Protonation and alkylation of benzoyl(carbamoyl)-palladium(II) and -platinum(II) complexes to give cationic benzoyl complexes with O-protonated and O-alkylated carbamoyl ligands. Characterization of an intermediate in the reaction of trans-[Pd(COPh)(CO)(PMe 3) 2]BH 4 with pyrrolidine to give trans-Pd(COPh)(CO [formula omitted]H 2)(PMe 3) 2

Abstract

trans-[Pd(COPh)(CO)(PMe 3) 2BF 4 ( 1) reacts with pyrrolidine to afford a cationic benzoylpalladium(II) complex with an O-protonated carbamoyl ligand trans-[Pd(COPh){C(OH)( N(CH 2) 3C H 2)}(PMe 3) 2] BF 4 ( 2b), which has been characterized by means of NMR spectroscopy. Complex 2b reacts further with pyrrolidine to give trans-Pd(COPh)(CO N(CH 2) 3C H 2)(PMe 3) 2 ( 3) together with the pyrrolidinium salt CH 2(CH 2) 3N H 2BF 4. The conversion of 2b to 3 is a reversible process, and treatment of 3 with the pyrrolidinium salt regenerates 2b. Thermodynamic and kinetic parameters for the protonation-deprotonation equilibration between 2b and 3 have been determined by means of NMR spectroscopy. Treatment of trans-Pd(COPh)(CO N(CH 2) 4C H 2)(PMe 3) 2 with Et 3OBF 4 affords trans-[Pd(COPh){C(OEt)( N(CH 2) 4C H 2)}(PMe 3) 2]BF 4 ( 4). Ethylation of benzoyl(carbamoyl)platinum complexes trans- and cis-Pt(COPh)(CONMe 2)(PPh 3) 2 with Et 3OBF 4 also gives corresponding O-ethylated carbamoyl complexes trans- and cis-[Pt(COPh){C(OEt)(NMe 2)}(PPh 3) 2]BF 4 ( 5 and 6, respectively).