C^C* cyclometalated platinum(<scp>ii</scp>) N-heterocyclic carbene complexes with a sterically demanding β-diketonato ligand – synthesis, characterization and photophysical properties
作者:M. Tenne、S. Metz、G. Wagenblast、Ingo Münster、T. Strassner
DOI:10.1039/c4dt03613a
日期:——
Neutral cyclometalated platinum(II) N-heterocyclic carbene complexes [Pt(C^C*)(O^O)] with C^C* ligands based on 1-phenyl-1,2,4-triazol-5-ylidene and 4-phenyl-1,2,4-triazol-5-ylidene, as well as acetylacetonato (O^O = acac) and 1,3-bis(2,4,6-trimethylphenyl)propan-1,3-dionato (O^O = mesacac) ancillary ligands were synthesized and characterized. All complexes are emissive at room temperature in a poly(methyl methacrylate) (PMMA) matrix with emission maxima in the blue region of the spectrum. High quantum efficiencies and short decay times were observed for all complexes with mesacac ancillary ligands. The sterically demanding mesityl groups of the mesacac ligand effectively prevent molecular stacking. The emission behavior of these emitters is in general independent of the position of the nitrogen in the backbone of the N-heterocyclic carbene (NHC) unit and a variety of substituents in 4-position of the phenyl unit, meta to the cyclometalating bond.
中性的环金属化铂(II) N-杂环碳烯配合物[Pt(C^C*)(O^O)],其中C^C*配体基于1-苯基-1,2,4-三氮唑-5-亚甲基和4-苯基-1,2,4-三氮唑-5-亚甲基,辅配体分别为乙酰丙酮酸根(O^O = acac)和1,3-双(2,4,6-三甲基苯基)丙-1,3-二酮酸根(O^O = mesacac),已被合成并表征。所有配合物在聚甲基丙烯酸甲酯(PMMA)基质中室温下均能发光,发射峰位于光谱的蓝色区域。对于含mesacac辅配体的所有配合物,观察到高的量子产率和短的衰减时间。mesacac配体中的空间位阻较大的萘基团有效地防止了分子堆积。这些发射体的光致发光行为通常与N-杂环碳烯(NHC)单元骨干中氮的位置以及与环金属化键位元对位的苯基单元的各种取代基无关。