TY - JOUR
T1 - The single-crystal electronic and electron spin resonance spectra of copper(II) doped bis(2,2′-bipyridyl)nitritozinc(II) nitrate and bis(2,2′-bipyridyl)nitritocopper(II) tetrafluoroborate
T2 - A fluxional CuN2N′2O2 chromophore
AU - Fitzgerald, William
AU - Murphy, Brigid
AU - Tyagi, Suresh
AU - Walsh, Bernadette
AU - Walsh, Andrew
AU - Hathaway, Brian
PY - 1981
Y1 - 1981
N2 - The single-crystal e.s.r. spectra and polarised electronic spectra of the copper(II) doped [Zn(bipy)2(ONO)][NO3] system are shown to be closely comparable to those previously reported for [Cu(bipy)2(ONO)][NO3]. The observation of more than four copper hyperfine lines in the single-crystal e.s.r. spectrum measured in the approximate bc plane is consistent with a two-dimensional misalignment of the CuN2N′2O2 chromophore and the temperature variability of the g and A factors are consistent with a two-dimensional fluxional model of the CuN2N′2O2 chromophore with a distorted square-pyramidal 4 + 1 + 1* structure and not with static disorder. This suggests that the structures of [Cu(bipy)2(ONO)][NO3] and [Cu(bipy)2(ONO)][BF4] are not genuine static stereochemistries of the copper(II) ion, but arise as a consequence of the fluxional model and are best referred to as pseudo cis distorted-octahedral structures. The electronic properties of 0.1-100% copper(II) doped [Zn(bipy)2(ONO)][NO3] are shown to be independent of the copper(II) concentration, and this suggests that the structure of the doped CuN2N′2O2 chromophore is independent of the structure of the ZnN2N′2O2 chromophore of the zinc host lattice, but correlates with the known structure of the [Cu(bipy)2(ONO)][NO3] complex, an example of the Non-co-operative Jahn-Teller Effect. The electronic reflectance spectrum of [Cu(bipy)2(ONO)][BF4] is closely comparable to that of the nitrate, despite having a significantly different, (4 + 1 + 1*) type, fluxional CuN4O2 chromophore structure.
AB - The single-crystal e.s.r. spectra and polarised electronic spectra of the copper(II) doped [Zn(bipy)2(ONO)][NO3] system are shown to be closely comparable to those previously reported for [Cu(bipy)2(ONO)][NO3]. The observation of more than four copper hyperfine lines in the single-crystal e.s.r. spectrum measured in the approximate bc plane is consistent with a two-dimensional misalignment of the CuN2N′2O2 chromophore and the temperature variability of the g and A factors are consistent with a two-dimensional fluxional model of the CuN2N′2O2 chromophore with a distorted square-pyramidal 4 + 1 + 1* structure and not with static disorder. This suggests that the structures of [Cu(bipy)2(ONO)][NO3] and [Cu(bipy)2(ONO)][BF4] are not genuine static stereochemistries of the copper(II) ion, but arise as a consequence of the fluxional model and are best referred to as pseudo cis distorted-octahedral structures. The electronic properties of 0.1-100% copper(II) doped [Zn(bipy)2(ONO)][NO3] are shown to be independent of the copper(II) concentration, and this suggests that the structure of the doped CuN2N′2O2 chromophore is independent of the structure of the ZnN2N′2O2 chromophore of the zinc host lattice, but correlates with the known structure of the [Cu(bipy)2(ONO)][NO3] complex, an example of the Non-co-operative Jahn-Teller Effect. The electronic reflectance spectrum of [Cu(bipy)2(ONO)][BF4] is closely comparable to that of the nitrate, despite having a significantly different, (4 + 1 + 1*) type, fluxional CuN4O2 chromophore structure.
UR - https://www.scopus.com/pages/publications/37049093207
U2 - 10.1039/DT9810002271
DO - 10.1039/DT9810002271
M3 - Article
AN - SCOPUS:37049093207
SN - 1470-479X
SP - 2271
EP - 2279
JO - Journal of the Chemical Society. Dalton Transactions
JF - Journal of the Chemical Society. Dalton Transactions
IS - 12
ER -