Two novel Keggin tungstocobaltates grafted by cobalt~(II)complex group(s): K[Co(phen)_2(H_2O)]_2[HCoW_(12)O_(40)] centre dot 2H_2O and [Co(2,2'-bipy)_3]_(1.5) {[Co(2,2'-bipy)_2(H_2O)] [HCoW_(12)O_(40)]} centre dot 0.5H_2O

摘要

Two novel inorganic-organic hybrid compounds composed of Keggin tungstocobaltate framework and cobalt(II)-N coordination complexes, K[Co(phen)_2(H_2O)]_2[HCoW_(12)O_(40)] centre dot 2H_2O (1) (phen = 1,10-phenanthroline) and [Co(2,2'-bipy)_3]_(1.5){[Co(2,2'-bipy)_2(H_2O)][HCo-W_(12)O_(40)] centre dot 0.5H_2O (2) (bipy = bipyridine), have been synthesized under hydrothermal conditions by directly using Keggin POMs as starting materials, which were characterized by elemental analyses, IR, TG analyses and X-ray single crystal diffraction. Crystal data for compound 1: C_(48)H_(41)Co_3KN_8O_(44)W_(12), triclinic, space group P-1, a = 10.918(5) A, b= 13.401(5) A, c = 13.693(5) A, alpha = 69.291(5) deg, beta = 71.568(5) deg, gamma = 78.421(5) deg, V= 1768.9(12) A~3, Z=l; for compound 2: C_(130)H_(104)Co_7N_(26)O_(83)W_(24), orthorhombic, space group, C2/c, a = 46.839(9) A, b = 14.347(3) A, c = 26.147(5) A, alpha = beta = gamma = 90 deg, V= 17,570(6) A~3, Z = 4. Compound 1 exhibits a pseudo-1D chainlike structure, in which potassium ions act as linkages of Keggin unit doubly grafted by [Co(phen)_2(H_2O)] complex. Compound 2 represents a [Co(2,2'-bipy)_2(H_2O)]~(2+) mono-grafted Keggin tungstocobaltate derivative with 1.5[Co(2,2'-bipy)_3]~(2+) countercations. The cyclic voltammetric behavior of 1-CPE is similar to the parent 3-CPE, but the cyclic voltammetric behavior of Co~(II) shows a little difference. Variable-temperature magnetic susceptibility measurement of compound 1 demonstrates the presence of antiferromagnetic interactions.