CuII-azide polymers with various molar equivalents of blocking diamine ligands: synthesis, structures, magnetic properties with DFT studies

Four new neutral copper-azido polymers [Cu-4(N-3)(8)(Me-hmpz)(2)](n) (1), [Cu-4(N-3)(8)(men)(2)](n) (2), [Cu-5(N-3)(10)(N,N-dmen)(2)](n) (3) and [Cu-5(N-3)(10)(N,N'-dmen)(5)](n) (4) [Me-hmpz = 1-methylhomopiperazine; men = N-methylethylenediamine; N, N-dmen = N, N-dimethylethylenediamine and N, N'-dmen = N, N'-dimethylethylenediamine] have been synthesized by using various molar equivalents of the chelating diamine ligands with Cu(NO3)(2)center dot 3H(2)O and an excess of NaN3. Single-crystal X-ray structures show that the basic asymmetric units of 1 and 2 are very similar, but the overall 1D structures were found to be quite different. Complex 3 with a different composition was found to be 2D in nature, while the 1D complex 4 with 1 : 1 metal to diamine ratio presented several new structural features. Cryomagnetic susceptibility measurements over a wide range of temperature were corroborated with density functional theory calculations (B3LYP functional) performed on the complexes 1-3 to provide a qualitative theoretical interpretation of their overall magnetic behavior.