Anion dependent self-assembly of "tetra-decker" and "triple-decker"luminescent Tb(III) salen complexes

The Schiff base complexes [Tb3L4(H2O)2]Cl and [Tb3L3(OAc)2Cl] both have unusual multi-decker architectures formed via intramolecular pi-pi interactions between phenylene units.     

Anion binding and luminescent sensing using cationic ruthenium(II) aminopyridine complexes

The synthesis of a series of ruthenium(II) based anion sensors of the type [Ru(eta(6)-C(6)H(4)MeCHMe(2))Cl(L)(2)][BF(4)] (2) is reported in which ligand L represents a series of substituted pyridinylmethyl-amine derivatives. The carbazole based ligand L(3) exhibits a fluorescent intraligand charge-transfer (ILCT) state that is quenched by ligand-to-metal charge transfer (LMCT) upon coordination to ruthenium in the 1:1 complex [Ru(eta(6)-C(6)H(4)MeCHMe(2))Cl(2)(L(3))] (1 c). The 1:2 complex 2 c is fluorescent, however, and acts as a fluorescent anion sensor because of the mixing of an anion-dependent charge-transfer component into the excited state. The 1:2 complexes of type 2 all exhibit interesting low symmetry (1)H NMR spectra that also are a useful handle on anion complexation. The electronic structures of L(3), 1 c and 2 c have been probed by time-dependent DFT calculations.     

Anion mediated structural motifs in silver(I) complexes with corannulene

The synthesis of three new silver(I) complexes with corannulene is reported. In the crystal these complexes form extended networks of Ag(+) ions, corannulene nuclei, and counterions, similar to the networks reported for Ag(+) with other polynuclear aromatic hydrocarbons (PAHs). The preferred Ag(+)-arene interaction is compared with the model developed by Kochi. The crystal motifs can be described by a classification scheme analogous to that developed by Etter for hydrogen-bonded networks in solids. The effect of counterion variation (ClO(4)(-), O(3)SCF(3)(-), BF(4)(-)) is noted to be substantial. Thus, although one can categorize the various networks, it is hard to predict an expected packing pattern on the basis of preferred binding in the metal/organic complex alone.     

Hydrothermal syntheses, crystal structures and luminescent properties of two novel silver (I) complexes with 5-methyl-2-pyrazinecarboxylate

The self-assembly of 5-methylpyrazine-2-carboxylate (Hmpca) with silver nitrate generated two coordination polymers [Ag₂(Hmpca)(mpca)(NO₃)] _n (1) and [Ag(mpca)] _n (2) in the presence of Er³⁺ or Mn²⁺ via hydrothermal synthesis. The complexes have been characterized by IR, elemental analyses and single-crystal X-ray diffraction. Complex 1 possesses a novel 1D looped-chain topology structure. Complex 2 shows an extended honeycomb-like 3D framework. The luminescent properties of complexes 1 and 2 were investigated.     

Synthesis of novel linear exo-bidentate bispyridine ligands and their complexes with silver(i) tetrafluoroborate

Novel exo-bidentate ligands containing two -pyridyl fragments and their complexes with silver(i) tetrafluoroborate were synthesized.     

New family of silver(I) complexes based on hydroxyl and carboxyl groups decorated arenesulfonic acid: syntheses, structures, and luminescent properties

Self-assembly of silver(I) salts and three ortho-hydroxyl and carboxyl groups decorated arenesulfonic acids affords the formation of nine silver(I)-sulfonates, (NH(4))·[Ag(HL1)(NH(3))(H(2)O)] (1), {(NH(4))·[Ag(3)(HL1)(2)(NH(3))(H(2)O)]}(n) (2), [Ag(2)(HL1)(H(2)O)(2)](n) (3), [Ag(2)(HL2)(NH(3))(2)]·H(2)O (4), [Ag(H(2)L2)(H(2)O)](n) (5), [Ag(2)(HL2)](n) (6), [Ag(3)(L3)(NH(3))(3)](n) (7), [Ag(2)(HL3)](n) (8), and [Ag(6)(L3)(2)(H(2)O)(3)](n) (9) (H(3)L1 = 2-hydroxyl-3-carboxyl-5-bromobenzenesulfonic acid, H(3)L2 = 2-hydroxyl-4-carboxylbenzenesulfonic acid, H(3)L3 = 2-hydroxyl-5-carboxylbenzenesulfonic acid), which are characterized by elemental analysis, IR, TGA, PL, and single-crystal X-ray diffraction. Complex 1 is 3-D supramolecular network extended by [Ag(HL1)(NH(3))(H(2)O)](-) anions and NH(4)(+) cations. Complex 2 exhibits 3-D host-guest framework which encapsulates ammonium cations as guests. Complex 3 presents 2-D layer structure constructed from 1-D tape of sulfonate-bridged Ag1 dimers linked by [(Ag2)(2)(COO)(2)] binuclear units. Complex 4 exhibits 3-D hydrogen-bonding host-guest network which encapsulates water molecules as guests. Complex 5 shows 3-D hybrid framework constructed from organic linker bridged 1-D Ag-O-S chains while complex 6 is 3-D pillared layered framework with the inorganic substructure constructing from the Ag2 polyhedral chains interlinked by Ag1 dimers and sulfonate tetrahedra. The hybrid 3-D framework of complex 7 is formed by L3(-) trianions bridging short trisilver(I) sticks and silver(I) chains. Complex 8 also presents 3-D pillared layered framework, and the inorganic layer substructure is formed by the sulfonate tetrahedrons bridging [(Ag1O(4))(2)(Ag2O(5))(2)](∞) motifs. Complex 9 represents the first silver-based metal-polyhedral framework containing four kinds of coordination spheres with low coordination numbers. The structural diversities and evolutions can be attributed to the synthetic methods, different ligands and coordination modes of the three functional groups, that is, sulfonate, hydroxyl and carboxyl groups. The luminescent properties of the nine complexes have also been investigated at room temperature, especially, complex 1 presents excellent blue luminescence and can sensitize Tb(III) ion to exhibit characteristic green emission.     

Syntheses and crystal structures of three structurally similar dinuclear silver(I) complexes

Three terephthalato-bridged dinuclear silver(I) complexes with the formulae Ag₂(5map)₄(tphth), [Ag₂(6map)₄(tphth)] · 2H₂O, and [Ag₂(4map)₄(tphth)] · 2H₂O (5map = 5-methyl-2-aminopyridine, 6map = 6-methyl-2-aminopyridine, 4map = 4-methyl-2-aminopyridine, tphth = terephthalate), have been synthesized and characterized by elemental analysis and single crystal X-ray diffraction. The Ag atom in each of the complexes is three-coordinate in a trigonal geometry with one carboxylate O atom and two pyridine N atoms. The characteristic difference among the complexes is the positions for the methyl groups of the aminopyridine ligands. The crystals of the complexes are stabilized by intermolecular N–H···O and O–H···O hydrogen bonds. Electronic supplementary material  The online version of this article () contains supplementary material, which is available to authorized users.     

2,2'-Biquinolines as test pilots for tuning the colour emission of luminescent mesomorphic silver(I) complexes

The synthesis and characterization of a series of 2,2'-biquinolines differently substituted in the 4,4'-position and their corresponding silver(I) derivatives obtained through reaction with silver triflate in a 1 : 1 stoichiometric ratio are reported. In order to perform a systematic investigation on the role played by the substituents on the coordination to the silver(I) centre, structural studies through single crystal X-ray diffraction have been performed on two Ag(I) model complexes. Unlike their analogous 2,2'-bipyridine ligands, the biquinolines have been found to behave only as chelated ligands towards the silver(I) ion, irrespective of the substituents. The coordination sphere of the Ag(I) is filled by a solvent molecule and, depending on the presence and nature of the substituents on the organic ligand, by an oxygen atom coming from a coordinated triflate or from a carboxylic group of a symmetrically related molecule, giving rise to neutral or ionic species. For the highest Ag(I) triflate homologues the presence of long and flexible peripheral tails makes it possible to achieve liquid crystalline properties with columnar organization whose high order is due to the large and rigid core. Moreover, the metal coordination induces in all the Ag(I) species interesting emission properties both in solution and condensed states, giving rise to blue or green emitters, depending on the nature of the substituents on the biquinoline units.     

Anion dependent formation of Ag(I) complexes of multidentate azine ligands: Synthesis and structural study

The extended structures of Ag-complexes of the azine based ligands phenyl-2-pyridyl ketone azine (L₁) and di-2-pyridyl ketone azine (L₂) are reported, and focus is made on the investigation of the influence of the anion and supramolecular interactions on the self-assembly. Using AgNO₃, AgClO₄ and CF₃COOAg salts as starting materials for both ligands in acetonitrile, we observed the formation of the dinuclear complexes [Ag₂(L₁)₂](NO₃)₂ (1a), [Ag₂(L₁)₂](ClO₄)₂ (1b), from L₁, the tetranuclear complexes [Ag₄(L₂)₂ (NO₃)(CH₃CN)₂](NO₃)₃ (2a), [Ag₄(L₂)₂(CF₃COO)₃CH₃CN](CF₃COO) (2b) and the linear chain polynuclear complex {[Ag₃(L₂)₂] (ClO₄)₃}_n (3) from L₂. The X-ray structures show that the molecular geometry depends on the choice of anion. The silver centers have distorted tetrahedral coordination geometry in all the complexes. Weak hydrogen bonding and other interactions result in 2-D and 3-D networks in these complexes.     

Ethylene sensing by silver(I) salt-impregnated luminescent films

Luminescent oligomers and polymers doped with silver(I) salts were used as optical sensors for ethylene and other gaseous small molecules. Films of poly(vinylphenylketone) (PVPK) or 1,4-bis(methylstyryl)benzene (BMSB) impregnated with AgBF(4), AgSbF(6), or AgB(C(6)F(5))(4) respond to ethylene exposures with a reversible emission quenching that is proportional to the pressure of the gas. Experiments with various analytes revealed that only gases capable of forming coordinate bonds with Ag(I) ions (i.e., ethylene, propylene, and ammonia) produced a sensing response. Comparison of the effects of ethylene and tetradeuterioethylene revealed that the emission quenching was due to enhanced vibrational relaxation. The Ag(I) ions are essential to the observed optical response. The oligomer/polymer support enhances the response characteristics of the impregnated salt by promoting separation of Ag(I) from its anion, a separation that improves accessibility of the Ag(I) ion to the gaseous analytes. Salts with large lattice energies, where the anion is not dissociated from Ag(I) in the matrix, fail to sensitize film responses. Photoluminescence experiments with Ag(I)-impregnated BMSB films established that the Ag(I) ions serve to communicate the analyte-binding signal to the support by altering the support-based emission. These experiments demonstrate a sensing paradigm where simultaneous coordination of Ag(I) ions to the support matrix and to a gaseous analyte enables the optical response.     

Complexation of trimeric copper(i) and silver(i) 3,5-bis(trifluoromethyl)pyrazolates with amine-borane

A complexation of trimeric copper(i) and silver(i) 3,5-bis(trifluoromethyl)pyrazolates ((ML)₃) with BH₃NEt₃ was studied by IR spectroscopy in hexane and dichloromethane solutions. In hexane, two complexes [(ML)₃][BH₃NEt₃]₂ (1) and [(ML)₃][BH₃NEt₃] (2) were formed depending on the ratio of reagents. In dichloromethane, only one complex [(ML)₃][BH₃NEt₃] (2) was found. The thermodynamic parameters (ΔH ^○, ΔS ^○) of complex 1 in hexane and complex 2 in dichloromethane were obtained. The complex [(AgL)₃][BH₃NEt₃] was isolated in the solid state, its structure was established by X-ray diffraction. The complex is formed due to two bridges B-H-Ag, one BH group is not involved in the complexation. In crystal, molecules 2 form supramolecular dimers due to the intermolecular interactions between metals of two macrocycles.     

Syntheses,structures, and luminescent properties of zinc(II) complexes based on imidazole derivative

Two new Zn(II) coordination complexes [ZnL₂(SCN)₂] (I) and [ZnL₂Cl₂] (II) have been pre-pared by self-assembly of corresponding metal salts with (E)-2-(3-(4-(1H-imidazole-1-yl)styryl)-5,5-dimethylcyclohexo-2-enylidene) malononitrile (L) and characterized by IR spectrum, elemental analysis and single-crystal X-ray diffraction. Complexes I and II are two-dimensional (2D) networks with different topology structures. The luminescence properties were investigated.     

Synthesis and crystal structures of four mixed-ligand silver(I) complexes with sandwich-like structure

The reaction of AgNO₃, with combinations of 4,4′-bipyridine (bpy), 1,2-di(4-pyridyl)ethylene (dpe), hexanedioic acid (HA), pyridine-3,5-dicarboxylic acid (pdc) and 3,3′4,4′-biphenyltetracarboxylic acid (bptc) in aqueous alcohol at room temperature produces block-like crystals of [Ag₂(bpy)₂](HA)₂·6H₂O, [Ag₂(bpy)₂(H₂O)](pdc)·3H₂O, [Ag₄(bpy)₄](bptc)·14H₂O and [Ag₂(dpe)₂(H₂O)₂](HA)·6H₂O. All four compounds consist of parallel 1D infinite bpy/dpe-silver cationic chains, interspersed with organic anions that play the role of charge compensation in the crystal structure. The lattice water molecules are situated among the framework of the crystal structure and stabilized by rich hydrogen-bonding interactions, which may play a role in the orientation of the organic anions in the crystal packing.     

Silver(I) complexes with (1-pyrazolyl)pyridazine ligands: Synthesis,crystal structures and luminescent properties

Four Ag(I) coordination complexes formulated as {[Ag(L¹)(ClO₄)]}_n (1), {[Ag(L¹)(NO₃)]}_n (2), {[Ag(L¹)(PF₆)]}₂ (3) and {[Ag(L²)](ClO₄)·CH₃OH}_n (4), (L¹ = 3,6-bis(1-pyrazolyl)pyridazine, L² = 3,6-bis(3,5-dimethyl-1-pyrazolyl)pyridazine) have been synthesized in the presence of different anions [ClO₄^? (1) and (4), NO₃^? (2), PF₆^? (3)] and structurally characterized by FT-IR spectra, elemental analysis and X-ray diffraction. Studies of X-ray diffraction reveal that complexes 1, 2 and 4 show infinite helical chains, which are the alternate left- and right-handed helical chains. Furthermore, helical chains are arranged to 2D sheet via C–H?O (from anion O atoms) hydrogen bonds. As the anion changed to PF₆^?, a dinuclear molecule is formed in complex 3, further constructing a 2D sheets by C–H?F hydrogen bonds. The photoluminescence properties of all the complexes 1–4 have been investigated in the solid state at room temperature.     

Syntheses,structures and luminescent properties of two Zn(II) complexes of N-2-nitrobenzenesulfonyl-glycine acid

Two luminescent zinc coordination complexes [Zn₂(2-NBS-gly)₄(H₂O)₄]?·?2H₂O (1), and Zn(Im)₂(2-NBS-gly)₂ (2), (2-NBS-glyH?=?N-2-nitrobenzenesulfonyl-glycine acid, Im?=?imidazole) have been synthesized and their crystal structures determined by X-ray crystallography. The Zn(II) in 1 is a five-coordinate geometry and can be described as a slightly distorted square-pyramid; complex 2 is four-coordinate, forming a distorted tetrahedron. Through hydrogen bonding, complex 1 forms a 2-D network and complex 2 forms a zigzag chain. Fluorescent analyses show that both 1 and 2 exhibit photoluminescence in the solid state and may be potential candidates for photoactive materials.     

Tetraphosphinite resorcinarene complexes: silver(I) capsule complexes

Resorcinarene tetraphosphinite ligands, P4, react with silver(I) trifluoroacetate or silver(I) triflate, AgX, to give the corresponding [Ag4X4(P4)] complexes. The resorcinarene skeleton in these complexes adopts a boat conformation with the silver(I) phosphinite units on the horizontal, rather than the upright, arene units of the resorcinarene. The [Ag4X4(P4)] complexes react with free P4 ligand to yield the [Ag2X2(P4)] or [AgX(P4)] complexes, which are characterized in solution by NMR spectroscopy to have a conformation opposite to that of the [Ag4X4(P4)] complexes; the silver(I) phosphinite groups are on the upright arene rings of the resorcinarene "boat" instead of the horizontal arene units. There is an easy equilibrium between these complexes. When X = triflate, the [Ag4X4(P4)] complexes disproportionate and add aqua ligands during slow crystallization to give "capsule complexes", which are characterized crystallographically as [Ag10(O3SCF3)10(OH2)6(P4)2], [Ag10(O3SCF3)6(OH2)8(P4)2][O3SCF3]4, or [Ag13(O3SCF3)13(OH2)7(P4)2] depending on the resorcinarene tetraphosphinite ligand P4 used. These unusual capsule complexes are formed by the tail-to-tail self-assembly of pairs of [Ag4(P4)]4+ units linked by additional silver ions that bind to the phenyl substituents of one resorcinarene through {Ag(eta2-C6H5)}+ binding and to the bridging triflate ligands, aqua ligands, or both of the other resorcinarene unit.     

Synthesis and crystal structures of copper(II) and silver(I) complexes of a biphenyl-bridged bipyrazolyl ligand

A semirigid bipyrazolyl ligand, 4,4??-bis[(3??,5??-diethyl-1H-pyrazol-4??-yl)methylene)]-1,1??-biphenyl (H₂L), and four of its Ag(I) and Cu(II) complexes have been prepared and structurally characterized. X-ray analysis demonstrates that the Ag(I) complexes are dinuclear molecular rectangle, while the Cu(II) complexes display a twisted rectangular structure. Two different conformations, namely cis and trans, have been observed for this bipyrazolyl ligand.