Amido Silicon Chalcogenide Compounds with Unprecedented Cluster Cores and Low Oxidation State Silicon Atoms

Abstract

Reactions of the bicyclic silicon(I) ring compound [Si 4 {N(SiMe 3 )Dipp} 4 ] 1 with the chalcogens O 2 , Se, Te and the group 16 element compounds TeP(nBu) 3 and Me 3 NO afforded unprecedented amido-substituted cage compounds such as [Si 4 Se 3 {N(SiMe 3 )Dipp} 4 ] 3-5 with two different tricyclo-heptane-[a]type cages and one with a defect-hetero-cubane-type Si 4 Se 3 core, and [Si 4 Te 6 {N(SiMe 3 )Dipp} 4 ] 6 with an adamantane-type cage. These compounds were examined by single-crystal X-ray diffraction, multinuclear NMR spectroscopy in solution, ESI mass spectrometry, UV/Vis spectroscopy, and DFT calculations.Si 4 Se 6 (Thex) 4 (Thex = 1,1,2-trimethylpropyl) is known with type II and type III cores. [11,12] In general, compounds with type II core can be converted to compounds with type III topology under thermal treatment. [11,12] By contrast, silicon tellurium compounds decorated by organic substituents are rare. Only the silatellurane with type III structural motif Si 4 (CH 2 ) 2 Te 4 Me 4 ·CDCl 3 was described with two methylene groups and four Te atoms at the two-coordinate positions in the adamantane-type cage (III) synthesized by the reaction of the disilylmethane CH 2 (SiMeCl 2 ) 2 with Li 2 Te. [13] In general, cage compounds with Si-Te bonds are scarce due to the high sensitivity of these compounds towards air and moisture. [14] Eur.

Cluster‐Glass for Low‐Cost White‐Light Emission

“…After removal of the solvent, the residue was redissolved in hexane and purified by column chromatography using hexane as eluent. Subsequent removal of the solvent in vacuo yielded 3.54 g (45%) of PhSi(CH 2 Cl) 3 ; 29 Synthesis and Characterization of Phenyl[(triphenylstannyl)methyl] silane, PhSi(CH 2 SnPh 3 ) 3 : A solution of Ph 3 SnCl (11.4 g, 29.7 mmol) in dry THF (400 mL), sodium (0.68 g, 29.7 mmol) and catalytic amount of naphthalene were placed under argon atmosphere into a 500 mL three-necked flask equipped with a magnetic stirring bar. The reaction mixture was stirred for 3 days, after that the reaction mixture was filtered whereupon the solution was cooled to −78 °C followed by dropwise addition of a solution of PhSi(CH 2 Cl) 3 (2.5 g, 9.9 mmol) in 50 mL of THF.…”

“…All compounds were obtained in good yields (55-65%) and all spectroscopic data are in agreement with data reported for related compounds. [28][29][30][31][32][33][34][35] It is worth noting that 1-3 represent rare examples of heteroadamantane-type cores with more than two components, and 3 adds to the very few adamantanetype compounds comprising telluride ligands in the cluster core, with the only known examples of this type so far being [{Cp(CO) 3 Mo} 4 Sn 4 Te 6 ], [Si 4 (CH 2 ) 2 Te 4 Me 4 ], and [Si 4 Te 6 {N(SiMe 3 ) Dipp} 4 ]. [28,29,36] Regarding compound 3, we emphasize in addition that our synthesis protocol affords a single product of a tellurium-based adamantane cluster with high purity according to 125 Te-NMR spectroscopy-in striking contrast to the (few) reported methods to form related compounds, which always yielded mixtures with other species.…”

“…The difference between the corresponding interatomic distancesand thus the irregularity of the cluster cores, get more significant with increasing atomic size of the respective chalcogen atom E (a detailed discussion of the structural features of 1, 2, and 3 can be found in Note S1, Supporting Information). [29,[36][37][38][39][40] This molecular inhomogeneity is the bases for the materials behavior, as reported and discussed in Sections 3-6. Note that related compounds of the type [(R 1 T 1 )(CH 2 ) 3 (R 2 T 2 )E 3 ] were recently reported for R 1 = Me, and E = O), which we modified here to be electron-rich substituents Ph for R 1 and R 2 besides more electron-rich chalcogen ligands E = S, Se, and Te.…”

Molecular Silicon Clusters

“…Still, some examples have been reported including Si 2 E 3 bicyclopentanes, 73,74 double-decker and adamantane-like Si 4 E 6 species, 75,76 Si 4 E 3 cages of different shape (E = S, Se), 77,78 polythiadisilabicycles Si 2 S x (x = 4−6) 79 as well as a Si 4 Te 6 adamantane. 78 For comprehensive accounts on silicon compound clusters, which have found numerous applications in materials science, the interesting reader is referred to some excellent reviews. 66−72 Three-dimensional cage molecules with a scaffold that solely consists of silicon atoms can be further subdivided into saturated silicon cages, 80,81 Zintl ions, 82−89 and siliconoids 90−92 depending on the inherent connectivity of the atoms, the substitution pattern (or the absence thereof), and their charge.…”

“…The chemistry of heavier silicon chalcogenide cages is much less explored. Still, some examples have been reported including Si 2 E 3 bicyclopentanes, , double-decker and adamantane-like Si 4 E 6 species, , Si 4 E 3 cages of different shape (E = S, Se), , polythiadisilabicycles Si 2 S x ( x = 4–6) as well as a Si 4 Te 6 adamantane . For comprehensive accounts on silicon compound clusters, which have found numerous applications in materials science, the interesting reader is referred to some excellent reviews. − …”