THEORETICAL COMPARISON OF THE ELECTRONIC-STRUCTURES OF [PHN2](- CAN THE BENZENEDIPHOSPHONIUM CATION EXIST IN THE GAS-PHASE() AND [PHP2](+) )

Ab initio quantum-chemical investigations are used to outline the main differences between the phenyldiazonium cation [PhN2](+) (la,b) and i ts P analogue [PhP2](+) (2a,b). Our results show that in contrast to 1 , 2b exists preferentially as a bridged structure. The phenyl ion affi nity toward P-2 has been determined and suggests that the phenyldiphos phonium cation should be stable in the gas phase and that it is probab ly accessible by reaction between P-2 and Ph+.