At 200 ℃ and 50 mPa, the oxidative carbonylation of amines catalyzed by organic gold complexes HAuCl 4, Au(PPh 3)Cl, Au(PPh 3) 2Cl, Au(PPh 3)NO 3 and [Au(PPh 3)] 2S afforded R(NHCO 2CH 3) n with a high conversion and...At 200 ℃ and 50 mPa, the oxidative carbonylation of amines catalyzed by organic gold complexes HAuCl 4, Au(PPh 3)Cl, Au(PPh 3) 2Cl, Au(PPh 3)NO 3 and [Au(PPh 3)] 2S afforded R(NHCO 2CH 3) n with a high conversion and selectivity. The best results were obtained when using the catalyst Au(PPh 3)Cl in the presence of PPh 3. The catalytic efficiency of catalytic Au(PPh 3)Cl was compared to Pd(PPh 3) 2Cl 2, e.g. the conversion was 97.2% and selectivity was 89% when using catalyst Au(PPh 3)Cl in the presence of PPh 3, while the conversion was 98.8% and selectivity was 86% when using catalyst Pd(PPh 3) 2Cl 2 in the presence of PPh 3. The experimental results suggested that Au complexes might be promising catalysts instead of Pd catalysts for the oxidative carbonylation of amines to carbamates.展开更多
The chemical kinetics of the monoesterification between terephthalic acid(TPA)and 1,4-butanediol (BDO)catalyzed by a metallo-organic compound was studied using the initial rate method.The experiments were carried out ...The chemical kinetics of the monoesterification between terephthalic acid(TPA)and 1,4-butanediol (BDO)catalyzed by a metallo-organic compound was studied using the initial rate method.The experiments were carried out in the temperature range of 463-483 K,and butylhydroxyoxo-stannane(BuSnOOH)and tetrabutyl titanate[Ti(OBu)4]were used as catalyst respectively.The initial rates of the reaction catalyzed by BuSnOOH or Ti(OBu)4 were measured at a series of initial concentrations of BDO(or TPA)with the concentration of TPA(or BDO)kept constant.The reaction orders of reagents were determined by the initial rate method.The results indicate that the reaction order for TPA is related with the species of catalyst and it is 2 and 0.7 for BuSnOOH and Ti(OBu)4 respectively.However,the order for BDO is the same 0.9 for the two catalysts.Furthermore,the effects of temperature and catalyst concentration are investigated,and the activation energies and the reaction rate constants for the two catalysts were determined.展开更多
The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-cry...The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-crystal diffraction. It belongs to orthorhombic with space group Pccn, a = 20.949(3), b = 17.470(3), c = 20.345(3) Angstrom, V = 7446(2) Angstrom(3), Z = 8, D-c = 1.242 g/cm(3), mu = 1.365 mm(-1), F(000) = 2864, R = 0.0544 and wR = 0.1417. The tin atom is of five-coordination in a trigonal bipyramidal structure by bridging two carboxylate groups in different directions and the resulting structure which contains straight twist large ring channels along the axes of a, b and c is a three-dimensional framework polymer containing two different tin atoms.展开更多
We designed and synthesized ligand L1 with C3 synametry in the paper, through self-assembly with silver nitrate obtained complexes 1 of silver double helix with three nuclear, that were used to characterize its struct...We designed and synthesized ligand L1 with C3 synametry in the paper, through self-assembly with silver nitrate obtained complexes 1 of silver double helix with three nuclear, that were used to characterize its structure by NMR and mass spectrometry, the complex silver as the catalytic sites, and the ligand L of hydrogen on the nitrogen fell microphone has certain basic, that can be used as an auxiliary Methylene dehydrogenation of Isopropyl methyl cyanoacetate, thereby accelerating the reaction. Further, the introduction of a chiral ligand to give complexes 2, to achieve an asymmetric aldol reaction of methyl isocyanoacetate.展开更多
The interactions between the new organometallic complexes, ferrocenesubstituted dithioocarborane conjugates （denoted as FcSB1, FcSB2 and FcSBCO） and hemoglobin （Hb） are investigated by electrochemistry, fluorescen...The interactions between the new organometallic complexes, ferrocenesubstituted dithioocarborane conjugates （denoted as FcSB1, FcSB2 and FcSBCO） and hemoglobin （Hb） are investigated by electrochemistry, fluorescence and UVvis absorption spectroscopy. The results demonstrate that FcSB1, FcSB2 and FcSBCO can bind to the heme iron center through the replacement of the weakly bound H20/02 in the distal heme pocket of Hb by their sulfur donor atoms, inducing the allosteric change from the R state （oxygenated conformation, relax） to T state （deoxygenated conformation, tense）. The binding affinity is in the order of FcSBCO〉FeSB2〉FeSB1. Moreover, the fluorescence study illustrates that the three ferrocenecarborane conjugates differently affect the quarterly and tertiary structures as well as the polarity in the surrounding of the Trp and Tyr residues in Hb. Typically, FcSB2 mainly induces alterations of the microenvironment around the 1337Trp residue which is located on the cql32 interface of Hb. Such distinct influences are attributed to the structural features of FcSB1, FcSB2 and FcSBCO containing hydrophobic ferrocenyl and carboranyl units as well as C=O group. Screening the proteinbinding behavior can signify the potential bioactivity of such molecules and may be helpful in the future development of promising multifunctional metallodrugs.展开更多
Chirality-specific growth of single-walled carbon nanotubes(SWNTs) remains a challenge for their practical applications in electronics. Here, we explored the surface growth of SWNTs by utilizing the atomic-precise sil...Chirality-specific growth of single-walled carbon nanotubes(SWNTs) remains a challenge for their practical applications in electronics. Here, we explored the surface growth of SWNTs by utilizing the atomic-precise silver cluster complex [Ag_(15){1,3,5–(C:C)_3–C_6H_3}_2(Py[8])_3–(CF_3SO_3)_3](CF_3SO_3)_6(Py[8] is abbreviation for octamethylazacalix[8]pyridine) as a catalyst precursor. The diameters of most acquired SWNTs distributed in the range of 1.2–1.4 nm, which is suitable for making high performance field-effect transistors. The high quality of the obtained SWNTs was evidenced by Raman spectroscopy and electrical measurements. Successful growth of high quality SWNTs in this study foresees that rational design of metal-organic complexes as growth catalysts can open up a new avenue for the controllable synthesis of SWNTs.展开更多
Transition metal-catalyzed decarboxylative cross-coupling reactions have recently emerged as a new and important category of organic transformations that find versatile applications in the construction of carbon-carbo...Transition metal-catalyzed decarboxylative cross-coupling reactions have recently emerged as a new and important category of organic transformations that find versatile applications in the construction of carbon-carbon and carbon-heteroatom bonds. The use of relatively cheap and stable carboxylic acids to replace organometallic reagents enables the decarboxylative cross-coupling reactions to proceed with good selectivities and functional group tolerance. In the present review we summarize the various types of decarboxylative cross-coupling reactions catalyzed by different transition metal complexes. The scope and applications of these reactions are described. The challenges and opportunities in the field are discussed.展开更多
This review discusses chiral-at-metal complexes and introduces enantiomorphs from assembly structure.Owing to the diverse coordination number and activity of metal ions as chiral centers, abundant structures for chira...This review discusses chiral-at-metal complexes and introduces enantiomorphs from assembly structure.Owing to the diverse coordination number and activity of metal ions as chiral centers, abundant structures for chiral selectivity, catalysis, and polarized light-response are the notable advantages of the chiral-at-metal complexes. The rational design and preparation of linear multi-dentate ligands is a good choice to improve the stability of chiral complexes, such as multi-bonding structure for high stability as a self-limiting system. The bio-significance and potential application of chiral-at-metal complexes are discussed, such as the synergistic effect of catalysis and chiral selectivity of the metal center in enzymes.Enzyme could be remolded to replace the original central metal ions with highly active rare earth or precious metal ions to form artificial metalloenzyme or to remove the ‘‘redundant" part around the metal center to improve the accessibility of substrate. The polarized light-response mechanism of chiral opsin is introduced in relation to its role in animal migration. Metal-organic frameworks(MOFs) are crystalline and porous materials built from metal nodes or clusters and organic linkers and provide the possibility to prepare artificial enantiomorphs. The preparations, applications, and characterization methods of MOF enatiomorphs are therefore introduced. We hope this review inspires researchers at all levels of their career to consider the title topic in their own research in terms of its application and potential value.展开更多
Based on isolobal analogy,the definition of metallafuran was described and its synthetic chemistry was briefly summarized.In the structure of furan,when one of CH groups was replaced by an isolobal metal fragment ML n...Based on isolobal analogy,the definition of metallafuran was described and its synthetic chemistry was briefly summarized.In the structure of furan,when one of CH groups was replaced by an isolobal metal fragment ML n(M=metal;L=ligand),the corresponding organometallic complex was called metallafuran,which should be two possible isomers called a-metallafuran(metal fragment at a-carbon of original furan)and b-metallafuran(metal fragment at b-carbon of original furan).As an organometallic complex,a-metallafuran has two resonant forms:one can be viewed as carbonyl coordinated vinyl metal complex and the other can be viewed as alkoxymetal carbene.Therefore,a-metallafuran was also called chelated vinyl ketone metal complex or oxametallacyclopentadiene in the early literatures.For synthesis of metallafurans,a-metallafurans were very common and easily prepared,for example,from alkynes insertion into acyl metal complexes and so on.While there were rare examples reported for b-metallafurans.In this mini review,the synthetic chemistry of metallafuran was mainly focused on its formation mechanism.展开更多
文摘At 200 ℃ and 50 mPa, the oxidative carbonylation of amines catalyzed by organic gold complexes HAuCl 4, Au(PPh 3)Cl, Au(PPh 3) 2Cl, Au(PPh 3)NO 3 and [Au(PPh 3)] 2S afforded R(NHCO 2CH 3) n with a high conversion and selectivity. The best results were obtained when using the catalyst Au(PPh 3)Cl in the presence of PPh 3. The catalytic efficiency of catalytic Au(PPh 3)Cl was compared to Pd(PPh 3) 2Cl 2, e.g. the conversion was 97.2% and selectivity was 89% when using catalyst Au(PPh 3)Cl in the presence of PPh 3, while the conversion was 98.8% and selectivity was 86% when using catalyst Pd(PPh 3) 2Cl 2 in the presence of PPh 3. The experimental results suggested that Au complexes might be promising catalysts instead of Pd catalysts for the oxidative carbonylation of amines to carbamates.
文摘The chemical kinetics of the monoesterification between terephthalic acid(TPA)and 1,4-butanediol (BDO)catalyzed by a metallo-organic compound was studied using the initial rate method.The experiments were carried out in the temperature range of 463-483 K,and butylhydroxyoxo-stannane(BuSnOOH)and tetrabutyl titanate[Ti(OBu)4]were used as catalyst respectively.The initial rates of the reaction catalyzed by BuSnOOH or Ti(OBu)4 were measured at a series of initial concentrations of BDO(or TPA)with the concentration of TPA(or BDO)kept constant.The reaction orders of reagents were determined by the initial rate method.The results indicate that the reaction order for TPA is related with the species of catalyst and it is 2 and 0.7 for BuSnOOH and Ti(OBu)4 respectively.However,the order for BDO is the same 0.9 for the two catalysts.Furthermore,the effects of temperature and catalyst concentration are investigated,and the activation energies and the reaction rate constants for the two catalysts were determined.
基金the National Natural Science Foundation of China (No. 20271025)the Natural Science Foundation of Shandong province (No. Z2001B02)the State Key Laboratory of Crystal Materials,Shandong University
文摘The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-crystal diffraction. It belongs to orthorhombic with space group Pccn, a = 20.949(3), b = 17.470(3), c = 20.345(3) Angstrom, V = 7446(2) Angstrom(3), Z = 8, D-c = 1.242 g/cm(3), mu = 1.365 mm(-1), F(000) = 2864, R = 0.0544 and wR = 0.1417. The tin atom is of five-coordination in a trigonal bipyramidal structure by bridging two carboxylate groups in different directions and the resulting structure which contains straight twist large ring channels along the axes of a, b and c is a three-dimensional framework polymer containing two different tin atoms.
文摘We designed and synthesized ligand L1 with C3 synametry in the paper, through self-assembly with silver nitrate obtained complexes 1 of silver double helix with three nuclear, that were used to characterize its structure by NMR and mass spectrometry, the complex silver as the catalytic sites, and the ligand L of hydrogen on the nitrogen fell microphone has certain basic, that can be used as an auxiliary Methylene dehydrogenation of Isopropyl methyl cyanoacetate, thereby accelerating the reaction. Further, the introduction of a chiral ligand to give complexes 2, to achieve an asymmetric aldol reaction of methyl isocyanoacetate.
基金supported by the National Basic Research Program of China (2010CB732404, 2010CB923303)the National Natural Science Foundation of China (21175020, 90713023, 20925104)+4 种基金the Project of High Technology Research and Development Program of China (2007AA022007)Gongdong Province (2011B090400357)the Natural Science Foundation of Jiangsu Province (BK2008149, BK2010052)C. W. acknowledges the Fundamental Research Funds for the Central Universities (ZYGX2011J099)the support by the Open Research Fund of State Key Laboratory of Bioelectronics, Southeast University (2011E09)
文摘The interactions between the new organometallic complexes, ferrocenesubstituted dithioocarborane conjugates （denoted as FcSB1, FcSB2 and FcSBCO） and hemoglobin （Hb） are investigated by electrochemistry, fluorescence and UVvis absorption spectroscopy. The results demonstrate that FcSB1, FcSB2 and FcSBCO can bind to the heme iron center through the replacement of the weakly bound H20/02 in the distal heme pocket of Hb by their sulfur donor atoms, inducing the allosteric change from the R state （oxygenated conformation, relax） to T state （deoxygenated conformation, tense）. The binding affinity is in the order of FcSBCO〉FeSB2〉FeSB1. Moreover, the fluorescence study illustrates that the three ferrocenecarborane conjugates differently affect the quarterly and tertiary structures as well as the polarity in the surrounding of the Trp and Tyr residues in Hb. Typically, FcSB2 mainly induces alterations of the microenvironment around the 1337Trp residue which is located on the cql32 interface of Hb. Such distinct influences are attributed to the structural features of FcSB1, FcSB2 and FcSBCO containing hydrophobic ferrocenyl and carboranyl units as well as C=O group. Screening the proteinbinding behavior can signify the potential bioactivity of such molecules and may be helpful in the future development of promising multifunctional metallodrugs.
基金the National Natural Science Foundation of China (21322303, 51372134 and 21573125)the financial support from the National Natural Science Foundation of China (21132005, 21421064 and 21522206)+1 种基金the National Program for Thousand Young Talents of Chinathe National Basic Research Program of China (2013CB834501)
文摘Chirality-specific growth of single-walled carbon nanotubes(SWNTs) remains a challenge for their practical applications in electronics. Here, we explored the surface growth of SWNTs by utilizing the atomic-precise silver cluster complex [Ag_(15){1,3,5–(C:C)_3–C_6H_3}_2(Py[8])_3–(CF_3SO_3)_3](CF_3SO_3)_6(Py[8] is abbreviation for octamethylazacalix[8]pyridine) as a catalyst precursor. The diameters of most acquired SWNTs distributed in the range of 1.2–1.4 nm, which is suitable for making high performance field-effect transistors. The high quality of the obtained SWNTs was evidenced by Raman spectroscopy and electrical measurements. Successful growth of high quality SWNTs in this study foresees that rational design of metal-organic complexes as growth catalysts can open up a new avenue for the controllable synthesis of SWNTs.
文摘Transition metal-catalyzed decarboxylative cross-coupling reactions have recently emerged as a new and important category of organic transformations that find versatile applications in the construction of carbon-carbon and carbon-heteroatom bonds. The use of relatively cheap and stable carboxylic acids to replace organometallic reagents enables the decarboxylative cross-coupling reactions to proceed with good selectivities and functional group tolerance. In the present review we summarize the various types of decarboxylative cross-coupling reactions catalyzed by different transition metal complexes. The scope and applications of these reactions are described. The challenges and opportunities in the field are discussed.
基金supported by the National Natural Science Foundation of China (21675090, 21435001, and 21375064)
文摘This review discusses chiral-at-metal complexes and introduces enantiomorphs from assembly structure.Owing to the diverse coordination number and activity of metal ions as chiral centers, abundant structures for chiral selectivity, catalysis, and polarized light-response are the notable advantages of the chiral-at-metal complexes. The rational design and preparation of linear multi-dentate ligands is a good choice to improve the stability of chiral complexes, such as multi-bonding structure for high stability as a self-limiting system. The bio-significance and potential application of chiral-at-metal complexes are discussed, such as the synergistic effect of catalysis and chiral selectivity of the metal center in enzymes.Enzyme could be remolded to replace the original central metal ions with highly active rare earth or precious metal ions to form artificial metalloenzyme or to remove the ‘‘redundant" part around the metal center to improve the accessibility of substrate. The polarized light-response mechanism of chiral opsin is introduced in relation to its role in animal migration. Metal-organic frameworks(MOFs) are crystalline and porous materials built from metal nodes or clusters and organic linkers and provide the possibility to prepare artificial enantiomorphs. The preparations, applications, and characterization methods of MOF enatiomorphs are therefore introduced. We hope this review inspires researchers at all levels of their career to consider the title topic in their own research in terms of its application and potential value.
基金supported by the National Natural Science Foundation of China (21302158 and 21472156)the National Basic Research Program of China (2012CB821600)
文摘Based on isolobal analogy,the definition of metallafuran was described and its synthetic chemistry was briefly summarized.In the structure of furan,when one of CH groups was replaced by an isolobal metal fragment ML n(M=metal;L=ligand),the corresponding organometallic complex was called metallafuran,which should be two possible isomers called a-metallafuran(metal fragment at a-carbon of original furan)and b-metallafuran(metal fragment at b-carbon of original furan).As an organometallic complex,a-metallafuran has two resonant forms:one can be viewed as carbonyl coordinated vinyl metal complex and the other can be viewed as alkoxymetal carbene.Therefore,a-metallafuran was also called chelated vinyl ketone metal complex or oxametallacyclopentadiene in the early literatures.For synthesis of metallafurans,a-metallafurans were very common and easily prepared,for example,from alkynes insertion into acyl metal complexes and so on.While there were rare examples reported for b-metallafurans.In this mini review,the synthetic chemistry of metallafuran was mainly focused on its formation mechanism.
