| The synthesis of group 7 carbonyl complexes had been widely studied as intermediates in a number of catalytic reactions, such as hydrogenation, the water-gas shift reaction, and carboalkoxylation of alkenes. Water soluble, low valent carbonyl compounds of Re and Tc are receiving current attention due to their potential application in radioimmunotherapy and protein labeling. Numerous polynuclear group 7 carbonyl complexes that are either doubly or triply bridged by hydroxide, alkoxide or aryloxide have been isolated and characterized, however, to date the ligand exchange chemistry of these complexes has received little attention.;In this work, the reactivity of [Et4N][Re2(CO) 6(mu-OR)3] (R = H, CH3) complexes in ligand substitution reactions is discussed. The reaction of these two compounds with a myriad of alcohols, carboxylic acids, and bifunctional ligands that possess different functionalities was explored. The ligand exchange reaction proceeds provided that the leaving alcohol is more basic than the incorporated alcohol or carboxylate to yield a variety of new polynuclear complexes, some of them with very interesting structures and photophysical properties. By incorporating additional functionality into these complexes, new molecules with potential utility for the assembly of supramolecular arrays are now available. |
