Preparation and Crystal Structures of Binuclear Copper(II) Complexes of N,N′,N″,N'″-Tetrakis(2-aminoethyl)1,4,8,11-tetraazacyclotetradecane Containing Azide, Cyanate, or Thiocyanate Ion

Three binuclear copper(II) complexes of N,N′,N″,N'″-tetrakis(2-aminoethyl)-1,4,8,11-tetraazacyclotetradecane (taec), [Cu2(taec)N3](ClO4)3 (1), [Cu2(taec)(NCO)](ClO4)3 (2), and [Cu2(taec)(NCS)2](ClO4)2·H2O (3), were prepared and characterized. The crystal structures of these complexes were determined by single-crystal X-ray analysis. In all the complexes taec coordinates to each copper through two ring- and two pendant-nitrogen atoms. Complexes 1 and 2 adopt similar structures, where N3− and NCO− are incorporated into the cavity of taec as a bridging group (end-on fashion). The structure of 3 is substantially different from those of 1 and 2 in that each copper is independently coordinated by NCS−-nitrogen. The spectral and magnetic properties were discussed in relation to the molecular structures.