Effect of the silicon atom on the electron density distribution in the organosilicon 1,2-hydroxyamines molecules

Abstract

In the framework of the theory of MO LCAO by the TPSS / cc-pVTZ, Hirshfield and NBO analysis methods in the molecules of 4-(dimethylamino)-1,1-diethylsilacyclopentan-3-ol and 2-(dimethylamino)- 5-trimethylsilylcyclohexan-1-ol the nature of the influence of the silicon atom on remotely located nitrogen and oxygen atoms has been studied. More pronounced in 4-(dimethylamino)-1,1-diethylsilacyclopentan-3-ol molecule, this effect is determined by the geometric parameters (endocyclic arrangement of the silicon atom), which favor the formation of MOs with a large Si contribution. According to NBO analysis, the interaction between the orbitals of the Si-C5 bonds and the orbitals of the C3-N and C1-O bonds in the silacyclopentane fragment of the 4-(dimethylamino)-1,1-diethylsilacyclopentan-3-ol molecule, has a donor-acceptor character. The calculated data are in qualitative agreement with the results of 1H and 29Si NMR spectroscopy.