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1.
本文利用环聚合分子动力学方法对C(1D)+H2反应开展了详细的理论研究. 计算中使用了最近构建的Zhang-Ma-Bian(ZMB)从头算势能面,该势能面对锥形交叉附近区域以及范德华区域均有精确的描述. 环聚合分子动力学计算得到的热反应速率常数与最新实验值吻合很好. 与前人计算结果比较,发现在?1A′电子基态的ZMB-a势能面上获得的反应速率常数远大于前人构建的RKHS势能面上的结果,这是由于ZMB势能面上的范德华鞍具有与之前势能面上的范德华阱完全不同的动态学作用,表明环聚合分子动力学方法能够处理范德华作用引起的势能面拓扑结构所导致的动态学效应. 本文还揭示了b1A′′电子激发态ZMB-b势能面以及量子效应对反应的重要性. 相似文献
2.
二氧化碳(CO2)光催化还原技术因兼具解决能源和全球变暖问题的潜力而受到关注。金属铁络合物作为分子型催化剂,具有价格低廉、量子效率高、结构可调控和选择性好等优势,表现出优异的CO2光催化还原性能,成为CO2光催化还原领域的研究热点。本文综述了近年来基于金属铁络合物光催化二氧化碳还原研究进展。介绍了铁金属络合物(如:铁卟啉、铁多吡啶、五齿铁配合物)CO2均相光催化还原体系,总结了体系的构成以及作用机理等,着重关注了体系的催化效率和产物的选择性。此外,综述了以半导体纳米材料/量子点作为光敏剂,金属铁络合物作为催化剂的非均相催化体系的研究进展。最后,对该领域未来的研究方向和所面临的挑战做出展望。 相似文献
3.
Hui. ZHANG Li-Li. ZENG Yue-Kui. WANG Shi. CAO Dong. GUO Dan. LI Xue-Ming. FANG Li-Rong. LIN 《物理化学学报》2015,31(12):2229-2250
A correlation between the electronic circular dichroism (ECD) spectra and the absolute configurations of a serials' chiral salen-Ni(Ⅱ) complexes was investigated. The solid-state structures, absolute configurations, and preferential conformations in solution of quasi-planar chiral [Ni(salen)] complexes were studied using their crystal structures, solid-state and solution ECD spectra in combination with theoretical ECD calculations. Furthermore, two different nomenclatures for the absolute configurations of square-planar [M(salen)] complexes were inspected carefully, and suggestions for proper use of them are discussed. The calculated ECD spectra of [Ni(sal-R, R-chxn)] [sal-R, R-chxn = (R, R)-1, 2-cyclohexylene bis(salicylicdeneiminate)] in dichloromethane solution revealed that the first ECD band in the visible region was dominated by the ligandto-metal charge transfer transition (LMCT), which was incorrectly assigned to a d-d transition in the literature. When the absolute configuration of [Ni(sal-R, R-chxn)] was Λ, the first ECD absorption band in the visible region was positive. This ECD fingerprint is universally applicable for assigning the absolute configurations of other square-planar chiral [Ni(salen)] and six-coordinate trans-[CoⅢ(salen)L2] complexes with a "closed-shell" electronic structure. This work provides some insight into the coordination stereochemistry and chiroptical properties of chiral [M(salen)] complexes. Additionally, this work is significant for the understanding of chiral recognition and asymmetric catalytic mechanisms. 相似文献
4.
ZHANG Xiao-Ya ZHENG Cong-Ye ZHENG Xue-Li FU Hai-Yan YUAN Mao-Lin LI Rui-Xiang CHEN Hua 《物理化学学报》2015,31(4):738-742
Using silica as a support, 2-(diphenylphosphino)ethyltriethoxysilane (DPPES) was anchored on silica surface by a grafting method to produce a bonded phosphine (denoted as SiO2(PPh2)), which displays excellent performance. The supported SiO2(PPh2)/Rh catalyst was formed in situ in 1-octene hydroformylation with SiO2(PPh2) as ligand and Rh(acac)(CO)2 as precursor (acac: acetylacetone). SiO2(PPh2) and SiO2(PPh2)/ Rh were characterized by Fourier transform infrared (FTIR) spectroscopy. The effects of the ratio of phosphine to rhodium ([P]/[Rh]) and reaction temperature on 1-octene hydroformylation were investigated. Results show that an increase of the ratio of phosphine to rhodium can greatly improve the selectivity for aldehydes and decrease the rhodium leaching in organic phase. Under the moderate conditions: [P]/[Rh]=12, 363 K, 2 MPa, and 1.5 h, the conversion of 1-octene and the selectivity for aldehydes were 98.4% and 95.3%, respectively. The catalytic activity could compare with homogeneous catalysis with DPPES or triphenylphosphine (TPP) as ligand. The reaction activity was clearly unchanged after the SiO2(PPh2)/Rh catalyst was reused four times, with the conversion of 1-octene remaining at 97.0%, the rhodium content leaching in organic phase detected by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was less than 0.1%. 相似文献
5.
系统总结了作为柴油车尾气消除反应(NH3-SCR)催化材料的八元环沸石分子筛(CHA, AEI, RTH)的研究进展, 讨论了不同方法合成的八元环沸石分子筛在NH3-SCR反应中的性能差异, 并对未来八元环分子筛的发展趋势进行了展望. 相似文献
6.
将(+)-新孟基和(+)-异莰基引入茚环结构中,合成得到三个茚环3-位手性基团取代的桥联二茚配体化合物1a~3a.利用这些配体化合物的二锂盐与四氯化锆反应,最终分离得到两个C2-对称的亚乙基桥联取代二茚锆络合物2b和3b,相应具类内消旋结构、C1-对称的锆络合物2c和3c未能分离得到纯品.所有配体化合物和络合物均通过1H NMR、13C NMR、元素分析(或HRMS)的鉴定.对络合物2c进一步用X射线单晶衍射测定了晶体结构.2c属正交晶系,其空间群为P2(1)2(1)2(1),晶胞参数a=10.946(4),b=13.377(4),c=24.294(8),α=β=γ=90°,Mr=694.94,V=3557(2)3,Dc=1.298 g/cm3,Z=4,F(000)=1464,μ=0.486 mm-1,R=0.0296,wR=0.0683[I2σ(I)]. 相似文献
7.
A fluorescent probe with a coumarin moiety bound to rhodamine 6G hydrazide(l) was synthesized. Its sensing behavior toward various metal ions was investigated with fluorescence methods. Compound I displays different fluorescence emission responses to Al^3+ and Ca^2+ at the same excitation wavelength in the visible light region, while no changes occur after the addition of other metal ions. The binding ratios of the complexs of 1-Al^3+ and 1-Ca^2+ are both 2:1 according to the Job plot and high resolution mass spectrometer(HRMS) experiments. Moreover, emission spectrum of 1-Ca^2+ complex and absorption spectrum of the rbodamine dyes overlap largely. When Al^3+ was added to the 1-Ca2+ system, calcium in complex 1-Ca2+ can be displaced by Al^3+, resulting in the output of another ratiometric sensing signal, which demonstrates that the 1-Ca^2+ complex can be served as a new and effective fluorescence resonance energy transfer(FRET) donor for rhodamine derivatives. 相似文献
8.
制备了异烟酸氮氧化物(简计为HINO)/磷钼酸镍有机-无机络合物({[Ni(H2O)8][H(H2O)2.5](HINO)4(PMo12O40)}n;简计为1)掺杂硅胶复合物(简计为1-SG1);采用红外光谱仪和X射线衍射仪证实了合成产物的结构.结果表明,化合物1的结构特征在1-SG1硅胶复合物中得以保留.与此同时,在约98%的相对湿度下,1-SG1在温度55~100℃范围内显示良好的导电性,其质子导电率达到8.98×10-3~1.03×10-2 S·cm-1;并且,在同等条件下,1-SG1的质子导电性优于化合物1. 相似文献
9.
10.