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β沸石骨架外阳离子分布 被引量:9
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作者 王颖霞 孟宪平 +3 位作者 李能 张婉静 林炳雄 刘希尧 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 1998年第8期1185-1190,共6页
运用结构化学理论和多晶X射线散射技术,确定了β沸石骨架外阳离子的位置.这些阳离子随机地分布在β沸石层错结构中6套不同的结晶学位置上,都处于三维通道内靠近六元环,并与6个骨架氧配位.从其几何环境和配位情况来看,β沸石骨... 运用结构化学理论和多晶X射线散射技术,确定了β沸石骨架外阳离子的位置.这些阳离子随机地分布在β沸石层错结构中6套不同的结晶学位置上,都处于三维通道内靠近六元环,并与6个骨架氧配位.从其几何环境和配位情况来看,β沸石骨架外阳离子位置仅为一种类型,在Hβ沸石中,相应的质子酸中心也只有一种类型.此结论在NH3-TPD实验中得到证实.处于如此位置的阳离子和对应的酸中心易与反应物分子接触,据此推测Hβ沸石将是一种高活性、高选择性的酸催化剂.而Mβ沸石有望成为一种良好的氧化还原催化剂. 展开更多
关键词 Β沸石 结构 骨架外 阳离子益 质子酸位 沸石
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Theoretical Study on Electronic Gain-and-loss Properties of TEMPO and Its Derivates in Charge/Discharge Processes 被引量:1
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作者 Shu-cai Mao Jin-qing Qu Kang-cheng Zheng 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第2期161-168,I0003,共9页
Theoretical study on the electronic structures and related properties of 2,2,6,6-tetramethyl- l-piperidinyloxy (TEMPO) and its cationic lipid derivates in the charge/discharge processes has been carried out using th... Theoretical study on the electronic structures and related properties of 2,2,6,6-tetramethyl- l-piperidinyloxy (TEMPO) and its cationic lipid derivates in the charge/discharge processes has been carried out using the density functional theory (DFT) at the (U)B3LYP/6-31G(d,p) or 6-31+G(d,p) level. The changes and regularities of geometric and electronic properties of these compounds in the charge/discharge processes were revealed in detail. The compu- tational results show that the substitute group plays a very important role in the electronic structures and related properties of TEMPOs during the charge/discharge processes. It is very interesting to find that after getting an electron, TEMPO is more stable in singlet state but the lipid is more stable in triplet state. For TEMPO, both the charge and the discharge processes greatly influence the electronic properties of N and O atoms of the radical part. For the cationic lipid, the discharge process mainly influences the pyridinium head and the charge process mainly influences the free radical head. Moreover, the solvent effect plays an important role in some bond lengths and the charge population of the free radical head. In addition, the UV-Vis absorption spectra simulated using TDDFT at the 6-31G(d,p) with the experimental ones. of TEMPO and the lipid were calculated and or 6-31+G(d,p) level, in satisfying agreement 展开更多
关键词 2 2 6 6-tetramethyl-l-piperidinyloxy Charge/discharge process ELECTRONICSTRUCTURE Density functional theory calculation
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