The formation process and composition of the acrylonitrile/urea inclusion compounds （AN/UIC） with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry （DSC） and X-ra...The formation process and composition of the acrylonitrile/urea inclusion compounds （AN/UIC） with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. It is suggested that DSC can determine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of decomposition are obtained, which are 1.17 and 5361.53 J/mol, respec- tively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN.展开更多
The chemistry of inclusion compounds has a long history and is nowadays a subject of wide-ranging and intense study. With the awarding of the 1987 Nobel Prize in Chemistry to Donald J. Cram, Jean-Marie Lehn and Charle...The chemistry of inclusion compounds has a long history and is nowadays a subject of wide-ranging and intense study. With the awarding of the 1987 Nobel Prize in Chemistry to Donald J. Cram, Jean-Marie Lehn and Charles J. Pedersen for their fundamental work on 'host-guest' or 'supramolecular' systems, inclusion chemistry has come to the fore front in contemporary researches. Increasing varieties of novel inclusion compounds and new host molecules have been synthesized recently. The term 'crystal engineering' was coined by Schmidt to describe the rational design and control of molecular packing arrangements in the solid state, and the structural study of clathrates has contributed展开更多
文摘The formation process and composition of the acrylonitrile/urea inclusion compounds （AN/UIC） with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. It is suggested that DSC can determine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of decomposition are obtained, which are 1.17 and 5361.53 J/mol, respec- tively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29973005) and we are grateful to Hong Kong Research Grants Council Earmarked Grant (CUHK 456/95P) for supporting this research work.
文摘The chemistry of inclusion compounds has a long history and is nowadays a subject of wide-ranging and intense study. With the awarding of the 1987 Nobel Prize in Chemistry to Donald J. Cram, Jean-Marie Lehn and Charles J. Pedersen for their fundamental work on 'host-guest' or 'supramolecular' systems, inclusion chemistry has come to the fore front in contemporary researches. Increasing varieties of novel inclusion compounds and new host molecules have been synthesized recently. The term 'crystal engineering' was coined by Schmidt to describe the rational design and control of molecular packing arrangements in the solid state, and the structural study of clathrates has contributed
