3D coordination networks based on supramolecular chains as building units: synthesis and crystal structures of two silver(I) pyridyldiethynides

Two silver(I) pyridyldiethynides, [Ag2(3,5-C2PyC2).4CF3CO2Ag.4H2O] ( A) and [Ag 2(3,5-C2PyC2).3AgNO3.H2O](B), were synthesized by reactions of 3,5-diethynylpyridine with silver trifluoroacetate and silver nitrate in high yield, respectively. X-ray crystallographic studies revealed that in A pyridyldiethynide groups connect Ag 11 cluster units to generate 1D supramolecular chains as bridging ligands, where each ethynide group interacts with four silver atoms. These supramolecular chains bearing pyridyl groups are linked by silver ions to form wavelike layers, which are further connected by trifluoroacetate ligands to afford a 3D coordination network. However, B exhibits a different structural feature, where two ethynide groups in one pyridyldiethynide ligand coordinate to three and four silver atoms, respectively. These silver ethynide cluster units are linked through silver-ethynide and argentophilic interactions, leading to a double silver chain by sharing silver atoms in these units. In B, the silver double chains are further connected by bridging pyridyldiethynide groups to generate 2D networks, which interact through the Ag-N coordination bonds between silver atoms and pyridyl groups in the adjacent layers to generate a 3D coordination network. In these two compounds, trifluoroacetate and nitrate groups exhibit different bonding modes, indicating that the counterion is an important factor influencing the structures of supramolecular chains and coordination networks.     

Metal-assisted assembly of pyridine-containing arylene ethynylene strands to enantiopure double helicates

Pyridine-containing arylene ethynylene strands were connected to the 2- and 2'-positions of (R)- and (S)-1,1'-binaphthyl templates. The arylene ethynylene moieties underwent intramolecular coordination with Ag(I) or Cu(I) ion to afford enantiopure double helicates. The double-helical structure was elucidated on the basis of circular dichroic (CD) spectra. The importance of intramolecular complexation of the double strands for the helicate formation was confirmed by comparison with a ligand bearing a single strand. Connection of the strands through an ether linkage enabled a sorting out of the Cotton effect induced by double-helical arylene ethynylene moieties. The CD exciton chirality method unambiguously proved that the termini of the strands approach each other upon complexation and that the sense of the induced helicity is the same as predicted by molecular modeling.     

Synthesis,Characterization, and Photoluminescence Properties of Silver(I) Metal‐Organic Polymers with Nanochannels Based on 2‐Sulfoterephthalic Acid and Di(pyridin‐2‐yl)amine Ligands

Two new silver(I) 3D coordination polymers, namely [Ag₃(2‐stp)(dpa)]_n ( 1 ) and {[Ag₂(2‐stp)(H₂O)]?Hdpa}_n ( 2 ) (2‐NaH₂stp=sodium 2,5‐dicarboxysulfonate, dpa=di(pyridine‐2‐yl)amine) were synthesized. The complexes were characterized by elemental analysis, FT‐IR spectra, thermogravimetric analyses (TGA), and single‐crystal X‐ray diffraction. In complex 1 , three neighboring Ag ions are bridged by N‐ and O‐atom, forming a 3D coordination network. The molecular structure of 2 is cation? anion species, forming 3D host? guest supramolecular network with the [Hdpa]⁺ cations encapsulated in the nanochannels. The photoluminescence properties of the complexes were also investigated in the solid state at room temperature.     

Coordination chemistry of the solvated AgI and AuI ions in liquid and aqueous ammonia, trialkyl and triphenyl phosphite, and tri-n-butylphosphine solutions

The coordination chemistry of solvated Ag(I) and Au(I) ions has been studied in some of the most strong electron-pair donor solvents, liquid and aqueous ammonia, and the P donor solvents triethyl, tri-n-butyl, and triphenyl phosphite and tri-n-butylphosphine. The solvated Ag(I) ions have been characterized in solution by means of extended X-ray absorption fine structure (EXAFS), Raman, and (107)Ag NMR spectroscopy and the solid solvates by means of thermogravimetry and EXAFS and Raman spectroscopy. The Ag(I) ion is two- and three-coordinated in aqueous and liquid ammonia solutions with mean Ag-N bond distances of 2.15(1) and 2.26(1) A, respectively. The crystal structure of [Ag(NH3)3]ClO4.0.47 NH3 (1) reveals a regular trigonal-coplanar coordination around the Ag(I) ion with Ag-N bond distances of 2.263(6) A and a Ag...Ag distance of 3.278(2) A separating the complexes. The decomposition products of 1 have been analyzed, and one of them, [Ag(NH3)2]ClO4, has been structurally characterized by means of EXAFS, showing [Ag(NH3)2] units connected into chains by double O bridges from perchlorate ions; the Ag...Ag distance is 3.01(1) A. The linear bisamminegold(I) complex, [Au(NH3)2]+, is predominant in both liquid and aqueous ammonia solutions, as well as in solid [Au(NH3)2]BF4, with Au-N bond distances of 2.022(5), 2.025(5), and 2.026(7) A, respectively. The solvated Ag(I) ions are three-coordinated, most probably in triangular fashion, in the P donor solvents with mean Ag-P bond distances of 2.48-2.53 A. The Au(I) ions are three-coordinated in triethyl phosphite and tri-n-butylphosphine solutions with mean Au-P bond distances of 2.37(1) and 2.40(1) A, respectively.     

Synthesis,Structures, and Properties of Two Novel Supramolecular Architectures Constructed from [2,3‐f]Pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic Acid

Two new compounds, [Ag(Hppdb)]_n ( 1 ) and {[Ag₂(Hppdb)₂(bpe)] · 5.5H₂O}_n( 2 ) [H₂ppdb = [2,3‐f]pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic acid, bpe = trans‐1,2‐bis(4‐pyridyl)ethylene], were synthesized and characterized. In 1 , Hppdb^– ions link Ag^I cations to form an infinite 1D [–Ag–(Hppdb)–Ag–]_n chain, furthermore, the dimensionality is extended to 2D layers through synergistic π–π stacking, hydrogen‐bonding and weak Ag ··· O interactions. Correspondingly, the dimeric [(Ag)(Hppdb)]₂ subunits in 2 are connected by bpe ligands to generate a loop‐link‐shaped 1D chain motif, which is further joined through a R₂²(18)C–H ··· O hydrogen‐bonding ring to afford interesting diagonal/diagonal inclined catenation 2D + 2D → 3D supramolecular architectures. In addition, solid‐state properties such as photoluminescence and thermal stability of the two compounds were studied.     

Synthesis and fluorescence ion-sensory properties of the first dehydropyridoannulene-type cyclophane with enforced exotopic metal ion binding sites

The new twistophane 4 has been synthesised, which comprises a conjugated dehydropyridoannulene-type macrocyclic scaffold with outwardly projecting nitrogen-donor sites for the purpose of metal ion coordination. The macrocyclíc structure of 4 was assigned by using spectroscopic methods, and shown to exist in a twisted and chiral ground state conformation by semi-empirical theoretical calculations. A detailed spectroscopic investigation into the metal ion binding properties of 4 and precursor 11 revealed that they functioned as selective complexants, affording a fluorescence quenching output response characteristic of Pd(II) and Hg(II) ions. Furthermore, 4 also signalled the presence of Fe(II), Co(II), Ni(II) and Ag(I) ions by the precipitation of coordination polymers, and exhibited reversible proton-triggered fluorescence quenching behaviour. Macrocycle 4 thus represents a unique type of molecular sensory platform, which may find a wealth of potential applications such as the detection of heavy-metal pollutants, as well as for the fabrication of proton-switchable materials and coordination polymers with novel electronic and magnetic properties.     

Anion Effects on the Formation of Silver(I) Complexes with the Flexible Ligand 4,4′‐Bis(1,2,4‐triazol‐1‐ylmethyl)biphenyl

The reaction of 4,4′‐bis(1,2,4‐triazol‐1‐ylmethyl)biphenyl (btmb) with silver(I) salts of BF₄^–, NO₃^– and N₃^– led to the formation of four new silver(I) coordination polymers {[Ag(btmb)]BF₄}_n ( 1 ), {[Ag₂(btmb)₃](NO₃)₂(H₂O)₅}_n ( 2 ), [Ag₂(btmb)(N₃)₂]_n ( 3 ), and [Ag(btmb)(N₃)]_n ( 4 ). Their coordination number varies from 2 (in 1 ) to 3 (in 2 ), 4 (in 3 ), and 5 (in 4 ). Different from the single chain structure of 1 , complex 2 displays a 1D ladder‐like double chain framework, whereas complex 3 exhibits a 2D layered architecture. Complex 4 has the same anion as complex 3 but shows a different metal‐to‐ligand ratio and a 1D double‐zigzag chain structure. Both 3 and 4 have Ag ··· Ag argentophilic interactions. The ligand btmb adopts both cis or trans configuration in the studied complexes. A trans‐ or cis‐btmb ligand link silver ions with Ag ··· Ag distances of ≈?18 and 13 Å, respectively. BF₄^– and NO₃^– are non‐coordinating anions in 1 and 2 . N₃^– is the bridging anion in 3 (1,3‐bridging fashion) and 4 (1,1‐bridging fashion). These findings suggest that the coordination numbers around the Ag^I ion correlate to the coordination abilities of anions and the btmb to silver ratio. In addition, the influence of anions on thermal stability were also investigated. This work is a good example that nicely supports the less explored field of anion‐dependent structures of complexes with non‐pyridyl ligands.     

A triple helix of double helicates: three hierarchical levels of self-assembly in a single structure

The bis-bidentate bridging ligand L reacts with Ag(I) ions to form a conventional dinuclear [Ag(2)L(2)](2+) double helicate; individual double helicate units assemble via Ag···Ag interactions into infinite chains, three of which wrap around a central spine of anions to give a triple helical braid, which is therefore an infinite triple helix composed of molecular double helicate subunits.     

Distinct Chain/Layer Structures in Silver(I) Compounds: Synthesis,Structures, and Photoluminescent Properties

Two new hybrid inorganic‐organic compounds with different chain/layer structures, [Ag(bipy)]_n · n(Hdpa) · n(DMF) · n(H₂O) ( 1 ) and [Ag(dpa)_0.5(bix)_0.5]_n ( 2 ) [H₂dpa = diphenic acid, bipy = 4, 4′‐bipyridine, bix = 4, 4′‐bis(imidazol‐1‐ylmethyl)benzene, DMF = N,N′‐dimethylformamide] were successfully synthesized and characterized by elemental analysis, IR spectroscopy, and powder X‐ray diffraction. Single X‐ray analysis reveals that compound 1 is a one‐dimensional (1D) supramolecular double chain structure constructed by the combination of coordination bonds, hydrogen bonds, weak Ag ··· O and argentophilic interactions, compound 2 is a two‐dimensional (2D) undulated layer structure constructed by coordination bonds, weak Ag ··· O and argentophilic interactions. Moreover, the photoluminescent properties of the two compounds were also investigated in the solid state at room temperature.     

π‐Electron‐System‐Layered Polymer: Through‐Space Conjugation and Properties as a Single Molecular Wire

[2.2]Paracyclophane‐based through‐space conjugated oligomers and polymers were prepared, in which poly(p‐arylene–ethynylene) (PAE) units were partially π‐stacked and layered, and their properties in the ground state and excited state were investigated in detail. Electronic interactions among PAE units were effective through at least ten units in the ground state. Photoexcited energy transfer occurred from the stacked PAE units to the end‐capping PAE moieties. The electrical conductivity of the polymers was estimated using the flash‐photolysis time‐resolved microwave conductivity (FP‐TRMC) method and investigated together with time‐dependent density functional theory (TD‐DFT) calculations, showing that intramolecular charge carrier mobility through the stacked PAE units was a few tens of percentage larger than through the twisted PAE units.     

catena‐Poly[[disilver(I)(Ag—Ag)‐bis[μ‐1,1′‐(butane‐1,4‐diyl)diimidazole‐κ2N3:N3′]] bis(perchlorate)]: a double helix stabilized by ligand‐unsupported argentophilic interactions

The title compound, {[Ag₂(C₁₀H₁₄N₄)₂](ClO₄)₂}_n, is a one‐dimensional coordination polymer formed by Ag^I atoms linearly bridged by 1,1′‐(butane‐1,4‐diyl)diimidazole molecules. The chains have a helical arrangement and pairs of chains are held together by the rarely reported ligand‐unsupported Ag—Ag interaction [2.966 (1) Å], which results in a double‐helix structure. The double helix contains twisted 24‐membered metallomacrocycles, which are composed of four Ag atoms and two ligands. The Ag atoms lie on twofold axes.     

Coordination networks through the dimensions: from discrete clusters to 1D, 2D, and 3D silver(I) coordination polymers with rigid aliphatic amino ligands

The use of a ligand directed strategy in the assembly of discrete clusters, 1D chains, 2D layers, and 3D networks using aliphatic N-donor ligands has been investigated. The ligands are a family of amines with rigid backbones [cis,cis-1,3,5-triaminocyclohexane (cis-tach), cis,trans-1,3,5-triaminocyclohexane (trans-tach), cis-1,3-diaminocyclohexane (cis-dach), and cis-3,5-diaminopiperidine (cis-dapi)], and their complexation with Ag(I) salts results in a diverse set of architectures with the following compositions: [Ag3(cis-tach)2]F3.4CH(3)OH.0.5H2O (1), [Ag3(cis-tach)2]F3.6H2O (2), ([Ag(cis-dach)]ClO4)n (3), ([Ag(cis-tach)]NO3)n (4), ([Ag(trans-tach)]PF6)n(5), and ([Ag(cis-dapi)]CF3SO3)n (6). Structural analysis shows that compounds 1 and 2 are discrete M(3)L(2) cage-type clusters with varying solvent molecule content. Short Ag...Ag contacts (3.021(8) A) are observed to dimerize discrete units in compound 2. Compound 3 is a 1D zigzag chain formed by coordination to the two primary amines of cis-dach, whereas the tridentate ligands in compounds 4 and 5 (cis-tach and trans-tach, respectively) are able to form tubular architectures by virtue of their ability to "wrap" round the channel walls. An infinite 2D coordination network is demonstrated by compound 6, in which the three coplanar amino donors of cis-dapi coordinate to the trigonal planar Ag(I) ions to form a layered structure of 6(3) topology. These are compared with a previously reported 3D structure, ([Ag(trans-tach)]NO3)n (7), that belongs to this family of architectures.     

Ag(I) coordination polymer with pyrazine sulfonic acid: synthesis,crystal structure,and fluorescence property

A one-dimensional rigid, linear Ag(I) coordination polymer with pyrazine sulfonic acid, [Ag₂L₂?·?H₂O] _n (L?=?pyrazine sulfonic acid) has been synthesized and characterized by elemental analyses, infrared spectroscopy, thermogravimetric analysis, and X-ray crystallography. The structure determination shows Ag(I) centers linked by bridging pyrazine ligands to give a double-chain structure sustained by weak Ag-O and Ag-N interactions. The sulfonate and pyrazine are all involved in hydrogen bonding interaction. The interactions combine with weak π-π stacking to play deciding roles defining the supramolecular structures. A powder X-ray diffraction study implies good phase purity. Solid-state fluorescence quenching and thermal stability are also discussed.     

Potential Applications of Cucurbit[n]urils and Their Derivatives in the Capture of Hazardous Chemicals

Cucurbit[n]urils (Q[n]s) are a relatively young family of macrocycles, consisting of glycoluril units bridged by methylene groups, and their unique structures have attracted extensive attention from chemists in recent decades. Due to the presence of a rigid hydrophobic inner cavity and two polar outer portals lined with carbonyl groups, Q[n]s not only encapsulate guest species into the cavity, but also coordinate with metal ions/clusters. Considerable achievements have been obtained in the fields of Q[n]s-based host–guest chemistry, coordination chemistry, as well as the combination of host–guest and coordination chemistry. Furthermore, the outer surface of Q[n]s has been demonstrated to be capable of interacting with definite species to generate supramolecular architectures in recent years. With more in-depth research into Q[n]s, their application studies have also emerged as a hot topic. This Minireview focuses on recent advances in the potential applications of solid-state materials based on Q[n]s and their derivatives for the capture and adsorption of hazardous chemicals from a solution or a gas mixture.     

Gas‐phase geometries and energies of bis(2,2′‐bipyridine) interacting either with Cu(I) or Ag(I): Computational study

With a polarized double‐zeta basis set, we carried out MP2 and density functional theory geometry optimization of bis(2,2′‐bipyridine) interacting either with Cu(I) or Ag(I). The computed gas‐phase geometries of both Cu and Ag complexes present tetrahedral distortions around the ions. However, geometry optimization on Cu or Ag ions complexing with ammonia molecules yield perfect tetrahedral coordination and interaction energies comparable to those of the bis(2,2′‐bipyridine) complexes. Solid‐state laboratory studies on complexes of the same metal ions with substituted bis(2,2′‐bipyridine) revealed tetrahedral distortions around the ions, even stronger than those computed in the gas phase. From our analysis of the potential interaction energies we conclude that the origin of the larger distortions in the solid state result from stacking interactions. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 395–404, 2003     

Pyrimidine-pyrimidine base pairs stabilized by silver(I) ions

In the presence of Ag(I) ions, the C-T and m(5)iC (5-methylisocytosine)-T base pairs showed comparable stability to the C-Ag(I)-C base pair, and the m(5)iC-C base pair was highly stabilized by the synergetic effect of Ag(I) coordination and possible hydrogen bonding.     

Syntheses and structures of M–Na (M=Zn,Mn) coordination polymers in which ligands and Na ions exhibit complex coordination modes

The novel heteronuclear complexes [Na₂Zn(dipic)₂(H₂O)] _n (1) and [Na₂Mn(dipic)₂(H₂O)₂] _n (2) (H₂dipic?=?pyridine-2,6-dicarboxylic acid) were synthesized and characterized by single-crystal X-ray diffraction, analysis, IR spectroscopy and thermogravimetric analysis. Complex 1 consists of infinite 2D double layers, which are further attached into a 3D network through π–π stacking. All sodium ions are 3-coordinate. Complex 2 has an intricate 3D structure, in which two sodium ions are differently involved in forming polymeric coordination units, and are 3- and 7-coordinate, respectively. Dipic anions act as multidentate ligands showing novel and unprecedented bridging coordination modes. One ligand coordinates to three metal ions and with five bonds; the other coordinates five metal ions with nine bonds.     

Complexes of Ag(I), Hg(I) and Hg(II) with multidentate pyrazolyl-pyridine ligands: From mononuclear complexes to coordination polymers via helicates, a mesocate, a cage and a catenate

The coordination chemistry of a series of di- and tri-nucleating ligands with Ag(I), Hg(I) and Hg(II) has been investigated. Most of the ligands contain two or three N,N'-bidentate chelating pyrazolyl-pyridine units pendant from a central aromatic spacer; one contains three binding sites (2 + 3 + 2-dentate) in a linear sequence. A series of thirteen complexes has been structurally characterised displaying a wide range of structural types. Bis-bidentate bridging ligands react with Ag(I) to give complexes in which Ag(I) is four-coordinate from two bidentate donors, but the complexes can take the form of one-dimensional coordination polymers, or dinuclear complexes (mesocate or helicate). A tris-bidentate triangular ligand forms a complicated two-dimensional coordination network with Ag(I) in which Ag...Ag contacts, as well as metal-ligand coordination bonds, play a significant role. Three dinuclear Hg(I) complexes were isolated which contain an {Hg2}2+ metal-metal bonded core bound to a single bis-bidentate ligand which can span both metal ions. Also characterised were a series of Hg(II) complexes comprising a simple mononuclear four-coordinate Hg(II) complex, a tetrahedral Hg(II)4 cage which incorporates a counter-ion in its central cavity, a trinuclear double helicate, and a trinuclear catenated structure in which two long ligands have spontaneously formed interlocked metallomacrocyclic rings thanks to cyclometallation of two of the Hg(II) centres.     

Syntheses,Structures, and Properties of Two Dicyanamide‐Bridged Polymers with a Schiff‐base Ligand

The dicyanamide‐bridged polymers with Schiff‐base ligand, [CoNaL(dca)]_n ( 1 ) and [Mn₂L(dca)₂]_n ( 2 ) [H₂L = bis(3‐methoxysalicylidene)benzene‐1,2‐diamine, dca = dicyanamide] were synthesized and characterized by elemental analyses, IR spectrroscopy and single‐crystal X‐ray diffraction. The solid‐state structures reveal that polymer 1 has double dca bridged loop‐like 1D chains, in which the heterodinuclear Co²⁺‐Na⁺ units (LCoNa) are bridged by dca with coordination mode μ_1,3,5. In polymer 2 , homodinuclear Mn²⁺‐Mn²⁺(LMnMn) units are linked by dca in μ_1,5‐bridging mode to form 2D planes. Magnetic susceptibility studies on 2 reveals antiferromagnetic coupling interactions between the adjacent Mn²⁺ ions in the LMnMn unit.     

Betaine-induced assembly of neutral infinite columns and chains of linked silver(I) polyhedra with embedded acetylenediide

Ten polymeric silver(I) double salts containing embedded acetylenediide: [(Ag2C2)2(AgCF3CO2)9(L1)3] (1), [(Ag2C2)2(AgCF3CO2)10(L2)3]H2O (2), [(Ag2C2)(AgCF3CO2)4(L3)(H2O)]0.75 H2O (3), [(Ag2C2)(1.5)(AgCF3CO2)7(L4)2] (4), [(Ag2C2)(AgCF3CO2)7(L5)2(H2O)] (5), [(Ag2C2) (AgC2F5CO2)7(L1)3(H2O)] (6), [(Ag2C2)(AgCF3CO2)7(L1)3(H2O)]2 H2O (7), [(Ag2C2)(AgC2F5CO2)6(L3)2] (8), [(Ag2C2)2(AgC2F5CO2)12(L4)2(H2O)4]H2O (9), and [(Ag2C2)(AgCF3CO2)6(L3)2(H2O)]H2O (10) have been isolated by varying the types of betaines, the perfluorocarboxylate ligands employed, and the reaction conditions. Single-crystal X-ray analysis has shown that 1-4 all have a columnar structure composed of fused silver(I) double cages, with C2(2-) species embedded in its stem and an exterior coat comprising anionic and zwitterionic carboxylates. For 5 and 6, single silver(I) cages are linked into a beaded chain through both types of carboxylate ligands. In 7, two different coordination modes of L1 connect the silver(I) polyhedra into a chain. For 8, the mu(2)-O,O' coordination mode of L3 connects the silver(I) double cages into a chain. Compound 9 exhibits a two-dimensional architecture generated from the cross-linkage of double cages by C2F5CO2-, L4, and [Ag2(C2F5CO2)2] units. Similar to 9, 10 is also a two-dimensional structure, which is formed by connecting the chains of linked double cages through [Ag2(CF3CO2)2] bridging.