The relative chemical shifts (△δ) △δwere put forward to investigate the microscopic structure of 1-ethyl-3-methyl-imidazolium tetrafluoroborate (EmimBF4) during the dilution process with water.The concentration-de...The relative chemical shifts (△δ) △δwere put forward to investigate the microscopic structure of 1-ethyl-3-methyl-imidazolium tetrafluoroborate (EmimBF4) during the dilution process with water.The concentration-dependent △δ(C2)H-(C4)H,△δ(C2)H-(C5)H and △δ(C4)H-(C5)H were analyzed.The results reveal that the variations of the microscopic structures of three aromatic protons are inconsistent.The strength of the H-bond between water and three aromatic protons follows the order:(C2)H···O 】 (C4)H···O 】 (C5)H···O.The concentration-dependent △δ(C6)H-(C7)H and △δ(C6)H-(C8)H indicate the formation of the H-bonds of (Calkyl)H···O is impossible,and more water is located around (C6)H than around (C7)H or (C8)H.The concentration-dependent △δ(C2)H-(C4)H and △δ(C2)H-(C5)H both increase rapidly when xwater 】 0.9 or so,suggesting the ionic pairs of EmimBF4 are dissociated rapidly.The turning points of concentration-dependent △δ(C2)H-(C4)H and △δ(C2)H-(C5)H indicate that some physical properties of the EmimBF4/water mixtures also change at the corresponding concentration point.The microscopic structures of EmimBF4 in water could be clearly detected by the relative chemical shifts.展开更多
A new transition metal complex, [Cu(N-MeIm)4(BF4)2](N-MeIm=N-methylated imidazoles, BF4= tetrafluoroborate), was synthesized via the solvothermal method in ionic liquid. The ionic liquid acts as thermal decompos...A new transition metal complex, [Cu(N-MeIm)4(BF4)2](N-MeIm=N-methylated imidazoles, BF4= tetrafluoroborate), was synthesized via the solvothermal method in ionic liquid. The ionic liquid acts as thermal decomposition reaction medium, soft temple agent and ligand compound. The central Cu(Ⅱ) ion is coordinated by four N atoms from four N-methylated imidazole ligands, and the four N-methylated imidazole rings are perpendicular to each other. The crystal structure of [Cu(N-MeIm)4(BF4)2] was determined by single crystal X-ray diffraction. The results of thermogravimetry(TG) and Fourier transform infrared spectrometry(FTIR) analyses were in accordance with that of crystal structure. The complex showed strong ligand-based absorbance with maximum wavelength at 208 and 231 nm, which are attributed to π-π* transition of the N-methylated imidazole ligands.展开更多
基金the National Natural Science Foundation of China (20773109 & 20704035)the Natural Science Foundation of Zhejiang Province (Y4090453)
文摘The relative chemical shifts (△δ) △δwere put forward to investigate the microscopic structure of 1-ethyl-3-methyl-imidazolium tetrafluoroborate (EmimBF4) during the dilution process with water.The concentration-dependent △δ(C2)H-(C4)H,△δ(C2)H-(C5)H and △δ(C4)H-(C5)H were analyzed.The results reveal that the variations of the microscopic structures of three aromatic protons are inconsistent.The strength of the H-bond between water and three aromatic protons follows the order:(C2)H···O 】 (C4)H···O 】 (C5)H···O.The concentration-dependent △δ(C6)H-(C7)H and △δ(C6)H-(C8)H indicate the formation of the H-bonds of (Calkyl)H···O is impossible,and more water is located around (C6)H than around (C7)H or (C8)H.The concentration-dependent △δ(C2)H-(C4)H and △δ(C2)H-(C5)H both increase rapidly when xwater 】 0.9 or so,suggesting the ionic pairs of EmimBF4 are dissociated rapidly.The turning points of concentration-dependent △δ(C2)H-(C4)H and △δ(C2)H-(C5)H indicate that some physical properties of the EmimBF4/water mixtures also change at the corresponding concentration point.The microscopic structures of EmimBF4 in water could be clearly detected by the relative chemical shifts.
基金Supported by the National Natural Science Foundation of China(Nos. 51104050, 51301050, 51202047), the Natural Science Foundation of Heilongjiang Province, China(No. E201413), the Technology Foundation for Selected Overseas Chinese Scholar of Heilongjiang Province, China(No. 159150130002), the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province, China(No.LBH-3236310448) and the Fundamental Research Funds for the Central Universities, China(No. GK2150260120).
文摘A new transition metal complex, [Cu(N-MeIm)4(BF4)2](N-MeIm=N-methylated imidazoles, BF4= tetrafluoroborate), was synthesized via the solvothermal method in ionic liquid. The ionic liquid acts as thermal decomposition reaction medium, soft temple agent and ligand compound. The central Cu(Ⅱ) ion is coordinated by four N atoms from four N-methylated imidazole ligands, and the four N-methylated imidazole rings are perpendicular to each other. The crystal structure of [Cu(N-MeIm)4(BF4)2] was determined by single crystal X-ray diffraction. The results of thermogravimetry(TG) and Fourier transform infrared spectrometry(FTIR) analyses were in accordance with that of crystal structure. The complex showed strong ligand-based absorbance with maximum wavelength at 208 and 231 nm, which are attributed to π-π* transition of the N-methylated imidazole ligands.