Synthesis,Structural Characterization and Catalytic Activity of Copper(Ⅰ)Complexes with Triphenylphosphine and Pyridine Derivatives

Two new Cu（Ⅰ） complexes [CuCl（3-PyOH）（PPh_3）_2]（1） and [Cu_2（μ-Cl）_2（4-Stpy）（Ph_3P）_3]（2）（PyOH = hydroxypyridine; stpy = styrylpyridine） with triphenylphosphine and pyridine derivatives have been synthesized and characterized by elemental analysis and X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group P2_1/c with a = 9.8945（7）, b = 37.266（2）, c = 10.9461（7） A, β = 116.0750（10）°, V = 3625.3（4） A^3, Z = 4, D_c = 1.350 Mg/cm^（-3）, μ = 0.801 mm^（-1）, F（000） = 1528, the final R = 0.0320 and w R = 0.0729 for 18568 observed reflections（I 〉 2σ（I））, R（all data） = 0.0413, wR（all data） = 0.0769, completeness to theta of 25.01 is 99.9% and GOF = 1.037. Compound 2 crystallizes in monoclinic, space group P2_1/c with a = 11.290（3）, b = 20.388（5）, c = 24.092（6） A, β = 102.028（4）°, V = 5424（2） A^3, Z = 4, D_c = 1.428 Mg/cm^（-3）, μ = 1.016 mm^（-1）, F（000） = 2408, the final R = 0.0568 and w R = 0.1486 for 27644 observed reflections（I 〉 2σ（I））, R（all data） = 0.0716, wR（all data） = 0.1592, completeness to theta of 25.01 is 99.9% and GOF = 1.056. Two new Cu（I） complexes have been utilized as catalysts for N-arylation of imidazole and both showed good catalytic activity.

Synthesis and Characterization of Polyamide-Containing 2, 6-(Substituded) pyridine Derivatives

A new series of acyelic aromatic polyamide pyridine derivatives a-h and a new macrocyclic polyamide containing pyridine ring i were synthesized by the reaction of N^2, N^6-his（2-aminoethyl） pyridine-2, 6-dicarboxamide or N^2 , N^6-bis （3-aminopropyl） pyridine-2,6-dicarboxamide with various acyl chloride. The compounds were characterized by MS, ^1H NMR, IR and elemental analysis. The single-crystal structure of g confirmed that the crystal is of triclinic, space group P-1 with Mr = 487.55, α=9.3031（19）, b=12.167（2） , c=126.50（3） nm, α=108.91（3）°, β= 97. 57（3）°, γ=102.07（3）°, Ⅴ= 1 293.5 nm, Z=2, Dc=1. 252 kg/m^3, μ=0. 086 mm^-1, F（000）=516, X-ray analysis reveals that there exist hydrogen bonding and network structure in the crystal.

Electrophysiological characterization of furo[3,2-b]pyridine derivatives as negative allosteric modulator of a7 nicotinic acetylcholine receptor

A series of lH-pyrrolo[3,2-b]pyridine (3a-3f) and fUroP,2-b]pyridine derivatives (4a-4g) were evaluated on human a7 nicotinic acetylcholine receptors (nAChRs) using two-electrode voltage clamp (TEVC) recording. A representative 2-(2-methoxyphenyl)- furo[3,2-b]pyridine 4f as negative allosteric modulator (NAM) selectively inhibited alpha7 nAChR over a3p4, a4p2 nAChRs and 5-HT3a receptor, with a potency of IC50 of 5.51 |1M and a maximum inhibition rate of 87.8%. The preliminary analysis of structure-activity relationship (SAR) suggested that compound 4f could serve as a basis for further discovery of potent and selective a7 nAChR NAMs.

Dye-sensitized photoanode decorated with pyridine additives for efficient solar water oxidation

Splitting water into hydrogen and oxygen by dye-sensitized photoelectrochemical cell(DSPEC)is a promising approach to solar fuels production.In this study,a series of pyridine derivatives as surface additives were modified on a molecular chromophore and water oxidation catalyst co-loaded TiO_(2)photoanode,TiO_(2)|RuP,1(RuP=Ru(4,4′-(PO3H2)2-2,2′-bipyridine)(2,2′-bipyridine)2,1=Ru(bda)(L)2,(bda=2,2′-bipyridine-6,6′-dicarboxylate,L=10-(pyridin-4-yloxy)decyl)phosphonic acid).The addition of pyridine additives was found to result in up to 42%increase in photocurrent.Under simulated sun-light irradiation,TiO_(2)|RuP,1,P1(P1=4-Hydroxypyridine)produced a photocurrent density of 1 mA/cm2 at a bias of 0.4 V vs.NHE in acetate buffer.Moreover,the observed photocurrents are correlated with the electron-donating ability of the substituent groups on pyridine ring.Transient absorption measurements and electrochemical impedance spectroscopy revealed that surface-bound pyridine can effectively retard the back-electron transfer from the TiO_(2)conduction band to the oxidized dye,which is a major process responsible for energy loss in DSPECs.

Synthesis of Porphyrin-Appended Pyridine as a Fluorescent Chemosensor for Cd（Ⅱ） and Hg（Ⅱ）

In this research, specific molecular sensors are classified according to the type of receptor-cation interaction, that is ligand-metal interactions. Receptors are based on a multidentate protoporphyrin-appended pyridine platform, which leaves at least a vacant coordination site for the incoming metal ions. A protoporphyrin-appended pyridine, 2,5-pyridine dicarboxyamidyl-8,13-bis（vinyl）-3,7,18,17-tetramethyl-21 H, 23 H-porphyrin（P-PTP）, was designed and synthesized. Its application as potential fluoroionophore for recognition of cadmium and mercury ions is reported. P-PTP shows chelation-enhanced fluorescence effect with Cd（Ⅱ） and Hg（Ⅱ） via the interruption of photoinduced electron transfer （PET） process, which has been utilized as the basis of the fabrication of the metal ions-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Cd（Ⅱ）- and Hg（Ⅱ）- sensitive chemosensors were investigated. It shows a linear response toward Cd（Ⅱ） and Hg（Ⅱ） in the concentration range of 1.0×10-3 to 1.0×10-7 M with a limit of detection of 1.0×10-7 M and 0.5×10-7M for Cd（Ⅱ） and Hg（Ⅱ）, respectively. The chemosensor shows good selectivity for Cd（Ⅱ） over a large number of other transition metal ions, i.e., Cu（Ⅱ）, Zn（Ⅱ） and mixed metal ions.

Stability of Rare Earth Ion-N,N′-bis(2′-Pyridine)methyl-1,10-Phenanthroline-2,9-Dimethanmine Binary Complexes

The stability constants of binary complexes Ln-L (Ln = La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+ Tb3+, Dy3+, Ho3+, L = N, N'-bis (2'-pyridine) methyl-1, 10-phenanthroline-2, 9-dimethanamine) were determined by pH potentiometric titration method at 25 +/- 0.1degreesC in 0.1 mol . L-1 NaClO4. The probable structures of the corresponding complexes were proposed. The influence of the metal ions to the stability of binary complexes and the stability difference between the complexes of rare earth ion and the corresponding complexes of Co2+, Ni2+, Cu2+ ions were discussed. The stability constants of the corresponding binary complex of radioactive Pm3+ ion were estimated by linear regression.

Crystal structures,two-photon absorption and theoretical calculation of a series of bis-vinylpyridine compounds synthesized by one-step solid state reaction

Three bis-vinylpyridine compounds (4,4′-bis(2-vinylpyridine)biphenyl L1,4,4′-bis(3-vinylpyridine) biphenyl L2,and 4,4′-bis (4-vinylpyridine)biphenyl L3) were synthesized by one-step solid-state reactions at room temperature,giving nearly quantitative yields. The compounds obtained were fully characterized by IR,MS and NMR spectroscopies. The structures of L2 and L3 were determined by single crystal X-ray diffraction analysis. No noticeable solvatochromism was observed in either one-photon absorption or one-photon excited fluorescence spectra. All of the compounds have high fluorescence quantum yields and long fluorescence lifetime. The linear and nonlinear optical properties of the compounds were investigated both experimentally and theoretically. Interestingly,the position of the nitrogen atom from pyridine influences their two-photon absorption across-sections.

Luminescence properties of the co-luminescence groups of Sm-La-pyridyl carboxylic acids

A novel ligand, N,N＇-（2,6-pyridinedicarbonyl）bis[N-（carboxymethyl）] （Lj） was designed and synthesized starting from pyri- dine-2,6-dicarboxylic acid （I）. The ligand （L0 and ititermediate product （3） were characterized by 1H nuclear magnetic resonance （NMR）, Fourier transform infrared spectrometer （FT-IR） spectra and elemental analysis. Besides, four novel co-luminescence systems of Sm-La-pyridyl carboxylic acids： K4Sm（1-x）Lax（L1）C13T1H20, K12Sm2（1-x）La2x（L2）3 C16y2H2O, K6Sm20 xyLa2x（L3）C16-y3H：O and K4Sm（1-x）Lax（L4）Cl3y4H20 （x was the mole fraction of La（III） in the mixed ions, the value was 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, respectively; Yl, Y2, Y3, Y4 were plus integer） were studied, and the mechanism of fluorescence enhancement effect was discussed detailedly.