U. Kolb et M. Drager, HYPERVALENT TIN-ORGANIC COMPOUNDS - VIBRATIONAL SPECTROSCOPY IN THE SOLID AS A TOOL FOR STRUCTURE DETERMINATION, SPECT ACT A, 53(4), 1997, pp. 517-529
A full set of IR- and Raman spectra down from 600 cm(-1) has been dete
rmined and assigned for 60 penta- or hexacoordinated tin-compounds in
the groups RSn(CH2CH2CH2)(3)N (R = Cl, Pr, I, Me), RR'Sn(MCH2CH2)(2)X
(R,R' = Cl, Br, I, Me, Ph; M = CH2, S; X = NMe, O, S), RPh2SnCH2CH2CH2
NMe2 (R = Cl, Br, I) and RMe2Sn-CHD-COOMe (R = F, Cl, Br, I, Me). In t
hese hypervalent compounds an approach of the donor atom X to the cent
ral atom tin outlines a 'path' of nucleophilic attack from a tetrahedr
on to a trigonal bipyramid. Along this 'reaction path' the bond length
s of the axial ligand increase continuously while the bond lengths of
the equatorial ligands slightly decrease. The number of similar hyperv
alent structures discussed in this paper enabled us to investigate the
change of stretching vibrations in a wide range of bond lengths in di
fferent atom pairs. Force constants were calculated from the data conc
erning the stretching vibrations at tin and plotted versus the accordi
ng distances obtained from X-ray structure analysis. The resulting beh
avior is discussed with the help of Morse potentials. (C) 1997 Elsevie
r Science B.V.