Determination by electron diffraction of the molecular structures of chloro- and bromo-tri(trimethylsilyl)methane in the gas phase

The molecular structures of chloro- and bromo-tris (trimethylsilyl)methane in the gas phase have been determined by electron diffraction. Both molecules have inner Si–C bonds which are longer than normal and wide Si–C–Si angles. Principal parameters (ra) for CCl (SiMe3)3, with estimated standard deviations in parentheses, are r(C–Cl) 182.3 (15) pm, r(Si–Cinner) 193.9(6) pm, r(Si–Couter) 188.2(2) pm, and angles Cl–C–Si 102.7(5)° and Couter–Si–Couter 109.6(4)°. The three trimethylsilyl groups are twisted 14.6(7)° from the staggered positions, and tilted 1.3(6)° away from the molecular three-fold axis. For CBr(SiMe3)3 the major parameters are r(C–Br) 191.1(35) pm, r(Si–Cinner) 195.4(15) pm, r(Si–Couter) 187.7(3) pm, Br–C–Si 106.5(6)° and Couter–Si–Couter 109.3(5)°. The trimethylsilyl groupos are twisted 13.5(7)° from the stagtgered positions, but the tilt angle of these groups could not be determinded.

[1]  P. Hitchcock,et al.  Metalation of Tris(trimethylsilyl)‐ and Tris(dimethylphenylsilyl)methane with Methylsodium: The First Dialkylsodate , 1994 .

[2]  C. Smith,et al.  Practical synthesis of tris (trimethylsilyl)methyl bromide and its conversion to the corresponding grignard reagent and (tris(trimethylsilyl)methyl)lithium , 1992 .

[3]  M. Westerhausen,et al.  Trimethylsilyl-substituierte Derivate des Dimethylzinks — Synthese, spektroskopische Charakterisierung und Struktur , 1991 .

[4]  H. Robertson,et al.  Determination of the gas-phase molecular structure of tris(trimethylsilyl)(trichlorosilyl) methane by electron diffraction , 1989 .

[5]  P. Hitchcock,et al.  Some [tris(trimethyl)- and [tris(dimethylphenyl)-silyl]methyl derivatives of phosphorus. The crystal structure of [tris(dimethylphenylsilyl)methylphosphonous dichloride , 1989 .

[6]  P. Hitchcock,et al.  Preparation and crystal structures of the crowded organotin fluorides (PhMe2Si)3CSnMe2F, (Me3Si)3CSnMe2F, and (Me3Si)3CSnPh2F , 1987 .

[7]  P. Hitchcock,et al.  The preparation and molecular structure of the highly sterically hindered tris(trimethylsilyl)methylboron compound (Me3Si)3CB(Ph)[O(CH2)4C(SiMe3)3] , 1982 .

[8]  R. Pritchard,et al.  A gas-phase electron diffraction study of the molecular structure of the sterically strained molecule tris(trimethylsilyl)methane, HC(SiMe3)3 , 1982 .

[9]  P. Hitchcock,et al.  The molecular structure of [dimethyl(phenyl)silyl]tris(trimethylsilyl)methane , 1981 .

[10]  D. Rankin,et al.  The gas-phase molecular structure of silyl(methyl)-acetylene (1-silabut-2-yne), determined by electron diffraction , 1981 .

[11]  D. Rankin,et al.  The molecular structure of difluorophosphine selenide,determined using a combination of gas electron diffraction and liquid-crystal NMR data , 1981 .

[12]  S. C. Nyburg,et al.  The crystal structure and absolute configuration of (+)-α-(1-naphthylphenylmethylsilyl)benzyl p-bromobenzoate , 1972 .

[13]  D. Walton,et al.  [Tris(trimethylsilyl)methyl]lithium: An alkyllithium compound of unusual stability , 1970 .

[14]  D. Seyferth,et al.  Halomethyl-metal compounds : XL. Trimethylsilyl-substituted bromomethyllithium and -magnesium reagents. Trimethyltindibromomethylmagnesium chloride , 1970 .

[15]  J. M. Hastings,et al.  An Electron Diffraction Investigation of the Structures of Neopentyl Chloride and Silico‐Neopentyl Chloride: The Determination of Intensities through the Use of a Rotating Sector , 1950 .