Copper(I) Alkynyl Clusters with Crystallization-Induced Emission Enhancement

Abstract

Four copper­(I) alkynyl complexes incorporating phosphate ligands, namely, [Cu16( t BuCC)12(PhOPO3)2] n (1; PhOPO3 = phenyl phosphate), [Cu16( t BuCC)12(1-NaphOPO3)2] n (2; 1-NaphOPO3 = 1-naphthyl phosphate), [VO4@Cu25( t BuCC)19(1-NaphOPO3)]­(PF6)0.5(F)0.5 (3), and [PO4@Cu25( t BuCC)19(1-NaphOPO3)]­(PF6)0.5(F)0.5 (4), were solvothermally synthesized and well-characterized by IR spectroscopy, powder X-ray diffraction, and single-crystal X-ray diffraction. Single-crystal X-ray analysis revealed that the Cu16 cluster-based coordination chain polymers 1 and 2 are formed by assembly during crystallization, while 3 and 4 contain high-nuclearity copper­(I) composite clusters enclosing orthovanadate and phosphate template ions, respectively, that are supported by ROPO3 2– ligands. Complexes 1–4 exhibit crystallization-induced emission enhancement. Their crystalline state shows strong luminescence, in striking contrast to the weak emission of the amorphous state and solution phase. A detailed investigation of the crystal structure suggests that well-arranged C–H···π and π···π interactions between the ligands are the major factors for this enhanced emission. Clusters 3 and 4 also exhibit photocurrent responses upon visible-light illumination.

Enhancing photoluminescence efficiency of atomically precise copper(i) nanoclusters through a solvent-induced structural transformation

“…S13 †), and the subtle shift of wavenumbers relative to the standard vibration of CuC (2100-2270 cm −1 ) was attributed to a coordinative interaction, which was also observed in other reported alkyne-metal clusters. 37 Meanwhile, X-ray photoelectron measurements were performed to determine the valence of copper ions. The binding energy for Cu 2p 3/2 of Cu 10 and Cu 18 is located at 933.38 and 932.93 eV, respectively, similar to other Cu(I) complexes and no satellite peaks are observed, 38 suggesting that all Cu have a +1 valence in both clusters (Fig.…”

Halide-bridged tetranuclear organocopper(i) clusters supported by indolyl-based NCN pincer ligands and their catalytic activities towards the hydrophosphination of alkenes

“…11,12 A pincer-type ligand is a kind of special multidentate ligand, with advantages of the formation of the desired complexes through the designed coordination mode and strong bonds between the ligand and the central metal, therefore making the complexes exhibit good thermal stability. [13][14][15] At present, most of the Cu(I) clusters are based on ligands such as pyrimidines, 16 quinolines, 17 carbazoles, 18 phosphines, 19,20 NHC (N-heterocyclic carbenes) 21 and alkynyls, 22 but there are fewer reported examples of Cu(I) clusters supported by the pincer ligand. 23 Indole is an electron-rich heterocyclic compound, which can be modified very easily and has various coordinating modes in comparison with indene; so it can serve as the skeleton of the pincer ligand.…”

Elongation of a Trigonal-Prismatic Copper Cluster by Diphosphine Ligands with Longer Spacers

“…However, copper complexes are much cheaper than their congeners and always have good photophysical properties. − The construction of copper­(I) clusters mainly includes two strategies: (i) applying copper­(I) precursors directly; , (ii) using comproportionation reactions by mixing copper­(II) salts with copper powders. − Reductions of copper­(II) salts by reducing agents are also good alternatives for the preparation of copper­(I) clusters, which may allow for the serendipity of copper hydride clusters with diverse structures and applications in catalysis, hydrogen storage, and so on. − The protecting ligands of copper hydride clusters include phosphines, − alkynyls, dithiocarbamates, , dithiophosphates, − thiols, − selenols, and carbenes . Alkynyls have been demonstrated to be a kind of versatile ligand in the formation of coin-metal nanoclusters with diverse coordination modes. , However, only a few reports of copper hydride clusters involve alkynyls. ,, Mixed-ligand-protected metal clusters were reported to exhibit higher stability and enhanced properties compared to single-ligand-protected ones . Although dithiophosphate–alkynyl-coprotected and selenol–phosphine-coprotected copper hydride clusters have been documented, there are no alkynyl–phosphine-coprotected ones.…”

“…However, copper complexes are much cheaper than their congeners and always have good photophysical properties. 18−20 The construction of copper(I) clusters mainly includes two strategies: (i) applying copper(I) precursors directly; 21,22 (ii) using comproportionation reactions by mixing copper(II) salts with copper powders. 23−26 Reductions of copper(II) salts by reducing agents are also good alternatives for the preparation of copper(I) clusters, which may allow for the serendipity of copper hydride clusters with diverse structures and applications in catalysis, hydrogen storage, and so on.…”

“…27,33,37 Mixed-ligand-protected metal clusters were reported to exhibit higher stability and enhanced properties compared to singleligand-protected ones. 21 Although dithiophosphate−alkynylcoprotected 37 and selenol−phosphine-coprotected 44 ■ EXPERIMENTAL SECTION Physical Measurements. UV−vis spectra were recorded on a Shimadzu 2550 spectrometer.…”