Cu(II)-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) (1), Cu(4)(N(3))(8)(men)(2) (2), Cu(5)(N(3))(10)(N,N-dmen)(2) (3) and Cu(5)(N(3))(10)(N,N'-dmen)(5) (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(NO(3))(2)·3H(2)O and an excess of NaN(3). 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.