Popis: |
Spin-unrestricted CNDO/2 calculations for the radicals (OH) 2 (O)PCH 2 , (CH 3 ) 3 P + CH 2 and (CH 2 CH) 3 P + CH 2 are reported. In each case potential energy profiles for the rotation of the CH 2 group around the PC bond are calculated with optimization of the PC distance. The results show ( i ) that it it essential to introduce d-orbital participation on phosphorus, (ii) that the height of the barrier to internal rotation depends critically on the symmetry of phosphorus environment, and (iii) that the delocalization of the unpaired electron to the phosphorus nucleus is very small. |