A novel two-dimensional silver(I) saccharinato coordination polymer constructed from weak Ag?C interactions: Synthesis, IR spectra and X-ray structure

A new dinuclear silver(I)-saccharinato (sac) complex with acetonitrile (MeCN), [Ag₂(sac)₂(MeCN)₂]_n has been synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The silver(I) ions are doubly bridged by two sac ligands, leading to a short argentophilic contact of 2.9074(3) Å. Each silver(I) ion exhibits a square-planar coordination geometry including the Ag-Ag bonds. The individual dimeric molecules are extended into a two-dimensional layered structure by weak Ag?C_sac (η²) interactions of ca. 3.2 Å. These interactions were discussed and compared with those found in the first silver(I)-sac complex [Ag(sac)]_n.     

The role of Ag···O and Ag···Ag interactions in silver(I) supramolecular frameworks constructed from benzene multicarboxylate and nitrogen ligands

Using a hydrothermal synthesis method, two Ag(I) coordination polymers, {[Ag₂(bbbm)₂]·(Hbtc)} _n (1) and {[Ag₂(mbim)₂(Hsip)]·H₂O} _n (2) (bbbm = N,N’-(1,4-butanediyl)bis-(benzimidazole), mbim = N,N′-(1,1-methyl)-bis-(imidazole), H₃btc = 1,3,5-benzenetricarboxylic acid, H₃sip = 5-sulfoisophthalic acid) were synthesized and characterized by physicochemical and spectroscopic methods and single crystal diffraction. The complex 1 features a 2D supramolecular network formed by left- and right-handed cationic [Ag(bbbm)] _n helical chains and Hbtc ligands with the link of Ag···O interactions, displaying an unusual trinodal (3,3,4)-connected 3,3,4L12 topology net. The complex 2 has a left-handed and a symmetric right-handed double-stranded [Ag₂(mbim)₂(Hsip)] _n helical chains. The adjacent [Ag₂(mbim)₂(Hsip)] _n helical chains are further linked by Hsip ligands through the combination of weak Ag···O coordinative interactions and ligand-supported Ag···Ag interactions to generate a 3D supramolecular framework, exhibiting a new type of topology of a trinodal (4,5,5)-connected net. The solid-state fluorescence properties of the compounds 1 and 2 were investigated.     

2,4′-Bipyridyl complexes with silver(I) and copper(II)

Summary Ag^I and Cu^II complexes with 2,4-bipyridyl (2,4-bipy or L) with the general formulae AgL₂X (where X = NO _inf3 ^sup– or ClO₄ ^-), CuL₂X₂·2H₂O (X = Cl^- or Br^-), CuL₄SO₄·4H₂O, CuL₄(NO₃)₂·2H₂O and CuL₄(ClO₄)₂·H₂O have been isolated pure and characterized by analytical, spectral and magnetic measurements. The thermal decomposition of these complexes was studied under non-isothermal conditions in air.     

Novel silver(I)-saccharinate complexes exhibiting Ag···π and C-H···Ag close interactions with a new coordination mode of saccharinate

Two novel silver(I) complexes, namely [Ag₂(μ₃-sac)₂(μ-nmpen)]_n (1) and [Ag(sac)(mpr)]₂ (2) (sac = saccharinate; nmpen = N-methyl-1,3-propanediamine; mpr = 2-methyl-1-pyrroline) have been synthesized and characterized by IR spectra, thermal (TG, DTG and DTA) analysis and single crystal X-ray diffraction techniques. Complexes crystallize in the monoclinic system with the space group C2/c and P2₁/c, respectively. In 1, Ag(I) ion exhibits a distorted tetrahedral geometry by tridentate μ₃-bridging sac and μ₂-bridging nmpen ligands. The sac ligand exhibits a new μ₃-coordination mode by means of μ₂-bridging O atom of sulfonyl group and N atom of imino group. Furthermore, complex 1 exhibits a two-dimensional polynuclear structure. In 2, the silver(I) ion is linearly coordinated by the N atoms of a sac and a mpr ligands, forming mononuclear species. The individual molecules are linked into dimers by Ag···C_sac (η¹) interactions between silver(I) ion and phenyl ring of the adjacent complex and these dimers are assembled into two-dimensional layered networks through weak Ag···Ag (3.507 Å), SO···Ag (2.961 Å) and π···π interactions. The most interesting structural features of complexes is the presence of obvious C-H···M hydrogen-bonding interactions between the Ag centers and H atoms of nmpen or mpr ligands.     

Crystal structures of two new dinuclear Ag(I) complexes constructed from 4,4′-biphenyldicarboxylic acid and N-containing ligands

The reaction of silver 4,4′-biphenyldicarboxylate with 1,3-diaminopropane (DAP) and 2-amino-5-methylpyridine (AMP) respectively results in the formation of two dinuclear silver(I) complexes: [Ag₂(DAP)₂](BPC)·2H₂O (1) and [Ag₂(BPC)(AMP)₄]·2H₂O (2), where BPC is 4,4′-biphenyldicarboxylate. The complexes are characterized by elemental analysis and X-ray crystallography. Complex 1 crystallizes in the triclinic system, P-1 space group, a = 8.585(2) Å, b = 8.849(2) Å, c = 9.890(3) Å, α = 107.893(3)°, β = 94.139(3)°, γ = 113.202(3)°, V = 640.9(3) ų, Z = 1. Complex 2 crystallizes in the triclinic system, P-1 space group, a = 11.818(3) Å, b = 13.132(4) Å, c = 13.281(4) Å, α = 92.571(4)°, β = 96.425(3)°, γ = 102.142(4)°, V = 1997.5(10) ų, Z = 2. Complex 1 consists of a macrocyclic dinuclear silver(I) dication, a 4,4′-biphenyldicarboxylate anion, and two water molecules of crystallization. Each Ag atom is in a linear coordination. Complex 2 consists of a dinuclear silver(I) complex molecule and two water molecules of crystallization. Each Ag atom is in a T-shaped coordination. The Ag...Ag separations are 5.127(2) Å in 1 and 3.172(2) Å in 2.     

New mercury(II) and silver(I) complexes containing NHC metallacrown ethers with the π-π stacking interactions

The oligoether-linked bis-benzimidazolium salt 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-^secbutyl)benzimidazolium-1-yl]iodide (H₂L¹ · I₂), 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-ethyl)benzimidazolium-1-yl]iodide (H₂L² · I₂) and 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-^secbutyl)benzimidazolium-1-yl]hexafluorophosphate (H₂L¹ · (PF₆)₂) and their three new mercury(II) and silver(I) complexes containing NHC metallacrown ethers, HgL¹ · (Hg₂ · I₆) (1), HgL² · I₂ (2) and AgL¹ · PF₆ (3) were prepared and characterized. In the packing diagrams of H₂L² · I₂, 1, 2 and 3 benzimidazole ring head-to-tail π-π stacking interactions are observed.     

Coordination polymers from kinetically labile copper(I) and silver(I) complexes: true macromolecules or solution aggregates?

Copper(I) and silver(I) coordination polymers have been prepared via conversion of equimolar amounts of o‐phenanthroline‐based bis‐bidentate ligand monomers, and [Cu(CH₃CN)₄]PF₆ or AgBF₄ as the respective metal comonomers. Using NMR spectroscopy, the homogeneous constitution of the diamagnetic products has been proved, and their average chain length has been estimated to be P_n ≥ 20. Moreover, NMR studies showed the multinuclear complexes to be open (dynamic) solution aggregates when dissolved in solvents that contain coordinating species like acetonitrile or pyridine. When strictly non‐coordinating solvents are used, on the other hand, the multinuclear complexes were found to be “true” polymers, i.e. macromolecules with a constant number of repeating units per individual chain in time. At very high dilution, finally, transformation of the originally formed chain molecules into cyclic oligomers was observed when coordinating solvents are used, but not in the case of non‐coordinating solvents.     

Review: Multimetallic silver(I)–pyridinyl complexes: coordination of silver(I) and luminescence

This review highlights some structural features and luminescent properties of homo- and hetero-multinuclear silver(I)–pyridinyl complexes. It focuses on the coordination and geometry of the silver(I) ions to the pyridinyl-nitrogen. For this reason, we have considered only pyridinyl-N–Ag(I) complexes whose crystal data are available. In addition, this review does not consider mononuclear silver(I)–pyridinyl complexes as these have been reviewed elsewhere. This is motivated by the fact that multinuclear silver(I)–pyridinyl complexes have been shown to be more stable in solution, possess enhanced properties, and have fascinating structures compared to their mononuclear counterparts. The introduction highlights pyridinyl ligands used in complexation of silver(I) ions. The main body highlights complexation of silver(I) through pyridinyl nitrogen and the interactions found in the multinuclear silver(I)–pyridinyl complexes as well as the coordination number and geometry of silver(I) centers. Though silver(I) has been flaunted to prefer linear twofold coordination geometry, from this review, it is clear that higher coordination numbers in varied geometries are possible. These include distorted trigonal planar, T-shaped, distorted tetrahedral, trigonal bipyramidal, and octahedral geometries. Coordination of silver(I) to pyridinyl ligands and their metalloligands has been observed to impart or enhance luminescent properties in the ensuing complexes.     

New N-heterocyclic carbene silver(I) and mercury(II) 2-D supramolecular layers by the π-π stacking interactions

The precursor 1-(9-anthracenylmethyl)-3-alkylbenzimidazolium chlorides (1a, alkyl = C₄H₉, 1b, alkyl = C₆H₁₃) and their three new NHC silver(I) and mercury(II) complexes {[1-(9-anthracylmethyl)-3-alkylbimy]MCl}₂ (2a, alkyl = C₄H₉, M = Ag; 2b, alkyl = C₆H₁₃, M = Ag; 3a, alkyl = C₄H₉, M = Hg; bimy = benzimidazol-2-ylidene) have been prepared and characterized. The crystal structures of 2a, 2b and 3a showed that 2-D supramolecular layers are formed by both benzimidazole ring head to tail π-π stacking interactions and anthracene ring face-to-face π-π stacking interactions.     

Metal complexes as ligands—VI: Bonding interactions of anionic nickel dithiolate complexes with the coordinately unsaturated bis(triphenylphosphine)copper(I) and bis(triphenylphosphine)silver(I) complex cations

The inert cations that accompany the anionic dithiolato complexes, Ni(L)₂²⁻(L = S₂C₂(CN)₂, S₂C:C(CN)₂, S₂C:NCN, S₂C:C(COOCH₃)₂, S₂C:C(COOC₂H₅)₂, and S₂C:N(C₆H₅) are readily replaced by the coordinately unsaturated M′(P(C₆H₅)₃)₂⁺ (M′ = Ag(I), Cu(I)) complex cations. The i.r. spectra of the crystalline polynuclear complexes Ni(L)₂[(P(C₆H₅)₃)_nM′]₂ (n = 2 or 3) thus obtained indicate that the anion-cation interactions occur primarily through the mercapto groups. In the Ni(S₂C:N(C₆H₅))₂[P(C₆H₅)₃)₃Cu]₂ complex the copper is coordinated to the carbimate nitrogen of the ligand. Interactions of Cu(P(C₆H₅)₃)₂⁺ with the Ni(S₂C₂(CN)₂)₂ ⁻² and Ni(S₂C:C(CN)₂)₂²⁻ complexes appear to occur with the π-system of the nitrile groups of the complex ligands. Dinuclear complexes of the composition [M′(P(C₆H₅)₃)₂]₂L also were obtained and their structures and properties are discussed.     

1D and 2D supramolecular structures of silver carborane dicyclohexylphosphine complexes constructed by C-H?H-B dihydrogen bonding interactions

Five new carborane dicyclohexylphosphine complexes, [Ag₂(μ-I)₂{1,2-(P Cy₂)₂-1,2-C₂B₁₀H₁₀}₂] (1), [Ag₂(SCN)₂{1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}₂]_n·CH₂Cl₂ (2), [Ag(ClO₄){1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}]·CH₂Cl₂ (3), [Ag₂(μ-NO₃)₂{1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}₂]·CH₂Cl₂ (4) and [Ag(SC₆H₄COOH){1,2-(PCy₂)₂-1,2-C₂B₁₀H₁₀}₂]·CH₂Cl₂ (5), have been synthesized by the reactions of 1,2-bis(dicyclohexylphosphino)-1,2-dicarba-closo-dodecaborane with AgX (X = I, SCN, ClO_4, NO₃ and SC₆H₄COOH) in CH₂Cl₂. The structures of the five complexes were characterized by elemental analysis, FT-IR, ¹H, ¹³C, ¹¹B and ³¹P NMR spectroscopy. X-ray structure analysis revealed that the structures of the complexes can be classified into three types. Complexes 1 and 4 are di-μ-X-bridged structures and complexes 3 and 5 are mononuclear structures, while complex 2 is a chain-like polymer. Complexes 1 and 2 form 2D supramolecular networks and complexes 3, 4 and 5 form 1D chains via C-H?H-B dihydrogen bonding interactions.     

Synthesis,structure, luminescence and electrochemical and antioxidant properties of anion-controlled silver(I) complexes with 2,2′-(1,4-butanediyl)bis-1,3-benzoxazole

To explore the influence of various anions on the self-assembly and properties of silver complexes, reactions of anions of silver salts with 2,2′-(1,4-butanediyl)bis-1,3-benzoxazole (BBO) afforded four complexes, formulated as [Ag₂(BBO)₂(p-toluenesulfonate)₂] ( 1 ), {[Ag(BBO)(picrate)]}_∞ ( 2 ), {[Ag(BBO)_1/2(o-coumarate)]·DMF}_∞ ( 3 ) and {[Ag₂(BBO)₃](PF₆)₂}_∞ ( 4 ). These complexes were characterized using elemental analysis, infrared spectroscopy and single-crystal X-ray diffraction. The crystal analysis results show that under the influence of coordination modes and steric hindrance of anions, the complexes exhibited binuclear ( 1 ), one-dimensional polymeric ( 2 and 3 ) and two-dimensional polymeric ( 4 ) structures. Compared with the BBO ligand, only complex 1 has a new emission peak at 428 nm, which is attributed to ligand–metal charge transfer. The emission peaks of complexes 2 – 4 are similar to those of the BBO ligand, which can be due to π–π* and n–π* transitions. These results indicate that anions can modulate the structures and luminescent properties of silver complexes. Moreover, cyclic voltammograms of 1 – 4 indicated an irreversible Ag⁺/Ag couple with the order of reversibility being 2 > 1 > 4 > 3 . In vitro antioxidant experiments showed that complex 3 has significant antioxidant activity against superoxide and hydroxyl radicals.     

π-Complexes of some cyclic allenes with silver(I) and copper(I)

The cyclic allenes, 1,2,6-cyclononatriene, 1,2,6-cyclodecatriene and 1,2,6,-cyclodecatetraene form well-defined crystalline π-complexes with silver(I) nitrate and copper(I) chloride. The IR spectra of these complexes show two new bands between 1650 and 1900 cm⁻¹ in place of the single allenic band around 1950 cm⁻¹ present in the non-coordinated allenes.     

Spectroscopic and structural properties of complexes of 3,3′-bis(2-benzimidazolyl)-2,2′-bipyridine with copper(I) and silver(I)

The pseudo-tetrahedral complexes [CuL₂]PF₆·7H₂O·CH₃OH (1) and [AgL₂]CF₃SO₃·H₂O (2) (L?=?3,3′-bis(2-benzimidazolyl)-2,2′-bipyridine) have been synthesized and characterized through crystal structure analyses, electrochemistry, and spectroscopic methods. X-ray structural analyses of 1 and 2 indicate that sterically constrained N₄ ligands L are cis and behave as bidentate chelates to a single metal ion in a pseudo-tetrahedral fashion through the benzimidazole. As two benzimidazolyl rings exhibit considerable steric hindrance, the bipyridine unit of L remains uncoordinated. The pseudo-tetrahedral cation [CuL₂]⁺ shows a quasi-reversible Cu^I/Cu^II oxidation–reduction wave in the CV in DMF (counter-ion PF₆^?). The fluorescence titration of L with copper(I), silver(I), and also with pH have been conducted to examine the selectivity. The ligand shows remarkably high selectivity and sensitivity for Ag(I).     

Copper (I) and silver (I) complexes of dithiomalonamide,NN′-dimethyl- and NN′-diphenyl-dithiomalonamide.

Some copper (I) and silver (I) complexes with dithiomalonamide (Hdtma), NN′-dimethyl-(HMe₂dtma) and NN′-diphenyl-dithiomalonamide (HPh₂dtma) were prepared: Cu(Hdtma)X (X² = Cl, Br, I(H₂O), ClO₄); Cu(HL)₂X (HMe₂dtma: X = Cl, Br, I, ClO₄; HPh₂dtma: X = Cl, Br, I); Ag(HL)X (Hdtma: X = Cl; HMe₂dtma: X = Br, ClO₄, BF₄; HPh₂dtma: X = Br, I); Ag₂(HL)₃X₂ (Hdtma: X = ClO₄, BF₄; HMe₂dtma: X = Cl; HPh₂-dtma: X = Cl, ClO₄); Ag₂(HMe₂dtma)I₂ and Ag₃(Hdtma)₂Br₃. Molar conductivities in DMF show that the complexes behave: M₂(HL)₃(ClO₄)₂ as 1:2 electrolytes, M(HL) (ClO₄ of BF₄) as 1:1 electrolytes; those of the halides Cu(HL)X and Cu(HL)₂X, are almost equal and intermediate between values for non-electrolytes and 1:1 electrolites. Infrared spectra indicate an S,N-coordination for all the complexes: ν(MN) bands in the region of 400–500 cm⁻¹ and ν(MS) bands in the region of 300–400 cm⁻¹ (for Hdtma), 300–320 cm⁻¹ (for HMe₂dtma) and 260–280 cm⁻¹ (for HPh₂dtma) are observed. No ν(MX) bands were identified in the halide complexes indicating that a mental—halide coordination, if present in the solid complexes, should be very weak.     

Higher oxidation states of silver—II reaction of ozone with silver (I) complexes in non-aqueous solvents

The ozonization of bis(orthophenanthroline)-silver(I) nitrate has been investigated in thirteen non-aqueous solvents both with and without the addition of several Lewis acids. The solvents included (1) dimethylsulphoxide, (2) dimethylformamide, (3) chloroform, (4) carbon tetrachloride, (5) benzene, (6) acetonitrile, (7) n-heptane, (8) ethyl acetate, (9) tetrahydrofuran, (10) acetic anhydride, (11) glacial acetic acid, (12) nitromethane, (13) nitroethane. The Lewis acids included anhydrous aluminium chloride, anhydrous iron(III) chloride, boron trifluoride and silver(I) ion. The oxidation of the silver(I) complex to the silver(II) complex occurred only in the protonic acid solvents, (11), (12) and (13), but the silver(II) complex could be isolated only from acetic acid. Mechanisms of ozonization are proposed which involve the enhancement of the electrophilic character of the ozone molecule by the proton of the particular solvent.     

Macrocyclic polythiaethers as solvent extraction reagents—IV Ag(I) and Hg(II) complexes with 1,4,7,10,13,16-hexathiacyclooctadecane

Complex formation by Ag(I) and Hg(II) with the macrocyclic polythiaether 1,4,7,10,13,16-hexathiacyclooctadecane (HTO) has been studied. Complexes corresponding to the general formulae [AgClO₄]_n·HTO (n = 1, 2, 3, respectively), [AgBF₄]₂·HTO, HgCl₂·HTO, [HgCl₂]₂·HTO, Hg(ClO₄)₂·HTO, Hg(BF₄)₂·HTO, and [Hg(CH₃COO)₂]₂·HTO have been isolated and characterized. According to conductivity data, the Hg(II) chlorides, acetate, and fluoroborate complexes are nonelectrolytes. The complex AgClO₄·HTO, [AgBF₄]₂·HTO, and [AgClO₄]₂·HTO are 1:1 electrolytes in nitrobenzene. IR spectra indicate the ionic character of the bonding in the mercury and silver perchlorate complexes. Solvent extraction of the metals from aqueous chloride and perchlorate solutions has been investigated.