Metal Pseudohalides Complexes. Part 11. Synthesis and Structural Determination of Di-μ-(1,1)-azido-bis[azido(2-benzoylpyridine)]dicopper(II) and Catena-di-μ(1,3)-azido[di-μ(1,1)-azido-bis(ethylnicotinate)dicopper(II)].