F-19 NMR-STUDY OF CIS-EFFECTS AND TRANS-EFFECTS OF SUBSTITUTED TRIPHENYLPHOSPHINE LIGANDS IN ARYLPHOSPHINE-TRI(4-FLUOROPHENYL)PHOSPHINEPLATINUM 4-FLUOROTHIOPHENOXIDES

A number of compounds of the type of trans-4-FC6H4Pt(PAr3)(2)SC6H4F-4, where Ar is a substituted phenyl group, have been prepared starting f rom the corresponding chlorides. By exchange reactions of trans-4-FC6H 4Pt[P(C6H4F-4)(3)]2SC6H4F-4 with the above-mentioned compounds or Ar3P , trans-4-FC6H4Pt[P(C6H4F-4)(3)][PAr3]SC6H4F-4 have been generated in solution. For the latter compounds, the effect of Ar3P on cis- and tra ns-ligands has been studied by the F-19 NMR technique. It has been sho wn that the cis- and trans-effects of Ar3P run parallel and are well d escribed by pK(a) values and ionization potentials of the unshared ele ctron pair in Ar3P, as well as by sigma(0) constants of the aryl group s.