Solvent-Free Organometallic Migratory Insertion Reactions

• Published in: Organometallics Vol. 22; no. 11; pp. 2284 - 2290
• Main Authors: Adeyemi, Olalere G., Coville, Neil J.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 26.05.2003
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om0301738

Migratory insertion reactions of organometallic complexes have been shown to occur in the absence of solvent and, more significantly, between solid reagents. Reaction between (η5-C5H5)M(CO)3Me (M = Mo, W) or (η5-C5H5)Fe(CO)2Me and PPh3 (no solvent) took place at temperatures between 40 and 90 °C and gave the products (η5-C5H5)M(CO)2(PPh3)COMe and (η5-C5H5)Fe(CO)(PPh3)COMe in moderate to good yield (60−99%). The Mo and W complexes reacted in the solid state when T < 80 °C. The decarbonylation of (η5-C5H5)Mo(CO)2(PPh3)COMe to yield (η5-C5H5)Mo(CO)2(PPh3)Me also occurred in the solid state (120 °C). Reaction of (η5-C5H5)Mo(CO)3Me with a range of ligands, L (L = PPh3, P(p-MeOC6H4)3, PCy3, PEt3, AsPh3, POPh3, P(OEt)3; 1:1 reagent ratio, 90 °C, 15 min), in the absence of solvent gave (η5-C5H5)Mo(CO)2(L)COMe (7−100% yield) and, on extended reaction, (η5-C5H5)Mo(CO)2(L)Me in varying yields. A kinetic study of the solid-state reaction between (η5-C5H5)Mo(CO)3Me and PPh3 yielded rate constants, e.g. k = 5.18 × 10-5 s-1 (Mo:P = 1:10; 50 °C), which compares with the literature solution data in toluene (k = (0.8−2.5) × 10-5 s-1, 50 °C) using similar metal to ligand ratios. The data are consistent with a pseudo-first-order reaction in the presence of PPh3. Diffusional effects on the reaction rate are detected at low temperature and low PPh3 ratios.