名称:
Polymeric complexes of copper(II) azide and 2,5-dimethylpyridine without and with solvent molecules. Synthesis, spectral and structural characterization of [Cu(2,5-dimethylpyridine) (N3)2]n and [Cu(2,5-dimethylpyridine) (N3)2(H2N-CHO)]2
摘要:
Catina di-mu(1,1)-azido[di-mu(1,1)-azidobis(2,5-dimethylpyridine(dicopper(II)] (1) and di-mu(1,1)-azidobis[azido(2,5-dimethylpyridine) (formamide)]dicopper(II) (2) were synthesized and characterized by spectroscopic and crystallographic methods. In the triclinic complex 1 the copper(II) centres are penta-coordinated by four nitrogen atoms from the azido ligands [Cu-N distances = 1.980(3)-2.249(4) Angstrom] and a fifth nitrogen from the organic molecule at a Cu-N bond length of 2.038(4) Angstrom. Both azido ligands function as mu(1,1) bridges to form chains of polyhedra along the crystallographic a axis. The dimeric molecule 2, which possesses a crystallographic inversion centre, contains both terminal and mu(1,1) bridging azido ligands. Each copper(II) atom is further coordinated by a 2,5-dimethylpyridine molecule [Cu-N = 1.998(4) Angstrom] and a formamide molecule via its carbonyl oxygen atom [Cu-O = 2.356(4) Angstrom] to give a distorted square pyramid. The IR absorption spectra reveal asymmetric azido ligands in both complexes, O-bonded formamide and hydrogen bonds as well, in 2. The solid and solution electronic spectra of both complexes exhibit more than one strong N-3(-) --> Cu-II charge-transfer transition band. The room-temperature EPR spectra of powdered samples and DMF solutions were recorded and discussed. (C) 1997 Elsevier Science Ltd.