TY - JOUR
T1 - Electrochemical, Chemical, and Spectroscopic Characterization of the frans-[Tetracarbonylbis(triphenylphosphine)chromium]+/0 Redox Couple
AU - Bagchi, R. N.
AU - Bond, A. M.
AU - Brain, G.
AU - Henderson, T. L.E.
AU - Colton, R.
AU - Kevekordes, J. E.
PY - 1984/3
Y1 - 1984/3
N2 - Electrochemical oxidation of trans-Cr(CO)4(PPh3)2 at mercury, silver, or platinum electrodes or chemical oxidation with AgC1O4, NOPF6 or NOBF4 produces trans-[Cr(CO)4(PPh3)2]+. The 17-electron monomeric cation has been characterized by analysis and a wide variety of electrochemical (polarographic, voltammetric, and controlled potential electrolysis) and spectroscopic (infrared, electron spin resonance) techniques. trans-[Cr(CO)4(PPh3)2]+ is light and moisture sensitive and unlike trans-Cr(CO)4(PPh3)2 reacts relatively rapidly with acetonitrile, acetone, iodide, and bromide as well as water. All reactions studied produce trans-Cr(CO)4(PPh3)2 as a product, in some cases (bromide and iodide) by redox reactions and in others by disproportionation. Electron-transfer catalysis reactions initiated via the ligand, L, substitution reaction trans-[Cr(CO)4(PPh3)2]+ + L ⟶ trans-[Cr(CO)4PPh3L]+ + PPh3 do not appear to be favored, although the observation of Cr(CO)5PPh3 as a reaction product with CO in the presence of light suggests that this step may be light catalyzed. This reaction, if it occurs, is a slow step relative to other pathways, and the [Cr(CO)4(PPh3)2]+/0 redox couple is not a good candidate for electron-transfer catalysis.
AB - Electrochemical oxidation of trans-Cr(CO)4(PPh3)2 at mercury, silver, or platinum electrodes or chemical oxidation with AgC1O4, NOPF6 or NOBF4 produces trans-[Cr(CO)4(PPh3)2]+. The 17-electron monomeric cation has been characterized by analysis and a wide variety of electrochemical (polarographic, voltammetric, and controlled potential electrolysis) and spectroscopic (infrared, electron spin resonance) techniques. trans-[Cr(CO)4(PPh3)2]+ is light and moisture sensitive and unlike trans-Cr(CO)4(PPh3)2 reacts relatively rapidly with acetonitrile, acetone, iodide, and bromide as well as water. All reactions studied produce trans-Cr(CO)4(PPh3)2 as a product, in some cases (bromide and iodide) by redox reactions and in others by disproportionation. Electron-transfer catalysis reactions initiated via the ligand, L, substitution reaction trans-[Cr(CO)4(PPh3)2]+ + L ⟶ trans-[Cr(CO)4PPh3L]+ + PPh3 do not appear to be favored, although the observation of Cr(CO)5PPh3 as a reaction product with CO in the presence of light suggests that this step may be light catalyzed. This reaction, if it occurs, is a slow step relative to other pathways, and the [Cr(CO)4(PPh3)2]+/0 redox couple is not a good candidate for electron-transfer catalysis.
UR - http://www.scopus.com/inward/record.url?scp=0037876509&partnerID=8YFLogxK
U2 - 10.1021/om00079a002
DO - 10.1021/om00079a002
M3 - Article
AN - SCOPUS:0037876509
SN - 0276-7333
VL - 3
SP - 4
EP - 9
JO - Organometallics
JF - Organometallics
IS - 1
ER -