Mixed-Ligand Cyanide Cobalt (III) Complexes with 1,2-Cyclohexanediaminetetraacetic Acid: Synthesis and Photochemical Properties

摘要

[Co(CN)2(H3Cdta)] · 2H2O (I) and Na2[Co(CN)(Cdta)] · 3H2· (II) (Cdta~(4-) is the 1,2-cyclo-hexanediaminetetraacetate) were synthesized. In I, the two cyanide ions and the Cdta nitrogen atoms are located in the equatorial plane, the carboxyl groups connected to different N atoms are in axial positions; in addition one of them, like two other uncoordinated carboxyl groups, is protonated. In II, Cdta is a pentaden-tate ligand coordinated in the cis-equatorial mode. UV excitation of the dicyano complexes at the ligand-to-metal charge transfer band gives organic derivatives of cobalt(III) stable enough for chromatographic isolation. Photolysis of II in neutral medium gives aqua(cyclohexanediaminetriacetato)cobalt (III) complexes as the final products.