Preparation and solution behavior of diphosphinepalladium nitrite complexes

Abstract

Diphosphinepalladium nitrite complexes of the type [Pd(NO 2) 2L 2] (L 2=dppm, dppe, dppp) have been prepared by treatment of [PdCl 2(CH 3CN) 2] with silver nitrite, followed by addition of the appropriate diphosphine. The nitrite complexes are fluxional in solution at 298 K, but on cooling to 220 K signals due to three species could be detected. These have been assigned to the N-bonded, the O-bonded, and the mixed coordination compounds. Treatment of [PdCl 2(dppe)] with two equivalents of TlPF 6, followed by addition of Na 15NO 2, produced [Pd( 15NO 2) 2(dppe)], whose 31P NMR spectrum allowed identification of the three isomers. The analogous platinum complex [Pt(NO 2) 2(dppe)] exists as a single isomer, which is static at 298 K, and a 15NO 2-labeling experiment indicated that it contains N-bonded nitrite ligands.