Copper(II)nitrito complexes with 2,2′-dipyridylamine. Crystal structures of the [(acetato)(2,2′-dipyridylamine)(nitrito-O,O′)copper(II)] and [(2,2′-dipyridylamine) (nitrito-O,O′)(μ-nitrito-O)copper(II)]2·2(acetonitrile)

The preparation and characterization of some copper(II)nitrito complexes with 2,2′-dipyridylamine (dipyam) are reported. The X-ray diffraction crystal structures of the [Cu(CH3COO)(dipyam)(ONO-O,O′)] (I) and [Cu(dipyam)(ONO-O,O′)(μ-ONO-O)]2·2CH3CN (II) complexes have been investigated. I consists of two crystallographically independent [Cu(acetato)(dipyam)(ONO)] neutral complexes, self-assembled by cooperative NH⋯O and CH⋯O intermolecular interactions in supramolecular tetrameric units. Each copper atom exhibits a tetrahedrally-distorted square-basal geometry of the N2O2 donor set, with the second oxygen atoms of the cis-monodentate nitrito and of the acetato group weakly bound in nearly axial positions. II is a rare example of a dinuclear nitrito copper(II) derivative containing both cis-monodentate and O-bridging nitrito ligands. Each metal ion shows a distorted square-pyramidal coordination with the basal oxygen from the nitrito bridge occupying the axial site of the centrosymmetric complex. The H-bonding between the dipyam amino groups and acetonitrile molecules prevents the self-assembling of the dinuclear complexes.