E. I. Brodskaya

N,N-Bis[ethoxy(methyl)silylmethyl]methylamines MeN[CH2SiMem(OEt)3-m]2 (m = 0-2). Synthesis and Reactions with Phenol

Previously unknown N,N-bis[ethoxy(methyl)silylmethyl]amines MeN[CH2SiMem(OEt)3-m]2 (m = 0-2) were synthesized. According to UV spectral data, only MeN[CH2SiMe2(OEt)]2 form hydrogen bond with phenol in a heptane solution. The amines with m = 0 and 1 fail to forms hydrogen bond with phenol [under the same conditions, N-(triethoxysilylmethyl)dimethylamine Me2NCH2Si(OEt)3 forms a strong hydrogen bond with phenol]. All the amines (m = 0-2) enter transetherification with phenol to give compounds of the general formula MeN[CH2SiMemm(OPh)n(OEt)3-m-n]2 (m = 0-2, n = 1-3). Refluxing of N,N-bis[ethoxy(methyl) silylmethyl]amines with excess phenol results in cleavage of the Si-C bond by phenol, providing phenoxysilanes MemmSi(OPh)4-m (m = 0-2) and trimethylamine.

Ab initio Calculations of the Geometry, Electronic Structure, and Vibrational Spectrum of (Acetoxymethyl)triflouorosilane

The geometries and electronic structures of various conformers of (acetoxymetyl)trifluorosilane, CH3C(O)OCH2SiF3, and also the frequencies and intensities of its vibration bands were studied by ab initio [RHF(6-31G*)] calculations. According to the experimental spectra and calculation results, the most stable is the conformation in which the donor-acceptor interaction = O→Si is realized. Analysis of the geometry, atomic charges, and molecular orbital energies shows that this donor-acceptor bond is mainly due to interaction of the lone electron pairs of the carbonyl oxygen atom with the vacant Σδ* orbitals of the C-Si-Fa moiety.

Ab initio Study of the Structure and Vibration Spectrum of N-Methyl-N-(trifluorosilylmethyl)acetamide

The effect of the O→Si donor-acceptor interaction on the geometric and electronic structure of N-methyl-N-(trifluorosilylmethyl)acetamide, and also the band frequencies and intensities in the vibration spectrum of this compound were studied by ab initio calculations in the RHF(6-31G*) approximation. The geometry, charge distribution pattern, and energy and nature of molecular orbitals show that the Oρarr;Si interaction is mainly determined by interaction of the oxygen lone electron pairs with the σ* orbitals of the C-Si-Fa fragment. The interaction of the occupied π orbitals of the N-C = O fragment with the unoccupied orbitals of the Si(Fe)2 fragment of suitable symmetry is weaker.