Through-bond interaction in compounds containing an SiOCCN group

Silatranes and Their Tricyclic Analogs

“…The second assignment was based on analysis of the dynamic orbitalcorrelation diagrams and the results of MNDO and AM1 calculations. It was noted that the increase in IP v 1 on shortening of the Si N bond is caused by the corresponding increase in the nitrogen atom pyramidality 196 , whereas the higher IP v 1 in silatranes relative to those in model compounds can be explained by a probable interaction between the nitrogen lone pair and the antibonding Ł MOs of the neighboring C C O fragments in the former molecules 216,217 . All these results demonstrate that the problems of MO structure and PE spectroscopy of silatranes are still open.…”

“…Spectroscopic studies of hydrogen bond formation between silatranes and such proton donors as phenol and methanol revealed enhanced basicity of silatranes relative to the corresponding organyltriethoxysilanes 150,216,217,221,234 . Analysis of the solvent effects on the spectroscopic basicity of these compounds showed that the oxygen atoms (equatorial in 1-organylsilatranes and axial in 1-alkoxysilatranes) rather than the nitrogen are the proton acceptor centers 216,217,221,234 .…”

“…Analysis of the solvent effects on the spectroscopic basicity of these compounds showed that the oxygen atoms (equatorial in 1-organylsilatranes and axial in 1-alkoxysilatranes) rather than the nitrogen are the proton acceptor centers 216,217,221,234 . A higher basicity of these atoms in silatranes and also in O-trimethylsilylated 2-aminoalkanols was explained by a peculiarity of throughbond interactions in compounds containing the Si O C C N fragment 216,217 . Recently it was shown, however, that the origin of the observed difference in basicity of silatranes and triethoxysilanes could be due to a difference between the anomeric effects in the molecules 198 .…”

“…The ultraviolet absorption spectra of silatranes display only an edge of the n-Ł band ( max < 190 nm) 216,220,221 . A hypsochromic shift of this band relative to that observed in the spectra of triethylamine (204 nm), triethanolamine and its tris-TMS derivative (195 196 nm) confirms the Si N bonding in silatranes.…”

Assignment of photoelectron spectra of silatranes: first ionization energies and the nature of the dative Si←N contact

“…2,14,17 It could be hoped that the photoelectron spectroscopy (PES) study would provide valuable information, which would help to solve the question about the nature of the Si'N interaction in I. [18][19][20][21][22][23][24] They were caused mainly by the fact that the known procedures for the synthesis and purification of I do not always allow us to deal with the ''ideally'' pure compounds. [18][19][20][21][22][23][24] They were caused mainly by the fact that the known procedures for the synthesis and purification of I do not always allow us to deal with the ''ideally'' pure compounds.…”