A Silver Complex of 6,7-Dicyanodipyridoquinoxaline:π-Stacking Interactions and Luminescence

The reaction of 6,7-dicyanodipyridoquinoxaline （DICNQ） with AgNO3 in a 1：1 molar ratio by solution method gave a new complex [Ag（DICNQ）2]NO3 1. Single-crystal X-ray diffraction analysis reveals that the complex crystallizes in the space group Ibca of orthorhombic system with eight formula units in a cell. Crystal data for 1： a = 15.7055（17）, b = 18.411（2）, c = 20.680（2）A, V = 5979.7（11）A3, Z = 8, C32Hl2AgN13O3, Mr = 734.42, Dc = 1.632 g/cm3, μ= 0.734 mm-1, F（000） = 2928, S = 1.023 and T= 293（2） K. The final R = 0.0659 and wR = 0.1927 for 2118 observed reflections with I 〉 2σ（I）, and R = 0.0801 and wR = 0.2196 for all data. The complex builds up a packing structure by π-π stacking interactions and shows a luminescent feature.

Syntheses, Characterizations, and Crystal Structures of Two Binuclear Silver Complexes Based on O,O'-Dialkyldithiophosphate and 1,10-Phenanthroline

Two binuclear silver complexes, [Ag2{μ-S2P（OCH2Ph）2}2（phen）2] （1） and [Ag2{μ- SEP（OCH2CH2Ph）2}E（phen）2] （2）, were synthesized and characterized by elemental analysis, infrared spectrum, thermo-gravimetric analysis and X-ray single-crystal diffraction. Complex 1 crystallizes in the triclinic system, space group P1 with a = 9.7881（4）, b = 10.7726（4）, c = 13.1952（6） A, a = 103.686（4）, ,8= 99.477（3）, ）, = 107.494（4）°, F= 1246.88（9）A3, Dc = 1.591 g.m-3 and Z = 1; Complex 2 is of monoclinic system, space group P2jn with a = 10.6014（8）, b = 24.3969（15）, c = 11.5353（10）A,β= 14.125（10）°, F= 2722.9（4） A3, Dc = 1.526 g.m-3 and Z = 2. In the molecules of 1 and 2, O,O＇-dialkyldithiophosphate anions, （PhCHEO）PS2 and （PhCH2CHEO）PS2 act as bridging ligands and connect two Ag（I） centers into a binuclear unit with AgES4P2 eight-membered rings in ＂chair＂ conformations. In both crystal structures, face-to-face π-π stacking interactions between the adjacent paralleling aromatic rings of 1,10-phenanthroline play a prominent role in the crystal packing and result in a 1D chain. And such 1D chains are further linked into 3D networks by weak intermolecular C-H...π interactions for 1.

A New Tetranuclear Silver Complex [Ag4(MMPzA)2(dmPz)4(H2DPC)2](H2O)4 and Its Antibacterial Activity

A new tetranuclear silver（I） complex with the formula of [Ag4（MMPzA）2（dmPz）4（H2DPC）2]（H2O）4（1, MMPz A = mono（3,5-bimethyl-pyrazolmethyl）amine）, dm Pz = 3,5-dimethylpyrazole, H2DPC = pyridine-3,4-dicarboxylic acid） has been synthesized and characterized by single-crystal X-ray diffraction method. The title complex crystallizes in the triclinic system, space group P1 with a = 10.5532（13）, b = 11.5071（18）, c = 13.3951（17） A, α = 97.3190（10）, β = 106.7360（10）, γ = 108.0770（10）o, V = 1438.3（3） A3, Z = 1, Dc = 1.691 g/cm3, F（000） = 736, μ = 1.421 mm-1, the final R = 0.0400 and w R = 0.0942 for 5097 observed reflections（I 〉 2σ（I））. The intermolecular hydrogen bonding interaction extends the complex into a 1D chain structure. In addition, the complex was tested in vitro for its antibacterial activity and it exhibited significant activity, especially against penicillium.

Quantum Chemistry Calculation of Quercetin-silver Complex

Three possible molecular structures of quercetin-silver complexes obtained from the reaction of quercetin and Ag^＋ in equivalent molar ratio were designed and optimized by using Gaussian 98 program at the B3LYP/LanL2DZ basis set. Through theoretical analysis, one of the three designed structures is discovered to have the most stable coordination position. Then its geometry structure, natural bond orbital analyses, vibrational frequency and biological activity were performed. The results show that it has good stability and relatively stronger antioxidative activity because it is favorably attacked by O2^-. Therefore theoretical foundation is provided for the development of new quercetin metal complexes with higher activity antioxidants.

Syntheses and Crystal Structures of Two Silver(Ⅰ) Complexes with Organic Carboxylic Acid and Bidentate N-donor Ligands

The title complexes（NH4）[Ag（dpe）（H2bptc）]（1） and Ag2（bpy）（ox）·7H2O（2） were synthesized via slow evaporation at room temperature,and characterized by elemental analysis and infrared spectra.The crystal of 1 crystallizes in triclinic,space group P1 with a = 8.3959（7）,b = 11.8088（12）,c = 12.8175（13） ,α = 85.507（2）,β = 79.245（1）,γ = 84.174（2）o,V = 1239.7（2） 3,Z = 2,C28H22AgN3O8,Mr = 636.36,Dc = 1.705 g/cm3,F（000） = 644 and μ（MoKα） = 0.874 mm-1.The final R = 0.0479 and wR = 0.1426 for 3632 observed reflections with I 〉2σ（I） and R = 0.0559 and wR = 0.1503 for all data.The crystal of 2 crystallizes in orthorhombic,space group Pnna with a = 17.2291（17）,b = 7.5289（6）,c = 21.369（2）,V = 2771.9（4） 3,Z = 4,C22H30Ag2N4O11,Mr = 742.24,Dc = 1.779 g/cm3,F（000） = 1488 and μ（MoKα） = 1.476 mm-1.The final R = 0.0648 and wR = 0.2058 for 1996 observed reflections with I 〉2σ（I） and R = 0.0769 and wR = 0.2192 for all data.X-ray diffraction reveals that in complexes 1 and 2,both 1,2-di（4-pyridyl）ethylene and 4,4＇-bipyridine act as typical bidentate N-donor ligands to link two Ag centers.3,3＇4,4＇-Biphenyltetracarboxylate and oxalate anions play the role of organic linkers and counter-ions to balance the cationic charge of AgI.The rich hydrogen-bonding interactions and ligand-unsupported Ag…Ag interactions as well as π-π stacking interactions contribute to the construction of three-dimensional sandwich-like frameworks.

Dinuclear Silver(Ⅰ) Complex Based on 1-Picolyl-3-propylbenzimidazolium Salt: Crystal Structure and Weak Interactions

1-Picolyl-3-propylbenzimidazolium bromide （LBr） was prepared from benzimida- zole by alkylation with 2-chloromethyl-pyridine in the presence of NaH, followed by quaternization with 1-bromopropane. Ligand LBr was treated with AgBr in CH2Cl2 to afford a dinuclear silver（I） complex L2Ag2Br4 （1）. In complex 1, a 2-D supramolecular layer is formed through two types of π-π stacking interactions. Fluorescent emission spectra of ligand LBr and complex 1 are described.

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C≡CPh)]_n with a NP_3 Ligand

Two silver(I) complexes were prepared by the reaction of [Ag(C≡CPh)]n with NP3 [NP3 = N(CH2CH2PPh2)3] or with NP3 and [Cu(CH3CN)4]ClO4. Complex 1 [(Ag2Cl(NP3)2)(Ag5- (C≡CPh)6)] contains both NP3 and PhC≡C- ligands. The complex cation is (Ag2Cl(NP3)2)+, in which two Ag(NP3)+ cations were bridged by a Cl- donor. The anion is (Ag5(C≡CPh)6)-, where five Ag+ ions are linked by six C≡CPh- to form a pentanuclear cluster. Complex 2 only contains NP3 ligand, where the silver center adopts a trigonal-bipyramidal geometry. Crystal data for 1: C133H116Ag7Cl3- N2P6, Mr = 2789.54, triclinic, space group P1, a = 13.0780(2), b = 15.3678(2), c = 31.2041(3) ?, α = 91.3928(7), β = 90.9328(8), γ = 96.0244(4)o, V = 6233.8(1) ?3, T = 293(2) K, Z = 2, Dc = 1.486 g/cm3, F(000) = 2796, μ = 1.266 mm-1, the final R = 0.0746 and wR = 0.1953 for 16475 observed reflections with I > 2σ(I). Crystal data for 2: C42H42AgClNO4P3, Mr = 861.00, trigonal, space group R3, a = 17.451(1), b = 17.451(1), c = 11.3985(7) ?, V = 3006.0(3) ?3, T = 293(2) K, Z = 3, Dc = 1.427 g/cm3, F(000) = 1326, μ = 0.731 mm-1, the final R = 0.0251 and wR = 0.0663 for 1499 observed reflections with I > 2σ(I).

Synthesis and Structural Study of a N-Heterocyclic Carbene Trinuclear Silver(Ⅰ)Complex

The bis-benzimidazolium salt bis[2-（N-ethylbenzimidazoliumyl）ethyl]amine hexafluorophosphate（LH2·（PF6）2） and its N-heterocyclic carbene silver（Ⅰ） complex[L2Ag3]（PF6）3（1）have been prepared and characterized.In complex 1,a trinuclear silver（Ⅰ） architecture is formed by two tridentate ligands and three silver（I） atoms,in which one 12- and two 7-membered rings are contained.In the crystal packing of 1,1D chain and 2D supramolecular layer are formed via intermolecular weak interactions,including π…π interactions and C-H…π contacts.Additionally,the fluorescence emission spectra of LH2-（PF6）2 and 1 are described.

Synthesis, Structural Characterization and DFT Studies of Silver(I) Complex Salt of Bis(4,5-dihydro-1<i>H</i>-benzo[g]indazole)

A new silver complex salt [Ag(N2C11H10)2]NO3 (where N2C11H10 = 4,5-dihydro-1H-benzo[g]indazole), has been synthesized and characterized by elemental and thermal analyses, IR and 1HNMR spectroscopies, single crystal X-ray structure determination and DFT studies. Its molecular structure comprises of a silver center coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole molecule giving rise to a cationic complex entity, [Ag(N2C11H10)2]+ with as counter ion. The bulk structure is consolidated by N–H…O, C–H…π, Ag…π and Ag…O intermolecular interactions, thus generating a pseudo-helical network. The optimized structure, frontier molecular orbitals (HOMO and LUMO) and global reactivity descriptors were investigated by performing DFT calculations.

Luminescence intensification of lanthanide complexes by silver nanoparticles incorporated in sol-gel matrix

We present how the luminescence of europium RR-2-P-oxides complexes can be increased by interaction of electronic levels of the complex with the radiation field of silver nanoparticles （NPs）. The procedure by which silver NPs are formed in a sol-gel polyurethane matrix precursor was elaborated. The formed Ag NPs were combined with Eu complex incorporated in ormocer matrix. The emission spectra of the complexes without silver NPs were compared with spectra of the same complexes with addition of silver NPs. As the result of the interaction of the electronic levels of lanthaaide ligands with silver plasmons, dramatic increase of luminescence was observed.

The Study on the Noncovalent Complexes of Silver Ion with Xanthone Diglycosides by Electrospray Ionization with Tandem Mass Spectrometry

The silver ionic complexes of xanthone glycosides were studied by ESI-MS/MS in the positive ion mode. The fragmentation pathways of silver ionic complexes under collisioninduced dissociation （CID） were investigated and the differences in MS/MS spectra of different silver ionic complexes of xanthones were correlated to the characterization of saccharide and the coordination pattern of silver ion with xanthones, including the glycosilation position and linkage type of disaccharide （1-2 and 1-6 linkages）.

Syntheses and Crystal Structures of Two Silver(I) Complexes Isolated by the Reaction of [Ag(PPh_3)_2(MeCN)](SbF_6) with a N_6 Ligand

Two silver(I) complexes were obtained by the reaction of a N6 ligand with [Ag(PPh3)2(MeCN)](SbF6). In complex [AgL1(PPh3)](SbF6) 1, the silver center is bound to three N donors of the nitrogen ligand and P donor of one triphenylphosphine group, forming an irregular AgN3P tetrahedron. In complex [Ag(PPh3)4](SbF6) 2, the Ag+ ion is coordinated to four triphenyl- phosphine groups, affording a tetrahedral geometry. Crystal data for complex 1: C30H37AgF6N6PSb, Mr = 856.25, orthorhombic, space group Pbca, a = 19.0702(9), b = 15.9047(7), c = 21.498(1) ?, V = 6520.5(6) ?3, Z = 8, Dc= 1.744 g/cm3, F(000) = 3408, μ = 1.544 mm-1, the final R = 0.0367 and wR = 0.1077 for 5325 observed reflections with I > 2σ(I); and those for 2: C72H60AgF6P4Sb, Mr = 1392.70, trigonal, space group R3, a = 14.4577(6), b = 14.4577(6), c = 51.544(2) ?, V = 9330.5(7) ?3, Z = 6, Dc= 1.487 g/cm3, F(000) = 4224, μ = 0.913 mm-1, the final R = 0.0352 and wR = 0.1089 for 3498 observed reflections with I > 2σ(I).

Synthesis and Electrochemical Properties of a New Tetraazamacrocyclic Complex of Silver (Ⅰ)

A novel silver (Il) complex AgL(ClO4), containing a tetraazamacrocyclic ligand hasbeen synthesized. Its electrochemical behavior was studied by cyclic voltammetry.

Synthesis and Crystal Structure of Binuclear Silver(I) Complex with 2-nitro-(2-pyridylsulfanylmethyl)benzene

The reaction of 2-nitro-（2-pyridylsulfanylmethyl）benzene L with silver nitrate produces a centrosymmetric binuclear complex bis（2-nitro-（2-pyridylsulfanylmethyl）benzene-N,S）- bis（nitrato-O,O）-disilver（Ⅰ）, [AgLNO3]2 1. The crystal is of triclinic, space group PI, with a = 7.383 （3）, b = 8.340（3）, c = 12..003（4） A, a = 95.069（6）, β = 93.498（5）, γ = 102.734（6）°, C24H20Ag2N6- O10S2, Mr= 832.32, V = 715.6（4） ,A^3, Z = 1, Dc = 1.931 g/cm^3, F（000） = 412,μ = 1.581 mm^-1, R= 0.0351 and wR = 0.0749 Each silver atom is tetrahedrally coordinated by two O atoms from bidentate nitrate, one S atom from a ligand and one N atom from another ligand. Furthermore, Ag- Ag interactions have been observed in the complex.

NON-POLLUTION PROCESS FOR COMPLEX REFRACTORY SILVER-GOLD ORES

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Synthesis, Rietveld Refinement and DFT Studies of Bis(4,5-dihydro-1<i>H</i>-benzo[g]indazole)silver(I) Hexafluorophosphate Complex Salt

The new salt bis(4,5-dihydro-1H-benzo[g]indazole)silver(I) hexafluorophosphate, [Ag(N2H10C11)2]PF6, has been synthesized in methanol at ambient temperature and characterized by elemental and thermal analyses, FTIR and 1HNMR spectroscopies, Rietveld refinement from powder diffraction data and DFT studies. The salt crystallizes in the triclinic space group P-1 with the parameters: a = 7.776 ?, b = 8.676 ?, c = 9.226 ?, α = 69.27° β = 89.86°, γ = 74.50°, V = 558.02 ?3, Z = 1. In the structure, the silver center is coordinated to two nitrogen atoms from two 4,5-dihydro-1H-benzo[g]indazole ligands, forming a centrosymmetric complex cation, [Ag(N2H10C11)2]+, with a linear coordination geometry around the silver center. The hexafluorophosphate ion, , acts as counter anion. The crystal packing is governed by N-H···F and C-H···F hydrogen bonds that interconnect the ionic constituents and Ag···F and Ag···π interactions help for the stabilization of the packing. The optimized structure was obtained at B3LYP/LanL2DZ level in the gas phase. The stability and reactivity of the structure were studied using respectively HOMO-LUMO gap and electronic global quantities (ionization potential (I) and electron affinity (A)) as descriptors.

Ultrafast Optical Kerr Effect of ConjugatedSilver Phenylacetylide Complex Oligomer

Silver phenylacetylide oligomer was found to exhibit prominent third-order nonlinear optical property, with susceptibility chi((3)) of 2.4x10(-14) esu (10(-4) mol/L in 1:1 dimethyl sulfoxide/CHCl3 mixed solution) and second-order hyperpolarizability gamma of 5.18x10(-32) esu via heterodyned ultrafast optical Kerr effect measurement. It existed mainly as 1:1 complex oligomers and polymers as characterized by mass spectroscopy and elemental analysis etc.

Molecular and electronic structure of several 2,3-dithienylquinoxalines and their 2:1 complexes with silver(I) nitrate

We have synthesized three bis (thienyl) quinoxalinesilver(I) complexes;however, unlike analogous silver(I) complexes of pyridylquinoxaline that utilize (N, N) bidentate behavior from the quinoxaline and pyridyl ring nitrogens, the bis(thienyl) quinoxaline ligands did not utilize the bonding potential of the thienyl rings to give (N, S) bonding modes. PES spectra modeling of these ligands indicates that the preferential metal bonding via only the quinoxaline nitrogen atoms is due to the N-rich, but S-poor, characters of the frontier orbitals.

Optical Properties of Chiral Azo-Schiff Base Mn(II) and Zn(II) Complexes with Silver Nanoparticles

Herein we have originally designed chiral azo-salen Mn(II) and Zn(II) complexes for interacting silver nanoparticles (AgNPs) exhibiting localized surface plasmon resonance (LSPR). Understanding excited state and reaction intermediate during light irradiation to return to ground state may be important for such composite systems. Therefore, we investigated such optical properties for systems using time-resolved luminescence and transient absorption measurements. DMSO solutions of the four newly prepared and characterized complexes (MMn, MZn, CMn, and CZn) and ethanol solutions of the composite materials of each complex with AgNPs were served for optical measurements. The time-correlated single photon counting (TCSPC), the streak camera which is much shorter period of time than TCSPC and transient absorption measurement, was performed for the eight samples. The fluorescence lifetime of the sole complexes and the composite materials with AgNPs was derived from curve-fitting analysis of luminescence decay curves of TCSPC. Lifetime of the composite systems with AgNPs was longer than that of the corresponding sole metal complexes for three cases. It was revealed that composite systems may go through three reaction intermediates during relaxation from excited state to ground state.

双咪唑硝基衍生物银(Ⅰ)配合物的合成及抗厌氧菌活性

以柔性双咪唑硝基衍生物1,3-二[1-(2-甲基-4-硝基咪唑)]丙烷(L1)和1,4-二[1-(2-甲基-4-硝基咪唑)丁烷(L2)分别与硝酸银发生反应,得到配合物{[Ag(L1)NO_(3)]·H_(2)O}_n(1)和[Ag(L2)_(2)NO_(3)]·2H_(2)O(2)。采用元素分析、摩尔电导率、紫外光谱、红外光谱、固体荧光光谱、电喷雾质谱及热重分析等方法对配合物(1)、配合物(2)的组成和化学结构进行了表征与确认。通过光谱法研究了配合物与小牛胸腺DNA(ct-DNA)的相互作用,并测试了配合物对ct-DNA黏度的影响。结果表明配合物(1)、配合物(2)分别以插入、部分插入模式与DNA作用。抗厌氧菌活性实验发现,配合物(1)对厌氧菌变形链球菌(Streptococcus mutans,UA 159)和伴放线放线杆菌(Aggregatibacter actinomycetemcomitans,ATCC 29523)的抗菌活性较强,最小抑菌浓度MIC为20~40μg/mL,推测银(Ⅰ)配合物的抗菌机理有可能部分靶向细菌的DNA。固体荧光光谱实验表明配合物(1)的荧光发射光谱强度远远高于其有机配体,几乎达到其有机配体发射强度的20倍,在光致发光领域具有潜在的应用前景。