Cl-35 NQR spectra of phosphorus chlorides and their molecular conformations in crystals. Part 1. Phosphorus (III) chlorides RPCl2

For the phosphorus chlorides RPCl2 (R = Cl, Me, ClCH2, CF3, Et, i - Pr, Me2 C = CH, PhCH = CH, Me2N, Et2N. Pr2N MeO, PhO) and R'PCl2 (R' = Ar, 2-thieny l) two linear correlations between the Cl-35 NQR frequencies and charges on the chlorine atoms of the PCl2 groups calculated by the MNDO procedure hav e been found. It was shown that the Cl-35 NQR spectra and the relative magn itudes of the charges on the chlorine atoms of the PCl2 groups can be used to determine conformation of the RPCl2 molecules in crystal. Ab initio (RHF /6-31 G* and MP2/6-31 G*) calculations showed that the gauche conformation of Me2NPCl2 molecule is more stable than trans conformation. In light of ab initio calculations electron diffraction results (Vilkov L.V., Khaikin L.S ., Dokl. Akad. Nauk SSSR, 168 (1966) 810) are erroneous. The NBO analysis c onfirmed the presence of donor-acceptor interactions between the lone pair orbital of the nitrogen atom and the antibonding orbitals of the P-Cl bonds . (C) 2000 Elsevier Science B.V. All rights reserved.