Proton affinities by reactant ion monitoring: Triphenyl group Va compounds

Proton affinities of a series of triphenyl Group Va compounds have been determined by bracketing using reactant ion monitoring: (C 6 H 5 ) 3 N = 904 ± 8 kJ mol −1 , (C 6 H 5 ) 3 P = 968 ± 5 kJ mol −1 , (C 6 H 5 ) 3 As = 904 ± 8 kJ mol −1 and (C 6 H 5 ) 3 Sb = 846 ± 8 kJ mol −1 . The large difference in substituent effect of phenyl for hydrogen between As or P and N may result from overlap of the 2p orbitals of N with the sp 2 orbitals on the ring carbons and lack of overlap for P or As. Proton affinities of phenylalkylphosphine oxides are essentially the same, 904 ± 8 kJ mol −1 , independent of alkyl group.