COPPER(I) AND COPPER(II) COMPLEXES OF A NEW TETRADENTATE CHELATING LIGAND CONTAINING IMIDAZOLE AND THIO ETHER GROUPS. THE X-RAY STRUCTURE OF TRIGONAL-BIPYRAMIDAL ((1,6-BIS(N-BENZYLIMIDAZOL-2-YL)-2,5-DITHIAHEXANE-N,N,S,S))BROMOCOPPER(I