Crystal and molecular structure of bis(β-alanine) zinc nitrate tetrahydrate. electron spin resonance and optical studies of copper(II) diluted in this compound.

Abstract

The structure of the title compound has been established by three-dimensional X-ray crystal structure analysis from diffractometer data. Crystals are monoclinic, space group P2 1/ n, with a = 23.891, b = 6.576, c = 5.519 Å, β = 95,67°, Z = 2. The structure was solved by direct methods (MULTAN) and refined by least-squares calculations to R = 0.042 for 886 independent reflexions. The zinc atom coordination in the centrotymmetric cation is octahedral with Zn-O(ala) 2.072 and Zn-O(water] 2.082 and 2..165 Å. ESR and optical studies reveal that copper(11) substitutes the Zinc ions in the host matrix, the local symmetry around Cu being at most C 2h. The experi- mental g and hyperfine values (g 1 = 2.400. g 2 = 2.097, g 3 = 2.084; A 1 = 0.0135, A 2 = 0.0022. A 3 = 0.0024 cm −1) could be reproduced within a crystal field model incorporating orbital reduction factors (k z = 0.875, k x = 0.860, k y, = 0.860). M.O. coefficients are roughly estimated.