Anion‐, Solvent‐, Temperature‐, and Mechano‐Responsive Photoluminescence in Gold(I) Diphosphine‐Based Dimers |
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| Authors: | Dr Andrea Deák Csaba Jobbágy Gábor Marsi Miklós Molnár Zoltán Szakács Dr Péter Baranyai |
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| Affiliation: | Hungarian Academy of Sciences, MTA TTK SZKI, “Lendület” Supramolecular Chemistry Research Group, 1117 Budapest, Magyar Tudósok k?rútja 2. (Hungary) |
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| Abstract: | A series of Au2(nixantphos)2](X)2 (nixantphos=4,6‐bis(diphenylphosphino)‐phenoxazine; X=NO3, 1 ; CF3COO, 2 ; CF3SO3, 3 ; Au(CN)2], 4 ; and BF4, 5 ) complexes that exhibit intriguing anion‐switchable and stimuli‐responsive luminescent photophysical properties have been synthesized and characterized. Depending on their anions, these complexes display yellow ( 3 ), orange ( 4 and 5 ), and red ( 1 and 2 ) emission colors. They exhibit reversible thermo‐, mechano‐, and vapochromic luminescence changes readily perceivable by the naked eye. Single‐crystal X‐ray studies show that the Au2(nixantphos)2]2+ cations with short intramolecular Au ??? Au interactions are involved as donors in an infinite N?H ??? X (X=O and N) hydrogen‐bonded chain formation with CF3COO? ( 2 C ) and aurophilically linked Au(CN)2]? counterions ( 4 C ). Both crystals show thermochromic luminescence; their room temperature red ( 2 C ) and orange ( 4 C ) emission turns into yellow upon cooling to 77 K. They also exhibit reversible mechanochromic luminescence by changing their emission color from red to dark ( 2 C ), and orange to red ( 4 C ). Compounds 1 – 5 also display reversible mechanochromic luminescence, altering their emission colors between orange ( 1 ) or red ( 2 ) to dark, as well as between yellow ( 3 ) or orange ( 4 and 5 ) to red. Detailed photophysical investigations and correlation with solid‐state structural data established the significant role of N?H ??? X interactions in the stimuli‐responsive luminescent behavior. |
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| Keywords: | gold hydrogen bonds luminescence mechanochromic stimuli responsive |
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