1282616-17-4Relevant articles and documents
Photosensitive azobispyridine gold(i) and silver(i) complexes
Bardají, Manuel,Barrio, Mónica,Espinet, Pablo
, p. 2570 - 2577 (2011/05/03)
The neutral and cationic dinuclear gold(i) compounds [(μ-N-N)(AuR) 2] (N-N = 2,2′-azobispyridine (2-abpy), 4,4′- azobispyridine (4-abpy); R = C6F5, C6F 4OC12H25-p, C6F4OCH 2C6H4OC12H25-p) and [(μ-N-N){Au(PR3)}2](CF3SO3) 2 (N-N = 2-abpy, 4-abpy, R = Ph, Me) have been obtained by displacement of a weakly coordinated ligand by an azobispyridine ligand. The corresponding silver(i) dinuclear [(μ-2-abpy){Ag(CF3SO 3)(PPh3)}2] and polynuclear [{Ag(CF 3SO3)(4-abpy)}n] compounds have been obtained. The molecular structures of [(μ-2-abpy){Au(PPh3)} 2](CF3SO3)2 and [(μ-4-abpy) {Au(PMe3)}2](CF3SO3)2 have been confirmed by X-ray diffraction studies and feature linear gold(i) centers coordinated by pyridyl groups, and non-coordinated azo groups. In contrast the X-ray structure of [(2-abpy){Ag(CF3SO 3)(PPh3)}2] shows tetracoordinated silver(i) centers involving chelating N-N coordination by pyridyl and azo nitrogen atoms. The gold(i) compounds with a long alkoxy chain do not behave as liquid crystals, and decompose before their melting point. The soluble gold(i) derivatives are photosensitive in solution and isomerize to the cis azo isomer under UV irradiation, returning photochemically or thermally to the most stable initial trans isomer. The silver(i) derivative [(2-abpy){Ag(CF3SO 3)(PPh3)}2] also photoisomerizes in solution under UV irradiation, showing that its solid state structure, which would block isomerization by azo coordination, is easily broken. These processes have been monitored by UV-vis absorption and 1H NMR spectroscopy. All these compounds are non-emissive in the solid state, even at 77 K.
