The glycosidation reactions of D-glucose with ethanol have been carried out over a reusable and separable heterogeneous catalyst, namely, ion exchange resin. Detailed kinetic data for these reactions are reported. A c...The glycosidation reactions of D-glucose with ethanol have been carried out over a reusable and separable heterogeneous catalyst, namely, ion exchange resin. Detailed kinetic data for these reactions are reported. A complex reaction model has been developed for interpreting the data. The reactions were found to be global second-order reactions and first -order with respect to each component. Meanwhile, a new regression method is applied to determine the rate constant from time-dependent profiles.展开更多
BACKGROUND The debate regarding diagnostic classification systems in psychiatry(categorial vs dimensional systems)has essential implications for the diagnosis,prevention and treatment of stress reactions.We previously...BACKGROUND The debate regarding diagnostic classification systems in psychiatry(categorial vs dimensional systems)has essential implications for the diagnosis,prevention and treatment of stress reactions.We previously found a unique pattern of stress reaction in a study executed during the coronavirus disease 2019 pandemic using large representative samples in two countries,and termed it the Complex Stress Reaction Syndrome(CSRS).AIM To investigate CSRS,Type A(psychiatric symptoms,spanning anxiety,depression,stress symptoms,and posttraumatic stress disorder(PTSD)),with or without long-coronavirus disease(COVID)residuals(CSRS,Type B,neuropsychiatric symptoms spanning cognitive deficits and fatigue,excluding systemic symptoms).Our two-tailed hypothesis was that CSRS is a condition related to an unrecognized type of stress reaction in daily life in the general population(Type A)or that it is related to the severe acute respiratory syndrome coronavirus 2 infection and its long-COVID residuals(Type B).METHODS 977 individuals in four continents(North America,Europe,Australia and the Middle East)completed the online study questionnaire in six languages using the Qualtrics platform.The study was managed by six teams in six countries that promoted the study on social media.The questionnaire assessed anxiety,depression,stress symptoms and PTSD(CSRS,Type A),cognitive deficits and fatigue(CSRS,Type B).The data were analyzed using Proportion Analyses,Multivariate Analysis of Co-Variance(MANCOVA),linear regression analyses and validated clinical cutoff points.RESULTS The results of the Proportion Analyses showed that the prevalence of 4 symptoms spanning anxiety,depression,stress symptoms,and PTSD was significantly higher than the most prevalent combinations of fewer symptoms across 4 continents,age groups,and gender.This supports the transdiagnostic argument embedded in the CSRS(Type A).The same pattern of results was found in infected/recovered individuals.The prevalence of the 4 psychiatric symptoms combination was significantly greater than that of 5 and 6 symptoms,when adding cognitive deficits and fatigue,respectively.MANCOVA showed a significant three-way interaction(age×gender×continent).Further analyses showed that the sources of this three-way interaction were threefold relating to two sub-populations at-risk:(1)Individuals that self-identified as non-binary gender scored significantly higher on all 4 psychiatric symptoms of the CSRS,Type A at young age groups(<50 years old)in North America compared to(self-identified)women and men located in the 4 continents studied,and to other ages across the adult life span;and(2)This pattern of results(CSRS,Type A)was found also in women at young ages(<40 years old)in North America who scored higher compared to men and women in other continents and other ages.Linear regression analyses confirmed the MANCOVA results.CONCLUSION These results show a combined mental health risk factor related to stress reactivity,suggesting that the CSRS is sensitive to populations at risk and may be applied to future identification of other vulnerable sub-populations.It also supports the transdiagnostic approach for more accurate prevention and treatment.Time will tell if such transdiagnostic syndromes will be part of the discussions on the next revisions of the traditional classification systems or whether the crisis in psychiatry further evolves.展开更多
In the present study, energetic and entropic changes are investigated on a comparative basis, as they occur in the volume changes of an ideal gas in the Carnot cycle and in the course of the chemical reaction in a lea...In the present study, energetic and entropic changes are investigated on a comparative basis, as they occur in the volume changes of an ideal gas in the Carnot cycle and in the course of the chemical reaction in a lead-acid battery. Differences between reversible and irreversible processes have been worked out, in particular between reversibly exchanged entropy (∆<sub>e</sub>S) and irreversibly produced entropy (∆<sub>i</sub>S). In the partially irreversible case, ∆<sub>e</sub>S and ∆<sub>i</sub>S add up to the sum ∆S for the volume changes of a gas, and only this function has an exact differential. In a chemical reaction, however, ∆<sub>e</sub>S is independent on reversibility. It arises from the different intramolecular energy contents between products and reactants. Entropy production in a partially irreversible Carnot cycle is brought about through work-free expansions, whereas in the irreversible battery reaction entropy is produced via activated complexes, whereby a certain, variable fraction of the available chemical energy becomes transformed into electrical energy and the remaining fraction dissipated into heat. The irreversible reaction process via activated complexes has been explained phenomenologically. For a sufficiently high power output of coupled reactions, it is essential that the input energy is not completely reversibly transformed, but rather partially dissipated, because this can increase the process velocity and consequently its power output. A reduction of the counter potential is necessary for this purpose. This is not only important for man-made machines, but also for the viability of cells.展开更多
Complexity phenomena like dynamic and static patterns, order from disorder, chaos and catastrophe were simulated by the application of 2-D reaction-diffusion CNN of two state variables and two diffusion coefficients t...Complexity phenomena like dynamic and static patterns, order from disorder, chaos and catastrophe were simulated by the application of 2-D reaction-diffusion CNN of two state variables and two diffusion coefficients transformed from Zhabotinksii model. They revealed somehow the mechanism of hydrothermal ore-forming processes, and answered several questions about the onset of ore forming.展开更多
A green heterogeneous catalyst for Heck reaction-chitosan-immobilized palladium complex was prepared. The catalyst exhibits high activity and stereoselectivity under the moderate reaction conditions. The catalyst can ...A green heterogeneous catalyst for Heck reaction-chitosan-immobilized palladium complex was prepared. The catalyst exhibits high activity and stereoselectivity under the moderate reaction conditions. The catalyst can be separated easily from the reaction mixture and reused after washing. Under the suitable reaction conditions, the cross-coupling of iodobenzene (ArI) with acrylic acid (AA) or acrylate can be achieved 93.3% or 99% yield of trans-cinnamic acid or trans-cinnamic ester.展开更多
Suzuki reaction of bromoallenes with arylboronic acids was successfully performed by using an air-stable hemilabile P-O coordinated cyclopalladated complex Pd(Ph_2PCH_2CO_2)_2 as a precatalyst,and the corresponding co...Suzuki reaction of bromoallenes with arylboronic acids was successfully performed by using an air-stable hemilabile P-O coordinated cyclopalladated complex Pd(Ph_2PCH_2CO_2)_2 as a precatalyst,and the corresponding coupling products were obtained in satisfactory to excellent yields.All products are unknown compounds which were characterized by ~1H NMR,^(13)C NMR,IR,and HRMS.展开更多
Abstract The complexes [M(CO);(CH;CN);](M=Mo, W)react with an equimolar quantity ofPhSnCl;in dichloromethane at room tempreture to afford new heterobinuclearcomplexes [PhCl;SnM(Cl)(CO);(CH;CN);] [M=Mo(1); ...Abstract The complexes [M(CO);(CH;CN);](M=Mo, W)react with an equimolar quantity ofPhSnCl;in dichloromethane at room tempreture to afford new heterobinuclearcomplexes [PhCl;SnM(Cl)(CO);(CH;CN);] [M=Mo(1); W(2)]. The complexes reactwith two equivalents of PR;R’(R=Ph, R’=Ph, Me; R=Cy, R’=H) to yield stablecomplexes [PhCl;SnM(Cl)(CO);(PR;R’);]. Reaction of[PhCl;SnM(Cl)(CO);(CH;CN);]with one equivalent of PPh;(CH;)nPPh;(n=I,2) or bulky phosphine ligands PBu;Clin dichloromethane at room tempreture to give [PhCl;SnMo(Cl)(CO);{PPh;(CH;)n-PPh;}] .CH;Cl;, [PhCl;SnMo(Cl)(CO);PBu;Cl]. CH;Cl;, respectively. The complexes1 and 2 react with phosphite donor ligands P(OMe);to give [PhCl;SnM(Cl)(CO);-{P(OMe);};]. All complexes have been characterized by elemental analysis, IRand;HNMR spectroscopies. Here we report the preliminary results of this work.展开更多
Some reactions of R3SnM(CO)5 (M = Mn, Re) with CH3CN or pyridine were investigated to give complexes R3SnMn(CO)3LL' or R3SnMn(CO)4L by a facile mild method. X-ray diffractions analyses show that, in contrast ...Some reactions of R3SnM(CO)5 (M = Mn, Re) with CH3CN or pyridine were investigated to give complexes R3SnMn(CO)3LL' or R3SnMn(CO)4L by a facile mild method. X-ray diffractions analyses show that, in contrast to the phosphine ligand occupying in axial position, nitrogen ligands occupy equatorial position.展开更多
In an acidic solution the mixed polynuclear complexes could be formed by association of rareearth-arsenazo Ⅲ complexing anions with copper o-phenanthrolinate cations.In this paper the formationconditions of lanthanum...In an acidic solution the mixed polynuclear complexes could be formed by association of rareearth-arsenazo Ⅲ complexing anions with copper o-phenanthrolinate cations.In this paper the formationconditions of lanthanum-arsenazo Ⅲ-copper-o-phenanthroline complex and its related reaction mechanismhave been studied in detail.The complex exhibits an absorption maximum at 663 nm and its apparent molarabsorptivity is found to be 1.22×105L·mol-1·cm-1.The molar ratio of the components in the complex isestimated to be La:arsenazo Ⅲ:Cu:Phen=1:1:1:3.Its possible molecular formula can expressed as[Cu(Phen)3](La-arsenazo Ⅲ).The reaction is used to determine micro amounts of lanthanum(or rareearths)in copper containning synthetic samples and satisfactory results are obtained.展开更多
Palladium is arguably the most versatile and most widely applied catalytic metal in the field of fine chemicals due to its high selectivity and activity. Palladium catalyst offers an abundance of possibilities of carb...Palladium is arguably the most versatile and most widely applied catalytic metal in the field of fine chemicals due to its high selectivity and activity. Palladium catalyst offers an abundance of possibilities of carbon-carbon bond formation in organic synthesis. In this research, three different Schiff base ligands have been prepared by condensation reaction between appropriate aldehyde or ketone with amine namely 2,2-dimethyl-1,3-propanediamine in the molar ratio of 2:1. The corresponding palladium (II) Schiff base complexes were prepared through the reaction between the Schiff base ligand with palladium (II) acetate in a molar ratio 1:1. FTIR, 1H-NMR and 13C-NMR spectroscopic data revealed that the ligands are N,N,O,O-tetradentate coordinated to the Pd atom through both the azomethine N atoms and phenolic O atoms. From X-ray Crystallographic analysis, it showed that the complex exists as square planar geometry. The synthesized palladium (II) Schiff base complexes were then subjected in catalytic Heck and Suzuki reaction of iodobenzene.展开更多
The kinetics of the reaction of [Ni(PnAO)—6H]° with formaldehyde was studied in H_2O—CH_3OH solution under neutral condition and a complicated mechanism with three steps including competitive, consecutive and r...The kinetics of the reaction of [Ni(PnAO)—6H]° with formaldehyde was studied in H_2O—CH_3OH solution under neutral condition and a complicated mechanism with three steps including competitive, consecutive and reverse reactions was proposed.展开更多
The catalytic properties of a series of cobalt complexes containing bidenated nitrogen ligand for displacement reaction of trialkylaluminum with ethylene is reported. Effect of different reaction time, temperature an...The catalytic properties of a series of cobalt complexes containing bidenated nitrogen ligand for displacement reaction of trialkylaluminum with ethylene is reported. Effect of different reaction time, temperature and cobalt complexes containing different ligand on catalyst performance has been investigated.展开更多
The complex Ginzburg-Landau equation (CGLE) has been used to describe the travelling wave behaviour in reaction-diffusion (RD) systems. We argue that this description is valid only when the RD system is close to t...The complex Ginzburg-Landau equation (CGLE) has been used to describe the travelling wave behaviour in reaction-diffusion (RD) systems. We argue that this description is valid only when the RD system is close to the Hopf bifurcation, and is not valid when a RD system is away from the onset. To test this, we study spirals and anti-spirals in the chlorite-iodide-malonic acid (CIMA) reaction and the corresponding OGLE. Numerical simulations confirm that the OGLE can only be applied to the CIMA reaction when it is very near the Hopf onset.展开更多
Precursors were prepared by solid state chemical reaction between LaCl_3 and C_2H_2O_4·2H_2O or NH_4HCO_3 at ambient temperature. Differential temperature analysis (DTA) and thermogravimetric analysis (TGA) were ...Precursors were prepared by solid state chemical reaction between LaCl_3 and C_2H_2O_4·2H_2O or NH_4HCO_3 at ambient temperature. Differential temperature analysis (DTA) and thermogravimetric analysis (TGA) were used to determine the decomposing temperature. Oxide (La_2O_3) was obtained by decomposing the precursor for about 2.5 h. X-ray diffraction (XRD), scanning electronic microscope (SEM) and ZETA potentiometer were respectively used to analyze the composition, morphology and size distribution of the products. The results show that La_2O_3 prepared by LaCl_3 and C_2H_2O_4·2H_2O is of ball-like shape and the diameter of particles (95%) is below 50 nm, while La_2O_3 prepared by LaCl_3 and NH_4HCO_3 is net-like.展开更多
Bis (methylcyclopentadienyl) lanthanide amido complex (MeCp) 2YbNPh2 (THF) reacted with n-hexyl isocyanate (n-nexylNCO) in 1:1 molar ratio to give {(MeC5H4)2Yb[OC(NPh2)N(n-hexyl)] }2(1). Complex 1 was...Bis (methylcyclopentadienyl) lanthanide amido complex (MeCp) 2YbNPh2 (THF) reacted with n-hexyl isocyanate (n-nexylNCO) in 1:1 molar ratio to give {(MeC5H4)2Yb[OC(NPh2)N(n-hexyl)] }2(1). Complex 1 was characterized by elemental analyses and X-ray diffraction. The title complex belongs to trigonal system and R-3 space group. Its unit cell parameters are a =2.9533(11) nm, b =2.9533(11) nm, c = 1.5873(6) nm, V= 11.9896(80) nm^3, Z =9, Dc= 1.562 mg·m^-3, μ = 3.536 mm^-1(Mo Kα), F(000) =5670, R =0.034, Rw =0.064. It is a dimeric structure with two symmetrical bridged oxygen atoms. Nitrogen atom is coordinated to the ytterbium atom to form a tricyclic backbone. The coordination number of ytterbium is 9. The whole molecule shows central symmetry.展开更多
The reactions of N-(O-hydoxyphenyl)-N'-phenylthiourea (L) derived from with Cu<sup>+</sup>, Cu<sup>2+</sup>, Co<sup>2+</sup> and Co<sup>3+</sup> chloride and/or iodi...The reactions of N-(O-hydoxyphenyl)-N'-phenylthiourea (L) derived from with Cu<sup>+</sup>, Cu<sup>2+</sup>, Co<sup>2+</sup> and Co<sup>3+</sup> chloride and/or iodide afford new metal complexes. The isolated complexes were synthesized by two different techniques (chemical and tribochemical methods). Two complexes were synthesized by the direct chemical reactions of N-(O-hydoxyphenyl)-N'-phenylthiourea (L) with MCl<sub>2</sub>·XH<sub>2</sub>O (M = Co<sup>2+</sup> and Cu<sup>2+</sup>;X = 6 in case of Co<sup>2+</sup> and X = 2 in case of Cu<sup>2+</sup>) in absolute EtOH. The general formulae of the two complexes derived by the chemical method are [Cu(L)<sub>2</sub>(EtOH)<sub>2</sub>]Cl<sub>2</sub> and [Co(L)<sub>2</sub>Cl<sub>2</sub>]Cl. These complexes were used to synthesize another two complexes using tribochemical reaction by grinding the previous chloride complexes with excess KI in agate mortar in the solid state. The isolated complexes have the general formulae, [Cu(L)I·H<sub>2</sub>O]·1/2H<sub>2</sub>O and [Co(L)I<sub>3</sub>(Et- OH)]·3EtOH. The results indicate the substitution of the chloride by iodide ions during grinding and extraction of the complexes by solvents. The IR spectra of the complexes suggest that L acts in a bidentate manner towards the metal ions. Moreover, the results of electronic spectra and magnetic measurements for the chloride complexes suggest distorted-octahedral structure for Cu<sup>2+</sup> and low-spin octahedral structures around the Co<sup>II</sup> and Cu<sup>2+</sup> ions, respectively. On the other hand the data suggest that the iodide complexes have square-planer and low-spin for the Cu<sup>+</sup> and Co<sup>3+</sup> ions, respectively. The results of mass spectra confirm the formulae proposed for the isolated complexes. The mechanisms of reduction of Cu<sup>II</sup> and oxidation of Co<sup>II</sup> for the metal complexes were elucidated.展开更多
The reaction of L (MAD) with Cu2+ and Co2+ chlorides affords new metal complexes. The isolated solid complexes were synthesized by two different techniques i.e., chemical and tribochemical methods. Four new complexes ...The reaction of L (MAD) with Cu2+ and Co2+ chlorides affords new metal complexes. The isolated solid complexes were synthesized by two different techniques i.e., chemical and tribochemical methods. Four new complexes were synthesized by direct chemical reactions of MCl2 (M = Co2+ and Cu2+) with MAD in absolute EtOH. The isolated solid complexes were used as starting compounds to synthesize another four new complexes using tribochemical technique by grinding the previous complexes in the solid state with excess KI in agate mortar. The results of the isolated complexes indicate the substitution of the chloride by iodide ions during grinding and extraction of the complexes by a mixture of solvents (EtOH + MeOH). Also, the results suggest that no reduction of Cu2+ or oxidation of Co2+ complexes is observed. The IR spectra of the complexes suggest that L acts in a bidentate manner. Moreover, the results of electronic spectra and magnetic measurements for the chloride and iodide complexes suggest distorted-octahedral and/or tetrahedral for Cu2+ and high-spin octahedral and/or tetrahedral structures around the Co2+ ion, respectively.展开更多
文摘The glycosidation reactions of D-glucose with ethanol have been carried out over a reusable and separable heterogeneous catalyst, namely, ion exchange resin. Detailed kinetic data for these reactions are reported. A complex reaction model has been developed for interpreting the data. The reactions were found to be global second-order reactions and first -order with respect to each component. Meanwhile, a new regression method is applied to determine the rate constant from time-dependent profiles.
文摘BACKGROUND The debate regarding diagnostic classification systems in psychiatry(categorial vs dimensional systems)has essential implications for the diagnosis,prevention and treatment of stress reactions.We previously found a unique pattern of stress reaction in a study executed during the coronavirus disease 2019 pandemic using large representative samples in two countries,and termed it the Complex Stress Reaction Syndrome(CSRS).AIM To investigate CSRS,Type A(psychiatric symptoms,spanning anxiety,depression,stress symptoms,and posttraumatic stress disorder(PTSD)),with or without long-coronavirus disease(COVID)residuals(CSRS,Type B,neuropsychiatric symptoms spanning cognitive deficits and fatigue,excluding systemic symptoms).Our two-tailed hypothesis was that CSRS is a condition related to an unrecognized type of stress reaction in daily life in the general population(Type A)or that it is related to the severe acute respiratory syndrome coronavirus 2 infection and its long-COVID residuals(Type B).METHODS 977 individuals in four continents(North America,Europe,Australia and the Middle East)completed the online study questionnaire in six languages using the Qualtrics platform.The study was managed by six teams in six countries that promoted the study on social media.The questionnaire assessed anxiety,depression,stress symptoms and PTSD(CSRS,Type A),cognitive deficits and fatigue(CSRS,Type B).The data were analyzed using Proportion Analyses,Multivariate Analysis of Co-Variance(MANCOVA),linear regression analyses and validated clinical cutoff points.RESULTS The results of the Proportion Analyses showed that the prevalence of 4 symptoms spanning anxiety,depression,stress symptoms,and PTSD was significantly higher than the most prevalent combinations of fewer symptoms across 4 continents,age groups,and gender.This supports the transdiagnostic argument embedded in the CSRS(Type A).The same pattern of results was found in infected/recovered individuals.The prevalence of the 4 psychiatric symptoms combination was significantly greater than that of 5 and 6 symptoms,when adding cognitive deficits and fatigue,respectively.MANCOVA showed a significant three-way interaction(age×gender×continent).Further analyses showed that the sources of this three-way interaction were threefold relating to two sub-populations at-risk:(1)Individuals that self-identified as non-binary gender scored significantly higher on all 4 psychiatric symptoms of the CSRS,Type A at young age groups(<50 years old)in North America compared to(self-identified)women and men located in the 4 continents studied,and to other ages across the adult life span;and(2)This pattern of results(CSRS,Type A)was found also in women at young ages(<40 years old)in North America who scored higher compared to men and women in other continents and other ages.Linear regression analyses confirmed the MANCOVA results.CONCLUSION These results show a combined mental health risk factor related to stress reactivity,suggesting that the CSRS is sensitive to populations at risk and may be applied to future identification of other vulnerable sub-populations.It also supports the transdiagnostic approach for more accurate prevention and treatment.Time will tell if such transdiagnostic syndromes will be part of the discussions on the next revisions of the traditional classification systems or whether the crisis in psychiatry further evolves.
文摘In the present study, energetic and entropic changes are investigated on a comparative basis, as they occur in the volume changes of an ideal gas in the Carnot cycle and in the course of the chemical reaction in a lead-acid battery. Differences between reversible and irreversible processes have been worked out, in particular between reversibly exchanged entropy (∆<sub>e</sub>S) and irreversibly produced entropy (∆<sub>i</sub>S). In the partially irreversible case, ∆<sub>e</sub>S and ∆<sub>i</sub>S add up to the sum ∆S for the volume changes of a gas, and only this function has an exact differential. In a chemical reaction, however, ∆<sub>e</sub>S is independent on reversibility. It arises from the different intramolecular energy contents between products and reactants. Entropy production in a partially irreversible Carnot cycle is brought about through work-free expansions, whereas in the irreversible battery reaction entropy is produced via activated complexes, whereby a certain, variable fraction of the available chemical energy becomes transformed into electrical energy and the remaining fraction dissipated into heat. The irreversible reaction process via activated complexes has been explained phenomenologically. For a sufficiently high power output of coupled reactions, it is essential that the input energy is not completely reversibly transformed, but rather partially dissipated, because this can increase the process velocity and consequently its power output. A reduction of the counter potential is necessary for this purpose. This is not only important for man-made machines, but also for the viability of cells.
文摘Complexity phenomena like dynamic and static patterns, order from disorder, chaos and catastrophe were simulated by the application of 2-D reaction-diffusion CNN of two state variables and two diffusion coefficients transformed from Zhabotinksii model. They revealed somehow the mechanism of hydrothermal ore-forming processes, and answered several questions about the onset of ore forming.
文摘A green heterogeneous catalyst for Heck reaction-chitosan-immobilized palladium complex was prepared. The catalyst exhibits high activity and stereoselectivity under the moderate reaction conditions. The catalyst can be separated easily from the reaction mixture and reused after washing. Under the suitable reaction conditions, the cross-coupling of iodobenzene (ArI) with acrylic acid (AA) or acrylate can be achieved 93.3% or 99% yield of trans-cinnamic acid or trans-cinnamic ester.
基金the National Natural Science Foundation of China(No.20603005) for financial supportpartly supported by the program for Changjiang Scholars and Innovative Research Teams in Universities (No.IRT0711)
文摘Suzuki reaction of bromoallenes with arylboronic acids was successfully performed by using an air-stable hemilabile P-O coordinated cyclopalladated complex Pd(Ph_2PCH_2CO_2)_2 as a precatalyst,and the corresponding coupling products were obtained in satisfactory to excellent yields.All products are unknown compounds which were characterized by ~1H NMR,^(13)C NMR,IR,and HRMS.
基金Supported by THE NATIONAL SCIENCE FOUNDATION OF CHINA
文摘Abstract The complexes [M(CO);(CH;CN);](M=Mo, W)react with an equimolar quantity ofPhSnCl;in dichloromethane at room tempreture to afford new heterobinuclearcomplexes [PhCl;SnM(Cl)(CO);(CH;CN);] [M=Mo(1); W(2)]. The complexes reactwith two equivalents of PR;R’(R=Ph, R’=Ph, Me; R=Cy, R’=H) to yield stablecomplexes [PhCl;SnM(Cl)(CO);(PR;R’);]. Reaction of[PhCl;SnM(Cl)(CO);(CH;CN);]with one equivalent of PPh;(CH;)nPPh;(n=I,2) or bulky phosphine ligands PBu;Clin dichloromethane at room tempreture to give [PhCl;SnMo(Cl)(CO);{PPh;(CH;)n-PPh;}] .CH;Cl;, [PhCl;SnMo(Cl)(CO);PBu;Cl]. CH;Cl;, respectively. The complexes1 and 2 react with phosphite donor ligands P(OMe);to give [PhCl;SnM(Cl)(CO);-{P(OMe);};]. All complexes have been characterized by elemental analysis, IRand;HNMR spectroscopies. Here we report the preliminary results of this work.
基金supported by the National Natural Science Foundation of China(No.29672018).
文摘Some reactions of R3SnM(CO)5 (M = Mn, Re) with CH3CN or pyridine were investigated to give complexes R3SnMn(CO)3LL' or R3SnMn(CO)4L by a facile mild method. X-ray diffractions analyses show that, in contrast to the phosphine ligand occupying in axial position, nitrogen ligands occupy equatorial position.
文摘In an acidic solution the mixed polynuclear complexes could be formed by association of rareearth-arsenazo Ⅲ complexing anions with copper o-phenanthrolinate cations.In this paper the formationconditions of lanthanum-arsenazo Ⅲ-copper-o-phenanthroline complex and its related reaction mechanismhave been studied in detail.The complex exhibits an absorption maximum at 663 nm and its apparent molarabsorptivity is found to be 1.22×105L·mol-1·cm-1.The molar ratio of the components in the complex isestimated to be La:arsenazo Ⅲ:Cu:Phen=1:1:1:3.Its possible molecular formula can expressed as[Cu(Phen)3](La-arsenazo Ⅲ).The reaction is used to determine micro amounts of lanthanum(or rareearths)in copper containning synthetic samples and satisfactory results are obtained.
文摘Palladium is arguably the most versatile and most widely applied catalytic metal in the field of fine chemicals due to its high selectivity and activity. Palladium catalyst offers an abundance of possibilities of carbon-carbon bond formation in organic synthesis. In this research, three different Schiff base ligands have been prepared by condensation reaction between appropriate aldehyde or ketone with amine namely 2,2-dimethyl-1,3-propanediamine in the molar ratio of 2:1. The corresponding palladium (II) Schiff base complexes were prepared through the reaction between the Schiff base ligand with palladium (II) acetate in a molar ratio 1:1. FTIR, 1H-NMR and 13C-NMR spectroscopic data revealed that the ligands are N,N,O,O-tetradentate coordinated to the Pd atom through both the azomethine N atoms and phenolic O atoms. From X-ray Crystallographic analysis, it showed that the complex exists as square planar geometry. The synthesized palladium (II) Schiff base complexes were then subjected in catalytic Heck and Suzuki reaction of iodobenzene.
文摘The kinetics of the reaction of [Ni(PnAO)—6H]° with formaldehyde was studied in H_2O—CH_3OH solution under neutral condition and a complicated mechanism with three steps including competitive, consecutive and reverse reactions was proposed.
文摘The catalytic properties of a series of cobalt complexes containing bidenated nitrogen ligand for displacement reaction of trialkylaluminum with ethylene is reported. Effect of different reaction time, temperature and cobalt complexes containing different ligand on catalyst performance has been investigated.
基金Project supported by the National Natural Science Foundation of China (Grant No 10274003) and the Department of Science and Technology of China.Acknowledgement We thank Cheng X, Wang C and Wang S for helpful discussion.
文摘The complex Ginzburg-Landau equation (CGLE) has been used to describe the travelling wave behaviour in reaction-diffusion (RD) systems. We argue that this description is valid only when the RD system is close to the Hopf bifurcation, and is not valid when a RD system is away from the onset. To test this, we study spirals and anti-spirals in the chlorite-iodide-malonic acid (CIMA) reaction and the corresponding OGLE. Numerical simulations confirm that the OGLE can only be applied to the CIMA reaction when it is very near the Hopf onset.
文摘Precursors were prepared by solid state chemical reaction between LaCl_3 and C_2H_2O_4·2H_2O or NH_4HCO_3 at ambient temperature. Differential temperature analysis (DTA) and thermogravimetric analysis (TGA) were used to determine the decomposing temperature. Oxide (La_2O_3) was obtained by decomposing the precursor for about 2.5 h. X-ray diffraction (XRD), scanning electronic microscope (SEM) and ZETA potentiometer were respectively used to analyze the composition, morphology and size distribution of the products. The results show that La_2O_3 prepared by LaCl_3 and C_2H_2O_4·2H_2O is of ball-like shape and the diameter of particles (95%) is below 50 nm, while La_2O_3 prepared by LaCl_3 and NH_4HCO_3 is net-like.
文摘Bis (methylcyclopentadienyl) lanthanide amido complex (MeCp) 2YbNPh2 (THF) reacted with n-hexyl isocyanate (n-nexylNCO) in 1:1 molar ratio to give {(MeC5H4)2Yb[OC(NPh2)N(n-hexyl)] }2(1). Complex 1 was characterized by elemental analyses and X-ray diffraction. The title complex belongs to trigonal system and R-3 space group. Its unit cell parameters are a =2.9533(11) nm, b =2.9533(11) nm, c = 1.5873(6) nm, V= 11.9896(80) nm^3, Z =9, Dc= 1.562 mg·m^-3, μ = 3.536 mm^-1(Mo Kα), F(000) =5670, R =0.034, Rw =0.064. It is a dimeric structure with two symmetrical bridged oxygen atoms. Nitrogen atom is coordinated to the ytterbium atom to form a tricyclic backbone. The coordination number of ytterbium is 9. The whole molecule shows central symmetry.
文摘The reactions of N-(O-hydoxyphenyl)-N'-phenylthiourea (L) derived from with Cu<sup>+</sup>, Cu<sup>2+</sup>, Co<sup>2+</sup> and Co<sup>3+</sup> chloride and/or iodide afford new metal complexes. The isolated complexes were synthesized by two different techniques (chemical and tribochemical methods). Two complexes were synthesized by the direct chemical reactions of N-(O-hydoxyphenyl)-N'-phenylthiourea (L) with MCl<sub>2</sub>·XH<sub>2</sub>O (M = Co<sup>2+</sup> and Cu<sup>2+</sup>;X = 6 in case of Co<sup>2+</sup> and X = 2 in case of Cu<sup>2+</sup>) in absolute EtOH. The general formulae of the two complexes derived by the chemical method are [Cu(L)<sub>2</sub>(EtOH)<sub>2</sub>]Cl<sub>2</sub> and [Co(L)<sub>2</sub>Cl<sub>2</sub>]Cl. These complexes were used to synthesize another two complexes using tribochemical reaction by grinding the previous chloride complexes with excess KI in agate mortar in the solid state. The isolated complexes have the general formulae, [Cu(L)I·H<sub>2</sub>O]·1/2H<sub>2</sub>O and [Co(L)I<sub>3</sub>(Et- OH)]·3EtOH. The results indicate the substitution of the chloride by iodide ions during grinding and extraction of the complexes by solvents. The IR spectra of the complexes suggest that L acts in a bidentate manner towards the metal ions. Moreover, the results of electronic spectra and magnetic measurements for the chloride complexes suggest distorted-octahedral structure for Cu<sup>2+</sup> and low-spin octahedral structures around the Co<sup>II</sup> and Cu<sup>2+</sup> ions, respectively. On the other hand the data suggest that the iodide complexes have square-planer and low-spin for the Cu<sup>+</sup> and Co<sup>3+</sup> ions, respectively. The results of mass spectra confirm the formulae proposed for the isolated complexes. The mechanisms of reduction of Cu<sup>II</sup> and oxidation of Co<sup>II</sup> for the metal complexes were elucidated.
文摘The reaction of L (MAD) with Cu2+ and Co2+ chlorides affords new metal complexes. The isolated solid complexes were synthesized by two different techniques i.e., chemical and tribochemical methods. Four new complexes were synthesized by direct chemical reactions of MCl2 (M = Co2+ and Cu2+) with MAD in absolute EtOH. The isolated solid complexes were used as starting compounds to synthesize another four new complexes using tribochemical technique by grinding the previous complexes in the solid state with excess KI in agate mortar. The results of the isolated complexes indicate the substitution of the chloride by iodide ions during grinding and extraction of the complexes by a mixture of solvents (EtOH + MeOH). Also, the results suggest that no reduction of Cu2+ or oxidation of Co2+ complexes is observed. The IR spectra of the complexes suggest that L acts in a bidentate manner. Moreover, the results of electronic spectra and magnetic measurements for the chloride and iodide complexes suggest distorted-octahedral and/or tetrahedral for Cu2+ and high-spin octahedral and/or tetrahedral structures around the Co2+ ion, respectively.