TY - JOUR
T1 - Mapping the unpaired electron density in [Pt(bipy)L2]- (bipy = 2,2′-bipyridine; L = Cl-, CN-, 13CN-)
T2 - A combined EPR-ENDOR-theoretical study
AU - McInnes, Eric J.L.
AU - Farley, Robert D.
AU - Macgregor, Stuart A.
AU - Taylor, Kenneth J.
AU - Yellowlees, Lesley J.
AU - Rowlands, Christopher C.
PY - 1998
Y1 - 1998
N2 - The X-band EPR and electron-nuclear double resonance (ENDOR) spectra of the formally d9, 17-electron radical anions [Pt(bipy)L2]- (bipy = 2,2′-bipyridine; L = Cl-, CN-, 13CN-) are reported. The 195Pt (I = 1/2, 34%) anisotropic hyperfine matrices are analysed in terms of both 5d and 6p contributions to the singly occupied molecular orbitals (SOMOs). For L = Cl- there is 5.0% 5dyz and 7.6% 6pz character, for L = CN- there is <1% 5dyz and 13.1% 6pz. The bulk of the unpaired electron density is delocalised about the bipy π* system and ENDOR spectra reveal the superhyperfine couplings to the 1H, 14N and 13C (L = 13CN-) nuclei. The unpaired electron densities in the 14N 2pz orbitals contributing to the π* systems are calculated to be 12% and 4% for L = Cl- and CN-, respectively. The cyanide π-orbitals make little contribution to the SOMO for [Pt(bipy)(CN)2]-. There is a good agreement with density functional theory (DFT) MO calculations on the radical anions. DFT calculations also show the atomic orbital compositions of the lowest unoccupied (LU) MO of [Pt(bipy)L2]- and the SOMO of [Pt(bipy)L2]- to be virtually identical.
AB - The X-band EPR and electron-nuclear double resonance (ENDOR) spectra of the formally d9, 17-electron radical anions [Pt(bipy)L2]- (bipy = 2,2′-bipyridine; L = Cl-, CN-, 13CN-) are reported. The 195Pt (I = 1/2, 34%) anisotropic hyperfine matrices are analysed in terms of both 5d and 6p contributions to the singly occupied molecular orbitals (SOMOs). For L = Cl- there is 5.0% 5dyz and 7.6% 6pz character, for L = CN- there is <1% 5dyz and 13.1% 6pz. The bulk of the unpaired electron density is delocalised about the bipy π* system and ENDOR spectra reveal the superhyperfine couplings to the 1H, 14N and 13C (L = 13CN-) nuclei. The unpaired electron densities in the 14N 2pz orbitals contributing to the π* systems are calculated to be 12% and 4% for L = Cl- and CN-, respectively. The cyanide π-orbitals make little contribution to the SOMO for [Pt(bipy)(CN)2]-. There is a good agreement with density functional theory (DFT) MO calculations on the radical anions. DFT calculations also show the atomic orbital compositions of the lowest unoccupied (LU) MO of [Pt(bipy)L2]- and the SOMO of [Pt(bipy)L2]- to be virtually identical.
UR - http://www.scopus.com/inward/record.url?scp=33748647978&partnerID=8YFLogxK
U2 - 10.1039/a804498h
DO - 10.1039/a804498h
M3 - Article
AN - SCOPUS:33748647978
SN - 0956-5000
VL - 94
SP - 2985
EP - 2991
JO - Journal of the Chemical Society - Faraday Transactions
JF - Journal of the Chemical Society - Faraday Transactions
IS - 19
ER -