Di-μ-cyanato-bis[(cyanato-κN)(tetramethylethylenediamine-κ2N, N')-copper(II)] and catena-poly[[μ3-cyanato-κ3O:N :N-bis[(cyanato-κN)(1,3-diaminopropane-κ2N, N')copper(II)]]-μ3-cyanato-κ3N :N :O]