Syntheses, X-ray structures, spectroscopic and magnetic studies of two new polymeric copper (II) azide complexes; [Cu (3-ethylpyridine) 2 (N 3) 2] n and [Cu (4-ethylpyridine) 2 (N 3) 2] n

Abstract

Two new 1:2 polymeric complexes of copper (II) azide with 3-ethylpyridine (1) and 4-ethylpyridine (2), have been synthesized and characterized by spectroscopic and crystallographic methods. The structure of complex (1) contains a dimeric [Cu (3-Etpy) 2 (N 3) 2] 2 unit and a monomeric [Cu (3-Etpy) 2 (N 3) 2] unit. Each copper atom in the dimeric unit attains a five coordination environment, whereas the copper atom in the second unit has an elongated octahedral geometry. In complex (2), each copper atom in the asymmetric unit is coordinated to the end nitrogens of two μ 2-1,3 azido ligands, a pair of trans 4-Etpy molecules and a nitrogen atom of a terminal azide group. This same nitrogen atom further links a neighboring copper atom at a long Cu–N distance of 2.920 (7) Å, thus connecting the asymmetric units giving rise to a 2D structure. The IR and electronic spectra are reported. Strong absorption bands due to N 3 → Cu IIMLCT transitions are observed in spectra of solids and solutions of both complexes. Magnetic susceptibility and EPR data of both complexes are presented and discussed.