A biphasic displacement of [60]fullerene from fac-(dihapto-[60]fullerene)(dihapto-1,10-phenanthroline) tricarbonyl molybdenum (0)

Abstract

The Lewis bases (=L) triphenylphosphine (PPh3) and tricyclohexyl phosphine (P(Cy)3) displace [60]fullerene (C60) from the complex fac-(η2-C60)(η2-phen)Mo(CO)3 (phen=1,10-phenanthroline). The progress of the reactions was followed observing the decrease of the absorbance values at 440nm and by monitoring the stretching carbonyl region from 1700 to 2100cm−1. The plots of absorbance vs. time were biexponential, indicative of a biphasic behavior, for reactions under flooding conditions where [L]≫[fac-(η2-C60)(η2-phen)Mo(CO)3]. The plot of absorbance vs. time consisted of two consecutive segments: the first segment of the plot was a decrease of absorbance with time followed by a second segment where the absorbance increased with time. The first segment of the biphasic plot was ascribed to the solvent-assisted displacement of C60 from fac-(η2-C60)(η2-phen)Mo(CO)3 and the second segment to decomposition of the complex fac-(η1-L)(η2-phen)Mo(CO)3 produced in the first of the two consecutive reactions. The rate constant values corresponding to the first segment of the biphasic plot are independent of the chemical nature of L, the molar concentration of L, and the molar concentration of C60 but dependent on the chemical nature of the solvent.