화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.117, No.23, 6308-6315, 1995
A Single-Crystal EPR and ESEEM Analysis of Cu(II)-Doped bis(L-Histidinato)Cadmium Dihydrate
A study was undertaken to investigate the nature of the hyperfine and quadrupole coupling parameters of the distant N-14 in Cu(II)-coordinated imidazole in bis(L-histidinato)cadmium dihydrate (I) to further our understanding of the ESEEM patterns obtained for copper proteins, where Cu(II) is coordinated to either N delta or N epsilon. Single crystal EPR data have been collected at 77 K in isotopically enriched Cu-63-doped crystals grown from D2O in order to obtain g and Cu(II) hyperfine tensors. From the obtained spectra, hyperfine splittings from two directly coordinated N-14 nuclei are evident. Single crystal ESEEM measurements at 4.2 K were used to determine the hyperfine and quadrupole tensors of the remote N-14 epsilon of the imidazole group ligated to the Cu(II). These tensors can be compared to those previously obtained for N-14 delta in Cu(II)-doped L-histidine HCl H2O (II) (Colaneri, M. J.; Peisach, J. J. Am. Chem. Sec. 1992, 114, 5335.).