Luminescence Solvato- and Vapochromism of Alkynyl-Phosphine Copper Clusters

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• 作者：Ilya S. Krytchankou ; Igor O. Koshevoy ; Vladislav V. Gurzhiy ; Vladimir A. Pomogaev ; Sergey P. Tunik
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：September 8, 2015
• 年：2015
• 卷：54
• 期：17
• 页码：8288-8297
• 全文大小：575K
• ISSN：1520-510X

文摘

The reaction of [Cu(NCMe)₄][PF₆] with aromatic acetylenes HC₂R and triphosphine 1,1,1-tris(diphenylphosphino)methane in the presence of NEt₃ results in the formation of hexanuclear Cu(I) clusters with the general formula [Cu₆(C₂R)₄{(PPh₂)₃CH}₂][PF₆]₂ (R = 4-X-C₆H₄ (1鈥?b>5) and C₅H₄N (6); X = NMe₂ (1), OMe (2), H (3), Ph (4), CF₃ (5)). The structural motif of the complexes studied consists of a Cu₆ metal core supported by two phosphine ligands and stabilized by 蟽- and 蟺-coordination of the alkynyl fragments (together with coordination of pyridine nitrogen atoms in cluster 6). The solid state structures of complexes 2鈥?b>6 were determined by single crystal XRD analysis. The structures of the complexes in solution were elucidated by ¹H, ³¹P, ¹H鈥?sup>1H COSY NMR spectroscopy, and ESI mass spectrometry. Clusters 1鈥?b>6 exhibit moderately strong phosphorescence in the solid state with quantum yields up to 17%. Complexes 1鈥?b>5 were found to form solvates (acetone, acetonitrile) in the solid state. The coordination of loosely bound solvent molecules strongly affects emission characteristics and leads to solvato- and vapochromic behavior of the clusters. Thus, solvent-free and acetonitrile solvated forms of 3 demonstrate contrasting emission in orange (615 nm) and blue (475 nm) regions, respectively. The computational studies show that alkynyl-centered IL transitions mixed with those of MLCT between the Cu₆ metal core and the ligand environment play a dominant role in the formation of excited states and can be considerably modulated by weakly coordinating solvent molecules leading to luminescence vapochromism.