Solution And Solid State Characterization Of A Cadmium Octaazacryptand Complex
INORGANIC CHEMISTRY(1996)
, Z = 2, a = 9.581(2) Angstrom, c = 17.003(4) Angstrom, V = 1351.2(5) Angstrom(3). Crystallographic data for 1b: monoclinic, C2/c, Z = 4, a = 10.500(2) Angstrom, b = 14.782(3) Angstrom, c = 19.395(4) Angstrom, beta = 99.30(2)degrees, V = 2971(1) Angstrom(3). The cadmium ions in both complexes are eight-coordinate and display similar coordination geometries but different ligand conformations, designated as parallel and oblique. The cadmium coordination sphere is best described as a bicapped octahedron. Through 2D NMR experiments we have found that the Cd is in a symmetric environment and the conformation of the ligand in solution is consistent with the parallel conformation observed in one of the solid state structures. The Cd-113 NMR shift of this eight-coordinate amine complex is 75 ppm relative to 0.1 M aqueous Cd(ClO4)(2), which correlates with shifts observed for other [2.2.2] cadmium polyoxa-polyaza cryptates.