Electron-transfer Chain Catalysis in Phosphine Replacement Reaction: Determination of Relative Donor Capability of Arylpyridylphosphines

Abstract

The slight differences in the donor capabilities of PPhnPy3 n (n = 0–3) could be measured directly in the equilibrium of phosphine replacement reaction on (g5 -C5H5)Fe(CO)2-phosphine complexes, taking advantage of the radical pathway to establish equilibrium rap idly. The simultaneous determination of equilibrium constants is done in a single experiment. The donor capability increases in the order PPh3 < PPh2Py < PPhPy2 < PPy3 with quantified ðg5-C5H5ÞFeðCOÞ2 þ-affinity scales at 1, 4.90, 11.0, and 20.3, respectively. 2006 Elsevier B.V. All rights reserved