Acridine N-Heterocyclic Carbene Gold(I) Compounds: Tuning from Yellow to Blue Luminescence |
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Authors: | Dr Moulali Vaddamanu Dr Arruri Sathyanarayana Yamane Masaya Shohei Sugiyama Ozaki Kazuhisa Dr Kavitha Velappan Muneshwar Nandeshwar Dr Kyohei Hisano Osamu Tsutsumi Prof Dr Ganesan Prabusankar |
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Institution: | 1. Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, TS, 502285 India;2. Department of Applied Chemistry, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, 525-8577 Japan;3. DAV-IITH, Kandi, TS, 502285 India |
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Abstract: | The synthesis and the luminescence features of three gold(I)-N-heterocyclic carbene (NHC) complexes are presented to study how the n-alkyl group can influence the luminescence properties in the crystalline state. The mononuclear gold(I)-NHC complexes, ( L1 )Au(Cl)] ( 1 ), ( L2 )Au(Cl)] ( 2 ), and ( L3 )Au(Cl)] ( 3 ) were isolated from the reactions between (tht)AuCl] and corresponding NHC ligand precursors, N-(9-acridinyl)-N’-(n-butyl)-imidazolium chloride, ( L1 .HCl)], N-(9-acridinyl)-N’-(n-pentyl)-imidazolium chloride, ( L2 .HCl)] and N-(9-acridinyl)-N’-(n-hexyl)-imidazolium chloride, ( L3 .HCl)]. Their single-crystal X-ray analysis reveals the influence of the n-alkyl groups on solid-state packing. A comparison of the luminescence features of 1 – 3 with n-alkyl substituents is explored. The molecules 1 – 3 depicted blue emission in the solution state, while the yellow emission (for 1 ), greenish-yellow emission (for 2 ), and blue emission (for 3 ) in the crystalline phase. This paradigm emission shift arises from n-butyl to n-pentyl and n-hexyl in the crystalline state due to the carbon-carbon rotation of the n-alkyl group, which tends to promote unusual solid packing. Hence n-alkyl group adds a novel emission property in the crystalline state. Density Functional Theory and Time-Dependent Density Functional Theory calculations were carried out for monomeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride and dimeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride to understand the structural and electronic properties. |
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Keywords: | Gold(I) Carbene Luminescence Coinage Metal Aurophilic Interactions |
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