Cyclometallated Pd(II) azido complexes containing 6-phenyl-2,2'-bipyridyl or 2-phenylpyridyl derivatives: synthesis and reactivity toward organic isocyanides and isothiocyanates

Cyclometallated palladium(II) azido complexes containing C,N,N- or C,N-donor ligands, Pd(N(3))L](HL = 6-phenyl-2,2'-bipyridine or 2-phenylpyridyl derivatives), showed different reactivities toward organic isocyanides and isothiocyanates. In particular, aryl isocyanides (CN-Ar) underwent insertion into the orthometallated Pd-C bond on the phenyl moiety of the supporting ligand (L) in Pd(N(3))L] or Pd(N(3))(PR(3))L] to selectively give carbodiimido Pd(N=C=N-Ar)L]], imidoyl Pd(N(3))(-C=N-Ar)(PR(3))L]], or imidoyl carbodiimido complexes Pd(N=C=N-Ar)(-C=N-Ar)L] or Pd(N=C=N-Ar)(-C=N-Ar)(PR(3))L]], depending on reaction conditions. Interestingly, reactions of Pd(N(3))(PR(3))L] with organic isothiocyanates gave unusual dinuclear complexes (micro-SCN(4)-R)PdL](2), exhibiting the concurrent S- and N-coordinating thio-tetrazole bridge.