The title compound (E)-2-[(4-tert-butyl-5-(4-methoxybenzyl)thiazol-2-ylimino)methyl]phenol was synthesized by the reaction of 5-(4-methoxybenzyl)-4-tert- butylthiazol-2-amine with salicylaldehyde, and its crys...The title compound (E)-2-[(4-tert-butyl-5-(4-methoxybenzyl)thiazol-2-ylimino)methyl]phenol was synthesized by the reaction of 5-(4-methoxybenzyl)-4-tert- butylthiazol-2-amine with salicylaldehyde, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 5.9362(8), b = 11.5070(15), c = 29.460(4)A, β= 97.326(3)°, V = 1995.9(5) A^3, Z = 4, F(000) = 808, C22H24N2O2S, Mr= 380.49, De= 1.266 g/cm^3, S = 1.031,μ = 0.181 mm^-1, the final R = 0.0474 and wR = 0.1441 for 4327 observed reflections (I 〉 2σ(I)). Intramolecular O-H…N hydrogen bond is observed in the crystal. The preliminary bioassay showed that the title compound exhibits 95% inhibition rate against Rhizoctonia solani at the test concentration of 500 mg/L.展开更多
The title compound trans-4-[(5-(2,4-dichlorophenoxy)-3-methyl- 1-phenyl-1H-pyrazol-4-yl)methyleneamino]- 1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 3 (C28H23Cl2N5O2, Mr = 532.41) has been synthesized and its...The title compound trans-4-[(5-(2,4-dichlorophenoxy)-3-methyl- 1-phenyl-1H-pyrazol-4-yl)methyleneamino]- 1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 3 (C28H23Cl2N5O2, Mr = 532.41) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1- with a = 8.9438(4), b = 11.6065(5), c = 14.2215(6)A, α = 112.566(1), β = 92.324(2), γ = 102.91(1)°, V= 1315.65(10) A^3, Z = 2, Dc = 1.344 g/cm^3,μ(MoKa) = 0.282 mm^-1, λ = 0.71073 A, F(000) = 552, the final R = 0.0587 and wR = 0.1578 for 5071 observed reflections (I 〉 2σ(I)). X-ray analysis reveals that the product is a thermodynamically stable trans isomer. Intra- and intermolecular C( 12)-H(12)…O(1) and C(28)-H(28)...O(1)# 1 hydrogen bonds were observed in the title compound.展开更多
The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene) amino] phenol (4-HBAP) were studied with H2O2, air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90℃. The structures...The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene) amino] phenol (4-HBAP) were studied with H2O2, air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90℃. The structures of the obtained monomer and polymer were confirmed by FT-IR, UV-Vis, 1H- and 13C-NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly[4-(4-hydroxybenzylidene amino) phenol] (P-4-HBAP) was found to be 48.3% (for H2O2 oxidant), 80.5% (for air O2 oxidant) and 86.4% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of P-4-HBAP was found to be 8950, 10970 g tool^-1 and 1.225, respectively, using H202; and l l610, 15190 g tool^-1 and 1.308 respectively, using air 02 and 7900, 9610 g mol^-1 and 1.216, respectively, using NaOC1. According to TG-DTA analyses, P-4-HBAP was more stable than 4-HBAP against thermal decomposition. The weight loss of P-4-HBAP was found to be 49.27% at 1000℃. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) values calculated from electrochemical measurement. Electrochemical energy gaps (Eg') of 4-HBAP and P-4-HBAP were found to be -5.46, -5.28; -2.26, -2.67; 3.20 and 2.61 eV, respectively. According to UV-Vis measurements, optical band gap (Eg) of 4-HBAP and P-4-HBAP were found to be 3.34 and 3.01 eV, respectively. Also, antimicrobial activities of 4-HBAP and P-4-HBAP were examined against selected some bacteria. The electrical conductivity of the polymer was measured after doping with iodine.展开更多
The zinc(Ⅱ) complex with Hpbx (Hpbx = 2-(benzoxazol-2-yl)phenol) and Hpbm (Hpbm = 2-(benzimidazol-2-yl)phenol), namely [Zn(pbm)2]1.633[Zn(pbx)212.367·DMF·2H2O 1, has been synthesized and chara...The zinc(Ⅱ) complex with Hpbx (Hpbx = 2-(benzoxazol-2-yl)phenol) and Hpbm (Hpbm = 2-(benzimidazol-2-yl)phenol), namely [Zn(pbm)2]1.633[Zn(pbx)212.367·DMF·2H2O 1, has been synthesized and characterized by X-ray crystallography, FTIR and elemental analysis. The coordination structures are statistically disordered and can be regarded as a co-crystal of [Zn(pbm)2] and [Zn(pbx)2] with the ratio of ca. 0.408/0.592. Solvate water and DMF molecules are also present in the lattice. Crystal data for 1; monoclinic, space group P21/c, Mr= 2049.02, Z = 2, α = 9.7571(6), b = 25.6415(16), c = 19.8675(10) A, β= 111.342(2)°, V = 4629.7(5) A^3, Dc = 1.470 g/cm^3,μ = 1.100 mm^-1, F(000) = 2104, R = 0.0575 and wR = 0.1282 for 5528 observed reflections (I〉2σ(I)). The photoluminescent spectra for this compound have also been studied.展开更多
The title compound has been synthesized and characterized crystallographicaUy. It is a co-crystal consisting of two different neutral zinc(H) complexes with Hbpbm (Hbpbm = 4- bromo-2-(benzimidazol-2-yl)phenol) a...The title compound has been synthesized and characterized crystallographicaUy. It is a co-crystal consisting of two different neutral zinc(H) complexes with Hbpbm (Hbpbm = 4- bromo-2-(benzimidazol-2-yl)phenol) and Hnpbm (Hnpbm = 2-(1-butylbenzimidazol-2-yl)phenol). One is a monomeric mixed-ligand complex of [Zn(bpbm)(npbm)] 1 and the other a dimer of [Zn2(npbm)4] 2 with their ratio of 2:1. Thus the overall formula for the title compound is 21.2. Adjacent 1 and 2 are connected to each other by intermolecular hydrogen bonding interactions in the lattice. The crystal data: monoclinic, space group P21/c, a = 15.0141(12), b = 20.9941(17), c = 18.4686(15) A, β = 97.445(2)°, V = 5772.4(8) A^3, Mr= 2429.68, Z = 2, Dc = 1.398 g/cm^3,μ = 1.579 -1 mm , F(000) = 2504, R = 0.0637 and wR = 0.1771 for 6464 observed reflections (I 〉 2σ(I)). The geometrical structure for 1 has also been theoretically optimized and compared with the experimental one.展开更多
The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenz...The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenzonitrile with optically active amino alcohol in chloroben-zene under dry,anaerobic conditions.It belongs to the orthorhombic system,space group P212121 with a = 5.786(5),b = 10.730(5),c = 19.722(5),C15H13NO2,Mr = 239.26,V = 1224.4(12)3,Z = 4 and Dc = 1.298 mg/m3.The final R = 0.0324 for 1627 observed reflections with Ⅰ 〉 2σ(Ⅰ) and Rw = 0.0826 for all data.The structure of compound 1 was determined by X-ray diffraction,NMR and HRMS.展开更多
This work investigated the separation of potassium from sodium in alkaline solution using substituted phenol-based extractants.Superior potassium extraction was achieved with 4-tert-butyl-2-(α-methylbenzyl)phenol(t-B...This work investigated the separation of potassium from sodium in alkaline solution using substituted phenol-based extractants.Superior potassium extraction was achieved with 4-tert-butyl-2-(α-methylbenzyl)phenol(t-BAMBP)than 4-sec-butyl-2-(α-methylbenzyl)phenol(BAMBP).The optimum conditions for the extraction were 1 mol/L t-BAMBP,3:1 volumetric phase ratio(O/A),and two extraction stages.After cross-current extraction,the extraction ratio of potassium reached 90.8%.After scrubbing with deionised water at phase ratio of 4:1 and scrubbing stage of 4,a sodium scrubbing efficiency of 88.2%was obtained.After stripping using 1 mol/L H_(2)SO_(4) at phase ratio of 3:1,the stripping efficiency of potassium reached 94.2%.The potassium/sodium(K/Na)concentration ratio increased 14.3 times from 0.15 in the feed solution to 2.3 in the stripping solution.The efficient separation of potassium from sodium in alkaline solution was achieved via solvent extraction with t-BAMBP.展开更多
The quantitative structure-activity relationship (QSAR) of 16 pyrazole compounds was studied by ab initio method at the HF/3-21G level using Guassian03 soft. The optimized structures together with some characteristi...The quantitative structure-activity relationship (QSAR) of 16 pyrazole compounds was studied by ab initio method at the HF/3-21G level using Guassian03 soft. The optimized structures together with some characteristic and electric parameters of the title compounds were obtained; some stereo-parameters were calculated by HyperChem software. Stepwise multiple regression method was adopted to establish bi- and tri-parametric models between biological activity and some parameters. The lager △E and logP, the higher biological activity; and the biological activity would be promoted with the smaller μ, QN and QPYRA. It provided a theory direction to synthesize some compounds with high activity.展开更多
Two d10 metal complexes Zn(NCS)2(C14HI3NO2)2 (1) and [Cd(NO3)2(CI4HI3NO2)2]. 4H20 (2) assembled by 2-methoxy-6-(phenyliminiomethyl) phenolate ligand (C14H13NO2, HL) have been synthesized and characteri...Two d10 metal complexes Zn(NCS)2(C14HI3NO2)2 (1) and [Cd(NO3)2(CI4HI3NO2)2]. 4H20 (2) assembled by 2-methoxy-6-(phenyliminiomethyl) phenolate ligand (C14H13NO2, HL) have been synthesized and characterized by elemental analysis, IR and TG The single-crystal X-ray diffraction studies demonstrated that complex 1 crystallizes in monoclinic, P21/c space group with a = 17.321(7), b = 11.781(0), c = 15.593(2) A, fl = 110.273(6)°, V = 2984.95 A3, Z = 4, C30H26N404SzZn, Mr = 636.04, F(000) = 1312, Dc = 1.415 g/cm3,μ(MoKa) = 1.004 mm"1, the final R = 0.0403 and wR = 0.0900 for 21441 observed reflections with I 〉 20(/). Complex 2 is of monoclinic system, space group C2/c with a = 16.7767(2), b = 10.8989(2), c = 17.4928(2) A, fl = 90.614(9)°, V= 3198.37 A3, Z = 4, C28H34N4O14Cd, Mr= 731.25, F(000) = 1528, Dc = 1.568 g'cm^-3, μ(MoKa) = 0.757 mm-1, the final R = 0.0361 and wR = 0.0857 for 19811 observed reflections with I 〉 2σ(I). The two complexes were formed by Schiff base 2-methoxy-6-(phenyliminiomethyl) phenolate ligand and formed a 3D supramolecular architecture by π-πstacking interactions. Moreover, the complexes are luminescent in the solid state. These observations indicate that the complexes are promising system for the development of potential photoactive materials.展开更多
The impurities in ethyl-2-[[2′-cyanobiphenyl-4-yl] methyl] amino]-3-nitrobenzoate,an intermediate for synthesis of candesartan cilexiti,were detected by LC-MSn. The structural assignment of these impurities was carri...The impurities in ethyl-2-[[2′-cyanobiphenyl-4-yl] methyl] amino]-3-nitrobenzoate,an intermediate for synthesis of candesartan cilexiti,were detected by LC-MSn. The structural assignment of these impurities was carried out by LC-MSn using electrospray ionization source and an ion trap mass analyzer. The formation of the impurities was discussed. Also the fragmentation pathways of these compounds were studied.展开更多
Non covalent interactions are quite common in all kinds of π-systems, such as π-π interactions, long range/short range van der waal force of interactions, ion-π interactions etc. Ab initio calculations are well es...Non covalent interactions are quite common in all kinds of π-systems, such as π-π interactions, long range/short range van der waal force of interactions, ion-π interactions etc. Ab initio calculations are well established and account well for the experimental long range interaction energies for small clusters of aromatic molecules and most of the calculations were carried out using the MPn methods. If a reasonably large basis set is used to calculate the stacking interaction energies for a cluster (dimer, trimer etc.) of aromatic molecules then the electron-electron correlation energy may be properly calculated. Moreover, ab initio calculations for aromatic π-systems show that the calculated stacking interaction energies highly depend on the basis set used and the electron correlation energy. In this investigation, the electron correlation of the stacked hydrated phenol systems has been accounted at MP2 level of calculations. We have calculated the π-π stacking interaction energies of the hydrated phenolic systems with different conformations.展开更多
基金the National Project of Scientific and Technical Supporting Programs and Ministry of Science & Technology of China (No.2006BAE01A01-4)
文摘The title compound (E)-2-[(4-tert-butyl-5-(4-methoxybenzyl)thiazol-2-ylimino)methyl]phenol was synthesized by the reaction of 5-(4-methoxybenzyl)-4-tert- butylthiazol-2-amine with salicylaldehyde, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 5.9362(8), b = 11.5070(15), c = 29.460(4)A, β= 97.326(3)°, V = 1995.9(5) A^3, Z = 4, F(000) = 808, C22H24N2O2S, Mr= 380.49, De= 1.266 g/cm^3, S = 1.031,μ = 0.181 mm^-1, the final R = 0.0474 and wR = 0.1441 for 4327 observed reflections (I 〉 2σ(I)). Intramolecular O-H…N hydrogen bond is observed in the crystal. The preliminary bioassay showed that the title compound exhibits 95% inhibition rate against Rhizoctonia solani at the test concentration of 500 mg/L.
基金the Science Research Foundation of Henan Institute of Science and Technology (No. 06036)
文摘The title compound trans-4-[(5-(2,4-dichlorophenoxy)-3-methyl- 1-phenyl-1H-pyrazol-4-yl)methyleneamino]- 1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 3 (C28H23Cl2N5O2, Mr = 532.41) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1- with a = 8.9438(4), b = 11.6065(5), c = 14.2215(6)A, α = 112.566(1), β = 92.324(2), γ = 102.91(1)°, V= 1315.65(10) A^3, Z = 2, Dc = 1.344 g/cm^3,μ(MoKa) = 0.282 mm^-1, λ = 0.71073 A, F(000) = 552, the final R = 0.0587 and wR = 0.1578 for 5071 observed reflections (I 〉 2σ(I)). X-ray analysis reveals that the product is a thermodynamically stable trans isomer. Intra- and intermolecular C( 12)-H(12)…O(1) and C(28)-H(28)...O(1)# 1 hydrogen bonds were observed in the title compound.
基金This work was financially supported by the TUBITAK Grants Commission for a research grant(No.TBAG-2451(104T062)).
文摘The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene) amino] phenol (4-HBAP) were studied with H2O2, air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90℃. The structures of the obtained monomer and polymer were confirmed by FT-IR, UV-Vis, 1H- and 13C-NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly[4-(4-hydroxybenzylidene amino) phenol] (P-4-HBAP) was found to be 48.3% (for H2O2 oxidant), 80.5% (for air O2 oxidant) and 86.4% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of P-4-HBAP was found to be 8950, 10970 g tool^-1 and 1.225, respectively, using H202; and l l610, 15190 g tool^-1 and 1.308 respectively, using air 02 and 7900, 9610 g mol^-1 and 1.216, respectively, using NaOC1. According to TG-DTA analyses, P-4-HBAP was more stable than 4-HBAP against thermal decomposition. The weight loss of P-4-HBAP was found to be 49.27% at 1000℃. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) values calculated from electrochemical measurement. Electrochemical energy gaps (Eg') of 4-HBAP and P-4-HBAP were found to be -5.46, -5.28; -2.26, -2.67; 3.20 and 2.61 eV, respectively. According to UV-Vis measurements, optical band gap (Eg) of 4-HBAP and P-4-HBAP were found to be 3.34 and 3.01 eV, respectively. Also, antimicrobial activities of 4-HBAP and P-4-HBAP were examined against selected some bacteria. The electrical conductivity of the polymer was measured after doping with iodine.
基金This work was supported by the Natural Science Foundation of Guangdong Province (No. 06301028)
文摘The zinc(Ⅱ) complex with Hpbx (Hpbx = 2-(benzoxazol-2-yl)phenol) and Hpbm (Hpbm = 2-(benzimidazol-2-yl)phenol), namely [Zn(pbm)2]1.633[Zn(pbx)212.367·DMF·2H2O 1, has been synthesized and characterized by X-ray crystallography, FTIR and elemental analysis. The coordination structures are statistically disordered and can be regarded as a co-crystal of [Zn(pbm)2] and [Zn(pbx)2] with the ratio of ca. 0.408/0.592. Solvate water and DMF molecules are also present in the lattice. Crystal data for 1; monoclinic, space group P21/c, Mr= 2049.02, Z = 2, α = 9.7571(6), b = 25.6415(16), c = 19.8675(10) A, β= 111.342(2)°, V = 4629.7(5) A^3, Dc = 1.470 g/cm^3,μ = 1.100 mm^-1, F(000) = 2104, R = 0.0575 and wR = 0.1282 for 5528 observed reflections (I〉2σ(I)). The photoluminescent spectra for this compound have also been studied.
基金This work was supported by the Natural Science Foundation of Guangdong Province (No. 06301028)
文摘The title compound has been synthesized and characterized crystallographicaUy. It is a co-crystal consisting of two different neutral zinc(H) complexes with Hbpbm (Hbpbm = 4- bromo-2-(benzimidazol-2-yl)phenol) and Hnpbm (Hnpbm = 2-(1-butylbenzimidazol-2-yl)phenol). One is a monomeric mixed-ligand complex of [Zn(bpbm)(npbm)] 1 and the other a dimer of [Zn2(npbm)4] 2 with their ratio of 2:1. Thus the overall formula for the title compound is 21.2. Adjacent 1 and 2 are connected to each other by intermolecular hydrogen bonding interactions in the lattice. The crystal data: monoclinic, space group P21/c, a = 15.0141(12), b = 20.9941(17), c = 18.4686(15) A, β = 97.445(2)°, V = 5772.4(8) A^3, Mr= 2429.68, Z = 2, Dc = 1.398 g/cm^3,μ = 1.579 -1 mm , F(000) = 2504, R = 0.0637 and wR = 0.1771 for 6464 observed reflections (I 〉 2σ(I)). The geometrical structure for 1 has also been theoretically optimized and compared with the experimental one.
文摘The compound phenol,2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl(1,C15H13NO2) was synthesized with a simple,one step method free of water and air.It was obtained in a moderate yield from the reaction of 2-hydroxybenzonitrile with optically active amino alcohol in chloroben-zene under dry,anaerobic conditions.It belongs to the orthorhombic system,space group P212121 with a = 5.786(5),b = 10.730(5),c = 19.722(5),C15H13NO2,Mr = 239.26,V = 1224.4(12)3,Z = 4 and Dc = 1.298 mg/m3.The final R = 0.0324 for 1627 observed reflections with Ⅰ 〉 2σ(Ⅰ) and Rw = 0.0826 for all data.The structure of compound 1 was determined by X-ray diffraction,NMR and HRMS.
基金Projects(52034002,U1802253)supported by the National Natural Science Foundation of ChinaProject(2019YFC1908401)supported by the National Technology Support Project of China。
文摘This work investigated the separation of potassium from sodium in alkaline solution using substituted phenol-based extractants.Superior potassium extraction was achieved with 4-tert-butyl-2-(α-methylbenzyl)phenol(t-BAMBP)than 4-sec-butyl-2-(α-methylbenzyl)phenol(BAMBP).The optimum conditions for the extraction were 1 mol/L t-BAMBP,3:1 volumetric phase ratio(O/A),and two extraction stages.After cross-current extraction,the extraction ratio of potassium reached 90.8%.After scrubbing with deionised water at phase ratio of 4:1 and scrubbing stage of 4,a sodium scrubbing efficiency of 88.2%was obtained.After stripping using 1 mol/L H_(2)SO_(4) at phase ratio of 3:1,the stripping efficiency of potassium reached 94.2%.The potassium/sodium(K/Na)concentration ratio increased 14.3 times from 0.15 in the feed solution to 2.3 in the stripping solution.The efficient separation of potassium from sodium in alkaline solution was achieved via solvent extraction with t-BAMBP.
基金talents in University (NCET-04-0649)the Natural Science Foundation of Shandong Province (Y2006B07, Z2006B01)
文摘The quantitative structure-activity relationship (QSAR) of 16 pyrazole compounds was studied by ab initio method at the HF/3-21G level using Guassian03 soft. The optimized structures together with some characteristic and electric parameters of the title compounds were obtained; some stereo-parameters were calculated by HyperChem software. Stepwise multiple regression method was adopted to establish bi- and tri-parametric models between biological activity and some parameters. The lager △E and logP, the higher biological activity; and the biological activity would be promoted with the smaller μ, QN and QPYRA. It provided a theory direction to synthesize some compounds with high activity.
基金supported by the Natural Science Foundation of Zhejiang Province (LY12B01003)
文摘Two d10 metal complexes Zn(NCS)2(C14HI3NO2)2 (1) and [Cd(NO3)2(CI4HI3NO2)2]. 4H20 (2) assembled by 2-methoxy-6-(phenyliminiomethyl) phenolate ligand (C14H13NO2, HL) have been synthesized and characterized by elemental analysis, IR and TG The single-crystal X-ray diffraction studies demonstrated that complex 1 crystallizes in monoclinic, P21/c space group with a = 17.321(7), b = 11.781(0), c = 15.593(2) A, fl = 110.273(6)°, V = 2984.95 A3, Z = 4, C30H26N404SzZn, Mr = 636.04, F(000) = 1312, Dc = 1.415 g/cm3,μ(MoKa) = 1.004 mm"1, the final R = 0.0403 and wR = 0.0900 for 21441 observed reflections with I 〉 20(/). Complex 2 is of monoclinic system, space group C2/c with a = 16.7767(2), b = 10.8989(2), c = 17.4928(2) A, fl = 90.614(9)°, V= 3198.37 A3, Z = 4, C28H34N4O14Cd, Mr= 731.25, F(000) = 1528, Dc = 1.568 g'cm^-3, μ(MoKa) = 0.757 mm-1, the final R = 0.0361 and wR = 0.0857 for 19811 observed reflections with I 〉 2σ(I). The two complexes were formed by Schiff base 2-methoxy-6-(phenyliminiomethyl) phenolate ligand and formed a 3D supramolecular architecture by π-πstacking interactions. Moreover, the complexes are luminescent in the solid state. These observations indicate that the complexes are promising system for the development of potential photoactive materials.
文摘The impurities in ethyl-2-[[2′-cyanobiphenyl-4-yl] methyl] amino]-3-nitrobenzoate,an intermediate for synthesis of candesartan cilexiti,were detected by LC-MSn. The structural assignment of these impurities was carried out by LC-MSn using electrospray ionization source and an ion trap mass analyzer. The formation of the impurities was discussed. Also the fragmentation pathways of these compounds were studied.
文摘Non covalent interactions are quite common in all kinds of π-systems, such as π-π interactions, long range/short range van der waal force of interactions, ion-π interactions etc. Ab initio calculations are well established and account well for the experimental long range interaction energies for small clusters of aromatic molecules and most of the calculations were carried out using the MPn methods. If a reasonably large basis set is used to calculate the stacking interaction energies for a cluster (dimer, trimer etc.) of aromatic molecules then the electron-electron correlation energy may be properly calculated. Moreover, ab initio calculations for aromatic π-systems show that the calculated stacking interaction energies highly depend on the basis set used and the electron correlation energy. In this investigation, the electron correlation of the stacked hydrated phenol systems has been accounted at MP2 level of calculations. We have calculated the π-π stacking interaction energies of the hydrated phenolic systems with different conformations.