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A cluster-based luminescent porous metal-organic framework has been constructed through a "cluster linker" approach. The luminescent gold(I) cluster, prefunctionalized with pyrazinyl groups, was used as a cluster linker, similar to an organic linker, to connect silver ions in order to form a 3D framework. 1D channels with 1.1 nm diameter were observed in the framework. The cluster with its intrinsic luminescence was incorporated into a porous framework to give a luminescent bifunctional NbO net. This MOF shows solvatochromic behavior, and the interactions between solvent molecules and silver ions inside the channels account for the changes in absorption and emission spectra., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An unprecedented trigonal prismatic (μ(6)-C)Au(6) structure has been found in a novel gold(I)-copper(I) cluster with a hypercoordinated carbon, [CAu(6)Cu(2)(dppy)(6)](BF(4))(4); the incorporation of copper ions enhances the rigidity and integrity of the cluster and turns on the bright red solution luminescence., (© The Royal Society of Chemistry 2011)

A gold(I)‐cluster‐based twin‐cage has been constructed by post‐clustering covalent modification of a hexa‐aldehyde cluster precursor with triaminotriethylamines. The cages‐on‐cluster structure has double cavities and four binding sites, which show site‐discriminative binding for silver(I) and copper(I) guests. The guests in the tripodal hats affect the luminescence of the cluster: the tetra‐silver(I) host–guest complex is weakly red‐emissive, while the bis‐copper(I)‐bis‐silver(I) one is non‐emissive but is a stimuli‐responsive supramolecule. The copper(I) ion inside the tri‐imine cavity is oxidation sensitive, which enables the release of the bright emissive precursor cluster triggered by H2O2 solution. The hybridization of a cluster with cavities to construct a cluster‐based cage presents an innovative concept for functional cluster design, and the post‐clustering covalent modification opens up new avenues for finely tuning the properties of clusters. [ABSTRACT FROM AUTHOR]

Anions have been used to regulate the structures and luminescence of heterometallic clusters. Introducing ClO4− into orange‐emissive, butterfly‐like [(C)(Au‐PPhpy2)6Ag4](BF4)6 (1, PPhpy2=bis(2‐pyridyl)phenylphosphine) leads to the formation of red‐emissive [(C)(Au‐PPhpy2)6Ag5(ClO4)3](ClO4)4 (2) with a novel trigonal bipyramidal structure; employing PhCO2− gives yellow‐emissive, hexagram‐like [(C)(Au‐PPhpy2)6Ag6(PhCO2)3](BF4)5 (3). Notably, 1 exhibits weak luminescence in CH2Cl2/CH3OH=1 : 1 (v : v) with a quantum yield (QY) of 0.05, whereas it was dramatically increased to 0.49 and 0.83 for 2 and 3, respectively. Theoretical calculation confirms that the involvement of anions in the electronic structures is responsible for the shifts of emission. The high QYs of 2 and 3 are attributed to the protection provided by ligands and anions. This work demonstrates that anions may serve as an extra designable factor beyond just counterions for functional metal clusters. [ABSTRACT FROM AUTHOR]

Acetelyenediide (C22−) species have been encapsulated in bimetallic and trimetallic clusters: [(AuL)6Ag7(C≡C)3](BF4)7 (2) and [(AuL)6AgCu6(C≡C)3](BF4)7 (3), L=phenylbis(2‐pyridyl)phosphine (PPhpy2). Single‐crystal X‐ray diffraction analysis revealed that they are isostructural and six silver atoms in 2 are replaced with copper in 3. Both clusters have a trefoil skeleton, which can be viewed as three trigonal bipyramidal (LAu‐C≡C‐AuL)M2Ag (M=Ag/Cu) motifs sharing a common silver atom. TDDFT calculations showed Cu‐doping significantly increases the energy level of (C2‐Cu)‐involved occupied orbital, thus inducing interesting transition coupling of dual‐emission at low temperature. This work not only provides a strategy for constructing heterometallic clusters, but also shows the prospect for pursuing novel thermochromic luminescent materials by incorporating multi‐congeneric metal components. [ABSTRACT FROM AUTHOR]

An alkynyl‐protected gold nanocluster, Au22(tBuC≡C)18 (1), has been synthesized and its structure has been determined by single‐crystal X‐ray diffraction. The molecular structure consists of a Au13 cuboctahedron kernel and three [Au3(tBuC≡C)4] trimeric staples. The cluster 1 has strong luminescence in the solid state with a 15 % quantum yield, and it displays interesting thermochromic luminescence as revealed by temperature‐dependent emission spectra. The enhanced room‐temperature emission is characterized as thermally activated delayed fluorescence. [ABSTRACT FROM AUTHOR]

Highlights • Ligand modification is a key method for preparation of carbon-centered gold clusters. • These clusters have high chemical stability. • These gold clusters are useful in cell imaging and chiral sensing. Abstract Gold clusters have attracted great interest for a long time, and homo and heterometallic gold clusters with hypercoordinated carbon are particularly interesting. This is due to their novel structures and intriguing physicochemical properties. In this review, recent results concerning homo and heterometallic gold(I) cluster compounds with hypercoordinated carbon are summarized, with emphasis on the rational design of phosphine ligands, synthesis of clusters, structure analysis, photophysical studies and their applications such as light emitters, cellular dyes and chirality sensors. We demonstrate that ligand modification, coordination of secondary metal ions and post-clustering functionalization are useful approaches in the preparation of carbon-centered homo and heterometallic gold clusters. The chemical stability of the cluster is enhanced through the binding between the hypercoordinated carbon and gold atoms. These gold clusters exhibit strong luminescence and are useful in cell imaging and chiral sensing. In addition, combine with ultrafast absorption experiments and quantum chemical calculations, the relationship between structures and properties of carbon-centered homo and heterometallic gold(I) clusters has been revealed. [ABSTRACT FROM AUTHOR]

Intensely luminescent coinage metal cluster [Au12Ag14(C≡CPh)20(mdppz)4(CH3OH)8](BF4)6 { 1, mdppz = 2-(3-methylpyrazinyl)diphenylphosphine} was synthesized and structurally characterized. Twenty alkynyl ligands (PhC≡C-), four mdppz ligands, and eight methanol molecules were found to co-stabilize the metal cluster. Interestingly, when the weakly ligated methanol molecules were removed, the green luminescence of 1 significantly redshifted to yellow; exposing the resulting yellow sample in methanol vapor immediately restores the green luminescence. Thus reversible luminescence response can be observed by removing and restoring methanol. Other small solvent molecules with weak coordination ability such as Me2CO, MeCN, and C2H5OH were also found to be good agents to trigger the vapochromism. [ABSTRACT FROM AUTHOR]

An intensely luminescent gold(I)-silver(I) cluster [(C)(AuPPhpy2)6Ag6(CF3CO2)3](BF4)5 (PPhpy2=bis(2-pyridyl)phenylphosphine) ( 3) is synthesized by the reaction of [(C)(AuPPhpy2)6Ag4](BF4)6 with AgCF3CO2. All eight faces of the octahedral C@Au6 core in 3 are capped, that is, six faces are capped by silver ions and two by tetrafluoroborates. Cluster 3 is intensely luminescent in solution with a quantum yield of 92 %. Ligation of CF3CO2− ions is vital for the construction and emission properties of 3, as confirmed by DFT calculations. BF4− ions are involved in the protecting sphere of the metal core, as evidenced by 19F NMR data. The participation of phosphines, CF3CO2−, and BF4− ions in the protection of the emissive core and the enhancement of the rigidity of the cluster result in the high emission efficiency. This is the first example of organic ligands and inorganic anions forming a rigid protecting sphere for luminescent coinage-metal clusters. [ABSTRACT FROM AUTHOR]

A red-near-IR dual-emissive nanocluster with the composition [Au10Ag2(2-py−C≡C)3(dppy)6](BF4)5 ( 1; 2-py−C≡C is 2-pyridylethynyl, dppy=2-pyridyldiphenylphosphine) has been synthesized. Single-crystal X-ray structural analysis reveals that 1 has a trigonal bipyramidal Au10Ag2 core that contains a planar Au4(2-py−C≡C)3 unit sandwiched by two Au3Ag(dppy)3 motifs. Cluster 1 shows intense red-NIR dual emission in solution. The visible emission originates from metal-to-ligand charge transfer (MLCT) from silver atoms to phosphine ligands in the Au3Ag(dppy)3 motifs, and the intense NIR emission is associated with the participation of 2-pyridylethynyl in the frontier orbitals of the cluster, which is confirmed by a time-dependent density functional theory (TD-DFT) calculation. [ABSTRACT FROM AUTHOR]

A gold(i)–silver(i) cluster bearing six carboxylate groups has been synthesized through the oxidation of its aldehyde precursor and the Au6 core of this cluster displays an octahedral or a trigonal prismatic configuration depending on the crystallization conditions. The reversible interconversion between these two isomers can be triggered in the solid state by the addition or removal of acetonitrile solvent molecules. Interestingly, luminescence changes were observed as each configuration shows different emission colors, yellow for octahedral type and red for the trigonal prismatic one. [ABSTRACT FROM AUTHOR]

A cluster-based luminescent porous metal-organic framework has been constructed through a 'cluster linker' approach. The luminescent gold(I) cluster, prefunctionalized with pyrazinyl groups, was used as a cluster linker, similar to an organic linker, to connect silver ions in order to form a 3D framework. 1D channels with 1.1 nm diameter were observed in the framework. The cluster with its intrinsic luminescence was incorporated into a porous framework to give a luminescent bifunctional NbO net. This MOF shows solvatochromic behavior, and the interactions between solvent molecules and silver ions inside the channels account for the changes in absorption and emission spectra. [ABSTRACT FROM AUTHOR]

Methanol drives the blue emissive complex, [Cu2(dppy)3(MeCN)](BF4)2(dppy = diphenylphosphino-pyridine), with a head-to-tail arrangement of the three bridging phosphine ligands to convert to its linkage isomer (head-to-head, green emissive) in the solid state, and the transformation could be reversibly realized through recrystallization in different solvents. [ABSTRACT FROM AUTHOR]

Small anions play a big role in the preparation of an intensely luminescent gold(I)–silver(I) cluster. In their Communication on page 7117 ff. Q.‐M. Wang and co‐workers show that the stepwise addition of silver ions to the gold‐cluster precursor enhances the rigidity of the cluster. The emissive core is fully protected by organic ligands and inorganic anions, which results in high emission efficiency. [ABSTRACT FROM AUTHOR]

The article presents a study on the synthesis, structure, and photophysical properties of a heteronuclear gold(I)-silver(I) cluster that is emissive in solution at room temperature. It notes that the report is the first regarding the luminescence from a gold(I) carbonium system. It cites the findings of the single crystal x-ray structural analysis on the cationic part of the complexes. It mentions that complex 2 is brightly emissive while complex 3 is soluble in polar solvents like chloroform.