An asymmetrical dinuclear copper(II) β-amino-oxime/oximato-diamine compound with Cu–(OH)–Cu and Cu–(N–O)–Cu bridging; [Cu2(detenoxH)(detenox)(OH)](ClO4)2 (detenoxH = 4,4-dimethyl-7-(N,N-diethylamine)-5-azaheptan-2-one oxime)