TY - JOUR
T1 - The nature of the lowest excited state and photosubstitution reactivity of tetracarbonyl-1,10-phenanthrolinetungsten(0) and related complexes
AU - Wrighton, Mark S.
AU - Morse, David L.
PY - 1975/9/23
Y1 - 1975/9/23
N2 - Absorption and emission spectral studies of M(CO)4L complexes (M = Cr Mo, W; L = 2,2′-bipyridine, 1,10-phenanthroline, 5-CH3-, 5-Cl-, 5-Br-, 5-NO2-1,10-phenanthroline) have been carried out and reveal that the lowest excited state in every case is charge-transfer (CT) in character, M→ CT in absorption, and in no case do the ligand field (LF) excited states cross below the CT state. Minimum energies of the LF states have been established by the spectroscopic study of cis-bis(pyridine)- and cis-bis(aliphatic amine)-tetracarbonylmetal(0) complexes which all have LF lowest excited states for M = Mo, W. For the M(CO)4L complexes emission is detectable for M = Mo or W and occurs in the range 14.40-15.66 kK with lifetimes of 7.9-13.3 μsec and quantum yields of 0.02-0.09 all in EPA solution at 77 K. For the bis-pyridine and -aliphatic amine complexes emission occurs only from the W complexes and is of the order of 3.0-4.0 kK higher in energy than for the M(CO)4L complexes. Photosubstitution of pyridine is efficient in cis-W(CO)4(py)2 (py = pyridine): Φ436nm = 0.23; Φ405nm = 0.27; and Φ366nm = 0.23. The M(CO)4L complexes have strongly wavelength dependent, but modest, quantum yields for CO substitution and show that the lowest CT state is unreactive. Typical values for CO substitution for M = W and L = 1,10-phenanthroline are: Φ436nm = 1.6 × 10-4; Φ405nm = 1.2 × 10-3; Φ366nm = 9.2 × 10-3; and Φ313nm = 2.2 × 10-2.
AB - Absorption and emission spectral studies of M(CO)4L complexes (M = Cr Mo, W; L = 2,2′-bipyridine, 1,10-phenanthroline, 5-CH3-, 5-Cl-, 5-Br-, 5-NO2-1,10-phenanthroline) have been carried out and reveal that the lowest excited state in every case is charge-transfer (CT) in character, M→ CT in absorption, and in no case do the ligand field (LF) excited states cross below the CT state. Minimum energies of the LF states have been established by the spectroscopic study of cis-bis(pyridine)- and cis-bis(aliphatic amine)-tetracarbonylmetal(0) complexes which all have LF lowest excited states for M = Mo, W. For the M(CO)4L complexes emission is detectable for M = Mo or W and occurs in the range 14.40-15.66 kK with lifetimes of 7.9-13.3 μsec and quantum yields of 0.02-0.09 all in EPA solution at 77 K. For the bis-pyridine and -aliphatic amine complexes emission occurs only from the W complexes and is of the order of 3.0-4.0 kK higher in energy than for the M(CO)4L complexes. Photosubstitution of pyridine is efficient in cis-W(CO)4(py)2 (py = pyridine): Φ436nm = 0.23; Φ405nm = 0.27; and Φ366nm = 0.23. The M(CO)4L complexes have strongly wavelength dependent, but modest, quantum yields for CO substitution and show that the lowest CT state is unreactive. Typical values for CO substitution for M = W and L = 1,10-phenanthroline are: Φ436nm = 1.6 × 10-4; Φ405nm = 1.2 × 10-3; Φ366nm = 9.2 × 10-3; and Φ313nm = 2.2 × 10-2.
UR - https://www.scopus.com/pages/publications/0001332070
U2 - 10.1016/S0022-328X(00)89307-9
DO - 10.1016/S0022-328X(00)89307-9
M3 - Article
AN - SCOPUS:0001332070
SN - 0022-328X
VL - 97
SP - 405
EP - 419
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 3
ER -