کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1323807 | 1499896 | 2013 | 7 صفحه PDF | دانلود رایگان |
• We synthesize four Re complexes with [1,3,4]oxadiazole moiety.
• The complex containing moiety at 4,4′-positions shows strongest intensity.
• The electronic structures of complexes are theoretically investigated.
Four bipyridine ligands substituted by the [1,3,4]oxadiazole moieties at different positions, 4,4′- bis(5-phenyl-[1,3,4]oxadiazol-2-yl)-2,2′-bipyridine (L1), 4,4′-bis[5-(4-tert-butyl-phenyl)-[1,3,4] oxadiazol-2-yl]-2,2′-bipyridine (L2), 5,5′-bis(5-phenyl-[1,3,4]oxadiazol-2-yl)-2,2′-bipyridine (L3), and 5,5′-bis[5-(4-tert-butyl-phenyl)-[1,3,4]oxadiazol-2-yl]-2,2′-bipyridine (L4), and their corresponding rhenium(I) Re(CO)3Cl(L) complexes (1–4) were synthesized and characterized by the elemental analysis, IR, 1H NMR and UV–vis spectroscopy. The complex 2 is also determined by the crystal structure analysis. In the UV–vis spectra complexes 1, 2 and 4 show intense spin-allowed intraligand (π→π*) transitions and weak metal to ligand charge-transfer dπ (Re)→π* (diimine) (MLCT) bands in THF solution. Complexes 1, 2 and 3 show efficient photoluminescent emission assigned to dπ (Re)→π* (diimine) MLCT phosphorescence at ambient temperature, and the different substitution position of [1,3,4]oxadiazole moieties in bipyridine ligands has a great effect on both absorption and emission properties of complexes. Among complexes 1, 2 and 3, the 4,4′-disubstituted complex 1 exhibits the strongest phosphorescence emission both in aerated THF solution (a quantum yield of 1.1%) and solid state. Meanwhile, the ground-state electronic structure and absorption spectra of 1–4 are investigated theoretically by DFT and TD-DFT methods.
Four Re(CO)3Cl(L) complexes with oxadiazole moieties attached to 4,4′- or 5,5′-positions of the 2,2′-bipyridine ligand have been investigated. The complex containing [1,3,4]oxadiazole groups at 4,4′-positions of 2,2′-bipyridine shows stronger phosphorescence emission than those 5,5′-disubstituted by the same groups.Figure optionsDownload as PowerPoint slide
Journal: Journal of Organometallic Chemistry - Volume 743, 15 October 2013, Pages 37–43