摘要/Abstract
合成了两个系列的以2-芳基-6-(1H-砒唑-1-基)砒啶[芳基=苯基(L1),2,4-二氟苯基(L2),3,5-二甲基苯(L3),3-甲氧基苯基(L4),2-噻吩基(L5),2-苯并噻吩基(L6)]为环金属化配体,以苯乙炔基或苯基为辅助配体的铂化合物1a~6a和1b~6b.其中2b,3b和5b的结构用X射线晶体衍射方法进行了测定.结果表明,辅助基团苯基与配位平面采取一种扭曲的构型.Pt—C(苯基)键较Pt—C(炔基)键弱.对铂化合物的光物理性质包括吸收和发射光谱进行了研究.苯乙炔基取代的铂化合物1a~6a在室温溶液里发射较强的磷光,而苯基取代的确铂化合物1b~3b仅发射很弱的光.但是,化合物4b~6b发射比较强的光,尽管发光效率还是比相应的4a~6a低.这一现象表明4b~6b和4a~6a的激发态可能定域在三齿环金属化配体上.化合物1a~6a表现的较高发光效率可能是因为较强的和刚性的炔基配体.
关键词: 铂络合物, 磷光材料, 晶体结构, 光物理
Two series of platinum complexes, 1a~6a and 1b-6b, based on tridentate cyclometalating ligands 2-aryl-6-(1H- pyrazol-1-yl)pyridine [Ar=phenyl (L1), 2,4-difluorophenyl (L2), 3,5-dimethylphenyl (L3), 3-methoxyphenyl (L4), 2-thienyl (L5), 2-benzothienyl (L6)], and phenylethynyl and phenyl ancillary ligand were synthesized and characterized. The X-ray crystal structures of 2b, 3b and 5b were determined, which revealed a twisted orientation of the phenyl ligand with respect to the coordination plane and a weaker Pt—C(phenyl) bond compared with the Pt—C(alkynyl) bond in 1a. Photophysical properties including electronic absorption and emission spectra were studied. Complexes 1a~6a based on the phenylethynyl ligand were strongly emissive, while 1b~3b based on the phenyl ligand were only weakly emissive. However, 4b~6b displayed lower but decent photoluminescent quantum yields than those of 4a~6a, which is explained by the localization of the excited states in the tridentate cyclometalating ligands. The higher quantum efficiencies displayed by the complexes 1a~6a may be attributed to the stronger and more rigid acetylide ligand.
Key words: platinum complexes, phosphorescent materials, crystal structure, photophysics
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