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81.
Cr3+:MgAl2O4晶体EPR参量及其电子精细光谱的研究 总被引:4,自引:0,他引:4
考虑了SS(Spin-Spin)作用和SOO(Spin-Other-Orbit)作用,采用完全对角化方法,结合自旋Hamiltonian理论,研究了Cr3+∶MgAl2O4晶体EPR参量及其吸收光谱,理论与实验符合甚好. 在此基础上,进一步研究了4A2(3d3)离子EPR参量的微观起源. 研究表明,EPR参量起源于四种微观机制:(1) SO(Spin-Orbit) 耦合机制;(2) SS耦合机制;(3)SOO耦合机制;(4) SO~SS~SOO总联合作用机制. 在这些机制中,SO机制是最主要的. 相似文献
82.
83.
Thiourea compounds are excellent agents of bioactive substance. A number of biological activities are associated with substituted thiourea derivatives. A survey of literature reveals that some work has been reported on benzoylthiourea, which has found plenty of applications as a facile and simple ligand in determination of trances of the transition metal and as an available starting material in preparation of a wide variety of metal complexes. In recent years,N-benzoyl-N'-(2-hydroxyethyl)-thiourea has attracted considerable attention as selective reagents for the liquid-liquid extraction and preconcentration of platinum group metals and its antifungle activity.As a part of our works in studying coordination behaviours of N-benzoyl-N'-(2-hydroxyethyl)-thiourea and its bioactivity, in view of these observations and in continuation of our previous works on it, the present work was reported on the crystal structure of N-benzoyl-N'-( 2-hydroxyethyl)-thiourea.The crystals structure in the monoclinic system and space group of P21/c of N-benzoyl-N'-(2-hydroxyethyl)- thiourea (C10H12N2O2S) was determined from single-crystal X-ray diffraction analysis, a = 17.083 (3) A, b = 4.5490 (10) A, c = 14.279 (3)A, a = 90.00°, a = 102.44(3)°, a = 90.00 °, Ⅴ = 1083.6 (4)A3, Z = 4, Dc = 1.375 Mg/m3, i (Mo Ka)= 0.280 mm-1, F(000) =472. The final R and u R are 0.0399 and 0.0881 for 783 observed reflections [Ⅰ>26(Ⅰ)].Fig. 1 shows the molecular crystal structure of N-benzoyl-N'-(2-hydroxyethyl)thiourea indicating that the carbonyl and thiocarbonyl moieties are pointing in approximate opposite directions. The six atoms in the ring structure hydrogen bonded are almost in one plane. The N(2)-H proton pendant arm extends to the carbonyl oxygen atom, forms hydrogen bond between them.The existence of hydrogen bond in benzoyl-thiourea molecular six-membered ring structure has significant implications on coordination properties, suggest the possibility of intramolecular hydrogen bond controlled coordination behaviors of these potentially bidentate ligands. In the coordination compound reported by Bourne et al.,cis-bis(N-benzoyl-N'-propylthiourea)dichloroplatinum(Ⅱ), the two ligand molecules bind to Pt(Ⅱ)via the sulfur atoms only, the carbonyl oxygen atom being locked into hydrogen bond similar to that in the free ligands. 相似文献
84.
The title compound is a bifunctional receptors including a thiourea group and a crown ether ring. Due to many possible potentials as a new class of reagents for membrane transports,ion-selective electrodes as well as reaction catalysts, the design and synthesis of bifunctional receptors for simultaneous binding of cations and anions is of ongoning interest in srprarnolecular chemistry1-5. In bifunctional receptors, the binding sites for anions and cations are covalently linked so as to exhibit allosteric or cooperative complexation where the binding affinity for anions(cations)is modified as a result of the cation(anion) complexation.Literature[6] reported that the ability of the thiourea group to bind anions is significantly enhanced when Na+ is bound to the crown moiety. To date, however only a few receptors of this class have been reported.6-8In this paper, we report an improved procedure under microwave irradiation that gives higher yields of title compound and needs fewer reaction times than traditional method.The structure of this compound was determined by IR ,element analysis and X-ray analysis.Scheme 1 The reaction equationThe crystal belongs to triclinic crystal system, P-1 space group, a=0.9547(0)nm, b=1.3637(3)nm,c=1.6029(3)nm, α =75.33(3) , β =83.62(3) , γ =70.99(3) ,Z=4,Dc=1.335g/cm3,F(000)=816,R1= 0.0557 ,wR2=0.1281. It is assembled into a three-dimensionalsupramolecule by intermolecular hydrogen bonds. 相似文献
85.
Qing An WU Zhen Yuan XU Mei ZHENG Dan Qian XU Jun XU Yin Chu SHENCollege of Chemical Engineering Materials Zhejiang University of Technology Hangzhou 《中国化学快报》2004,(7)
Six new 13-O-acylavermectin Bl aglycones(3-8) were synthesized from avermectin B1 aglycone and their bioactivities were evaluated against Spodoptera exigua, Spodoptera eridania, Tetranychus urticae and Aphis fabae. 相似文献
86.
FengSHI HongYangLI XiaoJunPENG RongZHANG XiaoQiangCHEN JiangLiFAN LiChengSUN 《中国化学快报》2004,15(12):1407-1410
As photosensitizer for solar cell, a new ruthenium (Ⅱ) complex with four ester groups had been synthesized, in which a phenol substituted by {[(2-hydroxy-5-tert-butylbenzyl)(pyridyl-2-methyl)amino]methyl} is covalently linked to ruthenium (Ⅱ) tris-bipyridine. The structures of the new compounds were confirmed by NMR and ESI-MS spectra. The electrochemical and photochemical properties were also studied. 相似文献
87.
Baker‘s yeast mediated reduction of optically active diketone is described. The two keto groups are efficiently differentiated and the ee value of the recovered material is considerably raised. It affords highly optically active key intermediates efficiently for the synthesis of natural polyhydroxylated agarofuran products. 相似文献
88.
XiangBaoMENG HuiLI QingLI ZhongJunLI 《中国化学快报》2004,15(7):777-778
An unusual reductive ring-opening reaction of phthalimide with sodium hydride in anhydrous DMF was observed for the first time. The presumed mechanism was described in detail. 相似文献
89.
Ming Zhao WANG Guan Liang CAI Ling XIA Jun Jian YAO Hong Yan CHEN Zhao Xing MENG Bo Li LIUDepartment of Chemistry Beijing Normal University Beijing Chemical Defense Institute PLA Beijing 《中国化学快报》2004,15(4):495-497
The crystal structures of two potential tumor imaging agents and therapeutic agents -copper(Ⅱ) complexes with salicylidene-tyrosinato Schiff base and nitrogen-donor chelating Lewis base, [Cu(sal-tyr)(bipy)] 1 and [Cu(sal-tyr)(phen)]2CH3OH 2 are presented. Our work is helpful to get deep understanding of novel 64Cu tumor imaging agents and therapeutic agents. 相似文献
90.
本文通过研究匹配问题的实例空间,匈牙利算法和解空间三者之间的关系,指出S实例空间的数目与问题复杂度之间的关系既不是充分也不是必要的,而如何对问题的解空间进行合理的分解才能是问题的关键。 相似文献