Isostructural trigonal-bipyramidal CuII and nominally 1% CuII-doped ZnII complexes with N5 ligation.

Cu(C6H18N4)(C10H10N2)2, (1-benzylimidazole)[N,N-bis(2-aminoethyl)-1,2-ethanediamine]copper(II) diperchlorate (1), M(r) = 566.88, monoclinic, P2(1)/c, a = 10.549 (1), b = 9.2465 (9), c = 25.256 (2) A, beta = 101.42 (1) degrees, V = 2415 (1) A3, Z = 4, Dm = 1.54 (1), Dx = 1.559 Mg m-3, lambda (Mo K alpha) = 0.71073 A, mu = 1.18 mm-1, F(000) = 1172, T = 296 (1) K, R = 0.048, wR = 0.069 for 3063 reflections. Zn0.99Cu0.01(C6H18N4)(C10H10N2)2, 1% CuII-doped (1-benzylimidazole)[N,N-bis(2-aminoethyl)-1,2-ethanediamine]zinc(II) diperchlorate (2), M(r) = 568.72, monoclinic, P2(1)/c, a = 10.708 (1), b = 9.229 (2), c = 25.205 (2) A, beta = 101.867 (8) degrees, V = 2438 (1) A3, Z = 4, Dm = 1.54 (1), Dx = 1.549, lambda (Mo K alpha) = 0.71073 A, mu = 1.30 mm-1, F(000) = 1176, T = 295 (1) K, R = 0.041, wR = 0.055 for 3282 reflections. The isostructural distorted trigonalbipyramidal MN5 cations are separated by perchlorate anions. Equatorial M--N distances are similar in both cations [range 2.083 (3) to 2.105 (3) A for (1); 2.073 (3) to 2.084 (3) A for (2)]. In contrast, the axial M--N distances differ substantially [2.043 (3) and 1.971 (3) A for (1); 2.255 (4) and 2.054 (3) A for (2)]. Axial contraction in the copper complex (1) is consistent with a dz2 ground state.