Relationship between the ratio of ligand to metal and the coordinating ability of anions. Synthesis and structural properties of AgX-bearing bis(4-pyridyl)dimethylsilane (X- = NO2-, NO3-, CF3SO3-, and PF6-)

Studies of the anion effects on the molecular construction of a series of AgX complexes with bis(4-pyridyl)dimethylsilane (L) (X- = NO2-, NO3-, CF3SO3-, and PF6-) have been carried out. Formation of the skeletal bonds appears to be primarily associated with a suitable combination of bidentate N-donors of L and a variety of coordination geometries of Ag(I) ions. The L:Ag(I) ratios of the products are dependent on the nature of the polyatomic anions. The 1:1 adduct Ag(I)-L for NO2-, 3:4 adduct for NO3-, 2:3 adduct for CF3SO3-, and 1:2 adduct for PF6- have been obtained. A linear relationship between the ratio of ligand to metal and the coordinating ability of anions was observed. [Ag(NO2)(L)] has a unique sheet structure consisting of double helices, and [Ag3(L)4](NO3)3 is a 2 nm thick interwoven sheet structure consisting of nanotubes. The compound [Ag2(L)3](CF3SO3)2 affords a characteristic ladder-type channel structure, and [Ag(L)2](PF6) is a simple 2D grid structure.     

Self-assembly of multinuclear coordination species with chiral bipyridine ligands: silver complexes of 5,6-CHIRAGEN(o,m,p-xylidene) ligands and equilibrium behaviour in solution

The complexation reactions between Ag- and a series of enantiopure ligands belonging to the CHIRAGEN (from CHIRAlity GENerator) family (L1, L2, L3, based on (-)-5,6-pinene bipyridine) have been studied in solution. It has been shown that the length of the bridge plays a fundamental role in the self-assembly processes leading to different compounds: mononuclear complexes (with L3), mixtures of polynuclear complexes (with L2) and circular helicates (with L 1). Although the absolute configuration of the chiral centres in all three ligands is the same, the metal-centred chirality of L3 (delta) is inverted with respect to that in the other two complexes with L1 and L2 (delta). The metal configuration is thus opposite in the mononuclear complex with respect to the polynuclear species. Detailed thermodynamic studies were carried out for the Ag+ and L1 ligand system by 1H and 109Ag NMR spectroscopy (as a function of concentration, temperature and pressure). At low temperature and high pressure, the [Ag6L1(6)]6+ hexanuclear circular helicate forms a tetranuclear circular helicate [Ag4L1(4)]4+: 2[Ag6L1(6)]6+ <=> 3 [Ag4L1(4)]4+. The thermodynamics parameters, obtained by temperature and pressure variation, have the following values: K298 = (8.7 +/- 0.7) x 10(-5) mol x kg(-1), deltaHo = -15.65 +/- 0.8 kJ x mol(-1), deltaSo = -130.2 +/- 3 J x mol(-1) x K(-1) and deltaVo(256 K)= -160 +/- 12 cm3 x mol(-1). The reaction volume calculated according to Connolly's method indicates that the calculated structure of [Ag4L1(4)]4+ is plausible. Both the signs and large magnitudes of deltaSo and deltaVo are counterintuitive, yet can be understood by modelling methods.     

Synthesis and antimicrobial activities of silver(I) sulfanylcarboxylates. Structural isomers with identically or unequally coordinated Ag centers in an Ag4S4 ring

We have investigated the reactions of silver nitrate and 3-(aryl)-2-sulfanylpropenoic acids [H(2)xspa, x: p = 3-phenyl-, f = 3-(2-furyl)-, t = 3-(2-thienyl)-, py = 3-(2-pyridyl)-] and 2-cyclopentylidene-2-sulfanylacetic acid (H(2)L) in 1 : 1 and 2 : 1 molar ratios. The 1 : 1 molar ratio gave compounds of type [Ag(HL)]; reaction of these compounds with diisopropylamine and NaOH gave [HQ][Ag(L)] (HQ = diisopropylammonium) and Na[Ag(L)] x H(2)O, respectively. These compounds, as well as those of type [Ag(2)(L)] obtained with the 1 : 2 molar ratio, were isolated and characterized by IR and NMR ((1)H and (13)C) spectroscopy. (109)Ag NMR spectroscopy and ESI-MS spectrometry were also used in some cases. The crystal structures of [HQ][Ag(pspa)] (11), in which the presence of structural isomers was detected, and [HQ][Ag(cpa)] (15) were determined by X-ray diffractometry. The antimicrobial activity of the complexes against E. coli, S. aureus, B. subtilis, P. aeruginosa/Resistant P. aeruginosa, and C. albicans was tested.     

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.     

Structural diversity of silver(I) 4,6-dipyridyl-2-aminopyrimidine complexes: effect of counteranions and ligand isomerism

Using two ligands, 4,6-bis(2-pyridyl)-2-aminopyrimidine (L1) with two N,N'-chelating sites and 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (L2) (as the isomer of L1) containing one chelating site and one bridging unit, a series of novel Ag(I) complexes varying from zero- to two-dimensions have been prepared and their crystal structures determined via single-crystal X-ray diffraction. The two ligands are employed for the first time in coordination chemistry. The structures of compounds 1-3 are directed by the counteranions adopted in the reaction system: The reaction of L1 with AgNO3 yielded a dimer [Ag2L12](NO3)2 (1). The reaction of L1 with AgCF3SO3 led to a one-dimension "V-shaped" chain {[AgL1](CF3SO3)}n (2). When AgSCN was used, a one-dimension ladder {[Ag2L1(SCN)2].H2O}n (3) was obtained. While ligand L2 reacted with AgNO3, a two-dimension {[Ag2(L2)2](NO3)2.H2O}n (4) was prepared with the help of an argentophilic interaction. Compounds 1-4 display room-temperature photoluminescence.     

Ligand-directed molecular architectures: self-assembly of two-dimensional rectangular metallacycles and three-dimensional trigonal or tetragonal prisms

Three angular ditopic ligands (1,3-bis(benzimidazol-1-ylmethyl)-4,6-dimethylbenzene L(1), 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L(2), and 1,4-bis(benzimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene L(3)) and one tripodal ligand 1,3,5-tris(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L(4) have been prepared. Reaction of these shape-specific designed ligands with different metal salts affords a series of discrete molecular architectures: [Ag(2)L(1)(2)](BF(4))(2) 1, [Ag(2)L(2)(2)](CF(3)SO(3))(2) 2, [CF(3)SO(3)(-) subset Ag(2)L(3)(2)]CF(3)SO(3) 3, [CF(3)SO(3)(-) subset Ag(2)L(3)(3)]CF(3)SO(3) 4, [ClO(4)(-) subset Cu(2)L(2)(4)](ClO(4))(3) 5, [4H(2)O subset Ni(2)L(2)(4)Cl(4)].6H(2)O 6, [BF(4)(-) subset Ag(3)L(4)(2)](BF(4))(2) 7, [ClO(4)(-) subset Ag(3)L(4)(2)](ClO(4))(2) 8, and [CuI(3)(2-) subset Cu(3)L(4)(2)](2)[Cu(2)I(4)] 9. The compounds were characterized by elemental analysis, ESI-MS, IR, and NMR spectroscopy, and X-ray crystallography. 1 is a dinuclear metallacycle with 2-fold rotational symmetry in which two syn-conformational L(1) ligands are connected by two linearly coordinated Ag(+) ions. 2 and 3 are structurally related, consisting of rectangular structures assembled from two linearly coordinated Ag(+) ions and two L(2) or L(3) ligands. The structure of 4 is a trigonal prismatic box consisting of two Ag(+) ions in trigonal planar coordination linked by three L(3) ligands, while the structures of 5 and 6 are tetragonal prismatic cages constructed by two square planar Cu(2+) or Ni(2+) ions linked by four L(2) ligands. The topologies of 7-9 are similar to that of 4; however, these three structures are assembled from three linearly coordinated Ag(+) or Cu(+) ions and two tripodal ligands, representing an alternative strategy to assembling a trigonal prism. (1)H NMR and ESI-MS were utilized to elucidate the solution structures of these macrocycles.     

Influence of neutral ligands on the structures of silver(I) sulfonates

This article represents a systematical examination of the structures of silver(I) sulfonates incorporating neutral ligands. To survey the influence of the properties of neutral ligands on the structures of silver(I) sulfonates, three kinds of sulfonate anions (L1=1-naphthalenesulfonate, L2=p-toluenesulfonate, and L3=1, 3, 6, 8-pyrenetetrasulfonate) and three kinds of neutral ligands (pyrazine, Pyr, a divergent bidentate ligand; hexamethylenetetramine, hmt, a divergent tetradentate ligand; and beta-picoline, Pic, a monodentate ligand) were selected for study, and five novel silver(I) sulfonates containing neutral ligands have been synthesized: [Ag(L1)(Pyr)].H2O, Ag(L2)(Pyr), Ag4(L3)(Pyr)4(H2O)2, [Ag(L1)(hmt)].H2O, and Ag(L1)(Pic)2. The crystal structures have been determined by single-crystal X-ray diffraction, and these compounds show a variety of structures with different dimensionalities. Moreover, the luminescent properties of compounds and are also discussed.     

Synthesis and characterization of silver(I) coordination networks bearing flexible thioethers: anion versus ligand dominated structures

This report describes the synthesis and X-ray characterization of a series of L(n)AgX complexes wherein Ln = PhS(CH2)nSPh (n = 2, 4, 6, 10) and X = CF3SO3-, CF3COO-, CF3CF2COO-, CF3CF2CF2COO-, NO3-, and ClO4-. This study was undertaken in order to rationalize the structure of the coordination networks formed as a function of the anion coordinating strength and the ligand structure. The following complexes were examined: with L(2), CF3SO3- (1), CF3COO- (2), ClO4- (3); L4, CF3SO3- (4), CF3COO- (5), CF3CF2COO- (6), CF3CF2CF2COO- (7); L6, CF3COO-.H2O (8), CF3CF2COO- (9), CF3CF2CF2COO- (10); and L10, NO3- (11). The anions selected are classified in three groups of increasing coordinating strength: perchlorates, fluorosulfonates, and perfluorocarboxylates. Except in two cases, all complexes form 2D-coordination networks. The 2D-network in 1 (L2, CF3SO3-) is made up of Ag(I) and L2, while the anion is only a terminal co-ligand that completes the trigonal coordination around Ag(I). In 4 (L4, CF3SO3-), a 1D-coordination polymer, [Ag-L4-]infinity, is observed where the anions are coordinated to Ag(I) in a trigonal fashion. The perfluorocarboxylates form tetrameric units in a zigzag shape, but only with the L4 ligand. In these (6 and 7), the silver-silver distances are very short, especially those of the central bond, indicating the presence of weak Ag-Ag interactions. Dimers, with short silver-silver distances, are observed with ligands L2 and L6 and perfluorocarboxylates. In 8 (L6, CF3COO-.H2O), a 3D channel-like structure is built through water molecules that connect adjacent layers. An unusual stoichiometry is noted in 3 (L2, ClO4-, acetone); Ag:L is 4:2.5. In 11 (L10 and NO3-), the nitrate acts as a bidentate ligand and an [Ag-NO3-]infinity chain is formed. Adjacent chains are linked by the L10 ligands into a 2D-coordination network.     

萘啶酮的单核和双核银配合物的合成与晶体结构

合成了萘啶酮的单核和双核银配合物Ag₂(L₁)₂(HL₁=5，7-二甲基-1，8-萘啶-2-酮) (1)和[Ag(HL₂)(PPh₃)₂]·2H₂O(H₂L₂=1，8-萘啶-2,7-二酮) (2)。并通过元素分析，红外光谱及X-射线单晶衍射对其进行了结构表征。配合物1的晶体属单斜晶系，P1空间群。中心金属银为三配位T型几何构型，Ag-Ag间距离为0.274 8(2) nm，具有强的Ag…Ag作用。配合物2的晶体属三斜晶系，P2₁/n空间群。银与1个氮原子及2个磷原子形成三配位结构。     

Novel aggregation of [Ni(thiolato)2(amine)2]-type square planes assisted by silver(I) ions

Treatment of [Ni(L)][L =((-)SCH(2)CH(2)NH[double bond, length as m-dash]C(CH(3))-)(2)] with Ag(+) in water gave a pinwheel-like S-bridged Ni(II)(3)Ag(I)(2) structure in [Ag(2)[Ni(L)](3)](2+), which further reacted with [Ni(L)] to produce a Ni(II)(4)Ag(I)(2) structure in [Ag(2)[Ni(L)](4)](2+) and a Ni(II)(7)Ag(I)(4) structure in [Ag(4)[Ni(L)](7)](4+).     

Adjusting the frameworks of silver(I) complexes with new pyridyl thioethers by varying the chain lengths of ligand spacers, solvents, and counteranions

In our efforts to systematically investigate the effects of the linker units of flexible ligands and other factors on the structures of Ag(I) complexes with thioethers, five new flexible pyridyl thioether ligands, bis(2-pyridylthio)methane (L(1)()), 1,3-bis(2-pyridylthio)propane (L(3)()), 1,4-bis(2-pyridylthio)butane (L(4)), 1,5-bis(2-pyridylthio)pentane (L(5)), and 1,6-bis(2-pyridylthio)hexane (L(6)), have been designed and synthesized, and the reactions of these ligands with Ag(I) salts under varied conditions (varying the solvents and counteranions) lead to the formation of eight novel metal-organic coordination architectures from di- and trinuclear species to two-dimensional networks: [Ag(3)(L(1)())(2)(ClO(4))(2)](ClO(4)) (1), [[AgL(3)](ClO(4))]( infinity ) (2), [[Ag(2)(L(4))(2)](ClO(4))(2)(CHCl(3))]( infinity ) (3), [[AgL(4)](ClO(4))(C(3)H(6)O)]( infinity ) (4), [[Ag(2)L(4)](NO(3))(2)]( infinity ) (5), [Ag(2)L(4)()(CF(3)SO(3))(2)]( infinity ) (6), [[AgL(5)](ClO(4))(CHCl(3))](2) (7), and [[AgL(6)()](ClO(4))]( infinity ) (8). All the structures were established by single-crystal X-ray diffraction analysis. The coordination modes of these ligands were found to vary from N,N-bidentate to N,N,S-tridentate to N,N,S,S-tetradentate modes, while the Ag(I) centers adopt two-, three-, or four-coordination geometries with different coordination environments. The structural differences of 1, 2, 3, 7, and 8 indicate that the subtle variations on the spacer units can greatly affect the coordination modes of the terminal pyridylsulfanyl groups and the coordination geometries of Ag(I) ions. The structural differences of 3 and 4 indicate that solvents also have great influence on the structures of Ag(I) complexes, and the differences between 3, 5, and 6 show counteranion effects in polymerization of Ag(I) complexes. The influences of counterions and solvents on the frameworks of these complexes are probably based upon the flexibility of ligands and the wide coordination geometries of Ag(I) ions. The results of this study indicate that the frameworks of the Ag(I) complexes with pyridyl dithioethers could be adjusted by ligand modifications and variations of the complex formation conditions.     

Controlling the framework formation of silver(I) coordination polymers with 1,4-bis(phenylthio)butane by varying the solvents,metal-to-ligand ratio,and counteranions

The reactions of 1,4-bis(phenylthio)butane (L) with Ag(I) salts in varied conditions (varying the solvents, metal-to-ligand ratios, and counteranions) lead to the formation of four new two-dimensional (2D) coordination polymers with different network structures: [Ag(2)L(3)(ClO(4))(2)](infinity) 1, [Ag(2)L(3)(ClO(4))(2) x CH(3)OH](infinity) 2, [[AgL(2)](ClO(4))](infinity) 3, and [AgLNO(3)](infinity) 4. All the structures were established by single-crystal X-ray diffraction analysis. Crystal data for 1: triclinic, P-1, a = 11.0253(9) A, b = 11.3455(9) A, c = 11.5231(9) A, alpha = 93.931(2) degrees, beta = 92.689(2) degrees, gamma = 112.9810(10) degrees, Z = 2. 2: triclinic, P-1, a = 11.9147(13) A, b = 16.1534(17) A, c = 16.2259(17) A, alpha = 74.977(2) degrees, beta = 69.030(2) degrees, gamma = 69.986(2) degrees, Z = 2. 3: triclinic, P-1, a = 12.1617(9) A, b = 12.5054(10) A, c = 13.1547(10) A, alpha = 64.3370(10) degrees, beta =85.938 (2) degrees, gamma = 69.3010(10) degrees, Z = 2. 4: monoclinic, P2(1)/c, a = 5.4032(17) A, b = 16.974(6) A, c = 19.489(6) A, beta = 94.234(6) degrees, Z = 4. In all four complexes, each Ag(I) center has a tetracoordination geometry, and the 2D networks consist of fused large macrometallacyclic ring systems. The "hexagonal" 42-membered rings, Ag(6)L(6), observed in 1 and 2 are nearly identical, which could be considered as unique examples of self-sustaining noninterpenetrated frameworks formed with flexible ligands. The repeating rectangular 28-membered macrometallacycle, Ag(4)L(4), is the basis for the network of 3, in which the perchlorate anions occupy the voids to prevent the ring from collapsing. In 4, columns of the fused rectangular 22-membered rings, Ag(4)L(2)(NO(3))(2), are cross-linked through the L ligands to form a unique 2D network consisting of two types of 22-membered repeating units.     

树枝状纳米银颗粒的制备与电活性

在Ag(NH3)2+溶液中,在钛基体上电沉积出树枝状纳米银颗粒,研究了沉积电位对树枝状纳米银颗粒形成的影响,探讨了这种树枝状纳米银颗粒形成的机理,并研究了这种钛基树枝状纳米银电极(Ag/Ti)在碱性溶液中对甲醛氧化的电催化活性。结果表明,在30 mmol/LAg(NH3)2+以及沉积电位在-1.8～-1.2 V(vsAg)时,形成了形态为树枝状的纳米银颗粒。在沉积电位为-1.6 V(vs Ag),Ag(NH3)2+浓度为30 mmol/L的溶液中,电沉积制备的这种树枝状纳米银电极(Ag/Ti)对甲醛氧化具有强的电催化活性。循环伏安曲线表明,在0.1 mol/LNaOH溶液中以及甲醛的浓度范围在0～40 mmol/L,甲醛浓度和它的氧化峰电流密度呈现良好的线性关系,检测下限达到0.662 mmol/L,这种新型的树枝状纳米银电极有望作为甲醛检测的传感器。     

Polyhedral C2@Agn cages distorted by ancillary pyridine N-oxide ligands in silver-acetylenediide complexes

Reactions of the pyridine N-oxide ligands L, L2 and L3 with the silver acetylenediide-containing system under hydrothermal conditions gave rise to four silver-acetylenediide complexes bearing interesting C2@Agn motifs: (Ag2C2)2(AgCF3CO2)8(L1)3.5 (1), (Ag2C2)2(AgCF3CO2)8(L2)2 (2), (Ag2C2)(AgCF3CO2)4(L3) (3) and [(Ag7(C2)(CF3SO3)3(L3)2(H2O)2] x 2CF3SO3 (4) (L = nicotinic acid N-oxide, L(1) = pyridine N-oxide, L2 = 1,2-bis(4-pyridyl)ethane N,N'-dioxide, L3 = 1,3-bis(4-pyridyl)propane N,N'-dioxide), which exhibit new distorted polyhedral C2@Agn cage motifs. Complex 1 has a pair of acetylenediide dianions encapsulated in a Ag(14) aggregate composed of three polyhedral parts, whereas 2 contains an irregular (C2)2@Ag13 double cage. In 3, the basic building unit is a centrosymmetric (C2)2@Ag12 double cage with each component single cage taking the shape of a highly distorted triangulated dodecahedron with one missing vertex. As to complex 4, the core is a C2@Ag7 single cage in the form of a slightly distorted monocapped trigonal prism with four cleaved edges that include all three vertical sides. Furthermore, in the silver-rich environment, the pyO-type ligands are induced to exhibit unprecedented coordination modes, such as the mu(5)-O,O,O,O',O' ligation mode of L2 in 2 and the mu4-O,O,O',O' mode of L3 in 3 and 4.     

Novel boxlike dinuclear or chain polymeric silver(I) complexes with polypyridyl bridging ligands: syntheses, crystal structures, and spectroscopic and electrochemical properties

The syntheses, characterization, crystal structures, and photophysical and electrochemical properties of two dinuclear and two polymeric Ag(I) complexes with three polypyridyl ligands, 2,3-di-2-pyridylquinoxaline (L(1)), 2,3-di-2-pyridyl-5,8-dimethoxyquinoxaline (L(2)), and 2,3,7,8-tetrakis(2-pyridyl)pyrazino[2,3-g] quinoxaline (L(3)), are described. The structures of the two boxlike dinuclear complexes with L(1) and L(2) and two chemically the same but differently crystallized one-dimensional zigzag chain coordination polymers also consisting of boxlike dinuclear subunits have been elucidated by X-ray analysis. [AgL(1)(CH(3)CN)](2)-(BF(4))(2).2CHCl(3) (1): monoclinic, C2/c; a = 28.631(2), b = 12.2259(11), c = 14.3058(12) A; beta = 99.180(2) degrees; Z = 4. [AgL(2)(CH(3)CN)(2)](2)(ClO(4))(2) (2): triclinic, P1; a = 12.3398(2), b = 13.750(2), c = 14.326(7) A; alpha = 83.494(3), beta = 74.631(3), gamma = 76.422(3) degrees; Z = 4. [[Ag(2)L(3)(NO(3))(2)].CH(3)CN](infinity) (3a): monoclinic, P2(1)/c; a = 9.5836(8), b = 13.4691(12), c = 14.0423(12) A; beta = 107.753(2) degrees; Z = 4. [Ag(2)L(3)()(NO(3))(2)](infinity) (3b): monoclinic, P2(1)/c; a = 8.4689(6), b = 16.0447(12), c = 11.7307(8) A; beta = 102.051(1) degrees; Z = 2. The structures of the dinuclear complexes 1 and 2 are similar to each other, with the two intramolecular Ag(I) centers of each complex being spanned by two ligands thus forming a unique boxlike cyclic dimer. In 1, each Ag(I) center is four-coordinated by three nitrogen atoms of two L(1) ligands and a CH(3)CN nitrogen donor, taking a distorted tetrahedral coordination geometry. The coordination environment of Ag(I) in 2 is similar to that in 1, except the formation of an additional weak coordination bond with the oxygen atom of the methoxy group of L(2). The structures of 3a,b are very similar to each other, except for the stacking patterns in the crystal lattices, and the cyclic boxlike dinuclear unit, which is similar to the structure of 1, constitutes the fundamental building block to form the one-dimensional zigzag chain structures due to the "end-on" nature of L(3). 1-3 exhibit metal-perturbed intraligand transitions in solution in 360-390 nm regions. Cyclic voltammetric studies of these complexes show the presence of reduction peak at approximately -0.5 V vs Fc(+/0). In the solid state at 77 K, they exhibit broad emission that may be assignable to originate from the metal-perturbed intraligand transitions.     

Ag(I) and Cu(II) discrete and polymeric complexes based on single- and double-armed oxadiazole-bridging organic clips

Four new oxadiazole-bridging ligands (L1-L4) were designed and synthesized by the reaction of 2,5-bis(2-hydroxyphenyl)-1,3,4-oxadiazole with isonicotinoyl chloride and nicotinoyl chloride, respectively. L1 and L3 are unsymmetric single-armed ligands (4- or 3-pyridinecarboxylate arm), and L2 and L4 are symmetric double-armed ligands (4- or 3-pyridinecarboxylate arms). Nine new complexes, [Ag(L1)]PF6.CH3OH (1), [Ag(L1)]ClO4.CH3OH (2), Cu(L2)(NO3)2.2(CH2Cl2) (3), [Cu(L2)2](ClO4)2.2(CH2CCl2) (4), Cu(L2)Cl2 (5), [Cu4(L3)2(H2O)2](L3)4(ClO4)4 (6), [Ag(L4)(C2H5OH)]ClO4 (7), [Ag(L4)(C2H5OH)]BF4 (8), and [Ag(L4)(CH3OH)]SO3CF3 (9), were isolated from the solution reactions based on these four new ligands, respectively. L1, L2, and L3 act as convergent ligands and bind metal ions into discrete molecular complexes. In contrast, L4 exhibits a divergent spacer to link metal ions into one-dimensional coordination polymers. New coordination compounds were fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. In addition, the luminescent and electrical conductive properties of these new compounds were investigated.     

Synthesis, characterization, crystal structure and preliminary reactivity behaviour of new heteropolytopic ligands based on the 1,3,5-triazine spacer and pyrazolyl, tris-pyrazolylmethyl and tris-pyrazolylethoxy bonding fragments

Four new potentially polytopic nitrogen donor ligands based on the 1,3,5-triazine fragment, L(1)-L(4) (L(1) = 2-chloro-4,6-di(1H-pyrazol-1-yl)-1,3,5-triazine, L(2) = N,N'-bis(4,6-di(1H-pyrazol-1-yl)-1,3,5-triazin-2-yl)ethane-1,2-diamine, L(3) = 2,4,6-tris(tri(1H-pyrazol-1-yl)methyl)-1,3,5-triazine, and L(4) = 2,4,6-tris(2,2,2-tri(1H-pyrazol-1-yl)ethoxy)-1,3,5-triazine) have been synthesized and characterized. The X-ray crystal structure of L(3) confirms that its molecular nature consists of a 1,3,5-triazine ring bearing three tripodal tris(pyrazolyl) arms. L(1), L(2), and L(4) react with Cu(I), Cu(II), Pd(II) and Ag(I) salts yielding mono-, di-, and oligonuclear derivatives: [Cu(L(1))(Cy(3)P)]ClO(4), [{Ag(2)(L(2))}(CF(3)SO(3))(2)]·H(2)O, [Cu(2)(L(2))(NO(3))(2)](NO(3))(2)·H(2)O, [Cu(2)(L(2))(CH(3)COO)(2)](CH(3)COO)(2)·3H(2)O, [Pd(2)(L(2))(Cl)(4)]·2H(2)O, [Ru(L(2))(Cl)(OH)]·CH(3)OH, [Ag(3)(L(4))(2)](CF(3)SO(3))(3) and [Ag(3)(L(4))(2)](BF(4))(3). The interaction of L(3) with Ag(I), Cu(II), Zn(II) and Ru(II) complexes unexpectedly produced the hydrolysis of the ligand with formation, in all cases, of tris(pyrazolyl)methane (TPM) derivatives. In detail, the already known [Ag(TPM)(2)](CF(3)SO(3)) and [Cu(TPM)(2)](NO(3))(2), as well as the new [Zn(TPM)(2)](CF(3)SO(3))(2) and [Ru(TMP)(p-cymene)]Cl(OH)·2H(2)O complexes have been isolated. Single-crystal XRD determinations on the latter derivatives confirm their formulation, evidencing, for the Ru(II) complex, an interesting supramolecular arrangement of the anions and crystallization water molecules.     

Silver(I) complexes with oxazoline-containing tripodal ligands: structure variation via counter anions and reaction conditions

Seven new silver(I) complexes of the formula [Ag2(L)2(CF3SO3)2] (1), [Ag2(L)2(CH3SO3)2] (2) [Ag2(L)2](BF4)2 (3), [Ag3(L)2(NO3)2]NO3.5H2O (4), [Ag2(L)(NO3)2].CH3OH (5), [Ag2(L)2](ClO4)2 (6) and [Ag3(L)2(CH3CN)3](ClO4)3 (7) have been synthesized by reactions of 1,3,5-tris(2-oxazolinyl)benzene (L) with varied silver(I) salts under different conditions. The influences of counter anions and reaction conditions on the structure of the complexes are discussed. Three complexes , 1, 2 and 3 with two kinds of different 1D chain structures were obtained under the same synthetic conditions by using different silver(I) salts, and the ligand L was found to adopt bis-monodentate (1 and 2) and tris-monodentate (3) coordination modes respectively. On the other hand, by using the same silver(I) nitrate or silver(I) perchlorate but different reaction solvents, 4 and 5 or 6 and 7 were isolated respectively. Complexes 4and 5 have different 1D chain structures, and 6 is isostructural with . However, 7 is a tri-nuclear, propeller-shaped M3L2 supramolecular capsule in which L adopts a cis,cis,cis-conformation, while the ligand L in 3-6 has cis,trans,trans-conformation. The results revealed that the nature of the counter anions, such as their size, coordination ability and coordination mode, and the reaction conditions all have great impact on the structure of the complexes. The complexes were also characterized by electrospray mass spectrometry. Furthermore, complex 7 exhibited modest second-harmonic-generation (SHG) efficiency.     

Mechanochromism of Ag(I) complexes with iPrNHC(S)NHP(S)(OiPr)2

Reaction of the potassium salt of iPrNHC(S)NHP(S)(OiPr)(2) (HL) with AgPF(6) leads to the hexanuclear [{Ag(3)(iPrNHC(S)NP(S)(OiPr)(2)-S,S')(3)}(2)] ([(Ag(3)L(3))(2)]) complex. The reversible conversion between yellow-emitting ([(Ag(3)L(3))(2)]) and blue-emitting ([Ag(3)L(3)]) materials on grinding and recrystallization was established. [Ag(3)L(3)] was also prepared by a mechanically induced solid-state reaction.     

Assembly of a heterobinuclear 2-D network: a rare example of endo- and exocyclic coordination of Pd(II)/Ag(I) in a single macrocycle

The S3O2 macrocycle L1 was synthesized by a dithiol-dihalide coupling reaction under high-dilution conditions. The reaction of L1 with K2PdCl4 afforded an exocoordinated complex 1, [cis-Cl2Pd(L1)], which can then be manipulated to provide a heterobinuclear complex 3, {[Pd(L1)Ag(NO3)(2.5)](NO3)(0.5)}n, utilizing endocyclic Pd(II) and exocyclic Ag(I) in a single macrocycle through a successive reaction with AgNO3. The network of 3 contains a unique honeycomb-like 2-D sheet made up of the repeating unit [Ag6(NO3)6].