STRUCTURAL AND SPECTROSCOPIC INVESTIGATION OF DI-ü-(1,1)-AZIDO-DI(O,O′-NITRATO)TETRAKIS(3-ACETYLPYRIDINE) DICOPPER(II)

Abstract A mixed-ligand, 1:2 complex for copper(II) azide with 3-acetylpyridine, namely, di-ü(1,1)-azido-di-(O,O′-nitrato)tetrakis(3-acetylpyridine)dicopper(II), has been synthesized and characterized by spectroscopic and X-ray crystallographic methods. Spectroscopic results suggest bidentate chelate nitrato groups and a ü(1,1) bridging azido ligand. The dimeric molecule, which possesses a crystallographic inversion centre, contains two ü(1,1) bridging azido ligands. Each copper(II) atom in the cyclic Cu2N2 ring is further coordinated by two oxygen atoms from a bidentate, chelating nitrato group [Cu-O = 2.022(8) and 2.571(9)Å] and two nitrogen atoms [Cu-N = 1.995(7) and 2.014(8)Å] from the 3-acetylpyridine molecules. The coordination environment of the copper atom may be described as a very distorted tetragonal bipyramid with a nitrogen atom of an azide group and one oxygen atom of a nitrato group occupying the apical sites. The azido ligands are almost linear [N-N-N angle = 175.9(10)°] and asymmetric (Nα-Nβ = 1.235(12) and Nβ-Nγ = 1.127(13)Å].