Hypercoordinated Oligosilanes Based on Aminotrisphenols.

The hypercoordinated silicon chlorides ClSi[(o-OC(6)H(4))(3)N] (3) and ClSi[(OC(6)H(2)Me(2)CH(2))(3)N] (5) were used for the synthesis of catenated derivatives (Me(3)Si)(3)SiSi[(o-OC(6)H(4))(3)N] (9), (Me(3)Si)(3)SiSiMe(2)SiMe(2)Si(SiMe(3))(2)Si[(o-OC(6)H(4))(3)N] (11), and (Me(3)Si)(3)SiSi[(OC(6)H(2)Me(2)CH(2))(3)N] (13) in reactions with (Me(3)Si)(3)SiK·THF (7) or (Me(3)Si)(3)SiK·[18-crown-6] (8). It was found that the nature of the (Me(3)Si)(3)SiK solvate determines the product of interaction, resulting in the formation of (Me(3)Si)(3)Si(CH(2))(4)OSi[(OC(6)H(2)Me(2)CH(2))(3)N] (12) or 13. Compounds obtained were characterized using multinuclear NMR and UV-vis spectroscopy and mass spectrometry. The molecular structures of 3, 9, and 11-13 were investigated by single-crystal X-ray analysis, featuring hypercoordinated Si atoms in a trigonal-bipyramidal coordination environment with O atoms in the equatorial plane. The structure of the side product [N(CH(2)C(6)H(2)Me(2)O)(3)Si](2)O (6) was also studied, indicating highly tetrahedrally distorted trigonal-bipyramidal environment at the Si atoms, which was confirmed by crystal density functional theory calculations indicating the very weak Si ← N interaction. The Si···N interatomic distances span a broad range (2.23-2.78 à ). The dependence of structural and NMR parameters for hypercoordinated catenated compounds from the type of the ligand was established.