiMe)3)21, Sn10(Hyp)622, and {[Li([12]crown-4)2]}2 [Sn10(Hyp)4]23. Here, we present the synthesis of a metastable Sn(I)Cl solution within a homemade co-condensation apparatus and describe its reactivity with LiHyp to give the metalloid cluster [Sn10(Hyp)4]2- 1 in high yield.

<table><tbody><tr><td>Tin, 99.999%</td><td>ABCR</td><td>AB122397</td><td></td></tr><tr><td>Hydrogen chloride N28, 99.8%</td><td>Air Liquide</td><td>P0820S10R0A001</td><td>Toxic</td></tr><tr><td>Toluene anhydrous, 99.8%</td><td>Sigma Aldrich</td><td>244511</td><td></td></tr><tr><td>Tri-n-butylphosphine, &amp;#62;93.5%</td><td>Sigma Aldrich</td><td>90827</td><td>Toxic</td></tr><tr><td>TMEDA, &amp;#62;99.5%</td><td>Sigma Aldrich</td><td>411019</td><td></td></tr><tr><td>12-crown-4</td><td>Sigma Aldrich</td><td>194905</td><td>Toxic</td></tr><tr><td>THF anhydrous, &amp;#62;99.9%</td><td>Sigma Aldrich</td><td>401757</td><td></td></tr><tr><td>Sodium, 99.95%</td><td>Sigma Aldrich</td><td>262715</td><td></td></tr><tr><td>Benzophenone, &amp;#62;99%</td><td>Sigma Aldrich</td><td>427551</td><td></td></tr><tr><td>Differential pressure manometer</td><td>MKS</td><td>MKS Baratron 223B</td><td></td></tr><tr><td>Mass flow controller&amp;nbsp;</td><td>Bronckhorst&amp;nbsp;</td><td>Low &amp;Delta;p flow mass flow controller</td><td></td></tr><tr><td>High frequency generator</td><td>Trumpf H&amp;uuml;ttinger</td><td>TruHeat MF 5020</td><td></td></tr><tr><td>NMR spectrometer</td><td>Bruker</td><td>Bruker DRX-250</td><td></td></tr><tr><td>Glovebox</td><td>GS Systemtechnik</td><td></td><td></td></tr><tr><td>Argon 5.0</td><td>Westfalen</td><td></td><td></td></tr><tr><td>Nitrogen 4.8</td><td>Westfalen</td><td></td><td></td></tr><tr><td>Graphite</td><td>SGL</td><td></td><td></td></tr><tr><td>Quartz glass tube</td><td>Gebr. Rettberg GmbH</td><td></td><td></td></tr><tr><td>Steel transferring cannula</td><td>Rohre Ketterer</td><td></td><td></td></tr><tr><td>Balance</td><td>Kern</td><td>Kern PFB200-3</td><td></td></tr><tr><td>Oil diffusion pump</td><td>Balzers</td><td>Balzers Diff900</td><td></td></tr><tr><td>Rotary vane pump</td><td>Balzers</td><td>Balzers QK100L4D</td><td></td></tr><tr><td>Pyrometer</td><td>Sensotherm</td><td>6285</td><td></td></tr><tr><td>Schlenk tubes with glassy stopcocks</td><td>Gebr. Rettberg GmbH</td><td>J.-Young-type valve with glassy stopcock</td><td></td></tr></tbody></table>

the synthesis of [sn10(si(sime3)3)4]2- using a metastable sn(i) halide solution synthesized via a co-condensation technique

The number of well-characterized metalloid tin clusters, synthesized by applying the disproportionation of a metastable Sn(I) halide in the presence of a sterically demanding ligand, has increased in recent years. The metastable Sn(I) halide is synthesized at&#160;&#34;outer space conditions&#34; via the preparative co-condensation technique. Thereby, the subhalide is synthesized in an oven at high temperatures, around 1,300 &#176;C, and at reduced pressure by the reaction of elemental tin with hydrogen halide gas (e.g., HCl). The subhalide (e.g., SnCl) is trapped within a matrix of an inert solvent, like toluene at -196 &#176;C. Heating the solid matrix to -78 &#176;C gives a metastable solution of the subhalide. The metastable subhalide solution is highly reactive but can be stored at -78 &#176;C for several weeks. On heating the solution to room temperature, a disproportionation reaction occurs, leading to elemental tin and the corresponding dihalide. By applying bulky ligands like Si(SiMe3)3, the intermediate metalloid cluster compounds can be trapped before complete disproportionation to elemental tin. Hence, the reaction of a metastable Sn(I)Cl solution with Li-Si(SiMe3)3 gives [Sn10(Si(SiMe3)3)4]2- 1 as black crystals in high yield. 1 is formed via a complex reaction sequence including salt metathesis, disproportionation, and degradation of larger clusters. Further, 1 can be analyzed by various methods like NMR or single crystal X-ray structure analysis.

The principle of the matrix isolation technique in conjugation with the preparative co-condensation technique is shown (Figure 1), as well as the setup of the co-condensation apparatus (Figure 2) and the graphite reactor (Figure 3). Figures 4 and 5 show photos of the assembly of the co-condensation apparatus. In Figure 6, the gas supply components with the mass flow controller are shown. ...

Watch this Scientific Journal Video about The Synthesis of [Sn10SiSiMe334]2- Using a Metastable SnI Halide Solution Synthesized via a Co-condensation Technique at JoVE.com

The Synthesis of [Sn10SiSiMe334]2- Using a Metastable SnI Halide Solution Synthesized via a Co-condensation Technique

The disproportionation reaction of a metastable Sn(I) chloride solution, obtained via the preparative co-condensation technique, is used for the synthesis of a metalloid tin cluster compound.

The Synthesis of [Sn10(Si(SiMe3)3)4]2- Using a Metastable Sn(I) Halide Solution Synthesized via a Co-condensation Technique

The number of well-characterized metalloid tin clusters, synthesized by applying the disproportionation of a metastable Sn(I) halide in the presence of a ...

the-synthesis-sn10-si-sime3-3-42-using-metastable-sn-i-halide

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Chemistry

8.4K Views.  University of Tübingen. The disproportionation reaction of a metastable Sn(I) chloride solution, obtained via the preparative co-condensation technique, is used for the synthesis of a metalloid tin cluster compound.

Video: The Synthesis of [Sn10SiSiMe334]2- Using a Metastable SnI Halide Solution Synthesized via a Co-condensation Technique

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

A protocol for in situ aqueous synthesis of a bis(iminoguanidinium) ligand and its utilization in selective separation of sulfate is presented.

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

Combining Solid-state and Solution-based Techniques: Synthesis and Reactivity of Chalcogenidoplumbates(II or IV)

The phases of &#34;PbCh2&#34; (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica glass ampules). Reduction of such phases by elemental alkaline metals in amines affords crystalline chalcogenidoplumbate(II) salts comprised of [PbTe3]2- or [Pb2Ch3]2- anions, depending upon which sequestering agent for the cations is present: crown ethers, like 18-crown-6, or cryptands, like [2.2.2]crypt. Reactions of solutions of such anions with transition-metal compounds yield (poly-)chalcogenide anions or transition-metal chalcogenide clusters, including one with a &#181;-PbSe ligand (i.e., the heaviest-known CO homolog).
In contrast, the solid-state synthesis of a phase of the nominal composition &#34;K2PbSe2&#34; by successive reactions of the elements and by the subsequent solvothermal treatment in amines yields the first non-oxide/halide inorganic lead(IV) compound: a salt of the ortho-selenidoplumbate(IV) anion [PbSe4]4-. This was unexpected due to the redox potentials of Pb(IV) and Se(-II). Such methods can further be applied to other elemental combinations, leading to the formation of solutions with binary [HgTe2]2- or [BiSe3]3- anions, or to large-scale syntheses of K2Hg2Se3 or K3BiSe3 via the solid-state route.
All compounds are characterized by single-crystal X-ray diffraction and elemental analysis; solutions of plumbate salts can be investigated by 205Pb and 77Se or 127Te NMR techniques. Quantum chemical calculations using density functional theory methods enable energy comparisons. They further allow for insights into the electronic configuration and thus, the bonding situation. Molecular Rh-containing Chevrel-type compounds were found to exhibit delocalized mixed valence, whereas similar telluridopalladate anions are electron-precise; the cluster with the &#181;-PbSe ligand is energetically favored over a hypothetical CO analog, in line with the unsuccessful attempt at its synthesis. The stability of formal Pb(IV) within the [PbSe4]4- anion is mainly due to a suitable stabilization within the crystal lattice.

Combining Solid-state and Solution-based Techniques: Synthesis and Reactivity of ChalcogenidoplumbatesII or IV

The synthesis of chalcogenidoplumbates(II,IV) via the in situ reduction of nominal "PbCh2" (Ch = Chalcogen) and via a solid-state reaction and subsequent solvothermal reactions is presented. Additionally, reactivities of plumbate(II) solutions are portrayed, which yield the heaviest-known CO homolog known to date: the &#181;-PbSe ligand.

The phases of &#34;PbCh2&#34; (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica ...

Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for applications in two-dimensional nanoelectronics devices. Although many methods to synthesize SnSe nanocrystals have been developed, a simple way to fabricate large-sized single-layer SnSe flakes remains a great challenge. Herein, we show the experimental method to directly grow large-sized single-layer rectangular SnSe flakes on commonly used SiO2/Si insulating substrates using a straightforward two-step fabrication method in an atmospheric pressure quartz tube furnace system. The single-layer rectangular SnSe flakes with an average thickness of ~6.8 &#197; and lateral dimensions of about 30 &#181;m &#215; 50 &#181;m were fabricated by a combination of vapor transport deposition technique and nitrogen etching route. We characterized the morphology, microstructure, and electrical properties of the rectangular SnSe flakes and obtained excellent crystallinity and good electronic properties. This article about the two-step fabrication method can help researchers grow other similar two-dimensional, large-sized, single-layer materials using an atmospheric pressure system.

A protocol is presented demonstrating a two-step fabrication technique to grow large-sized single-layer rectangular shaped SnSe flakes on low-cost SiO2/Si dielectrics wafers in an atmospheric pressure quartz tube furnace system.

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for ...

Engineering

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and porous metal-dithiolene network in the highly ordered single crystalline state. Unlike the highly reactive free-standing thiols, which tend to decompose and complicate the crystallization of metal-thiolate open frameworks, the thioester reacts in situ to provide the thiol species, serving to mitigate the reaction between the mercaptan units and the metal centers, and to improve crystallization consequently. Specifically, the thioester was synthesized in a one-pot procedure: an aromatic bromide (hexabromotriphenylene) reacted with excess sodium thiomethoxide under vigorous conditions to first form the thioether intermediate product. The thioether was then demethylated by the excess thiomethoxide to provide the thiolate anion that was acylated to form the thioester product. The thioester was conveniently purified by standard column chromatography, and then used directly in the framework synthesis, wherein NaOH and ethylenediamine serve to revert in situ the thioester to the thiol linker for assembling the single-crystalline Pb(II)-dithiolene network. Compared with other methods for thiol synthesis (e.g., by cleaving alkyl thioether using sodium metal and liquid ammonia), the thioester synthesis here uses simple conditions and economical reagents. Moreover, the thioester product is stable and can be conveniently handled and stored. More importantly, in contrast to the generic difficulty in accessing crystalline metal-thiolate open frameworks, we demonstrate that using the thioester for in situ formation of the thiol linker greatly improves the crystallinity of the solid-state product. We intend to encourage broader research efforts on the technologically important metal-sulfur frameworks by disclosing the synthetic protocol for the thioester as well as the crystalline framework solid.

Here, we present a one-pot, transition-metal-free synthesis of thiols and thioesters from aromatic halides and sodium thiomethoxide, followed by the preparation of single crystals of a metal-dithiolene network using thiol species generated in situ from the more stable and tractable thioester.

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and ...

Synthesis of Bimetallic Pt/Sn-based Nanoparticles in Ionic Liquids

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular physico-chemical properties of ionic liquids (ILs) are exploited to control both nucleation and growth processes. The nanoparticles form colloidal sols of very high colloidal stability in the IL, which is particularly interesting in view of their use as quasi-homogeneous catalysts. Procedures for both nanoparticle extraction in conventional solvents and for nanoparticle precipitation are presented. The size, structure and composition of the synthesized nanocrystals are confirmed using inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX). By this, we show that the nanocrystals are random-type alloy and of small (2-3 nm) size. The catalytic activity and selectivity in the hydrogenation of &#945;,&#946;-unsaturated aldehydes is tested in a semi-continuous batch-type reactor. In this context, the bimetallic Pt/Sn-based nanoparticles reveal a high selectivity towards the unsaturated alcohol.

A protocol for the synthesis of bimetallic nanoparticles in ionic liquids and the procedure of their catalytic testing in the selective hydrogenation of unsaturated aldehydes are described.

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular ...

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared according to the methodology developed by surface organometallic chemistry (SOMC). In this framework, catalytic cycles can be determined by isolating crucial intermediates. All air-sensitive materials are handled under inert atmosphere (using gloveboxes or a Schlenk line) or high vacuum lines (HVLs, &#60;10-5 mbar). The preparation of SiO2-700 (silica dehydroxylated at 700 &#176;C) and subsequent applications (the grafting of complexes and catalytic runs) requires the use of HVLs and double-Schlenk techniques. Several well-known characterization methods are used, such as Fourier-transform infrared spectroscopy (FTIR), elemental microanalysis, solid-state nuclear magnetic resonance spectroscopy (SSNMR), and state-of-the-art dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP-SENS). FTIR and elemental microanalysis permit scientists to establish the grafting and its stoichiometry. 1H and 13C SSNMR allows the structural determination of the hydrocarbon ligands coordination sphere. DNP SENS is an emerging powerful technique in solid characterization for the detection of poorly sensitive nuclei (15N, in our case). SiO2-700 is treated with about one equivalent of the metal precursor compared to the amount of surface silanol (0.30 mmol&#183;g-1) in pentane at room temperature. Then, volatiles are removed, and the powder samples are dried under dynamic high vacuum to afford the desired materials [(&#8801;Si-O-)Hf(&#951;2&#960;-MeNCH2)(&#951;1-NMe2)(&#951;1-HNMe2)]. After a thermal treatment under high vacuum, the grafted complex is converted into metal imido silica complex [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)]. [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] effectively promotes the metathesis of imines, using the combination of two imine substrates, N-(4-phenylbenzylidene)benzylamine, or N-(4-fluorobenzylidene)-4-fluoroaniline, with N-benzylidenetert-butylamine as substrates. A significantly lower conversion is observed with the blank runs; thus, the presence of the imido group in [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is correlated to the catalytic performance.

A new group IV metal catalyst for imine metathesis is prepared by grafting amine metal complex onto dehydroxylated silica. Surface metal fragments are characterized using FT-IR, elemental microanalysis, and solid-state NMR spectroscopy. Further dynamic nuclear polarization surface enhanced NMR spectroscopy experiments complement the determination of the coordination sphere.

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared ...

Synthesis of Low-Valent MOFs from Multitopic Phosphine Linkers

Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers

Metal-organic frameworks (MOFs) are the subject of intense research focus due to their potential applications in gas storage and separation, biomedicine, energy, and catalysis. Recently, low-valent MOFs (LVMOFs) have been explored for their potential use as heterogeneous catalysts, and multitopic phosphine linkers have been shown to be a useful building block for the formation of LVMOFs. However, the synthesis of LVMOFs using phosphine linkers requires conditions that are distinct from those in the majority of the MOF synthetic literature, including the exclusion of air and water and the use of unconventional modulators and solvents, making it somewhat more challenging to access these materials. This work serves as a general tutorial for the synthesis of LVMOFs with phosphine linkers, including information on the following: 1) the judicious choice of the metal precursor, modulator, and solvent; 2) the experimental procedures, air-free techniques, and required equipment; 3) the proper storage and handling of the resultant LVMOFs; and 4) useful characterization methods for these materials. The intention of this report is to lower the barrier to this new subfield of MOF research and facilitate advancements toward novel catalytic materials.

Author Spotlight: Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers  

Here, we describe a protocol for the synthesis of low-valent metal-organic frameworks (LVMOFs) from low-valent metals and multitopic phosphine linkers under air-free conditions. The resulting materials have potential applications as heterogeneous catalyst mimics of low-valent metal-based homogeneous catalysts.

Metal-organic frameworks (MOFs) are the subject of intense research focus due to their potential applications in gas storage and separation, biomedicine, ...

Production of CdSe&#45;SnSe Nanocomposites from Consolidated SnSe Particles

Solution&#45;Processed, Surface&#45;Engineered, Polycrystalline CdSe&#45;SnSe Exhibiting Low Thermal Conductivity

In recent years, solution processes have gained considerable traction as a cost-effective and scalable method to produce high-performance thermoelectric materials. The process entails a series of critical steps: synthesis, purification, thermal treatments, and consolidation, each playing a pivotal role in determining performance, stability, and reproducibility. We have noticed a need for more comprehensive details for each of the described steps in most published works. Recognizing the significance of detailed synthetic protocols, we describe here the approach used to synthesize and characterize one of the highest-performing polycrystalline p-type SnSe. In particular, we report the synthesis of SnSe particles in water and the subsequent surface treatment with CdSe molecular complexes that yields CdSe-SnSe nanocomposites upon consolidation. Moreover, the surface treatment inhibits grain growth through Zenner pinning of secondary phase CdSe nanoparticles and enhances defect formation at different length scales. The enhanced complexity in the CdSe-SnSe nanocomposite microstructure with respect to SnSe promotes phonon scattering and thereby significantly reduces the thermal conductivity. Such surface engineering provides opportunities in solution processing for introducing and controlling defects, making it possible to optimize the transport properties and attain a high thermoelectric figure of merit.

Author Spotlight: Advancing Energy Solutions Using Nanocomposites as Processed Thermoelectric Materials

CdSe-SnSe nanocomposites are produced by consolidating surface-engineered SnSe particles. A simple aqueous synthesis is employed to produce SnSe particles. Coating SnSe particles with CdSe molecular complexes allows for controlling grain size and increasing the number of defects present in the nanocomposite, thus lowering the thermal conductivity.

In recent years, solution processes have gained considerable traction as a cost-effective and scalable method to produce high-performance thermoelectric ...

Synthesis of High-ZT Thermoelectric Materials via Mechanochemical Methods

Demonstrating the Simplicity and In Situ Temperature Monitoring of the Mechanochemical Synthesis of Metal Chalcogenides Suitable for Thermoelectrics

Mechanochemical synthesis is an extremely useful strategy to reach thermoelectric materials due to its solvent-free one-step character, as the targeted thermoelectricity (TE) materials in a nanocrystalline format can be prepared by mere high-energy milling of elemental precursors. Nevertheless, the subsequent densification method (e.g., spark plasma sintering or hot pressing) is required afterward, similarly to other synthetic methodologies. In this study, the simplicity of mechanochemical synthesis is&#160;presented for two selected metal chalcogenides, namely copper sulfide (Cu1.8S, digenite) and tin selenide (SnSe, svetlanaite), which are known for high ZT values. These compounds can be prepared via a mechanically induced self-propagating reaction (MSR), which is a combustion-like process instantly yielding the products in a very short timeframe (within 1 min). The occurrence of MSR can be well-tracked by in situ temperature monitoring since an abrupt temperature increase occurs at the moment of MSR. We have developed a device which is capable of monitoring the temperature inside the milling jar every 80 ms during planetary ball milling, and it is therefore possible to very precisely track the moment of MSR ignition. The developed device presents an improvement in the monitoring capabilities in comparison with commercially available analogs. This contribution aims to provide a visual insight into all steps, with simple high-energy ball milling of elements to reach TE materials and in situ temperature monitoring being the central points.

Here, we present a protocol to synthesize two metal chalcogenides (Cu1.8S and SnSe) suitable for thermoelectrics via an ultrafast (second-range), solvent-free, and one-step mechanochemical synthesis using elemental precursors. Simultaneously, we demonstrate the monitoring of the temperature in the jar during planetary ball milling in situ by the newly developed device.

Mechanochemical synthesis is an extremely useful strategy to reach thermoelectric materials due to its solvent-free one-step character, as the targeted ...

Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups

Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9n- (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry.3-6 Notable milestones are the oxidative coupling of Ge94- clusters to oligomers and infinite chains,7-19 their metallation,14-16,20-25 capping by transition-metal organometallic fragments,26-34 insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization,35-47 addition of main-group organometallic fragments as exo-bonded substituents,48-50 and functionalization with various organic residues by reactions with organic halides and alkynes.51-58 
This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge94- clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC&equiv;CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2]2-. For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left undisturbed for a few days, the so-layered solutions produced orange crystalline blocks of [K(18-crown-6)]2[Ge9(HCCH2)2]&bull;en which were characterized by single-crystal X-ray diffraction. 
The process highlights standard reaction techniques, work-up, and analysis towards functionalized deltahedral Zintl clusters. It is hoped that it will help towards further development and understanding of these compounds in the community at large.

We present the high-temperature synthesis of intermetallic precursors K4Ge9, their dissolution in ethylenediamine to form Ge94- deltahedral Zintl ions, and the reaction of the clusters with alkynes to form organo-Zintl ions. The latter are characterized by electrospray mass spectrometry in solutions and by single-crystal X-ray diffraction in the solid state.

Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 ...

The Synthesis of [Sn₁₀(Si(SiMe₃)₃)₄]²^- Using a Metastable Sn(I) Halide Solution Synthesized via a Co-condensation Technique

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