Synthesis and structural studies of tripodal and planar [N-C-N] − intramolecular coordination systems involving pyrazole donor groups, including oxidative addition of an aryl-bromine bond to platinum(II). Crystal structures of [PtClMe 2{(pz) 2CR(CH 2)- N,N′,C′}] with R = Me or CH 2Cl

Abstract

The complex [PtMe 2(μ-SEt 2)] 2 undergoes oxidative addition reactions with chloro-2,2-bis(pyrazol-1-yl)propanes and 2,6-(pzCH 2) 2C 6H 3Br to form platinum(IV) complexes PtClMe 2{(pz) 2CR(CHX)- N,N′,C″} and PtBrMe 2{2,6-(pzCH 2) 2C 6H 3- N,N′,C″ 1}, respectively, with the ligands present as tripodal [N-C-N] − systems. Structural studies of two of the complexes show distorted octahedral geometry, ' fac-PtClC 3N 2', with (pz) 2CMeCH 2 − and (pz) 2C(CH 2Cl)CH 2 − forming NPtN and NPtC angles at platinum ca. 7–12° less than 90°. The reagent 1,3-(pzCH 2) 2C 6H 4 undergoes cyclomellation with palladium(II) acetate to form Pd(O 2CMe){2,6-(pzCH 2) 2C 6H 3- N,N′,C″ 1}, which has the ligand present as a planar [N-C-N] − donor.