Pyridine-2-carboxylato chelated acylrhodium(III) organometallics: Spectroscopic, structural and theoretical studies

Abstract The heterogeneous phase reaction of Rh( Me L sb )(PPh 3 ) 2 Cl 2 ( 1 ) with the sodium salt of three differently substituted picolinate ligands [Na(R-pic), R = H, Me, Cl] in dichloromethane–acetone–water medium afforded the complexes of the type Rh(L al )(PPh 3 ) 2 (R-pic) ( 2 (R)) in excellent yield. These are the first examples of acylrhodium(III) complexes with the picolinate ligand. The chelation of the picolinate ligand is attended with the cleavage of the two Rh Cl bonds and concomitant hydrolysis of the aldiminium function in 1 . The picolinate ligand is coordinated to the rhodium center as bidentate N,O-donor forming five-membered chelate ring. The spectral (UV–Vis, IR, NMR) and electrochemical data of the complexes are reported. The identity of 2 (H) has been established by single-crystal X-ray structure determination which revealed distorted octahedral RhCNO 2 P 2 coordination sphere. The pairs (P,P), (C,O) and (O,N) define the three trans directions. The electronic structures and the absorption spectra of the complexes are also scrutinized by the density functional theory (DFT) and time-dependent DFT analysis.