| Abstract
| - The photosubstitution mechanism ofM(CO)4(phen) with PR3 to producefac-M(CO)3(PR3)(phen)depends on the nature of M (Cr, Mo, W), the nature of R (Me,Bun, Ph), the concentration of PR3,the irradiation wavelength, and the applied pressure. Thecharacteristic effect of pressure on the substitution ofMo(CO)4(phen) byPBun3 as a function of irradiationwavelength demonstrates the changeover in substitutionmechanism.
- The photosubstitution reactions of M(CO)4(phen)(M = Cr, Mo, W; phen = 1,10-phenanthroline) withPR3 (R =Me, Bun, Ph) to formM(CO)3(PR3)(phen) were studied as afunction of excitation wavelength, entering nucleophileconcentration, and pressure. Ligand field photolysis in generalresults in a dissociative substitution mechanism,whereas charge-transfer photolysis can, depending on the nature of Mand PR3, proceed according to an associativemechanism. The chemical and physical variables studied result in asystematic tuning of the photosubstitutionmechanism. Nucleophile concentration, excitation wavelength, andpressure dependencies reveal unique mechanisticinformation. The results are discussed in reference to availableliterature data, and a complete mechanistic analysisis presented.
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