Pyridine(diimine) Chelate Hydrogenation in a Molybdenum Nitrido Ethylene Complex

Addition of H2 gas to the aryl-substituted pyridine­(diimine) molybdenum nitride (iPrPDI)­Mo­(N)­(C2H4) ([1-(N)­(η2-C2H4)]; iPrPDI = 2,6-(2,6-iPr2-C6H3NCMe)2C5H3N) in the presence of the rhodium hydride precatalyst (η5-C5Me5)­(py-Ph)­Rh­(H) ([Rh–H]; py-Ph = 2-phenylpyridine) resulted in partial hydrogenation of the central pyridine of the iPrPDI chelate to yield (iPrTHPDI)­Mo­(N)­(C2H4) ([2-(N)­(η2-C2H4)]; iPrTHPDI = 2,6-(2,6-iPr2-C6H3NCMe)2C5H6N). The product, [2-(N)­(η2-C2H4)], was structurally and spectroscopically characterized, and its electronic structure was examined by density functional theory (DFT). The stepwise addition of H atoms from [Rh–H] to [1-(N)­(η2-C2H4)] was computed to be thermodynamically viable by DFT.