Inorganic Chemistry, Vol.42, No.9, 3026-3035, 2003
One-dimensional collective electronic effects in the helically stacked Cs-2[Ni(CN)(4)]center dot H2O and Cs-2[Pt(CN)(4)]center dot H2O: X-ray structure, polarized specular reflectance, and ZINDO calculations
The X-ray structure of Cs-2[Ni(CN)(4)].H2O and the polarized single-crystal UV absorbance spectra of Cs-2[Ni(CN)(4)].H2O and Cs-2[Pt(CN)(4)].H2O are presented. The two complexes are isostructural, with helical arrangements of M(CN)(4)(2-) ions in which there is moderate metal-metal electronic perturbation resulting in a spectral red shift from solution in the UV absorbance spectra. In addition, we have modeled the nickel system with a ZINDO calculation of a three-molecule segment of the helix and have found remarkably good agreement with experiment, including excellent reproduction of the red shift. Crystal data are as follows: Cs-2[Ni(CN)(4)].H2O, hexagonal, space group P6(1), a = 9.5260(10) Angstrom, c = 19.043(2) Angstrom, V = 1496.5(3) Angstrom(3), T = 100 K, Z = 6, 4335 observed data, R = 0.016, R-w = 0.034.