Comparative properties of fluorous phosphine ligand complexes: W(CO) 5L F. Crystal structure of W(CO) 5P(C 6H 4-4-CH 2CH 2(CF 2) 7CF 3) 3

Abstract

The compounds W(CO) 5P(C 6H 4-4-CH 2CH 2(CF 2) 7CF 3) 3 ( 1) and W(CO) 5P(CH 2CH 2(CF 2) 5CF 3) 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(CH 2CH 2(CF 2) 5CF 3) 3 > P(C 6H 4-4-CH 2CH 2(CF 2) 7CF 3) 3 > PPh 3 > P( p-tolyl) 3 > P( n-octyl) 3. The X-ray crystal structure of W(CO) 5P(C 6H 4-4-CH 2CH 2(CF 2) 7CF 3) 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.