Single-crystal, solid-state, and solution Cd-113 and Se-77 NMR and X-ray single-crystal study of a [Cd(SeR)(2)(N-donor)(2)] complex

摘要

Cd(Se-2,4,6-i-Pr-3-C6H2)(2)(bpy)] (1) has been characterized by X-ray crystallography and studied by solution and solid-state Cd-113 and Se-77 NMR to serve as an analog for biologically occurring [M(S-Cys)(2)(His)(2)] centers. The unit cell parameters for 1 are as follows: a = 21.99(2) Angstrom, b = 21.43(4) Angstrom, c = 16.72(3) Angstrom, V = 7881.3(4) Angstrom(3), Z = 8, orthorhombic space group, Peen. Two chemically inequivalent cadmiums and seleniums are found per unit cell. The principal values of the cadmium chemical shift tensors are (delta(11) = 752 ppm, delta(22) = 570 ppm, delta(33) = 93 ppm) and (delta(11) = 733 ppm, delta(22) = 547 ppm, delta(33) = 100 ppm) with respect to 0.1 M aq. Cd(ClO4)(2). Those for selenium are (delta(11) = -950 ppm, delta(22) = -1040 ppm, delta(33) = -1599 ppm) and (delta(11) = -933 ppm, delta(22) = -1069 ppm, delta(33) = -1586 ppm) with respect to solid (NH4)(2)SeO4. The orientation of the cadmium chemical shift tensor is similar to that of the previously published sulfur analog. [References: 15