STRUCTURES IN SOLUTION OF ADDUCTS OF 2,10-DIMETHYL-2,6,10-TRIAZA-1-PHOSPHABICYCLO[4.4.0]DECANE AND SUBSTITUTED BENZILS

Abstract

2,10-Dimethyl-2,6,10-triaza-1-phosphabicyclo[4.4.0]decane has been allowed to react with p,p′-dimethoxybenzil, p,p′-dimethylbenzil, p-methoxy-p′-fluorobenzil, p-fluorobenzil, p,p′-difluorobenzil, p-nitrobenzil and p,p′-dinitrobenzil. Although these materials could not be isolated in pure form because of rapid decomposition, the ³¹P and ¹³C NMR spectra indicated that they are all pentacoordinated. Variable temperature NMR studies showed that they all undergo intramolecular ligand reorganization reactions. These rearrangements could be slowed on cooling for all of the adducts except for the p-nitro and p,p′-dinitro compounds. The activation energies were very similar, 11–12 kcal/mole, for those adducts which showed variable temperature changes in their NMR spectra. The ligand reorganization process is discussed.