Heterolytic and homolytic S_NO bond dissociation energies are determined in acetonitrile at 25 ℃ by using titration calorimetry and electrochemical measurements with a well designed thermodynamic cycle. The results s...Heterolytic and homolytic S_NO bond dissociation energies are determined in acetonitrile at 25 ℃ by using titration calorimetry and electrochemical measurements with a well designed thermodynamic cycle. The results suggest that S_NO compounds in vivo may release NO in a manner of homolytic bond dissociation. Other effects that influence the bond energies are also discussed. [WT5HZ]展开更多
There is an increasing interest for the study of NO affinity of organic nitrite,for the biological and physiological effects of organic nitrites seem to be due to their ability releasing NO.In this paper,NO chemical a...There is an increasing interest for the study of NO affinity of organic nitrite,for the biological and physiological effects of organic nitrites seem to be due to their ability releasing NO.In this paper,NO chemical affinities of ten benzyl nitrites were determined respectively by titration calorimetry and from a thermodynamic cycle in acetonitrile solution.The results show that ΔHhet of O—NO in the O-nitroso compounds were substantially larger than the corresponding ΔHhomo of O—NO in the same compounds,suggesting that these O-nitroso compounds were much easier release NO radical by the O—NO bond homolytic cleavage.It is believed that the structural and energetic information disclosed in this work should be useful in understanding chemical and biological functions of organic nitrites.展开更多
Titration calorimetry has been used to study the thermodynamics of reaction in toluene solution of 2-thenoyltriflueroacetone(TTA)complexes of rare earths(RE=Y,Nd,Eu,Yb)with N,N dimethylheptyl-acetamide(N503)at 298.15 ...Titration calorimetry has been used to study the thermodynamics of reaction in toluene solution of 2-thenoyltriflueroacetone(TTA)complexes of rare earths(RE=Y,Nd,Eu,Yb)with N,N dimethylheptyl-acetamide(N503)at 298.15 K.The heat of the reaction was determined with a TRONAC Model 1250 automatic isoperibol calorimeter.The data and figures of titration curve were recorded by the com- puter automatically.An iterative technique of least-square analysis was used to calculate the equilibrium con- stants and the thermodynamic functions including the entropy and free energy changes,minimizing the error square sum by a computer program.展开更多
The reactions between sodium iodide, potassium iodide and a series of N-(parasubstituted phenyl) nitrogen-hetero-15-crown-5 were studied by titration calorimetry at 25 ℃ in ethanol. It was found that the aza-crown et...The reactions between sodium iodide, potassium iodide and a series of N-(parasubstituted phenyl) nitrogen-hetero-15-crown-5 were studied by titration calorimetry at 25 ℃ in ethanol. It was found that the aza-crown ethers and the alkali metal ions form 1:1complexes. The electron-donating substituent on the phenyl ring may enhance the ligation ability of the macrocyclic ligand. It was found that linear thermodynamic function relationships exist in the systems studied.展开更多
文摘Heterolytic and homolytic S_NO bond dissociation energies are determined in acetonitrile at 25 ℃ by using titration calorimetry and electrochemical measurements with a well designed thermodynamic cycle. The results suggest that S_NO compounds in vivo may release NO in a manner of homolytic bond dissociation. Other effects that influence the bond energies are also discussed. [WT5HZ]
文摘There is an increasing interest for the study of NO affinity of organic nitrite,for the biological and physiological effects of organic nitrites seem to be due to their ability releasing NO.In this paper,NO chemical affinities of ten benzyl nitrites were determined respectively by titration calorimetry and from a thermodynamic cycle in acetonitrile solution.The results show that ΔHhet of O—NO in the O-nitroso compounds were substantially larger than the corresponding ΔHhomo of O—NO in the same compounds,suggesting that these O-nitroso compounds were much easier release NO radical by the O—NO bond homolytic cleavage.It is believed that the structural and energetic information disclosed in this work should be useful in understanding chemical and biological functions of organic nitrites.
基金This project was supported by the National Natural Science Foundation of China
文摘Titration calorimetry has been used to study the thermodynamics of reaction in toluene solution of 2-thenoyltriflueroacetone(TTA)complexes of rare earths(RE=Y,Nd,Eu,Yb)with N,N dimethylheptyl-acetamide(N503)at 298.15 K.The heat of the reaction was determined with a TRONAC Model 1250 automatic isoperibol calorimeter.The data and figures of titration curve were recorded by the com- puter automatically.An iterative technique of least-square analysis was used to calculate the equilibrium con- stants and the thermodynamic functions including the entropy and free energy changes,minimizing the error square sum by a computer program.
文摘The reactions between sodium iodide, potassium iodide and a series of N-(parasubstituted phenyl) nitrogen-hetero-15-crown-5 were studied by titration calorimetry at 25 ℃ in ethanol. It was found that the aza-crown ethers and the alkali metal ions form 1:1complexes. The electron-donating substituent on the phenyl ring may enhance the ligation ability of the macrocyclic ligand. It was found that linear thermodynamic function relationships exist in the systems studied.
