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Synthesis,Characterization, and Properties of Tetraphenylethylene-Based Tetrakis-NHC Ligands and Their Metal Complexes |
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| Authors: | Li-Ying Sun Ting Feng Dr Rajorshi Das Prof Dr F Ekkehardt Hahn Prof Dr Ying-Feng Han |
| Institution: | 1. Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127 P. R. China
These authors contributed equally to this work.;2. Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127 P. R. China;3. Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127 P. R. China Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 30, 48149 Münster, Germany |
| Abstract: | The development of highly emissive dinuclear AgI or AuI complexes M2L](PF6)2 (L= 2 a , 2 b ; M=Ag, Au) derived from tetraphenylethylene (TPE)-based tetrabenzimidazolin-2-ylidene ligands is reported. The new complexes exhibit a remarkable fluorescence enhancement compared to their parent benzimidazolium salts. The quantum yield (ΦF) value for salt H4- 2 a (PF6)4 in dilute solution (c=10−5 m ) was found to be less than 1 %, whereas its metal complexes show ΦF values up to 55 % at similar solution concentration. This observation can be attributed to the rigidification of the TPE skeleton upon metalation resulting in a restriction of the intramolecular rotation of the phenyl groups. Functionalization of the complexes M2 2 b ](PF6)2 (M=Ag, Au) with terminal coumarin groups and subsequent photoirradiation yielded the complexes M2 3 b ](PF6)2 (M=Ag, Au) bearing a new type of ligand with an unaffected TPE moiety. |
| Keywords: | carbenes fluorescence organometallic chemistry photochemistry transmetalation |