Recent work has revealed substantial differences in the structure, spectroscopic properties, and reactivity of heterobimetallic Zr/Co complexes of the general form XZr(R′NPR2)3CoY (R′ = iPr, 2,4,6-trimethylphenyl, 3,5-dimethylphenyl; R = Ph, iPr; X, Y = halides or neutral donor ligands) as a function of nitrogen and phosphorus donor atom substituents. To probe the electronic differences between these ligands, a series of Mo(CO)5(R2PNHR′) complexes has been synthesized (R = Ph, R′ = iPr (2a); R = iPr, R′ = iPr (2b), 2,4,6-trimethylphenyl (2c), 3,5-dimethylphenyl (2d), 4-methylphenyl (2e), 4-trifluoromethylphenyl (2f), 4-methoxyphenyl (2g)). Thermolysis of Mo(CO)6 with the corresponding phosphinoamine ligands 1a-1g affords 2a-2g. The infrared carbonyl stretching frequencies of these complexes have been compared to probe the effects of phosphorus and nitrogen substituents on the electronic properties of the phosphinoamine ligands.
Lee, K. H., Napoline, J. W., Bezpalko, M. W., Foxman, B. M., & Thomas, C. M. (2015). Probing substituent effects in phosphinoamine ligands using Mo(CO)5L complexes. Polyhedron, 87, 354–360. https://doi.org/10.1016/j.poly.2014.12.005