Paul D. Lickiss

Silicon derivatives of the metals of groups 1 and 2

Abstract An account is given of the syntheses, structures and reactions of compounds containing group 1 or 2 elements bonded to silicon. The review concentrates mainly on the group 1 derivatives as these are far more numerous than those of the group 2 elements. Silyllithium compounds are discussed in most detail, particularly Ph 3 SiLi and (Me 3 Si) 3 SiLi for which convenient syntheses are available. The use of silyllithium reagents for organometallic and inorganic synthetic purposes is described and an outline of some of the more important reactions in organic chemistry is given.

Hydrogen-bonding in organosilanetriols. The crystal structures of tris(trimethylsilyl)silyl- and tris(trimethylsilyl)-methyl-silanetriols

Abstract The organosilanetriols (Me 3 Si) 3 CSi(OH) 3 and (Me 3 Si) 3 SiSi(OH) 3 both crystallize as hexameric hydrogen-bonded cages with no hydrogen bonding between the cages. Both (Me 3 Si) 3 CSi(OH) 3 and (Me 3 Si) 3 SiSi(OH) 3 are remarkably thermally stable as solids, melting with decomposition only at 285–290 and 210–213°C, respectively.

Some derivatives of tris(dimethylsilyl)methane. A novel bicyclic tris(disiloxane) with a manxane structure

Abstract The compounds (XMe2Si)3CH with X = H, F, Cl, Br, HO, MeO, EtO and Me3SiO have been prepared. On heating (HOSiMe2)3CH loses water to give HC(SiMe2OSiMe2)3CH, 2,2,4,4,6,6,8,8,9,9,11,11-dodecamethyl-3,7,10-trioxa-2,4,6,8,9,11-hexasila[3.3.3]bicycloundecane. The structure of the latter has been determined by X-ray diffraction and found to be of the manxane type.

Oxidation of sterically hindered organosilicon hydrides using potassium permanganate

Abstract The one-pot synthesis of Ph3SiOH, 1Bu2Si(OH)2, (Me3Si)3CSi(OH)3 and (Me3Si)3CSiMe2OH directly from the corresponding bulky silicon hydrides using KMnO4 is described. The size of the substituents, the silane: KMnO4 stoichiometry, the solvent and the application of ultrasound were all shown to influence the rate of the reactions.

The crystal structure of (HOMe2Si)2O

Abstract X-Ray crystallography shows that in the solid state, molecules of(HOMe 2 Si) 2 O are extensively hydrogen bonded together to form zig-zag double chains with no bonding between the chains.

Crystal structure of [Li(tmen)2][Li{C(SiMe3)3}2]. A multinuclear magnetic resonance study of tris(trimethylsilyl)methyllithium–tetrahydrofuran(1/2) and –N,N,N′,N′-tetramethylethylenediamine (1/1)(tmen)

A single-crystal X-ray study of (Me3Si)3CLi·tmen (tmen =N,N,N′,N′-tetramethylethylenediamine) shows that it crystallises with the ionic structure [Li(tmen)2][Li{C(SiMe3)3}2] but that the anions pack with different orientations from those in crystalline [Li(thf)4][Li{C(SiMe3)3}2](thf = tetrahydrofuran). The 1H, 7Li, 13C and 29Si NMR spectra of (Me3Si)3CLi·2thf and (Me3Si)3CLi·tmen in thf and toluene, and 7Li, 13C and 29Si NMR spectra of the solids are described. Spectra obtained from solutions below ca. 25 °C show the presence of ion pairs [Li(thf)4][Li{C(SiMe3)3}2] or [Li(tmen)2][Li{C(SiMe3)3}2], together with further species which appear to be different in thf and toluene. Spectra from solutions at higher temperatures show inter-species exchange on the NMR timescale.

The plasma enhanced chemical vapour deposition of CuInSe2

Abstract We report the first successful chemical vapour deposition (CVD) of chalcopyrite CuInSe 2 . Thin films with compositions around the Cu : In : Se stoichiometric ratio 1:12 have been grown using a glow discharge enhanced CVD process. Film structure is analysed using X-ray camera techniques and Rutherford backscattering spectroscopy.

Hydrogen bonding in organosilicon hydroxides: crystal structures of dicyclohexylsilanediol and bis(hydroxydimethylsilyl)bis(trimethylsilyl)methane

Abstract An X-ray diffraction study has shown that dicyclohexylsilanediol crystallizes as hydrogen-bonded dimers linked by further hydrogen bonding into ladder chains, the hydrogen bonding being closely similar to that in the crystal of i-Pr 2 Si(OH) 2 . The diol (Me 2 Si)P 2 C(SiMe 2 OH) 2 forms infinite chains with one oxygen within a molecule linked by hydrogen bonding to the other, which in turn is hydrogen-bonded to the oxygen of another molecule.

Some tetrasilylmethane derivatives

Abstract The preparations are described of the compounds: (i) C(SiMe2X)4 with X = H, F, Cl, Br, I, OMe, OEt, OCOMe and OCOCF3; (ii) (HMe2Si)4 − nC(SiMe2X)n with X = Cl, Br, I, n = 1–3; X = OH, n = 1 or 2; and X = OMe, n = 1; (iii) (Me3Si)4 − nC(SiMe2X)n with X = H, Cl, Br, n = 1–3; X = I, n = 2 or 3; and X = OCOMe, n = 2; (iv) (ClSiMe2)3SiMe2OH and (ClMe2Si)3C(SiMe2OCOMe). (Not all the products were isolated.) The reaction between (Me3Si)4C and IX with X = Cl or Br provide good routes to the corresponding C(SiMe2X)4 compounds.

The molecular structure of [dimethyl(phenyl)silyl]tris(trimethylsilyl)methane

Abstract The structure of the crowded molecule (Me3Si)3C(SiMe2Ph) has been determined by single crystal X-ray diffraction. The steric strain manifest itself mainly in lengthening of the Me3SiC and Me2PhSiC bonds (average length 1.920(6) ,ac>A ) and closing up of the CSiC angles within the Me3Si and Me2PhSi groups (average 105.2(10)°), with correspondingly large C(1)SiC angles (113.5(13)°; C(1) is the central carbon atom).