首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 29 毫秒
1.
1 INTRODUCTION The research on organic polyamines is currently of great interest because of their potential applica- tions as useful organic ligands, in which the amine nitrogen atoms have strong coordination ability to the transition metal ions and recognition function[1~4]. Their transition metal complexes play an excellent role in catalysis and mimic studies on dismutase and chlorophyll[5~7]. Therefore much attention has been focused on their syntheses and applications[8~11]. Our group…  相似文献   

2.
冯云龙 《结构化学》2003,22(2):133-136
1 INTRODUCTION The interest in the complexes of transition metals with ligands ketoxime[1, 2] as potential models for metal binding sites in ferroverdin[3, 4] has prompted the investigation on the structures and the overall coordination geometry of the metal centers in these complexes. Oxime derivatives are interesting ligands since the ketoximes are found to chelate transition metals through the N (oxime) and O (ketone) atoms[5, 6]. However, monodentate coordination via only one O or …  相似文献   

3.
1 INTRODUCTION The determination of structures of adsorbed cya- nide (CN) and cyanate (OCN) on transition metal surfaces is important for understanding their bon- ding and reactivity in catalysis and other surface phenomena[1~4]. During the past decade, the adsorp- tion of CN and CN-containing on transition metal surfaces has received a great deal of attention in both experimental[5~20] and theoretical[1~5, 13, 20~33] inves-tigations, and the previous work about the adsorp- tion of…  相似文献   

4.
1 INTRODUCTION A variety of transition metal complexes with barbiturates have been prepared owing to their important roles in clinical detection and identi- fication of drug[1~5]. They have the general formula of M(Ⅱ)(barb)2L2, where M is a transition metal (Co, Cr, Zn, Cu etc), barb the anion of a substituted barbituratic acid and L an organic base, usually pyridine. In these complexes, the donor atom in the barbiturate anion is a deprotonated nitrogen atom and, the coordination …  相似文献   

5.
The development of economic and environmentally friendly extractants to recover cobalt metal is required due to the increasing demand for this metal.In this study,solvent extraction of Co(Ⅱ) from aqueous solution using a mixture of N,N’-carbonyl difatty amides(CDFAs) synthesised from palm oil as the extractant was carried out.The effects of various parameters such as acid,contact time,extractant concentration,metal ion concentration and stripping agent and the separation of Co(Ⅱ) from other metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ) were investigated.It was found that the extraction of Co(Ⅱ) into the organic phase involved the formation of 1:1 complexes.Co(Ⅱ) was successfully separated from commonly associated metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ).Co(Ⅱ) stripping from the loaded organic phase was studied in aqueous solution.These results are useful to recover Co(Ⅱ) from aqueous solution utilising(CDFAs) as an extractant.  相似文献   

6.
1 INTRODUCTION The interest in the complexes of transition met-als with ketoxime ligands[1, 2] as potential modelsfor metal binding sites in ferroverdin[3, 4] hasprompted the investigations on the structures andthe overall coordination geometry of the metalcenters in these complexes. Oxime derivatives areinteresting ligands since the ketoximes are foundto chelate transition metals through the N (oxime)and O (ketone) donors[5~10]. Herein we report thesynthesis…  相似文献   

7.
1 INTRODUCTIONThe design and synthesis of metal-organic coor- dinated polymer have attracted considerable atten- tion in recent years. The infinite networks construc- ted from transition metal complexes have intere- sting structures as well as potential applications as smart electronic, magnetic porous materials, cataly- sis, host-guest chemistry, and so on[1~4]. In the as- sembly and synthesis of polymer structures, the me- tal ions, bi- or multi-dentate ligand, solvent and the ratio of …  相似文献   

8.
1 INTRODUCTION A recent feature in the development and progress of chemical research is the concern for molecular assemblies, ensembles, and all of structural aggre- gates[1]. The self-assembly of transition metal ions and N-containing organic ligands has been proven a popular approach for the construction of supramo- lecular architecture[2~7]. 3-(3-Pyridyl)acrylic acid is an excellent ligand, not only due to its prolific coor- dination sites but also to its potential hydrogen bon- ding…  相似文献   

9.
1 INTRODUCTION Polyoxometalates (POMs) are one of the most widely used inorganic components due to their at- tractive electronic and molecular properties with va- rious applications in catalysis, medicine, materials science[1~3] and so on. Exploration of transition me- tal complex cations as well as organic component which functions as ligand as building blocks in the construction of metal oxide composite materials is a fruitful strategy[4, 5]. Among the polyoxometalates studied to dat…  相似文献   

10.
The theoretical study of small molecules containing transition metal atoms is one of the most active areas in quantum chemistry1. Very extensive studies have been done on first and second row transition metal hydrides2,3, oxides4-6 and the transition metal dimers7-9. But theoretical studies on the third row transition metal compounds are comparatively scarce.Tungsten is an important element for catalytic reactions, and the knowledge of the interaction between W and C/N atom has basis importan…  相似文献   

11.
The theoretical study of small molecules containing transition metal atoms is one of the most active areas in quantum chemistry1. Very extensive studies have been done on first and second row transition metal hydrides2,3, oxides4-6 and the transition metal dimers7-9. But theoretical studies on the third row transition metal compounds are more scarce.Platinum is an important element for catalytic reactions, and the knowledge of the interaction between Pt and C/N atom is basic, but important fo…  相似文献   

12.
1 INTRODUCTION Recently, for the fluorescent properties, Schiff base has been more and more important and widely studied in density optical memories, nonlinear op- tics (NLO), organic light-emitting diodes (OLED), polymer LED and electrogenerated chemilumines- cence (ECL)[1~5]. Thiosemicarbazones are a kind of Schiff bases with thiourea and good ligands easily chelating with transition metal ions. Although they have been studied extensively for a long time due to their chemical and b…  相似文献   

13.
1 INTRODUCTION Recently, much interest has been focused on various extended framework due to their intriguing architectures, new topologies and potential applications in microelectronics, nonlinear optics, molecular selection, ion exchange and catalysis[1~4] . In the last few years, a wide range of infinite structures with diverse topologies has been prepared by the reaction of metal ions with mulriple organic ligands[5~9]. However, up to now, much of the work has been concentrated on c…  相似文献   

14.
1 INTRODUCTION Many crown ethers have been synthesized[1, 2] and widely used[3~5]. The amide-type acyclic poly- ethers with versatile molecular structures offer many advantages over the traditional crown ethers, such as their potential activity for ion-selective electrodes[6] and the extraction of metal ions[7], so they have attracted much scientific attention[8~10]. In an effort to investigate the effect of skeleton of acyclic polyether on the extractability of metal ions, and to find …  相似文献   

15.
1 INTRODUCTION The synthesis and study of transition metal com-plexes incorporating organic free radicals have arou-sed great interest in the field of molecular magne-tism[1]. Nitronyl nitroxide radicals (NITR), stable or-ganic radicals, have been widely used as molecularunits in the design and construction of magnetic ma-terials[2~5]. These radicals are especially attractivedue to that their donor atoms can assemble an exten-ded coordination geometry with changing magneticcoupling. A…  相似文献   

16.
1 INTRODUCTION Palladium (Ⅱ) coordination and organometallic compounds usually show square planar environments at the metal center[1], and have experienced an im- portant development in the past years due to their acting as intermediates in different types of catalytic reactions and numerous applications in organic synthesis[2]. Although palladium plays an increase- ingly recognized role as a biometal[3], little is known about the structure and function of palladium compounds in living …  相似文献   

17.
1 INTRODUCTION Macrocyclic[1~5] and macrobicyclic[6~11] com- pounds and their derivatives are great interesting ligand systems because they are good hosts for metal anions, neutral molecules and organic cation guests. Recently, many ligands in these fields have been rapidly developed and studied. Herein we will report the synthesis, crystal structure and characteri- zation of a novel 42-membered [2+2] macrocyclic compound obtained by the condensation of diethyl- lenetriamine with 4,4-d…  相似文献   

18.
林鸿  冯云龙 《结构化学》2005,24(5):573-576
1 INTRODUCTION Organic-inorganic hybrid material has captured the imaginations of chemists due to its potential applications in electric conductivity, magnetism, ion exchange and catalysis[1~2]. Coordination polymers with special structures have been well prepared by the reaction of transition metal ions and special orga- nic ligands. As a kind of multi-dentate ligand, aro- matic polyoxybiontic anion can coordinate with metal ion to form chain, layer and network struc- tures[3~6]. 1,3,5…  相似文献   

19.
The effect of N,N,N',N'-tetraalkyl terephthalamide (TATA) on the non-isothermal crystallization and melting characteristics ofpolypropylene (PP) was studied. The addition of TATA can lead to the formation ofβ-crystal PP. With the increase in TATA concentration the degree of crystallinity for β-crystal PP increased significantly, and that for a-crystal PP decreased, which indicated that TATA effectively induced the formation of β-crystal PP. WAXD also revealed the existence of β-crystal PP after the introduction of TATA into PP. PP containing TATA crystallized at a temperature range of 5-10℃ higher than that of pure PP, and the half-crystallization time (t1/2) and Avrami exponent (n) of PP at the same cooling rate were decreased by the addition of TATA, indicating that TATA influenced the crystallization rate and crystallization growth mode of PP. The rate constant of crystallization of PP containing TATA (Zc) was larger than that of pure PP, which further indicated that the crystallization of PP was accelerated by the addition of TATA.  相似文献   

20.
1 INTRODUCTION The synthesis of new molecular magnetic mate- rials that combine transition metal ions and pure organic radicals as ligating sites has attracted much more attention in the last few years[1~4]. Nitronyl ni- troxide radicals, independently or in combination with metal ions, have been one of the most studied systems in molecular magnetism for understanding the radical-radical or metal-radical interactions as well as for synthesizing organic ferromagnets and metal-radical magne…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号