Ligand-unsupported Ag Research Articles

Self-assembled three-dimensional coordination polymer with ligand-unsupported Ag–Ag bonds based on tetrazole-1-acetic ligand: Synthesis, structure, and properties

A new compound, [Ag2(tza)(NO3)]n(1), was obtained by reactions of 1H-Tetrazole-1-acetic (Htza) with AgNO3, and characterized by elemental analysis, infrared spectroscopy, and single crystal X-ray diffraction, respectively. The X-ray diffraction analysis reveals that compound 1 is three-dimensional (3D) metal-organic framework constructed by double-layer architecture and the ligand-unsupported Ag–Ag bonds, and displays an unprecedented (3, 6)-connected topological network with 1D hexagon channels of two sizes. The 1D zigzag Ag-metallic chain built from ligand-supported Ag–Ag bonds is observed in 1. Furthermore, the photoluminescence of 1 has also been investigated, and the result exhibits blue photoluminescence in the solid state at room temperature, which shows that this complex may be a good candidate for photoactive material. According to the crystal structures, the TDDFT/6-31G(d) approach was applied to study the photoluminescence emission of 1, and the calculated results are in good agreement with the experimental results.

Crystal Structures and Cytotoxicity of Four Silver(I)carboxylate Complexes with 1,2-Ethylenediamine Analogues

Four silver(I) compounds, [Ag(dapn)(dnbc)]n·1.5nH2O (1), [Ag(en)]n[Ag(dnbc)2]n·2nH2O (2), [Ag(en)]n[Ag(nbc)2]n·2nH2O (3) and [Ag(dapn)]n -(nbc)n·2nH2O (4), where dapn = 1,2-diaminopropane, dnbc = 3,5-dinitrobenzoate, en = 1,2-diaminoethane and nbc = 4-nitrobenzoate, have been synthesized and characterized by X-ray diffraction. The Ag(I) ions show T-shaped coordination geometry in compound 1 but linear coordination geometry in compounds 2, 3 and 4. There are ligand-unsupported Ag…Ag interaction in compounds 2 and 3 with Ag…Ag distance of 3.177 ~3.267 Å. All the four complexes showed high cytotoxicity properties.

Synthesis, structures and antimicrobial activities of silver(I) complexes derived from 2-propyl-1H-imidazole-4,5-dicarboxylic acid

Two new silver(I) complexes based on propyl-substituted imidazole-4,5-dicarboxylic acid, {[Ag2(Hpimdc)(H2O)](H2O)}n (1) and {[Ag2(Hpimdc)(pda)](2H2O)}n (2) (H3pimdc=2-propyl-1H-imidazole-4,5-dicarboxylic acid; pda=1,2-propanediamine) were synthesized and structurally characterized. The single-crystal X-ray determination reveals that in complexes 1 and 2 the silver atoms are linearly coordinated. Doubly deprotonated µ3-Hpimdc2− ligand in 1 behaves as an N,O-bridging coordiation mode to offer an infinite 1D linear chain, while µ2-Hpimdc2− in 2 adopts an N,N′-bridging mode to give an infinite 1D zigzag chain in the presence of pda as an auxiliary ligand. The adjacent 1D chains in 1 are further linked to form a 2D layer structure by ligand unsupported Ag⋯Ag interactions (Ag1⋯Ag2#=3.088Å and Ag2⋯Ag2#=3.098Å). Antimicrobial testing indicates that complex 2 with MIC100 being 0.19mM was more active against Gram-negative bacteria Escherichia coli (E. coli) than complex 1 with MIC100 being 0.28mM. Complexes 1 and 2 have the slightly different influence on the growth of Gram-positive bacteria Staphylococcus aureus (S. aureus) (MIC100 being 0.28mM for 1 and 0.24mM for 2). Both 1 and 2 exhibit good inhibitory activities against jack bean urease with the respective IC50 values of 1.68±0.07 and 1.85±0.14µM.

A Multinary Silver Cluster, Multicoordinated Silver Supramolecular Framework With a 2D Anionic Water Aggregation

A new 3D supramolecular framework, [Ag6(2-PyBIM)6(ClO4)6(CH3OH)2(H2O)11] (1) (2-PyBIM = bis[(2-pyridinyl)-imidazol-1-yl]methane), has been prepared and structurally characterized. Compound 1 exhibits a 2D cationic network as a wave-like brick wall with a multi-coordinated Ag mode (di-, tri-, and tetranitrogen coordinated Ag centers) and multinary Ag cluster centers (Ag, Ag2, and Ag3) with the ligand-unsupported Ag—Ag interaction, encapsulated in an unprecedented 2D perchlorate-methanol-water layer of [(ClO4)6(CH3OH)4(H2O)11]6– anions. Additionally, the thermal stabilities and photoluminescence spectra of the complex 1 are also discussed.

Anion-driven Ag(I) coordination architectures: structural diversity and photoluminescence behaviors

To observe anion impact on structural diversity of coordination architectures, three 1-D Ag(I) complexes with distinct features have been prepared, {[Ag(bpbib)2(NO3)]·C3NH9O)}n (1), [Ag2(bpbib)2·(BF4)2]n (2), and [Ag2(bpbib)2·(ClO4)2]n (3), by the reactions of 4,4′-bis((2-(pyridin-2-yl)-1H-benzo[d]imidazol-1-yl)methyl)biphenyl (bpbib) with Ag(I) salts. Complex 1 is a 1-D helical chain, whereas 2 and 3 bear ligand-unsupported Ag(I)···Ag(I) interaction-directed 1-D structural motif, with synergetic working of flexible organic linker and anions. All complexes exhibit strong triplet state emission at cryogenic temperatures, which profits from the reduction of nonradiative transitions.

The silver(I) coordination polymer [AgO2PPh2]n and unsupported Ag⋯Ag interactions derived from aminophosphinate and phosphinic acid

The ligand N-tert-butyl-1,1-diphenylphosphinamine, Ph2P-N(H)CMe3, was prepared from tert-butylamine and diphenylchlorophosphine. The phosphine portion of the ligand became partially oxidized in air to form Ph2P(O)N(H)CMe3, L1, whilst further oxidation led to diphenylphosphinic acid, Ph2P(O)OH. X-ray analysis revealed that ligand L1 was isolated in the solid-state in a dimeric polymorphic form, different from the previously reported trimeric form. Ligand L1 was subsequently treated with solid AgSO3CF3 in THF which formed a rare silver(I) dinuclear complex of the type [Ag(CF3SO3){OPPh2N(H)CMe3}2{Ag(OPPh2N(H)CMe3)2}]SO3CF3, 1, and consists of ligand unsupported Ag⋯Ag interactions of 2.89Å coordinating through two O donor atoms from the two separate silver units (A and B) and with no coordination through the N atom. Further, silver unit A contains a 3-coordinate Ag(I) center, bent significantly from a linear geometry due to interaction from the triflate O donor atom, whilst unit B remained essentially 2-coordinate and linear. The diphenylphosphinate reacted with solid AgSO3CF3 in THF at room temperature and this led to an unusual Ag(I) coordination polymer, [Ag2{(μ-O)OPPh2}{O2PPh2}]n2, consisting of two different bonding modes of O-donor atoms in a 4-coordinate arrangement around the Ag(I) center. Compounds L1, 1 and 2 were all obtained in moderate to good yields, and analyzed by single crystal X-ray studies, solution 1H and 31P NMR, IR, and elemental analyses.

Di-, tri-, and tetranuclear silver(I) complexes of phenanthroline-functionalized NHC ligands

A few polynuclear silver(I)–NHC complexes have been synthesized via the reactions of phenanthroline-functionalized imidazolium salts with Ag2O at room temperature. The structures of di-, tri-, and tetranuclear silver complexes were fully characterized. The two N-phenanthrolinylimidazolylidene ligands in [Ag4(L1)4](PF6)4 (1), [Ag2(L2)2](PF6)2 (2), and [Ag2(L3)2](PF6)2 (3) are head-to-head arranged. Complex 1 contains a short ligand-unsupported Ag–Ag bond being 3.152(1) Å representing the first example of strictly linear Ag4 cluster stabilized by NHCs. Trinuclear [Ag3(L4)2](PF6)3 (4) of phenanthroline-bridged biscarbene ligands contains a linearly arranged Ag3 core. [Ag3(L5)2](PF6)3 (5) and [Ag3(L4)2](PF6)3 (7) are also trinulear Ag(I) complexes. Binuclear [Ag2(L6)2](PF6)2 (6) exhibits a twisted macrocyclic structure with the Ag–Ag separation at 3.162(1) Å. In 1–4, the silver ions are held together by two ligands in close proximity with the Ag–Ag distances between 2.810(1) and 2.922(1) Å. The fluorescent properties of these silver complexes have also been briefly studied.

An unusual three-dimensional self-penetrating network derived from cross-linking of two-fold interpenetrating nets via ligand-unsupported Ag–Ag bonds: synthesis, structure, luminescence, and theoretical study

A novel coordination polymer Ag4L2(4,4′-bpy)(H2O)2·6H2O (1) (H2L = bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxydiimide, 4,4′-bpy = 4,4′-bipyridine) has been synthesized and characterized by IR spectroscopy, elemental analysis, X-ray powder diffraction and single-crystal X-ray diffraction. Compound 1 exhibits a two-fold interpenetrated array. Remarkably, adjacent sets of 2D interpenetrating sheets are ultimately cross-linked into an unusual three-dimensional self-penetrating network when ligand-unsupported Ag–Ag bonds are taken into account. Theoretical computational methods were applied to further identify argentophilic interactions in this structure. Additionally, thermal stability analysis and luminescent property of this compound are also studied in this paper.

A novel photoluminescent silver(I) wire supported by 4-tert-butylbenzoate and ligand-unsupported Ag⋯Ag interactions

Abstract A novel silver(I) wire sustained by 4-tert-butylbenzoate and ligand-unsupported Ag⋯Ag interactions, [Ag3(tbb)3(NH3)2]n (1, Htbb = 4-tert-butylbenzoic acid), has been synthesized and structurally characterized. In 1, three tbb ligands bind three Ag(I) ions to form a trinuclear subunit through ligand-supported Ag⋯Ag interactions. The inversion-related subunits are further extended to an infinite 1D zigzag Ag(I) wire through the ligand-unsupported Ag⋯Ag interactions. Argentophilicity (3.0283(14)–3.0910(17) A) plays an important role in determining the infinite silver(I) wire. The thermal stability and luminescent behavior of 1 were also discussed.

Assembly of 1D, 2D and 3D silver(I) coordination polymers with nitrilotriacetate and 2-aminopyrimidyl mixed ligands

Three mixed ligands coordination polymers (CPs) [Ag1.5(apym)(nta)0.5]n (1), [(NH4)Ag2(mapym)(nta)·(H2O)3]n (2), [Ag2(dmapym)3(Hnta)]n (3) (apym=2-aminopyrimidine, mapym=4-methyl-2-aminopyrimidine, dmapym=4, 6-dimethyl-2-aminopyrimidine, H3nta=nitrilotriacetate) were synthesized and characterized. For 1–3, as the substituents change from H to one methyl and two methyl groups, the dimensionalities of 1–3 decrease from three-dimension (3D) to one-dimension (1D) due to the steric effect of methyl groups. For 1, the μ2-apym ligands link the Ag(I) ions to form a 1D double-chain incorporating ligand unsupported Ag···Ag interaction. The nta3− ligands extend the 1D double-chain into a 3D framework. In 2, one heptadentate nta3− ligand binds four Ag(I) ions and incorporates μ2-mapym ligand to link metal centers to form a 2D sheet which can be simplified to be a 103 net. Complex 3 features a 1D chain structure incorporating Hnta2− and monodentate dmapym ligands. The substituents on the pyrimidyl ring intensively influence the coordination environments of metal ion and the coordination modes of the carboxyl group, and thus determine the structures of the CPs. The photoluminescent properties of 1–3 were also investigated.

Ammine(2,2′-bipyridine-κ2N,N′)silver(I) nitrate: a dimer formed by π–π stacking and ligand-unsupported Ag...Ag interactions

Reaction of AgNO(3) and 2,2'-bipyridine (bipy) under ultrasonic treatment gave the title compound, [Ag(C(10)H(8)N(2))(NH(3))]NO(3). The crystal structure consists of dimers formed by two symmetry-related Ag(I)-bipy monomers connected through intra-dimer pi-pi stacking and ligand-unsupported Ag...Ag interactions. A crystallographic C2 axis passes through the mid-point of and is perpendicular to the Ag...Ag(i)(-x + 1, y, -z + 1/2) axis. In addition, each Ag(I) cation is coordinated by one chelating bipy ligand and one ammine ligand, giving a trigonal coordination environment capped by the symmetry-equivalent Ag atom. Molecules are assembled by Ag...Ag, pi-pi, hydrogen-bond (N-H...O and C-H...O) and weak Ag...pi interactions into a three-dimensional framework. Comparing the products synthesized under different mechanical treatments, we found that reaction conditions have a significant influence on the resulting structures. The luminescence properties of the title compound are also discussed.

Two novel luminescent silver(I) coordination polymers containing octanuclear silver cluster units or ligand unsupported Ag⋯Ag interactions constructed from 5-sulfoisophthalic acid (H3SIP) and organic amine

Self-assembly of Ag(NO3)2 with 5-sulfoisophthalic acid monosodium salt (NaH2SIP) in the presence of piperazine (pip) or 4,4′-bipyridyl (bpy) produced two new silver(I) coordination polymers, {(H2pip)2[Ag8(SIP)4(H2O)4](H2O)4}n (1) and {[Ag(bpy)][Ag(HSIP)(bpy)](H2O)2}n (2), respectively. Single-crystal X-ray diffraction reveals that compound 1 has a 2D silver carboxylate-sulfonate layered structure containing an uncommon octanuclear [Ag8(CO2)8] cluster wherein the eight silver(I) atoms form two intersecting Ag4 planes. The 2D layers are further linked by the H2pip molecules through hydrogen bonds into a 3D supramolecular structure. Compound 2 features a 2D supramolecular network formed by silver(I)-bpy double chains and HSIP ligands through the combination of coordination bonds, ligand unsupported Ag⋯Ag interactions and weak Ag⋯O coordinative interactions. In the solid state at room temperature, compound 1 exhibits blue photoluminescence with a maximum at 450 nm upon excitation at 365 nm. Compound 2 shows green photoluminescence with a maximum at 564 nm upon excitation at 392 nm.

An iodide/anion exchange route to benzimidazolylidene silver complexes from benzimidazolium iodide: Crystal structures of N, N′-dibutylbenzimidazolylidene silver chloride, bromide, cyanide and nitrate

Syntheses of N, N′-dibutylbenzimidazolylidene silver complexes having chloride, nitrate or cyanide as an anion part through an iodide/anion exchange from N, N′-dibutylbenzimidazolium iodide are described, representing a practical route to benzimidazolylidene silver complexes from readily accessible benzimidazolium iodide. The crystal structures of N, N′-dibutylbenzimidazolylidene silver chloride, bromide, cyanide and nitrate have been determined, showing a close ligand-unsupported Ag–Ag interaction in [(NHC) 2]Ag +[AgX 2] − and a “T” shape geometry about the silver(I) cation in complexes of chloride, bromide and cyanide, but a nearly linear shape in the bis( N, N′-dibutylbenzimidazolylidene) silver complex [ ( NHC ) 2 Ag ] + NO 3 - with non-coordinating nitrate anion.

Syntheses, crystal structures and photoluminescences of two (4,4) topological coordination networks derived from the flexible bipyridyl ligands

Two new 2D coordination polymers, [Ag 4(μ-4,4′-bpp) 3(1,3-bdc) 2] n · 2 nH 2O ( 1) and [Ag(μ-4,4′-bpp) 2ClO 4] n ( 2) (4,4′-bpp = 2,2′-bis(4-pyridylmethyleneoxy)-1,1′-biphenylene; 1,3-bdc = 1,3-benzenedicarboxylate) have been synthesized using three-layer diffusion methods. Single-crystal X-ray analyses reveal that they are both extended grid networks of the (4,4) topology. In complex 1, a chain built by Ag(I) centers with T-shaped and linear geometries is further connected by the interesting ligand-unsupported Ag⋯Ag interactions as well as the conjugated π systems to form an interdigitated 2-D coordination network. The corrugated (4,4) sheets of 2 are packed in the ab planes and stacked along the c direction with the anions ClO 4 - occupying the gaps in the squares.

Syntheses, structures and properties of three novel coordination polymers with a flexible asymmetrical bridging ligand

Three novel coordination polymers with different structural motifs, [Ag(pmtmb)] n ( 1), [Cd(pmtmb) 2(H 2O)] n ( 2) and [Cu(pmtmb) 2] n ( 3), have been synthesized with a flexible asymmetrical bridging ligand, 4-(2-pyrimidylthiomethyl)benzoic acid (Hpmtmb). X-ray diffraction analyses show that 1 is a 2D layer containing unusual zigzag Ag chains based on mixed ligand-supported and ligand-unsupported Ag–Ag interactions, 2 is a necklace structure that further linked through hydrogen bonding to form a 2D sheet, and 3 is a 3D compact framework full assembled from 1D centipede-like chains via π–π stacking interactions. Interestingly, the ligand pmtmb adopts different configurations and coordination modes in the solid structures of these complexes. Furthermore, three complexes exhibit remarkable thermal stability and the complexes 1 and 2 exhibit intense green and purple luminescence, respectively.

Syntheses, IR spectra, thermal analyses, crystal structures, luminescence properties and DFT calculations of two silver–saccharinato complexes with 2-(dimethylaminomethyl)-3-hydroxypyridine and N-(2-aminoethyl)pyrrolidine

Two new silver(I)–saccharinato (sac) complexes, [Ag(sac)(dmamhpy)] ( 1), [Ag 2(sac) 2(aeprd) 2] ( 2), (dmamhpy=2-(dimethylaminomethyl)-3-hydroxypyridine and aeprd= N-(2-aminoethyl)pyrrolidine, have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. X-ray diffraction analyses reveal that complexes 1 and 2 have a dimeric structure containing three-coordinate silver(I) ions with a distorted T-shaped coordination of AgN 3. The dimeric structure of complex 1 is achieved by aromatic π⋯π stacking interactions, while the dimeric structure of complex 2 was governed by ligand unsupported Ag⋯Ag interaction with Ag–Ag contact of 3.1444(3) Å. The dimeric units are further linked by hydrogen bonds and C–H⋯π interactions into a three-dimensional supramolecular network so that the structure of 1 has solvent accessible voids with a volume of 132.1 Å 3. IR spectra and thermal analysis data for 1 and 2 are in agreement with the crystal structures. Complex 2 displays intense luminescence with emission maximum at 373 nm upon excitation at 210 nm. On the basis of experiment, both complexes were calculated by DFT-B3LYP/3-21G in gaussian 03.

Syntheses and structures of metal tetrazole coordination polymers

Two salts and seven copper(I/II) and silver(I) coordination polymers containing tetrazolyl ligands have been hydro(solvo)thermal synthesized by metal salts, NaN3 and various nitriles generated via [2 + 3] cycloaddition reactions of organonitriles and sodium azide. The study also shows that in some cases the azide can play a dual role in the in situ syntheses of metal tetrazole complexes, namely, starting material for tetrazole ligand and co-ligand in the tetrazole-based coordination complexes. Compounds and are simple salts of ammonium and sodium 5-methyltetrazolate. Compound has a 3-D framework with intersecting channel and unprecedented (4(9).6(6)) topology constructed from mixed-valent Cu8 clusters. Compounds and are isomorphous, and have 3-D organic-inorganic frameworks constructed by [M2(mtta)]+ (Hmtta = 5-methyltetrazole) ribbon and [M2(N3)]+ (M = Cu, Ag) layer two types of structural motifs, which contains an mu(4)-1,1,1,3 azide. Compound is a 3-D four-connected chiral complex with (4(2).8(4))(Cu)(4(2).8(2).10(2))(tta) topology. The structure of consists of 2-D three-connected layers that are linked by ligand-unsupported Ag(I)...Ag(I) interactions to form a 3-D supramolecular array. Compound shows a 3-D chiral framework containing tetrahedrally and linearly coordinated Ag(I) ions and mu3- and mu4-two types of 5-propyltetrazolate. Compound has a 2-D layered structure formed by linkage of [Ag(tetrazolyl)] ribbons via C-C and N-Ag bonds. Magnetic measurement confirmed that there are two Cu(II) ions and six Cu(I) ions per Cu8 unit consistent with a mixed-valent Cu(I,II) complex.

Synthesis, structures, and photoluminescent properties of two ligand unsupported silver(i) coordination polymers from isonicotinate anions

Assembly of isonicotinate acid (HL) and Ag(I) by a layer-separating diffusion method at ambient temperature gave rise to two novel structural coordination polymers with ligand unsupported Ag⋯Ag interactions, namely, [(Ag4L4)·H2O·0.5CH3OH]n (1) and [(Ag3L2)NO3]n (2). Compound 1 is the first example of double-layer architecture and features an alternative stacking mode with Ag⋯Ag interactions, π–π interactions and Ag⋯O interactions. The synthesis of compound 2 offered us an opportunity to study the role of counteranions in Ag⋯Ag interactions. Both compounds display intense room temperature photoluminescence in the solid state.

Syntheses and characterizations of a series of silver-carboxylate polymers

Self-assembly reaction of H3btc (1,3,5-benzenetricarboxylic acid), H2ta (1,4-benzenedicarboxylic acid) or 1,2,4,5-benzenetetracarboxylic dianhydride with Ag(NO3) in mixed H2O/MeOH solution at room temperature gave rise to four novel 3D polymeric silver(I) complexes, [{Ag(H2btc)}{Ag2(Hbtc)}]n (1), [Ag(ta)1/2]n (2), [Ag2(btec)1/2]n (3) and [{Ag3(btec)3/4}{Ag(H2O)2(btec)1/4}]n (4) (H4btec=1,2,4,5-benzenetetracarboxylic acid). Complex 1 crystallizes in orthorhombic space group Fddd, with a=14.877(5), b=25.926(1), c=36.377(7) Å, Z=32. Complex 2 crystallizes in monoclinic space group P21/c, with a=7.257(6), b=8.949(8), c=6.346(5) Å, β=111.654(3)°, Z=4. Complex 3 crystallizes in orthorhombic space group P21/c, with a=8.333(8), b=6.335(5), c=10.964(9) Å, Z=4, whereas complex 4 crystallizes in triclinic space group P1̄, with a=7.509(1), b=9.351(1), c=10.307(7) Å, α=69.514(2), β=84.521(2), γ=83.638(2)°, Z=2. All compounds possess 3D framework and short Ag–Ag contacts are present in 1–4. In 1, the ligand unsupported Ag–Ag interactions play an important role in the formation of the complex, which is constructed by silver chains formed by Ag–Ag interactions and carboxylate spacers.

Syntheses, Crystal Structures, and Cytotoxicity Evaluation of two Chain‐like and Diamond‐like Silver(I) Complexes

AbstractTwo coordination polymers [Ag(dach)]n(NO3)n (1) and [Ag(teda)(F3CSO3)]n (2) (dach = 1, 2‐diaminocyclohexane, teda = 1, 4‐diazabicyclo[2.2.2]octane) have been synthesized and characterized by X‐ray single crystal analysis and cytotoxicity investigation. Compound 1 has a one‐dimensional chain‐like structure which is extended by ligand unsupported Ag···Ag interactions, hydrophobic interaction and hydrogen bonds into a three‐dimensional supramolecular array while compound 2 shows three‐dimensional diamond‐like framework constructed by coordination bonds. The high cytotoxities of these two compounds imply that they are potential candidates for antitumor agents.