Dicarboxylic Acids Induced Tandem Transformation of Silver Nanocluster

Structural transformation of metal nanoclusters (NCs) is of great ongoing interest regarding their synthesis, stability, and reactivity. Although sporadic examples of cluster transformations have been reported, neither the underlying transformation mechanism nor the intermediates are unambiguous. Herein, we have synthesized a flexible 54-nuclei silver cluster (Ag54) by combining soft (tBuC≡C-) and hard (nPrCOO-) ligands. The existence of weakly coordinated nPrCOO- enhances the reactivity of Ag54, thus facilitating the dicarboxylic acid to induce structural transformation. X-ray structural analyses reveal that Ag54 transforms to Ag28 cluster-based 2D networks (Ag28a and Ag28b) induced by H2suc (succinic acid) and H2glu (glutaric acid), whereas with H2pda (2,2'-(1,2-phenylene)diacetic acid), a discrete Ag28 cluster (Ag28c) is isolated. The key intermediate Ag17 that emerges during the self-dissociation of Ag54 was isolated by using cryogenic recrystallization and characterized by X-ray crystallography. The "tandem transformation" mechanism for the structure evolution from Ag54 to Ag28a is established by time-dependent electrospray ionization mass spectrometry (ESI-MS) and UV-vis spectroscopy. In addition, the catalytic activity in the 4-nitrophenol reduction follows the sequence Ag28c > Ag28b > Ag28a > Ag54 due to more bare silver sites on the surface of the Ag28 cluster unit. Our findings not only open new avenues to the synthesis of silver NCs but also shed light on a better understanding of the structural transformation mechanism from one cluster to another or cluster-based metal-organic networks induced by dicarboxylates.

Synthesis, structure, fluorescence, electrochemical, and antioxidant studies of a new silver(I) complex with 2,6-bis(N-methylbenzimidazol-2-yl)pyridine

A new silver(I) complex of the type [Ag2(mbbp)2](pic)2·DMF·CH3OH [mbbp = 2,6-bis( N-methylbenzimidazol-2-yl)pyridine] is synthesized and analyzed using a range of spectroscopic and crystallographic techniques. This compound contains cationic Ag2(mbbp)2 dimers, in which the crossed eight-shaped structure is formed by two mbbp ligands bridging two silver(I) centers and Ag–Ag bonds. Two-dimensional supramolecular networks of the silver(I) complex are connected by π···π interactions and hydrogen bonds. Hirshfeld analyses are performed to support the aforementioned intermolecular interactions. The effect of π···π stacking interactions on the fluorescence properties of the complex is investigated. Cyclic voltammetry indicates two irreversible redox processes. In addition, an antioxidant assay in vitro demonstrates that the silver(I) complex displays excellent scavenging activity toward hydroxyl radicals.

Advances in ligand-unsupported argentophilic interactions in crystal engineering: an emerging platform for supramolecular architectures

Ligand-unsupported argentophilic interactions are described, emphasizing reticular design and recent developments in advanced synthetic strategies, and highlighting diverse interactions that are useful for the construction of unmitigated networks.

Crystal structure of catena-poly[diaqua-bis(μ2-4-((4-(pyridin-2-ylmethoxy)phenyl)diazenyl)benzoato-κ3 O,O′:N)cadmium(III)], Cd(C19H14O3N3)2(H2O)

C38H30N6O7Cd, monoclinic, C2/c (no. 15), a = 16.937(3) Å, b = 6.1323(12) Å, c = 33.322(7) Å, β = 99.31(3)°, V = 3415.4(12) Å3, Z = 4, R gt(F) = 0.0314, wR ref(F 2) = 0.0668, T = 296(2) K.

Crystal structure of catena-poly[(μ2-pentane-1,5-dicarboxylato-κ2 O:O′)-(μ2-2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole-κ2 N:N′)zinc(II)] sesquihydrate, C17H21N4O5.5Zn

C17H21N4O5.5Zn, monoclinic, P21/c (no. 14), a = 9.4009(12) Å, b = 13.8160(18) Å, c = 15.1299(19) Å, β = 95.507(3)°, V = 1956.0(4) Å3, Z = 4, R gt(F) = 0.0590, wR ref(F 2) = 0.1495, T = 298(2) K.

Synthesis, Structures, and Properties of Polynuclear Silver(I) Complexes Containing Tetra-Phosphine Ligand with Ag⋅⋅⋅C Interactions

Reaction of AgNO3 and N,N,N′,N′-tetrakis((diphenylphosphino)methyl)benzene-1,4-diamine (pbaa) with sodium N-ethyldithiocarbamate (Na(Etdtc)) in CH3CN/toluene and CH3CN/DMF solvents produced two Ag4S4-based coordination complexes [Ag4(pbaa)(µ-κ1S,κ2S-Etdtc)4] (1) and [Ag4(pbaa)(µ-κ1S,κ2S-Etdtc)2(µ-κ1S,κ1S-Etdtc)2] (2). Structural analysis shows that the Ag4S4 cores in 1 are interconnected by one pbaa ligand in a tetradentate mode and four Etdtc– anions in a µ-κ1S,κ2S mode to form a three-layer conformation, whereas the Ag4S4 cores in 2 are linked by ligands pbaa (the tetradentate mode) and Etdtc– (the µ-κ1S,κ1S and µ-κ1S,κ2S modes) to yield the other type of three-layer conformation. In addition, in different solvent systems, the Ag atoms also form different types of weak Ag···C interactions with Ag···C distances of 3.297–3.344 Å in 1 and 3.237–3.416 Å in 2. The emission spectrum of complex 1 in DMF solution displays a broad orange–red emission peak at 518 nm, which may be assigned to the ligand-to-metal charge transfer transition.

Syntheses, structures and luminescence of a series of coordination polymers constructed with 4-substituted 1,2,4-triazole and biscarboxylate co-ligands

Eight coordination polymers were hydrothermal synthesized based on semi-rigid 4-substituted 1,2,4-triazole btpm and biscarboxylate ligands. 1–8 show the structural diversity based on mono-metal, bi-, tri- and tetra-nuclear metal clusters.

Five metal–organic frameworks from 3,4-dimethylphenyl substituted imidazole dicarboxylate: syntheses, structures and properties

Five metal–organic frameworks have been hydrothermally synthesized and structurally characterized.

A novel pentanuclear zinc coordination polymer with one-dimensional chain: synthesis, structure and luminescent property

One interesting pentanuclear zinc coordination polymer, [Zn(5)(OH)(2)(DTBA)(4)](n) (1) (DTBA=2,2'-dithiobisbenzoic acid) has been synthesized by hydrothermal method, and characterized by X-ray single crystal diffraction, elemental analyses, IR and TGA. The pentanuclear zinc unit exhibits pentagon configuration, which acts as secondary building unit to construct a one-dimensional chain structure by DTBA ligands. As far as we know, this kind of pentagon zinc unit is unprecedented. In addition, upon the excitation at 390 nm, the blue-fluorescence at 448 nm of the compound 1 was observed.