A new complex Mn(Htpc)2(H2O)2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic ...A new complex Mn(Htpc)2(H2O)2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic system, space group P■ with a = 5.0885(10), b = 6.5574(13), c = 14.016(3) ?, β = 90.67(3)o, V = 436.34(17) ?3, Z = 1, Dc = 1.793 g·cm-3, μ = 0.855 mm-1, Mr = 471.18, F(000) = 235, the final R = 0.0454 and wR = 0.1134 for 1998 observed reflections with I > 2σ(I). The Mn(Ⅱ) ion is coordinated by two N and two O atoms from two Htpc as well as two O atoms from two coordinated water molecules, forming a 0D motif with distorted octahedral coordinate geometry. The adjacent 0D units are linked into 1D chains through hydrogen bond O(1W)–H(1 WB)···O(2), and via the O(1 W)–H(1 WA)···O(1) hydrogen bond the neighboring 1D chains are connected into a 2D supramolecular layer. Moreover, the interactions between the ligand and its complex with CT-DNA were studied by EtBr fluorescence probe, which suggested that these compounds bind to CT-DNA through an intercalation mode. The binding constants were 0.41 and 0.64 for Htpc and complex 1, respectively. It indicates that the interaction between complex 1 and CT-DNA is stronger than Htpc.展开更多
Two novel ligands named 4-styrylpyridine-2,6-dicarboxylic acid (4-SPDA) and 4-(4-(2-(2, 6-dicarboxypyridin-4-yl)- vinyl)styryl)pyridine-2,6-dicarboxylic acid(DSPDA) and their complexes with Tb(Ⅲ) were synthesized and...Two novel ligands named 4-styrylpyridine-2,6-dicarboxylic acid (4-SPDA) and 4-(4-(2-(2, 6-dicarboxypyridin-4-yl)- vinyl)styryl)pyridine-2,6-dicarboxylic acid(DSPDA) and their complexes with Tb(Ⅲ) were synthesized and characterized by infrared spectrometry, 1H nuclear magnetic resonance, elemental analysis and gas chromatograph-mass spectrometry. The ligand synthetic route was optimized. The fluorescence properties of the complex in solid state, in different kind of solvents and in solutions with different pH values were investigated in detail. The results show that the yields of DSPDA and 4-SPDA reach over 78% by Wittig-Horner reaction and other eight pyridine-2, 6-dicarboxylic acid derivatives with different substituents on pyridine ring, and their complexes with Tb(Ⅲ) are also obtained. The fluorescence intensities of the complexes with electron-donating groups are more intense than those of the complexes with electron-withdrawing groups on pyridine ring; fluorescence intensities of the complexes are the strongest in neutral solution (pH=7), and the less the dipole moment of solvent molecule is, the stronger the fluorescence intensity is. It is found that the two ligands (4-APDA and DSPDA) are the good sensitizers for Tb(Ⅲ) ion.展开更多
The coordinated polymer [Ni（pda）（H2O）3]n 1 （pda = pyridine-2,3-dicarboxylate） with one-dimensional chain structure has been obtained by hydrothermal method. Its structure was determined by X-ray crystallography ...The coordinated polymer [Ni（pda）（H2O）3]n 1 （pda = pyridine-2,3-dicarboxylate） with one-dimensional chain structure has been obtained by hydrothermal method. Its structure was determined by X-ray crystallography with the following data： monoclinic, space group P21/c, a = 6.4153（4）, b = 21.6454（14）, c = 7.3783（5） A, β = 113.079（1）°, V = 942.56（11） A^3, Z = 4, C7H9NNiO7, Mr = 27.7.86, Dc = 1.958 g/cm^3,F（000） = 568 and μ（MoKa） = 2.081 mm^-1. The final R = 0.0194 and wR = 0.0515 for 1511 observed reflections with I 〉 2σ（I）. The title complex presents an infinite 1-D polymeric chain structure consisting of repeated basic units [Ni（pda）（H2O）3]n. The center Ni（Ⅱ） ions are coordinated by one nitrogen atom and three oxygen atoms from pda ligand as well as three H2O molecules in a slightly distorted octahedral environment. The intermolecular hydrogen bonds link the 1 D chains to form a 2D layered architecture.展开更多
Europium can form a stable chelate with pyridine-2,4,6-tricarboxylic acid (PTA) with a ratio of 1:1 in aqueous. The system, having the maximum excitation and emission wavelengths at 311.0 nm and 616.3 nm, separately, ...Europium can form a stable chelate with pyridine-2,4,6-tricarboxylic acid (PTA) with a ratio of 1:1 in aqueous. The system, having the maximum excitation and emission wavelengths at 311.0 nm and 616.3 nm, separately, shows a constant fluorescence intensity in the pH range of 11.0-12.0. The method has high selectivity and sensitivity as well as low effect from foreign ions. The optimum determinate conditions were obtained. The fluorescence intensity is a linear function of Eu3+, concentration in the range of 0.0029-1.5200 mu g center dot mL(-1) and the limit of detection is 2.90 ng center dot mL(-1).展开更多
This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of he...This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.展开更多
The structure of a zinc（Ⅱ） coordination complex（1）, [C14 H10 N3 O5 Zn1.5]n or [Zn1.5（bzim）（pydc）（H2 O）]n（H2 pydc = pyridine-2,3-dicarboxylic acid, Hbzim = benzimidazole）, has been determined by X-ray crys...The structure of a zinc（Ⅱ） coordination complex（1）, [C14 H10 N3 O5 Zn1.5]n or [Zn1.5（bzim）（pydc）（H2 O）]n（H2 pydc = pyridine-2,3-dicarboxylic acid, Hbzim = benzimidazole）, has been determined by X-ray crystallography and characterized by elemental analysis, IR spectrum and luminescence. Chemical formula： C14 H10 N3 O5 Zn1.5. It crystallizes in the monoclinic system, space group P21/c with a = 12.303（4）, b = 12.052（4）, c = 10.212（3） ？, β = 104.147（4）, V = 1468.3（8） ？3, Z = 4, Mr = 398.30, Dc = 1.802 g/cm3, F（000） = 800, μ = 2.501 mm-1 and S = 1.000. The 2-D network architecture of 1 is constructed from benzimidazole, zinc and pyridine-2,3-dicarboxylic acid. The quantum-chemical calculations have been performed on ‘molecular fragments’ extracted from the crystal structure using the B3 LYP method in Gaussian 09. The luminescence spectrum shows that complex 1 emits blue luminescence.展开更多
Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting...Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.展开更多
Protonating the pyridine rings of poly(pyridine-2,5-diyl) with dodecybenzenesulfonic acid and camphorsulphonic acid produces polymer materials which can be dissolved in chloroform (in contrast to the unprotonated poly...Protonating the pyridine rings of poly(pyridine-2,5-diyl) with dodecybenzenesulfonic acid and camphorsulphonic acid produces polymer materials which can be dissolved in chloroform (in contrast to the unprotonated polymer, which can only be dissolved in strong acids such as formic acid) and allows mixing the protonated polymers with other chloroform soluble conju- gated polymers for use in electronic devices. The protonating behavior of poly(pyridine-2,5-diyl) with two kinds of surfactants is different in some levels. Dodecybenzenesulfonic acid has higher protonating ability than camphorsulphonic acid.展开更多
The Schiff base pyridine-2-carboxaldehyde-4-aminoantipyrine （CI7H16N4O 1） and its perchlorate （C17H17N4O·ClO4 2） have been prepared and characterized by elemental analysis, IR spectra and single-crystal X-ray...The Schiff base pyridine-2-carboxaldehyde-4-aminoantipyrine （CI7H16N4O 1） and its perchlorate （C17H17N4O·ClO4 2） have been prepared and characterized by elemental analysis, IR spectra and single-crystal X-ray crystallography analysis. Both 1 and 2 crystallize in the monoclinic system, space group P21/c. For 1, a = 8.6820（12）, b = 24.934（3）, c = 7.0064（10） A,, β= 97.942（3）°, V = 1502.2（4） A^3, Z = 4, Dc = 1.293 g/cm^3, F（000） = 616,μ = 0.084 mm^-1, the final R = 0.0592 and wR = 0.1244. For 2, a = 5.9302（2）, b = 20.347（7）, c = 14.663（6） A, β= 90.200（9）°, V= 1769.201） A^3, Z = 4, Dc = 1.475 g/cm^3, F（000） = 816, μ = 0.254 mm^-1, the final R = 0.0533 and wR = 0.0819. As expected, both molecular structures of 1 and 2 adopt a trans configuration about the central C=N double bond. 2 is an ionic compound with the protonation at N（1） of pyridine-2-carboxaldehyde-4- aminoantipyrine.展开更多
The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ...The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ-pyS)_2(PPh_3)_2].The molecular structure of the title compound was determined by X-ray diffraction method.展开更多
A series of new Schiff bases derived from 2-aminopyridenes and various aromatic aldehydes have been synthesized and thoroughly investigated by 1H and 13C NMR spectroscopy. The imines were found to exist as only a sing...A series of new Schiff bases derived from 2-aminopyridenes and various aromatic aldehydes have been synthesized and thoroughly investigated by 1H and 13C NMR spectroscopy. The imines were found to exist as only a single E-isomer at ambient temperature. Interestingly, 1H- and 13C-NMR chemical shifts of the (CH=N) amino group are affected by the type of substituent group (X) on the aryl ring. Furthermore UV and IR Spectra of some of the title compounds are also reported.展开更多
The complex Zn(Mept) 2 (Mept=Bis(3-methyl-oxopyridine-2-thionato)) was obtained by the reaction of MeHpt with ZnSO 4 in ethanol. A single crystal X-ray study shows that the complex bis(3-Me-oxopyridine-2-thionato)zi...The complex Zn(Mept) 2 (Mept=Bis(3-methyl-oxopyridine-2-thionato)) was obtained by the reaction of MeHpt with ZnSO 4 in ethanol. A single crystal X-ray study shows that the complex bis(3-Me-oxopyridine-2-thionato)zinc(II) (Zn 2C 24 H 24 N 4O 4S 4) is a dimer. The oxygen and sulfur atoms from Mept ligand coordinates to a zinc atom forming (3-Me-oxopyridine-2-thionato)zinc(II) monomer, and every two monomeric units are linked centrosymmetrically by two oxygen bridges. The compound Zn(Mept) 2 belongs to the monoclinic system with space group P2 1/c, a=7.7627(9), b = 10.3335(7), c=17.4528(13) , β=99.134(9)°, V=1382.2(2) 3, Z=2, M r=691.46, D c=1.661 g/cm 3, μ=2.076 mm -1 , F(000)=704, R=0\^0463, R w=0.0747 for 3378 reflections with I>2σ(I). The coordination geometry about each Zn(II) ion is a distorted trigonal bipyramid. The Zn atom is coordinated by two sulfur atoms (Zn(1)-S(1) 2.307(1); Zn(1)-S(2) 2.295(2)) and one oxygen atom (Zn-O(2A) 2.126(3)) in the equatorial plane, while the two oxygen atoms of Mept ligands (Zn(1)-O(1) 2\^050(3), Zn(1)-O(2) 2\^172(3)) occupy the axial positions with O(1)-Zn(1)-O(2) 177\^2(1)°.展开更多
Two new lanthanide-pyridinetricarboxylic complexes formulated as [Lu（pyta）（H2O）3]（1） and [La（pyta）· （H2O）2]-1.SH2O（2） were synthesized through hydrothermal reactions of LuC13 or La（NO3）y6H2O with py...Two new lanthanide-pyridinetricarboxylic complexes formulated as [Lu（pyta）（H2O）3]（1） and [La（pyta）· （H2O）2]-1.SH2O（2） were synthesized through hydrothermal reactions of LuC13 or La（NO3）y6H2O with pyridine-2,4,6-tricarboxylic acid（H3pyta）, respectively, and characterized by X-ray crystallography. Complex 1 crystal- lized in the monoclinic system with space group P21/n, a=1.01930（12） nm, b=0.73423（9） nm, c=1.45449（17） Mm, β=94.734（2）° V=1.0848（2） nm3, Z=4. Complex 2 crystallized in the monoclinic system with space group P21/c, a=0.68474（8） nm, b=1.20982（15） nm, c=1.36063（17） nm, β=99.823（2）°, V=l.1106（2） nm3, Z=4. The overall structure of complex 1 consists of 2D binuclear Lu2（pyta）4-based grid coordination layers which are further extended into a 3D supramolecular architecture via hydrogen bonding interactions. With different coordination modes of the pyta ligand, complex 2 is a 3D porous network comprised of La-carboxylate framework.展开更多
A new one-dimensional （1-D） Zn（Ⅱ） nitronyl nitroxide complex bridged by pyridine-2,4-dicarboxylate anion, [Zn（NIT4Py）（2,4-PDA）（H2O）2], （NIT4Py = 2-（4′-pyridyl）-4,4,5,5- tetramethylimidazoline-1-oxyl-3-o...A new one-dimensional （1-D） Zn（Ⅱ） nitronyl nitroxide complex bridged by pyridine-2,4-dicarboxylate anion, [Zn（NIT4Py）（2,4-PDA）（H2O）2], （NIT4Py = 2-（4′-pyridyl）-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide and 2,4-PDA = pyridine-2,4-dicarboxylate anion）, has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.834（2）, b = 7.4376（10）, c = 18.295（3） A, β = 102.848（2）°, V = 2233.2（5） A^3, C19H23N4O3Zn, Mr = 500.78, Dc = 1.489 g/cm^3,μ（MoKa） = 1.152 mm^-1, F（000） = 1036, Z = 4, the final R = 0.0390 and wR = 0.0915 for 3234 observed reflections. In the complex, each zinc（Ⅱ） ion is six-coordinated by one nitrogen atom of the radical ligand （NIT4Py）, one nitrogen atom and two oxygen atoms of two 2,4-PDA anions and two oxygen atoms of two water molecules. Each 2,4-PDA anion bridges two Zn（Ⅱ） ions via a tridentate mode into a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.展开更多
Reaction of FeCIz＇6H20, pyridine-2,4,6-tricarboxylic acid（H3pyta） and NaOH in the hydrothermal system at 185 ℃ resulted in the formation of 1D coordination polymer[Fe（Hpyta）（H2O）2]（1） based on Fe-Hpyta chain...Reaction of FeCIz＇6H20, pyridine-2,4,6-tricarboxylic acid（H3pyta） and NaOH in the hydrothermal system at 185 ℃ resulted in the formation of 1D coordination polymer[Fe（Hpyta）（H2O）2]（1） based on Fe-Hpyta chains. When the abpt[abpt=-4-amino-3,5-bis（4-pyridyl）-l,2,4-triazole] ligand was employed in the reaction system, a 3D supramolecular porous network （H2bpt）[Fe（pyta）（H2O）2]·4H2O（2） was obtained. The framework was constructed with negative （Fe-pyta） chains and the positive H3bpt^＋ in situ, formed from the abpt reagent, to form 1D channels filled with guest water molecules via hydrogen-bonds. X-Ray diffraction crystal structure analysis shows that complex 1 crystallized in the monoclinic system, space group C2/c, a=1.1490（5） nm, b=0.9008（4） nm, c=1.0058（5） nm, B=107.254（9）°, V=0.9942（8） nm3, Z=4; and complex 2 crystallizes in the triclinic system, space group P1 with a=0.90392（11） nm, b=0.96027（11 ） nm, c=1.55540（18） nm, a=73.558（2）°,B= 86.126（2）°,r= 68.745（2）°, V=1.2059（2） nm^3 and Z=2.展开更多
The employment of N-hydroxy-pyridine-2-carboxamidine in the coordination chemistry of zinc（II）, nickel（II） and manganese（II） under solvothermal conditions is reported. Four complexes of compositions, [Zn2（O2CMe...The employment of N-hydroxy-pyridine-2-carboxamidine in the coordination chemistry of zinc（II）, nickel（II） and manganese（II） under solvothermal conditions is reported. Four complexes of compositions, [Zn2（O2CMe）3{（py）C（NH2）NOH}4]（OH） （1）, [Zn4（OH）2{（py）C（NH2）- NO}4CI2]＇3MeCN （2）, [Ni（SO4）（H20）{（py）C（NH2）NOH}2]＇H2O （3） and [Mn（SO4）{（py）C（NH2）- NOH}2]n （4）, have been synthesized by rationally choosing different metal salts and dexterously employing acetate and sulfate ions as the bridging groups. Luminescent properties for 2 suggested strong emission in the solid state at room temperature. Variable temperature （2.0-300 K） magnetic studies for the linear chain complex 4 indicate weak antiferromagnetic Mn（Ⅱ）...Mn（Ⅱ） exchange interactions.展开更多
We have described herein a catalyst-free preparation method of pyridine-2,6-bis(N-alkylthiazoline-2-thiones) (4a-i) by the reaction of primary amines, CS2, and pyridine-2,6-bis(2-bromo-1,3- dicarbonyl) derivatives (2a...We have described herein a catalyst-free preparation method of pyridine-2,6-bis(N-alkylthiazoline-2-thiones) (4a-i) by the reaction of primary amines, CS2, and pyridine-2,6-bis(2-bromo-1,3- dicarbonyl) derivatives (2a-c) in water. Also, we have described a catalyst free, green chemistry protocols to monobromination of pyridine-2,6-bis(2-bromo-1,3-dicarbonyl) derivatives with high yield, using NBS as a brominating agent, that led to eco-friendly isolation and purification proce-dures. Furthermore, we have studied the reactivity of pyridine-2,6-bis(2-bromo-1-methyl-pro- pane-1,3-dione) (2a) towards thiourea to afford 2,6-bis(5-benzoyl-2-aminothiazol-4-yl)pyridine (9).展开更多
基金Supported by the Scientific Research Foundation of Higher Education Institutions of Ningxia(No.NGY2017004)the National Natural Science Foundation of China(Nos.21763022 and 50564043)the Major Innovation Projects for Building First-class Universities in China’s Western Region(No.ZKZD2017003)
文摘A new complex Mn(Htpc)2(H2O)2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic system, space group P■ with a = 5.0885(10), b = 6.5574(13), c = 14.016(3) ?, β = 90.67(3)o, V = 436.34(17) ?3, Z = 1, Dc = 1.793 g·cm-3, μ = 0.855 mm-1, Mr = 471.18, F(000) = 235, the final R = 0.0454 and wR = 0.1134 for 1998 observed reflections with I > 2σ(I). The Mn(Ⅱ) ion is coordinated by two N and two O atoms from two Htpc as well as two O atoms from two coordinated water molecules, forming a 0D motif with distorted octahedral coordinate geometry. The adjacent 0D units are linked into 1D chains through hydrogen bond O(1W)–H(1 WB)···O(2), and via the O(1 W)–H(1 WA)···O(1) hydrogen bond the neighboring 1D chains are connected into a 2D supramolecular layer. Moreover, the interactions between the ligand and its complex with CT-DNA were studied by EtBr fluorescence probe, which suggested that these compounds bind to CT-DNA through an intercalation mode. The binding constants were 0.41 and 0.64 for Htpc and complex 1, respectively. It indicates that the interaction between complex 1 and CT-DNA is stronger than Htpc.
基金Project(20761002) supported by the National Natural Science Foundation of China
文摘Two novel ligands named 4-styrylpyridine-2,6-dicarboxylic acid (4-SPDA) and 4-(4-(2-(2, 6-dicarboxypyridin-4-yl)- vinyl)styryl)pyridine-2,6-dicarboxylic acid(DSPDA) and their complexes with Tb(Ⅲ) were synthesized and characterized by infrared spectrometry, 1H nuclear magnetic resonance, elemental analysis and gas chromatograph-mass spectrometry. The ligand synthetic route was optimized. The fluorescence properties of the complex in solid state, in different kind of solvents and in solutions with different pH values were investigated in detail. The results show that the yields of DSPDA and 4-SPDA reach over 78% by Wittig-Horner reaction and other eight pyridine-2, 6-dicarboxylic acid derivatives with different substituents on pyridine ring, and their complexes with Tb(Ⅲ) are also obtained. The fluorescence intensities of the complexes with electron-donating groups are more intense than those of the complexes with electron-withdrawing groups on pyridine ring; fluorescence intensities of the complexes are the strongest in neutral solution (pH=7), and the less the dipole moment of solvent molecule is, the stronger the fluorescence intensity is. It is found that the two ligands (4-APDA and DSPDA) are the good sensitizers for Tb(Ⅲ) ion.
文摘The coordinated polymer [Ni（pda）（H2O）3]n 1 （pda = pyridine-2,3-dicarboxylate） with one-dimensional chain structure has been obtained by hydrothermal method. Its structure was determined by X-ray crystallography with the following data： monoclinic, space group P21/c, a = 6.4153（4）, b = 21.6454（14）, c = 7.3783（5） A, β = 113.079（1）°, V = 942.56（11） A^3, Z = 4, C7H9NNiO7, Mr = 27.7.86, Dc = 1.958 g/cm^3,F（000） = 568 and μ（MoKa） = 2.081 mm^-1. The final R = 0.0194 and wR = 0.0515 for 1511 observed reflections with I 〉 2σ（I）. The title complex presents an infinite 1-D polymeric chain structure consisting of repeated basic units [Ni（pda）（H2O）3]n. The center Ni（Ⅱ） ions are coordinated by one nitrogen atom and three oxygen atoms from pda ligand as well as three H2O molecules in a slightly distorted octahedral environment. The intermolecular hydrogen bonds link the 1 D chains to form a 2D layered architecture.
基金This project was financially supported by the Natural Science Foundation of Gansu Province, China (ZR-97-21).
文摘Europium can form a stable chelate with pyridine-2,4,6-tricarboxylic acid (PTA) with a ratio of 1:1 in aqueous. The system, having the maximum excitation and emission wavelengths at 311.0 nm and 616.3 nm, separately, shows a constant fluorescence intensity in the pH range of 11.0-12.0. The method has high selectivity and sensitivity as well as low effect from foreign ions. The optimum determinate conditions were obtained. The fluorescence intensity is a linear function of Eu3+, concentration in the range of 0.0029-1.5200 mu g center dot mL(-1) and the limit of detection is 2.90 ng center dot mL(-1).
基金Project supported by the National Natural Science Foundations of China (Grant Nos.20673050 and 20973089)
文摘This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.
基金Supported by the Jilin Province Science and Technology Development Plan Item(No.20140204080GX)the Project of the Education Department of Jilin Province,China(No.JJKH20180777KJ)the Science and Technology Development Projects of Siping City(No.2017057)
文摘The structure of a zinc（Ⅱ） coordination complex（1）, [C14 H10 N3 O5 Zn1.5]n or [Zn1.5（bzim）（pydc）（H2 O）]n（H2 pydc = pyridine-2,3-dicarboxylic acid, Hbzim = benzimidazole）, has been determined by X-ray crystallography and characterized by elemental analysis, IR spectrum and luminescence. Chemical formula： C14 H10 N3 O5 Zn1.5. It crystallizes in the monoclinic system, space group P21/c with a = 12.303（4）, b = 12.052（4）, c = 10.212（3） ？, β = 104.147（4）, V = 1468.3（8） ？3, Z = 4, Mr = 398.30, Dc = 1.802 g/cm3, F（000） = 800, μ = 2.501 mm-1 and S = 1.000. The 2-D network architecture of 1 is constructed from benzimidazole, zinc and pyridine-2,3-dicarboxylic acid. The quantum-chemical calculations have been performed on ‘molecular fragments’ extracted from the crystal structure using the B3 LYP method in Gaussian 09. The luminescence spectrum shows that complex 1 emits blue luminescence.
文摘Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.
文摘Protonating the pyridine rings of poly(pyridine-2,5-diyl) with dodecybenzenesulfonic acid and camphorsulphonic acid produces polymer materials which can be dissolved in chloroform (in contrast to the unprotonated polymer, which can only be dissolved in strong acids such as formic acid) and allows mixing the protonated polymers with other chloroform soluble conju- gated polymers for use in electronic devices. The protonating behavior of poly(pyridine-2,5-diyl) with two kinds of surfactants is different in some levels. Dodecybenzenesulfonic acid has higher protonating ability than camphorsulphonic acid.
基金supported by the NSF of Guangxi Province (No. 0575046, 0575049)the Program for New Century Ten-Hundred-Thousand Excellent Talents of Guangxi (No. 2003223)+1 种基金the National Natural Science Foundation of China (No. 20361002, 30460153) as well as TRAPOYTNCET-04-0836 of Chinese Ministry of Education
文摘The Schiff base pyridine-2-carboxaldehyde-4-aminoantipyrine （CI7H16N4O 1） and its perchlorate （C17H17N4O·ClO4 2） have been prepared and characterized by elemental analysis, IR spectra and single-crystal X-ray crystallography analysis. Both 1 and 2 crystallize in the monoclinic system, space group P21/c. For 1, a = 8.6820（12）, b = 24.934（3）, c = 7.0064（10） A,, β= 97.942（3）°, V = 1502.2（4） A^3, Z = 4, Dc = 1.293 g/cm^3, F（000） = 616,μ = 0.084 mm^-1, the final R = 0.0592 and wR = 0.1244. For 2, a = 5.9302（2）, b = 20.347（7）, c = 14.663（6） A, β= 90.200（9）°, V= 1769.201） A^3, Z = 4, Dc = 1.475 g/cm^3, F（000） = 816, μ = 0.254 mm^-1, the final R = 0.0533 and wR = 0.0819. As expected, both molecular structures of 1 and 2 adopt a trans configuration about the central C=N double bond. 2 is an ionic compound with the protonation at N（1） of pyridine-2-carboxaldehyde-4- aminoantipyrine.
文摘The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ-pyS)_2(PPh_3)_2].The molecular structure of the title compound was determined by X-ray diffraction method.
文摘A series of new Schiff bases derived from 2-aminopyridenes and various aromatic aldehydes have been synthesized and thoroughly investigated by 1H and 13C NMR spectroscopy. The imines were found to exist as only a single E-isomer at ambient temperature. Interestingly, 1H- and 13C-NMR chemical shifts of the (CH=N) amino group are affected by the type of substituent group (X) on the aryl ring. Furthermore UV and IR Spectra of some of the title compounds are also reported.
文摘The complex Zn(Mept) 2 (Mept=Bis(3-methyl-oxopyridine-2-thionato)) was obtained by the reaction of MeHpt with ZnSO 4 in ethanol. A single crystal X-ray study shows that the complex bis(3-Me-oxopyridine-2-thionato)zinc(II) (Zn 2C 24 H 24 N 4O 4S 4) is a dimer. The oxygen and sulfur atoms from Mept ligand coordinates to a zinc atom forming (3-Me-oxopyridine-2-thionato)zinc(II) monomer, and every two monomeric units are linked centrosymmetrically by two oxygen bridges. The compound Zn(Mept) 2 belongs to the monoclinic system with space group P2 1/c, a=7.7627(9), b = 10.3335(7), c=17.4528(13) , β=99.134(9)°, V=1382.2(2) 3, Z=2, M r=691.46, D c=1.661 g/cm 3, μ=2.076 mm -1 , F(000)=704, R=0\^0463, R w=0.0747 for 3378 reflections with I>2σ(I). The coordination geometry about each Zn(II) ion is a distorted trigonal bipyramid. The Zn atom is coordinated by two sulfur atoms (Zn(1)-S(1) 2.307(1); Zn(1)-S(2) 2.295(2)) and one oxygen atom (Zn-O(2A) 2.126(3)) in the equatorial plane, while the two oxygen atoms of Mept ligands (Zn(1)-O(1) 2\^050(3), Zn(1)-O(2) 2\^172(3)) occupy the axial positions with O(1)-Zn(1)-O(2) 177\^2(1)°.
基金Supported by the Scientific and Technological Project of Guangdong Province,China(No.2006B36703005)
文摘Two new lanthanide-pyridinetricarboxylic complexes formulated as [Lu（pyta）（H2O）3]（1） and [La（pyta）· （H2O）2]-1.SH2O（2） were synthesized through hydrothermal reactions of LuC13 or La（NO3）y6H2O with pyridine-2,4,6-tricarboxylic acid（H3pyta）, respectively, and characterized by X-ray crystallography. Complex 1 crystal- lized in the monoclinic system with space group P21/n, a=1.01930（12） nm, b=0.73423（9） nm, c=1.45449（17） Mm, β=94.734（2）° V=1.0848（2） nm3, Z=4. Complex 2 crystallized in the monoclinic system with space group P21/c, a=0.68474（8） nm, b=1.20982（15） nm, c=1.36063（17） nm, β=99.823（2）°, V=l.1106（2） nm3, Z=4. The overall structure of complex 1 consists of 2D binuclear Lu2（pyta）4-based grid coordination layers which are further extended into a 3D supramolecular architecture via hydrogen bonding interactions. With different coordination modes of the pyta ligand, complex 2 is a 3D porous network comprised of La-carboxylate framework.
基金This work was supported by the National Natural Science Foundation of China (No. 20331010 and 20571045)
文摘A new one-dimensional （1-D） Zn（Ⅱ） nitronyl nitroxide complex bridged by pyridine-2,4-dicarboxylate anion, [Zn（NIT4Py）（2,4-PDA）（H2O）2], （NIT4Py = 2-（4′-pyridyl）-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide and 2,4-PDA = pyridine-2,4-dicarboxylate anion）, has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.834（2）, b = 7.4376（10）, c = 18.295（3） A, β = 102.848（2）°, V = 2233.2（5） A^3, C19H23N4O3Zn, Mr = 500.78, Dc = 1.489 g/cm^3,μ（MoKa） = 1.152 mm^-1, F（000） = 1036, Z = 4, the final R = 0.0390 and wR = 0.0915 for 3234 observed reflections. In the complex, each zinc（Ⅱ） ion is six-coordinated by one nitrogen atom of the radical ligand （NIT4Py）, one nitrogen atom and two oxygen atoms of two 2,4-PDA anions and two oxygen atoms of two water molecules. Each 2,4-PDA anion bridges two Zn（Ⅱ） ions via a tridentate mode into a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.
基金the Scientific and Technological Project of Guangdong Province, China(No.2006B36703005)
文摘Reaction of FeCIz＇6H20, pyridine-2,4,6-tricarboxylic acid（H3pyta） and NaOH in the hydrothermal system at 185 ℃ resulted in the formation of 1D coordination polymer[Fe（Hpyta）（H2O）2]（1） based on Fe-Hpyta chains. When the abpt[abpt=-4-amino-3,5-bis（4-pyridyl）-l,2,4-triazole] ligand was employed in the reaction system, a 3D supramolecular porous network （H2bpt）[Fe（pyta）（H2O）2]·4H2O（2） was obtained. The framework was constructed with negative （Fe-pyta） chains and the positive H3bpt^＋ in situ, formed from the abpt reagent, to form 1D channels filled with guest water molecules via hydrogen-bonds. X-Ray diffraction crystal structure analysis shows that complex 1 crystallized in the monoclinic system, space group C2/c, a=1.1490（5） nm, b=0.9008（4） nm, c=1.0058（5） nm, B=107.254（9）°, V=0.9942（8） nm3, Z=4; and complex 2 crystallizes in the triclinic system, space group P1 with a=0.90392（11） nm, b=0.96027（11 ） nm, c=1.55540（18） nm, a=73.558（2）°,B= 86.126（2）°,r= 68.745（2）°, V=1.2059（2） nm^3 and Z=2.
基金Supported by NNSFC(21272167 and 21201127)the Priority Academic Program Development of Jiangsu Higher Education Institution,Graduate Education Innovation Project in Jiangsu Province(CXZZ12_0808 and CXLX12_0784)KLSLRC(KLSLRC-KF-13-HX-1)
文摘The employment of N-hydroxy-pyridine-2-carboxamidine in the coordination chemistry of zinc（II）, nickel（II） and manganese（II） under solvothermal conditions is reported. Four complexes of compositions, [Zn2（O2CMe）3{（py）C（NH2）NOH}4]（OH） （1）, [Zn4（OH）2{（py）C（NH2）- NO}4CI2]＇3MeCN （2）, [Ni（SO4）（H20）{（py）C（NH2）NOH}2]＇H2O （3） and [Mn（SO4）{（py）C（NH2）- NOH}2]n （4）, have been synthesized by rationally choosing different metal salts and dexterously employing acetate and sulfate ions as the bridging groups. Luminescent properties for 2 suggested strong emission in the solid state at room temperature. Variable temperature （2.0-300 K） magnetic studies for the linear chain complex 4 indicate weak antiferromagnetic Mn（Ⅱ）...Mn（Ⅱ） exchange interactions.
文摘We have described herein a catalyst-free preparation method of pyridine-2,6-bis(N-alkylthiazoline-2-thiones) (4a-i) by the reaction of primary amines, CS2, and pyridine-2,6-bis(2-bromo-1,3- dicarbonyl) derivatives (2a-c) in water. Also, we have described a catalyst free, green chemistry protocols to monobromination of pyridine-2,6-bis(2-bromo-1,3-dicarbonyl) derivatives with high yield, using NBS as a brominating agent, that led to eco-friendly isolation and purification proce-dures. Furthermore, we have studied the reactivity of pyridine-2,6-bis(2-bromo-1-methyl-pro- pane-1,3-dione) (2a) towards thiourea to afford 2,6-bis(5-benzoyl-2-aminothiazol-4-yl)pyridine (9).
