Comparative properties of fluorous phosphine ligand complexes: W(CO)5LF. Crystal structure of W(CO)5P(C6H4-4-CH2CH2(CF2)7CF3)3

The compounds W(CO)5P(C6H4-4-CH2CH2(CF2)7CF3)3 (1) and W(CO)5P(CH2CH2(CF2)5CF3)3 (2) were synthesized in order to probe the electronic and physical effects of ligation by perfluorocarbon substituted tertiary phosphine ligands in a W(CO)5L complex. The π-accepting ability of the fluorous phosphines was found to rank with non-fluorous comparators as P(CH2CH2(CF2)5CF3)3 > P(C6H4-4-CH2CH2(CF2)7CF3)3 > PPh3 > P(p-tolyl)3 > P(n-octyl)3. The X-ray crystal structure of W(CO)5P(C6H4-4-CH2CH2(CF2)7CF3)3 shows strong intermolecular association of fluorous components but confirms that the para fluorocarbon subtituents have an insignificant effect on the tungsten coordination environment. Partition coefficients (toluene/perfluoromethylcyclohexane) were measured for compounds 1 and 2.