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 ')(mu-nitrito-O)copper(II)](2)center dot 2(acetonitrile)

The preparation and characterization of some copper(II)nitrito complexes wi th 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')(eta -ONO-O)](2). 2CH(3)CN (II) complexes have been investigated. I con sists of two crystallographically independent [Cu(acetato)(dipyam)(ONO)] ne utral complexes, self-assembled by cooperative N-H . . .O and C-H . . .O in termolecular interactions in supramolecular tetrameric units. Each copper a tom exhibits a tetrahedrally-distorted square-basal geometry of the N2O2 do nor 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 exa mple of a dinuclear nitrito copper(II) derivative containing both cis-monod entate and O-bridging nitrito ligands. Each metal ion shows a distorted squ are-pyramidal coordination with the basal oxygen from the nitrito bridge oc cupying the axial site of the centrosymmetric complex. The H-bonding betwee n the dipyam amino groups and acetonitrile molecules prevents the self-asse mbling of the dinuclear complexes. (C) 2000 Elsevier Science B.V. All right s reserved.