A mononuclear tungsten-benzilate, (NH4)2[WO2(Ph2COCOO)2]?H2O was ob- tained by the reaction of ammonium tungstate(VI) with excess benzilic acid in ethanol solution at pH 5~6. The title compound crystallizes in monocli...A mononuclear tungsten-benzilate, (NH4)2[WO2(Ph2COCOO)2]?H2O was ob- tained by the reaction of ammonium tungstate(VI) with excess benzilic acid in ethanol solution at pH 5~6. The title compound crystallizes in monoclinic system, space group P21/n with a = 8.1078(5), b = 25.797(2), c = 13.6815(8) ? b = 91.001(1)? V = 2861.1(3) 3, Dc = 1.719 g/cm3, F(000) = 1472, C28H32N2O10W, Mr = 740.41, m(MoKa) = 4.097 mm-1 and Z = 4. The full-matrix least-squares refinement resulted in R = 0.033 and Rw = 0.068 for 3974 observed reflections with I >2s(I). The tungsten atom is six-coordinated by two cis-oxo groups and two bidentate benzilate ligands through deprotonated a-alkoxyl and a-carboxyl groups, forming a stable five-membered chelate ring. The compound has a distorted octahedral geometry, which is mainly attributable to the bulky ligand-ligand repulsions.展开更多
The title complex [^n BuSn（O）O2C（OH）CPh2]6.2H2O has been synthesized by the reaction of n-BuSn（O）OH with benzilic acid in 1：1 molar radio and characterized by IR, ^1H NMR spectra and elemental analysis. The cry...The title complex [^n BuSn（O）O2C（OH）CPh2]6.2H2O has been synthesized by the reaction of n-BuSn（O）OH with benzilic acid in 1：1 molar radio and characterized by IR, ^1H NMR spectra and elemental analysis. The crystal structure was determined by X-ray diffraction. It crystallizes in triclinic, space group PI with a = 1.3543（2）, b = 1.4593（2）, c = 1.5293（2） nm, α = 102.075 （2）,β = 115.571 （2）, γ = 93.308（3）°, Z = 1, V = 2.6282（7） nm^3, Mr = 2550.21, Dc = 1.611 g/cm^3,μ = 1.477 mm^-1, F（000） = 1280, R = 0.0309 and wR = 0.0729. The structure shows a distorted octahedral configuration with six-coordination for the central tin atom.展开更多
Benzil,1,2-diphenylethane-1,2-dione, was used as an excellent electrocatalyst for reduction of carbon dioxide, CO. The reduction overpotential of COwas reduced about 900 m V in the presence of a benzil mediator. The c...Benzil,1,2-diphenylethane-1,2-dione, was used as an excellent electrocatalyst for reduction of carbon dioxide, CO. The reduction overpotential of COwas reduced about 900 m V in the presence of a benzil mediator. The chemical reaction of the product of the electrocatalytic reduction of CO,(activated CO,CO) with pyridine at a glassy carbon electrode, GCE, surface and in an acetonitrile-ButNClOsolution was investigated by cyclic voltammetry, chronoamperometry and controlled potential coulometry.By chronoamperometry, the catalytic rate constant, k, for the electron transfer between benzil and COwas obtained as 8.1 ± 0.4 Ms. The results indicate that pyridine has a strong interaction with the activated CO. The coulometry method was used to obtain the product of the pyridine chemical reaction with CO. The spectral characterizations of FTIR,H andC NMR of the coulometry experiment product proved that the pyridine anion radical, Py, was carboxylated by CO, and isonicotinic acid is the final major product.展开更多
Under microwave irradiation, the corresponding hydroxycyclopentenones were prepared in high yields by the cross-aldol reactions of benzil with various ketones. When the reactions were performed in various solvents und...Under microwave irradiation, the corresponding hydroxycyclopentenones were prepared in high yields by the cross-aldol reactions of benzil with various ketones. When the reactions were performed in various solvents under classical heating for a long time, they produced the products in relatively low yields.展开更多
9,10-Phenanthrenequinone（PQ） and benzil are important a-diketones. This manuscript explains the first comparison of PQ and benzil molecular properties. We have used 1H NMR, 13C NMR, 1H-IH COSY, HMBC, HMQC, UV-Vis ab...9,10-Phenanthrenequinone（PQ） and benzil are important a-diketones. This manuscript explains the first comparison of PQ and benzil molecular properties. We have used 1H NMR, 13C NMR, 1H-IH COSY, HMBC, HMQC, UV-Vis absorption and emission, CV and TGA experiments to study PQ and benzil that provided the following novel results. （1） The 1H NMR（CDC13） of PQ show δ 8.19（H1）, 8.02（H4）, 7.72（H3）, 7.47（H2） instead of an earlier reported 8.25（H4）, 8.08（H1）, 7.80（H2）, 7.55（H3）; （2） in the 13C NMR（CDCl3）, the C9/C10（C=O） signal of PQ appears upfield（6 180.3） compared to C9/Cl0（C=O） signal of benzil（6 194.5）, which shows higher electrophilic character（more attractive for nucleophiles） of C9/C10（C=O） of benzil; （3） the first 2max for the UV-Vis absorption and emission of PQ are blue-shifted compared to benzil despite increased conjugation attributed to the different symmetries（C2v for PQ and C2h for Benzil） of the two molecules; （4） the emission spectrum of benzil is broader compared to that of PQ due to slower relaxation of the excited state; （5） The CV study shows that PQ and benzil are good electron acceptors and PQ shows a better reduction process than benzil due to an extra ring that provides stability for the reduced species（mono or diradical anions）; （6） TGA shows the higher thermal stability of PQ than benzil attributed to the presence of phenanthrene unit in PQ.展开更多
A new mononuclear copper（Ⅱ） complex [（bipy）2Cu（PhCOO）]ClO4·（benzil） （bipy = 2,2＇-bipyridine, benzil = 1,2-diphenyl-ethane-1,2-dione） was synthesized by direct electrochemical oxidation of Cu electrode...A new mononuclear copper（Ⅱ） complex [（bipy）2Cu（PhCOO）]ClO4·（benzil） （bipy = 2,2＇-bipyridine, benzil = 1,2-diphenyl-ethane-1,2-dione） was synthesized by direct electrochemical oxidation of Cu electrode in an acetonitrile solution with benzoic acid, 2,2＇-bipyridine and benzoin. As soon as the current flowed in the cell, benzoin was oxidized to benzil quickly. The crystal structure was determined by X-ray diffraction. It belongs to monoclinic system, space group P21/c with a = 14.860（2）, b = 20.784（3）, c = 11.9150（17）A, β = 101.401（3）°, V= 3607.3（9）/k^3, Z = 4, M, = 806.69, D, = 1.485 g/cm^3, F（000） = 1660, μ = 0.742 mm^-1, R = 0.0788 and wR = 0.1519 for 6254 observed reflections （I 〉 2σ（I）. The complex contains a mononuclear [（bipy）2Cu（PhCOO）] cation, a solvate benzil molecule and a ClO4^- anion which locates around the cation outside acting as the counter ion. The Cu（ll） ion is coordinated by two 2,2＇-bipyridines and one benzoato ligand to form a distorted square-pyramid.展开更多
In the absence of organic solvents,the Lewis acid catalyzed cyclocondensation reactions between 1-naphthol and benzils gave 3-aryl-3-aryl'naphtho[1,2-b]furan-2(3H)-ones(NFs) in good yields(62%～70%)An electrophili...In the absence of organic solvents,the Lewis acid catalyzed cyclocondensation reactions between 1-naphthol and benzils gave 3-aryl-3-aryl'naphtho[1,2-b]furan-2(3H)-ones(NFs) in good yields(62%～70%)An electrophilic substitution mechanism involving formation of n-EPD/v- EPA complexes and rearrangement of aryl group was proposed.展开更多
The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α,5-cyclo-5α-cholestane-6-one,was established on the basis of NMR techniques and the mechanism of the formation of 2 was discus...The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α,5-cyclo-5α-cholestane-6-one,was established on the basis of NMR techniques and the mechanism of the formation of 2 was discussed.展开更多
The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy o...The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy on the front burner as a provider of clean and affordable energy for a sustainable society. We report the synthesis of a novel Schiff base with optical transparency in the visible and near IR region of the solar spectrum that can find application in the DSSCs photo-response mechanism. The synthesized crystal exhibited features that could handle some of the shortcomings of dye-sensitized solar cells which include wide band solar spectrum absorption and capability for swift charge transfer within the photoelectrodes. The synthesized Schiff base was characterized using x-ray diffractometer, UV/Visible spectrometer, Frontier transmission infrared spectrometer and conductometer. XRD data revealed the grown crystal to have an average crystallite size of 2.08 nm with average microstrain value of about 269.43. The FT-IR recorded transmission wave ѵ (CO) at 1207.7 cm<sup>−1</sup> while dominant wave occurred at ѵ1654.9 and ѵ1592.3 cm<sup>−1</sup> relating to ѵ (CN) stretching and ѵ (NH) bending respectively were observed. The IR spectrum revealed the bonding species and a probable molecular structure of 2,6-bis(benzyloxy)pyridine. The UV/Visible spectra convoluted to maximum peak within the near IR region suggesting that 2,6-bis(benzyloxy)pyridine can absorb both the visible and near IR region while its electrical conductivity was determined to be 4.58 µS/cm. The obtained result of the present study revealed promising characteristics of a photosensitizer that can find application in the photo-response mechanism of DSSCs.展开更多
Efficient room temperature phosphorescence (RTP) is rarely observed in pure organic luminogens. However, we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatogra...Efficient room temperature phosphorescence (RTP) is rarely observed in pure organic luminogens. However, we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography (TLC) plates, but become highly phosphorescent in crystal state at room temperature, exhibiting typical crystallization-induced phosphorescence (CIP) characteristics. The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions. Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons, thus giving boosted phosphorescent emission at room temperature.展开更多
A new and convenient synthetic method has been developed for the construction of stilbenes bearing electron-withdrawing group（s） by using benzils and arylmethyldiphenylphosphine oxides via sequences involving Wittig...A new and convenient synthetic method has been developed for the construction of stilbenes bearing electron-withdrawing group（s） by using benzils and arylmethyldiphenylphosphine oxides via sequences involving Wittig-Horner reaction and a rearrangement in the presence of t-BuOK in toluene under mild conditions. This approach could be readily applied to a facile synthesis of biologically important natural products, resveratrol and its derivatives, such as trimethoxystilbenes 1 （Z） and 2 （E）.展开更多
Optically active hydrobenzoins are very important building blocks for further derivation of biologically active complexes, natural products, and pharmaceutical compounds. In this paper, A practical approach has been d...Optically active hydrobenzoins are very important building blocks for further derivation of biologically active complexes, natural products, and pharmaceutical compounds. In this paper, A practical approach has been devel- oped for asymmetric hydrogenation of benzils with Ru（OTf）（TsDPEN）（rl6-cymene） as a pre-catalyst in methanol. Therefore, a series of chiral hydrobenzoins was synthesized in good yields with good to moderate diastereoselectiv- ities and good to excellent enantioselectivities.展开更多
Efficient room temperature phosphorescence(RTP)is rarely observed in pure organic luminogens.However,we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography(...Efficient room temperature phosphorescence(RTP)is rarely observed in pure organic luminogens.However,we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography(TLC)plates,but become highly phosphorescent in crystal state at room temperature,exhibiting typical crystallization-induced phosphorescence(CIP)characteristics.The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions.Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons,thus giving boosted phosphorescent emission at room temperature.展开更多
基金This work was supported by the Ministry of Science & Technology of China (001CB108906) and the National Natural Science Foundation of China (29933040)
文摘A mononuclear tungsten-benzilate, (NH4)2[WO2(Ph2COCOO)2]?H2O was ob- tained by the reaction of ammonium tungstate(VI) with excess benzilic acid in ethanol solution at pH 5~6. The title compound crystallizes in monoclinic system, space group P21/n with a = 8.1078(5), b = 25.797(2), c = 13.6815(8) ? b = 91.001(1)? V = 2861.1(3) 3, Dc = 1.719 g/cm3, F(000) = 1472, C28H32N2O10W, Mr = 740.41, m(MoKa) = 4.097 mm-1 and Z = 4. The full-matrix least-squares refinement resulted in R = 0.033 and Rw = 0.068 for 3974 observed reflections with I >2s(I). The tungsten atom is six-coordinated by two cis-oxo groups and two bidentate benzilate ligands through deprotonated a-alkoxyl and a-carboxyl groups, forming a stable five-membered chelate ring. The compound has a distorted octahedral geometry, which is mainly attributable to the bulky ligand-ligand repulsions.
基金This work was supported by the Natural Science Foundation of Hunan Province(05JJ40015) and Project supported by Science Foundation of Hengyang Normal University of China (2004D16)
文摘The title complex [^n BuSn（O）O2C（OH）CPh2]6.2H2O has been synthesized by the reaction of n-BuSn（O）OH with benzilic acid in 1：1 molar radio and characterized by IR, ^1H NMR spectra and elemental analysis. The crystal structure was determined by X-ray diffraction. It crystallizes in triclinic, space group PI with a = 1.3543（2）, b = 1.4593（2）, c = 1.5293（2） nm, α = 102.075 （2）,β = 115.571 （2）, γ = 93.308（3）°, Z = 1, V = 2.6282（7） nm^3, Mr = 2550.21, Dc = 1.611 g/cm^3,μ = 1.477 mm^-1, F（000） = 1280, R = 0.0309 and wR = 0.0729. The structure shows a distorted octahedral configuration with six-coordination for the central tin atom.
文摘Benzil,1,2-diphenylethane-1,2-dione, was used as an excellent electrocatalyst for reduction of carbon dioxide, CO. The reduction overpotential of COwas reduced about 900 m V in the presence of a benzil mediator. The chemical reaction of the product of the electrocatalytic reduction of CO,(activated CO,CO) with pyridine at a glassy carbon electrode, GCE, surface and in an acetonitrile-ButNClOsolution was investigated by cyclic voltammetry, chronoamperometry and controlled potential coulometry.By chronoamperometry, the catalytic rate constant, k, for the electron transfer between benzil and COwas obtained as 8.1 ± 0.4 Ms. The results indicate that pyridine has a strong interaction with the activated CO. The coulometry method was used to obtain the product of the pyridine chemical reaction with CO. The spectral characterizations of FTIR,H andC NMR of the coulometry experiment product proved that the pyridine anion radical, Py, was carboxylated by CO, and isonicotinic acid is the final major product.
基金Tarbiat Moallem University Research Council for partial support of this work.
文摘Under microwave irradiation, the corresponding hydroxycyclopentenones were prepared in high yields by the cross-aldol reactions of benzil with various ketones. When the reactions were performed in various solvents under classical heating for a long time, they produced the products in relatively low yields.
基金Supported by National Natural Science Foundation of China(Nos.20704016,20573040,20474024,20125421,90101026,50303007)Ministry of Education(No.20070183202)
文摘9,10-Phenanthrenequinone（PQ） and benzil are important a-diketones. This manuscript explains the first comparison of PQ and benzil molecular properties. We have used 1H NMR, 13C NMR, 1H-IH COSY, HMBC, HMQC, UV-Vis absorption and emission, CV and TGA experiments to study PQ and benzil that provided the following novel results. （1） The 1H NMR（CDC13） of PQ show δ 8.19（H1）, 8.02（H4）, 7.72（H3）, 7.47（H2） instead of an earlier reported 8.25（H4）, 8.08（H1）, 7.80（H2）, 7.55（H3）; （2） in the 13C NMR（CDCl3）, the C9/C10（C=O） signal of PQ appears upfield（6 180.3） compared to C9/Cl0（C=O） signal of benzil（6 194.5）, which shows higher electrophilic character（more attractive for nucleophiles） of C9/C10（C=O） of benzil; （3） the first 2max for the UV-Vis absorption and emission of PQ are blue-shifted compared to benzil despite increased conjugation attributed to the different symmetries（C2v for PQ and C2h for Benzil） of the two molecules; （4） the emission spectrum of benzil is broader compared to that of PQ due to slower relaxation of the excited state; （5） The CV study shows that PQ and benzil are good electron acceptors and PQ shows a better reduction process than benzil due to an extra ring that provides stability for the reduced species（mono or diradical anions）; （6） TGA shows the higher thermal stability of PQ than benzil attributed to the presence of phenanthrene unit in PQ.
基金This work was supported by the National Natural Science Foundation of China (No. 20503019)
文摘A new mononuclear copper（Ⅱ） complex [（bipy）2Cu（PhCOO）]ClO4·（benzil） （bipy = 2,2＇-bipyridine, benzil = 1,2-diphenyl-ethane-1,2-dione） was synthesized by direct electrochemical oxidation of Cu electrode in an acetonitrile solution with benzoic acid, 2,2＇-bipyridine and benzoin. As soon as the current flowed in the cell, benzoin was oxidized to benzil quickly. The crystal structure was determined by X-ray diffraction. It belongs to monoclinic system, space group P21/c with a = 14.860（2）, b = 20.784（3）, c = 11.9150（17）A, β = 101.401（3）°, V= 3607.3（9）/k^3, Z = 4, M, = 806.69, D, = 1.485 g/cm^3, F（000） = 1660, μ = 0.742 mm^-1, R = 0.0788 and wR = 0.1519 for 6254 observed reflections （I 〉 2σ（I）. The complex contains a mononuclear [（bipy）2Cu（PhCOO）] cation, a solvate benzil molecule and a ClO4^- anion which locates around the cation outside acting as the counter ion. The Cu（ll） ion is coordinated by two 2,2＇-bipyridines and one benzoato ligand to form a distorted square-pyramid.
文摘In the absence of organic solvents,the Lewis acid catalyzed cyclocondensation reactions between 1-naphthol and benzils gave 3-aryl-3-aryl'naphtho[1,2-b]furan-2(3H)-ones(NFs) in good yields(62%～70%)An electrophilic substitution mechanism involving formation of n-EPD/v- EPA complexes and rearrangement of aryl group was proposed.
文摘The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α,5-cyclo-5α-cholestane-6-one,was established on the basis of NMR techniques and the mechanism of the formation of 2 was discussed.
文摘The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy on the front burner as a provider of clean and affordable energy for a sustainable society. We report the synthesis of a novel Schiff base with optical transparency in the visible and near IR region of the solar spectrum that can find application in the DSSCs photo-response mechanism. The synthesized crystal exhibited features that could handle some of the shortcomings of dye-sensitized solar cells which include wide band solar spectrum absorption and capability for swift charge transfer within the photoelectrodes. The synthesized Schiff base was characterized using x-ray diffractometer, UV/Visible spectrometer, Frontier transmission infrared spectrometer and conductometer. XRD data revealed the grown crystal to have an average crystallite size of 2.08 nm with average microstrain value of about 269.43. The FT-IR recorded transmission wave ѵ (CO) at 1207.7 cm<sup>−1</sup> while dominant wave occurred at ѵ1654.9 and ѵ1592.3 cm<sup>−1</sup> relating to ѵ (CN) stretching and ѵ (NH) bending respectively were observed. The IR spectrum revealed the bonding species and a probable molecular structure of 2,6-bis(benzyloxy)pyridine. The UV/Visible spectra convoluted to maximum peak within the near IR region suggesting that 2,6-bis(benzyloxy)pyridine can absorb both the visible and near IR region while its electrical conductivity was determined to be 4.58 µS/cm. The obtained result of the present study revealed promising characteristics of a photosensitizer that can find application in the photo-response mechanism of DSSCs.
基金the National Natural Science Foundations of China (21104044)the National Basic Research Program of China (973 Program, 2013CB834701 and 2013CB834704)+1 种基金the Ph.D. Programs Foundation of Ministry of Education of China (20110073120040)the Shanghai Leading Academic Discipline Project (B202). W.Z.Y. thanks the Start-up Foundation and SMC-Chenxing Young Scholar Pro- gram of Shanghai Jiao Tong University.
文摘Efficient room temperature phosphorescence (RTP) is rarely observed in pure organic luminogens. However, we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography (TLC) plates, but become highly phosphorescent in crystal state at room temperature, exhibiting typical crystallization-induced phosphorescence (CIP) characteristics. The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions. Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons, thus giving boosted phosphorescent emission at room temperature.
文摘A new and convenient synthetic method has been developed for the construction of stilbenes bearing electron-withdrawing group（s） by using benzils and arylmethyldiphenylphosphine oxides via sequences involving Wittig-Horner reaction and a rearrangement in the presence of t-BuOK in toluene under mild conditions. This approach could be readily applied to a facile synthesis of biologically important natural products, resveratrol and its derivatives, such as trimethoxystilbenes 1 （Z） and 2 （E）.
基金Acknowledgement We are grateful for financial support from the Na- tional Natural Science Foundation of China （NSFC） （21072145）, the Foundation for the Authors of National Excellent Doctoral Dissertations of PR China （200931）, and the Natural Science Foundation of Jiangsu Province of China （BK2009115）. This project was also funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD）.
文摘Optically active hydrobenzoins are very important building blocks for further derivation of biologically active complexes, natural products, and pharmaceutical compounds. In this paper, A practical approach has been devel- oped for asymmetric hydrogenation of benzils with Ru（OTf）（TsDPEN）（rl6-cymene） as a pre-catalyst in methanol. Therefore, a series of chiral hydrobenzoins was synthesized in good yields with good to moderate diastereoselectiv- ities and good to excellent enantioselectivities.
文摘Efficient room temperature phosphorescence(RTP)is rarely observed in pure organic luminogens.However,we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography(TLC)plates,but become highly phosphorescent in crystal state at room temperature,exhibiting typical crystallization-induced phosphorescence(CIP)characteristics.The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions.Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons,thus giving boosted phosphorescent emission at room temperature.
