Quantum-chemical calculations on some derivatives of [n]-prismanes expanded by ethynyl or ethenyl groups have been performed using density functional theory （DFT） method.Their geometric structures,electronic structu...Quantum-chemical calculations on some derivatives of [n]-prismanes expanded by ethynyl or ethenyl groups have been performed using density functional theory （DFT） method.Their geometric structures,electronic structures,vertical ionization potentials and vertical electron affinities have been obtained at the B3LYP/6-31G＊＊ level of theory.Meanwhile,the total strain energy has been investigated in detail and compared with [n]-prismane and other derivatives.The present paper has also computed the enthalpies of formation for different isomers so as to evaluate their thermal stabilities.展开更多
The optimized molecular structure and harmonic vibrational frequencies of a 1,4-bis [ 2-（4-pyridyl）ethenyl]- benzene（BPENB） molecule were calculated via five popular density functional theory（DFI＇） methods. On ...The optimized molecular structure and harmonic vibrational frequencies of a 1,4-bis [ 2-（4-pyridyl）ethenyl]- benzene（BPENB） molecule were calculated via five popular density functional theory（DFI＇） methods. On the basis of the comparison between calculated and experimental results, it is concluded that the B3PW91 and B3LYP methods are superior to the others in optimizing structures, and the BPW91 method reproduces the observed fundamental fre-quencies most satisfactorily.展开更多
Two different kinds of configurations of 1,4-bis[2-(4-pyridyl)etheny 1]-benzene(trans-bpeb and c/5-bpeb)were achieved,and a bpeb dimer was synthesized in dimethyl sulfoxide(DMSO).Compared with the previous work that s...Two different kinds of configurations of 1,4-bis[2-(4-pyridyl)etheny 1]-benzene(trans-bpeb and c/5-bpeb)were achieved,and a bpeb dimer was synthesized in dimethyl sulfoxide(DMSO).Compared with the previous work that synthesized the bpeb dimer or polymer in crystal with a template agent needed,the reaction occurred in a solu・tion phase in the present method.A hand-held ultraviolet lamp(365 nm)with the power of 12 W and the Watt density of 0.35 mW/cm2 can realize the photodimerization of bpeb,instead of the high-power mercury lamp in most previous studies.Unlike other 2+2 cycloaddition in liquid state using catalysts even noble metals,no catalysts were required here,which is cost-saving.Only the trans-pbeb can start the cycloaddition and the formation of the close J-aggregations of Zra≪5-pbeb in DMSO is a precondition for explaining the 2+2 photodimerization.The productivity for the 2+2 cycloaddition product was achieved as 55.6%.展开更多
A Ni-RE-P-Al catalyst prepared by alkaline extraction of a rapidly quenched Ni-RE-P-Al alloy was characterized by means of ICP, BET, XRD, XPS and TEM. The results show that the rapidly quenched Ni-RE-P-Al alloy conta...A Ni-RE-P-Al catalyst prepared by alkaline extraction of a rapidly quenched Ni-RE-P-Al alloy was characterized by means of ICP, BET, XRD, XPS and TEM. The results show that the rapidly quenched Ni-RE-P-Al alloy contained less crystalline Al_3Ni than Al-Ni alloy. After alkaline extraction, most of Al in the Ni-RE-P-Al alloy was leached out and the resulted Ni-RE-P-Al catalyst presented a sponge structure similar to Raney Ni. Although crystalline Ni is the major phase in the Ni-RE-P-Al catalyst and Raney Ni, amorphous Ni-P phase has been detected in the Ni-RE-P-Al catalyst. Studies on catalytic hydrogenation of toluene, phenyl ethylene, acetylene benzene, nitrobenzene, cyclohexanone and adiponitrile in liquid phase showed that the activity and selectivity of this Ni-RE-P-Al catalyst are superior to those of Raney Ni, especially at low temperatures. The amorphous phase is considered to be responsible for its superior catalytic properties.展开更多
文摘Quantum-chemical calculations on some derivatives of [n]-prismanes expanded by ethynyl or ethenyl groups have been performed using density functional theory （DFT） method.Their geometric structures,electronic structures,vertical ionization potentials and vertical electron affinities have been obtained at the B3LYP/6-31G＊＊ level of theory.Meanwhile,the total strain energy has been investigated in detail and compared with [n]-prismane and other derivatives.The present paper has also computed the enthalpies of formation for different isomers so as to evaluate their thermal stabilities.
基金Supported by the National Natural Science Foundation of China(No.20473029)the Open Project Program of the Key Labora-tory for Supramolecular Structure and Materials of Ministry of EducationJilin University and the Fund for Doctor of Yantai University.
文摘The optimized molecular structure and harmonic vibrational frequencies of a 1,4-bis [ 2-（4-pyridyl）ethenyl]- benzene（BPENB） molecule were calculated via five popular density functional theory（DFI＇） methods. On the basis of the comparison between calculated and experimental results, it is concluded that the B3PW91 and B3LYP methods are superior to the others in optimizing structures, and the BPW91 method reproduces the observed fundamental fre-quencies most satisfactorily.
基金Supported by the National Natural Science Foundation of China(Nos.21873039,21573087,21573092).
文摘Two different kinds of configurations of 1,4-bis[2-(4-pyridyl)etheny 1]-benzene(trans-bpeb and c/5-bpeb)were achieved,and a bpeb dimer was synthesized in dimethyl sulfoxide(DMSO).Compared with the previous work that synthesized the bpeb dimer or polymer in crystal with a template agent needed,the reaction occurred in a solu・tion phase in the present method.A hand-held ultraviolet lamp(365 nm)with the power of 12 W and the Watt density of 0.35 mW/cm2 can realize the photodimerization of bpeb,instead of the high-power mercury lamp in most previous studies.Unlike other 2+2 cycloaddition in liquid state using catalysts even noble metals,no catalysts were required here,which is cost-saving.Only the trans-pbeb can start the cycloaddition and the formation of the close J-aggregations of Zra≪5-pbeb in DMSO is a precondition for explaining the 2+2 photodimerization.The productivity for the 2+2 cycloaddition product was achieved as 55.6%.
基金the National Natural Science Foundation of China.
文摘A Ni-RE-P-Al catalyst prepared by alkaline extraction of a rapidly quenched Ni-RE-P-Al alloy was characterized by means of ICP, BET, XRD, XPS and TEM. The results show that the rapidly quenched Ni-RE-P-Al alloy contained less crystalline Al_3Ni than Al-Ni alloy. After alkaline extraction, most of Al in the Ni-RE-P-Al alloy was leached out and the resulted Ni-RE-P-Al catalyst presented a sponge structure similar to Raney Ni. Although crystalline Ni is the major phase in the Ni-RE-P-Al catalyst and Raney Ni, amorphous Ni-P phase has been detected in the Ni-RE-P-Al catalyst. Studies on catalytic hydrogenation of toluene, phenyl ethylene, acetylene benzene, nitrobenzene, cyclohexanone and adiponitrile in liquid phase showed that the activity and selectivity of this Ni-RE-P-Al catalyst are superior to those of Raney Ni, especially at low temperatures. The amorphous phase is considered to be responsible for its superior catalytic properties.
