Structural studies on metal complexes of chiral cyclen. IV. Chloro[(2R,5R,8S,11S)-1,4,7,10-tetrabenzyl-2,5,8,11-tetraethyl-1,4,7,10-tetraazacyclododecane]copper(II) dichlorocuprate(I), [Cu(C44H60N4)Cl][CuCl2]