Synthesis, characterization, X-ray structures, and catalytic activity of new Mn(I) and Re(I) metal complexes of chelating phosphinopyridylamine and its sulfide ligands

The reaction of 4-Me-C₅H₃N-2-NH(PPh₂) (1) with Mn(CO)₅Br in refluxing chloroform produced the fac-[Mn(CO)₃Br{1-κ²P,N}] (2) and [Mn(CO)₂{1-κ²P,N}₂]Br (3) complexes. Furthermore, the refluxing of the monooxidized thioyl (4-CH₃)C₆H₃N-2-NH(P(S)Ph₂) (4) ligand with M(CO)₅Br (M = Mn, Re) in chloroform yielded the fac-[M(CO)₃Br{4-κ²S,N^py}] (M = Mn (5), Re(6)) complexes. The investigation of complexes 2, 3, 5, and 6 was carried out with the use of multinuclear NMR (¹H, ¹³C and ³¹P NMR), infrared spectroscopy, and the determination of crystal structures. Complexes 5 and 6 represent the inaugural structurally characterized instances of this category of chalcogenide ligands associated with Mn and Re metals documented thus far. Complexes 5 and 6 demonstrate significant catalytic efficacy in the hydrogenation of acetophenone derivatives to yield 1-phenylethanol derivatives, utilizing 2-propanol as a hydrogen source.