Studies of silyl and germyl Group VI species. Part IV. Dimethyl- and tetramethyl-disilyl chalcogenides and related species

Abstract

. Can. J. Chem. 58,2161Chem. 58, (1980. The symmetrically substituted disilyl chalcogenides (MenH,-,Si),E where E = 0 , S, Se, Te; n = 0 -+ 3, have been prepared and characterized spectroscopically and by cleavage reactions. The synthetic routes include reactions of halogenosilanes with water, mercury(I1) sulfide, lithium telluride, and complex thio-and seleno-aluminates. The spectroscopic propertiesof the (MeH,Si),E and (Me2HSi)2E species, which have not been reported previously, are discussed in some detail. JOHN E. DRAKE, BORIS M. GLAVINEEVSKI et RAYMOND T. HEMMINGS. Can. J. Chem. 58,2161Chem. 58, (1980. On a prkpark des chalcogknides disilylks (MenH3-,Si),E ou E = 0 , S, Se, Te; n = 0 + 3 symetriquement substituks et on les a caractkrise par spectroscopie et par des rkactions de clivage. Les diffkrentes synthtses font intervenir les rkactions des halogCnosilanes avec I'eau, le sulfure mercurique, le tellurure de lithium et les complexes de thio et de skIknoalurninates. On discute en dktail des propriktks spectroscopiques des composks (MeH2Si),E et (Me,HSi),E nouveaux.[Traduit par le journal]

Studies of silyl and germyl Group VI species. Part VII. The substituent effects of the vinyl group in 1,3-divinyltetramethyldisilyl chalcogenides

“…Similar trends of decreasing Si-E stretching frequencies have been observed in related silyl species (16). The remaining vibrational degrees of freedom involve only the deformations of the skeletal frame and they appear in the low-frequency region.…”

“…The trends in the values of the I3CH coupling constants parallel those for 'HG(Me), in that they fall between those for (SiMe3)?E and (HSiMe2),E (16). The effect of the chalcogen is substantial and leads to an increase in the ' "H coupling constants along the series This increase suggests that the s-hypothesis (the Fermi contract term) might not dominate the coupling mechanism between carbon and hydrogen.…”

“…Metathesis reactions between Group 1V halides and dilithium salts have been demonstrated previously for the synthesis of a number of disilyl and digermyl chalcogenides (16,18,21). In this study the method was extended to the synthesis of otherwise inaccessible vinyl-containing species, i.e.…”

N‐Heterocyclic Carbene (NHC)‐Stabilized Silanechalcogenones: NHC→Si(R2)E (E=O, S, Se, Te)

“…[8b] Nevertheless, these ñA C H T U N G T R E N N U N G (Si=E) (E = O, S, Se, Te) stretching modes are drastically larger than the corresponding values observed for SiÀE single-bond species (i.e., for (MeH 2 Si) 2 E, in which E = O, S, Se, Te), [12] which might suggest considerable double-bond character in 2 a,b-5 a,b. The latter Si=E multiple-bond character can be rationalized as previously discussed by a nonclassical Si=E p-binding interaction between the chalcogen lone-pair electrons and two antibonding Si À N s* orbitals that are located mainly at the silicon site.…”

From an Isolable Acyclic Phosphinosilylene Adduct to Donor‐Stabilized SiE Compounds (E=O, S, Se)

“…The n Si=S and n Si=Se stretching vibrations (3b: n Si=S = 665 cm À1 , 3a: n Si=Se = 578 cm À1 and 4a: n Si=Se = 577 cm À1 )a re shifted1 8a nd 37 cm À1 , respectively,t os maller wavenumbers in comparison to the analogous stretching vibrations in LSi(NHC)=E( L = CH[(C= CH 2 )CMe(NAr) 2 ], Ar = 2,6-iPr 2 C 6 H 3 )( n Si=S = 683 cm À1 , n Si=Se = 614 cm À1 ) [40] but are still larger than the corresponding values observedf or SiÀEs ingle-bond species( i.e.,f or (MeH 2 Si) 2 E, E = S, Se). [46] The n Si=O stretching vibrations of 4c (n Si=O = 1080 cm À1 )a re significantly bathochromically shifted relative to the corresponding wavenumbers of typical silanones (n Si=O = 1150-1300 cm À1 ) [47][48][49] and are almost similar to the n SiÀO stretching vibrations in (Me 2 HSi) 2 O( n SiÀO = 1074 cm À1 ). [46] These suggest the presence of az witterionic Si + ÀO À single bond instead of Si=Oi n4c.T his has been confirmed by density functional theory (DFT) studies at the B97-D/6-31G(d) level.…”