Pentacyanopropenide group as ligand in organometallic chemistry. Crystal structure and electrochemical studies of (Et 4N)[W(CO) 5{(C(CN) 2C(CN)C(CN) 2}

Abstract

The title complex has been obtained by reaction of the tetraethylammonium pentacyanopropenide with tungsten hexacarbonyl in acetone. Its crystal structure involves discrete [W(CO) 5{C 3(CN) 5}] − anions in which the organic fragment is N-coordinated via one of the nitrogen atoms of a cyano group borne by one of the terminal carbon atoms of the allylic skeleton. The anion presents a distorted octahedral coordination with a W–N bond length [2.168(5) Å] considerably longer than the W–C bond lengths [ cis-W–C in the range 1.998(7)–2.068(4) Å; trans-W–C 1.962(7) Å]. Cyclic voltammograms of this complex, recorded in CH 2Cl 2 and CH 3CN (Bu 4NPF 6 0.1 M), display a quasi-reversible reduction and irreversible oxidation waves.