TY - JOUR
T1 - The photochemistry of Mo(CNPh)6
T2 - Dissociative photosubstitution and evidence for 'hot' electron transfer
AU - Shaw, Lawton E.
AU - Langford, Cooper H.
N1 - Funding Information:
This work was supported by the Natural Sciences and Engineering Research Council of Canada. We acknowledge Professor A.D. Kirk of the University of Victoria for his assistance with recording nanosecond spectra and for helpful suggestions. Much of our understanding of photochemistry of MLCT states is a consequence of numerous conversations with Professor D.J. Stufkens.
PY - 2002
Y1 - 2002
N2 - The photosubstitution reactivity of Mo(CNPh)6 was investigated by studying the effects of nucleophile and nucleophile concentration. Substitution quantum yields were identical for pyridine and PPh3 as nucleophiles. Between 0.1 and 4 × 10-4 M pyridine, there was no change in quantum yield. These observations suggest that photosubstitution in Mo(CNph)6 is dissociative in character, not associative as previously thought. Photoinduced electron transfer from Mo(CNPh)6 to chloroform, producing [Mo(CNPh)6Cl]+, was also measured. While photosubstitution is wavelength independent, photoinduced electron transfer quantum yields are wavelength dependent. The electron transfer quantum yield is highest at 313 nm (0.77) and decreases to a constant value of 0.28 at 436 nm. It is proposed that this evidence supports a 'hot' electron transfer process, where electron transfer occurs prior to vibrational relaxation into the metal-to-ligand charge transfer (MLCT) manifold.
AB - The photosubstitution reactivity of Mo(CNPh)6 was investigated by studying the effects of nucleophile and nucleophile concentration. Substitution quantum yields were identical for pyridine and PPh3 as nucleophiles. Between 0.1 and 4 × 10-4 M pyridine, there was no change in quantum yield. These observations suggest that photosubstitution in Mo(CNph)6 is dissociative in character, not associative as previously thought. Photoinduced electron transfer from Mo(CNPh)6 to chloroform, producing [Mo(CNPh)6Cl]+, was also measured. While photosubstitution is wavelength independent, photoinduced electron transfer quantum yields are wavelength dependent. The electron transfer quantum yield is highest at 313 nm (0.77) and decreases to a constant value of 0.28 at 436 nm. It is proposed that this evidence supports a 'hot' electron transfer process, where electron transfer occurs prior to vibrational relaxation into the metal-to-ligand charge transfer (MLCT) manifold.
KW - 'Hot' electron transfer
KW - Mo(CNPh)
KW - Photosubstitution reactivity
UR - http://www.scopus.com/inward/record.url?scp=0036323571&partnerID=8YFLogxK
U2 - 10.1016/s0010-8545(02)00080-2
DO - 10.1016/s0010-8545(02)00080-2
M3 - Journal Article
AN - SCOPUS:0036323571
SN - 0010-8545
VL - 230
SP - 165
EP - 169
JO - Coordination Chemistry Reviews
JF - Coordination Chemistry Reviews
IS - 1-2
ER -