Synthesis of metal complexes

Studies involving 2,6-diacetylpyridine derivatives. Detailed studies by Nelson and coworkers supported by X-ray structural work by Drew and coworkers have elucidated many aspects of the template synthesis of metal complexes of a Schiff-base ligand series which includes the N4-donor system (83) and the N5-systems (84)-(86) (Nelson, 1980). Since... 

This article presents the principles known so far for the synthesis of metal complexes containing stable carbenes, including the preparation of the relevant carbene precursors. The use of some of these compounds in transition-metal-catalyzed reactions is discussed mainly for ruthenium-catalyzed olefin metathesis and palladium-Znickel-catalyzed coupling reactions of aryl halides, but other reactions will be touched upon as well. Chapters about the properties of metal- carbene complexes, their applications in materials science and medicinal chemistry, and their role in bioinorganic chemistry round the survey off. The focus of this review is on ZV-heterocyclic carbenes, in the following abbreviated as NHC and NHCs, respectively. 

A few interesting reactions of the R2Dtc ligands have been reported and should have bearing in the procedures used for the synthesis of metal complexes. 

The 1,2,3,5,6-pentathiepane was used for synthesis of metal complexes with platinum(O). The reaction of the... 

Von Zelewsky has published many examples of the stereoselective synthesis of metal complexes using what he refers to as chiragen ligands. These are enantiopure natural compounds synthesized from the natural product (—)-a-pinene, which is combined with species such as bipyridine units to provide impressive control of metal-centered chirality.159-161 In this section, we will focus on the determination of absolute configurations in terms of stereospecific formation from different points of view in connection with absolute conformations in the ligands. 

CLASSIC CONCEPTS OF COORDINATION IN THE SYNTHESIS OF METAL COMPLEXES... 

Gamovskii, A.D. Vasilchenko, I.S. Garnovskii, D.A. Modern Aspects of Synthesis of Metal Complexes. Fundamental Ligands Methods. LaPO Rostov-on-Don, 2000, 354... 

Synthesis of Metal Complexes on the Basis of 1,2-Bisthiosalicylideneiminatoethane (tsalen) (3.172) [355]... 

The above conventional synthetic methods are based on the use of metal salts or carbonyls as complex-formers. At the same time, as far back as at the end of the nineteenth century [504], the possibility of use of compact elemental metals for obtaining complex compounds was shown. This circumstance served as a basis for development of the electrochemical [10,24,201,202,206,505-507], gas-phase [201,202,508-512], and liquid-phase [201,202,513] syntheses of metal complexes using zero-valent metals. All these syntheses are united as direct synthesis of metal complexes [201,202,513]. Much literature is devoted to this area, generalized in a series of reviews [505-507,510-513] and monographs [10,201,202,206,508]. In this respect, only principal aspects of the direct synthesis and the most recent achievements of its application for obtaining various types of coordination and organometallic compounds will be discussed in this section. 

Synthesis of Metal Complexes in the Conditions of Ultrasonic Treatment... 

The theory of regioselective synthesis of metal complexes is based on the ideas of competitive coordination and the principle of hard and soft acids and bases (HSAB, Sec. 1.2.2). 

An approach to the regioselective synthesis of metal complexes was offered based on the joint use of chemical and electrochemical methods of synthesis of coordination compounds departing from the same ligands [11], for instance transformation (4.37). As a result of these reactions, chelates with the participation of different N atoms of the imidazole ring, of the ligand in coordination, are formed ... 

By evaluating the character of influence of an R1-substituent on the stereochemistry of ICC of azomethinic ligands of type 868, the following two effects are usually emphasized spatial, related to volume, and coordinatively-active, caused by the presence of additional donor centers. The first one causes, in the majority of cases, distortions of tetracoordinated polyhedra the second one increases the coordination number of a metal complex-former from 4 to 5 and later to 6. Guided by these considerations, it is possible to carry out the controlled synthesis of metal complexes with a programmed geometry of the coordination unit. 

The material of the present book is intensified in comparison with earlier, similar subject, monographs [1-4], in the detailed description of the modern state of selection of ligands and the main synthetic methods (Chaps. 2 and 3) and the presence of data on the controlled synthesis of metal complexes (Chap. 4) and synthesis of selected groups of coordination compounds (Chap. 5). However, the chapters mentioned above contain a series of shortcomings, related to the incomplete elucidation of the enormous amount of reported data and the limited examination of... 

The synthesis of metal complexes of type 213 can be performed by reacting metal-carbene complexes with selenium sources such as alkyneselenolates 203.430 Also the stability of unstable selenocarbonyl compounds such as selenoaldehydes can be enhanced by coordination to metal carbonyls and the reactivity of such complexes has been studied. Complex 216 can react with methylthiohexyne and the product is a different complex 217 with the selenium atom still coordinating to the metal carbonyl fragment (Scheme 66).431... 

Isatin, due to its cis a-dicarbonyl moiety, is a potentially good substrate for the synthesis of metal complexes, either alone or with other ligands. Their derivatives, mostly those substituted at C-3, such as isatin-3-hydrazones and isatin-3-imines bearing an extra heteroaromatic ring are also generally employed as ligands. In this manner, Schiff bases... 

The structural distortion of alkynes coordinated to hexacarbonyldi-cobalt units has been exploited in the synthesis of metal complexed cyclo[ 18-]carbon and cyc/o[24]carbon (see Scheme 17).182-184 One-pot reaction of the hexatriyne 44 with [Co2(CO)8] followed by dppm and then [Bu4N] F affords complex 45. The dppm imparts the extra stability necessary for the dicobalt unit to withstand treatment with [Bu4N]+F to remove the Si( Pr)3 groups. Oxidative coupling under high dilution conditions affords the cyclo-C18 (46) and cyclo-C24 (47) derivatives. 

Alternatively, the reaction of isolated selenocarbonyl compounds with transition metal complexes has been applied to the synthesis of metal complexes of type 53. The complexation of furanselenoamides and thiopheneselenoamides to Pd, Rh, and Ru halides is accompanied with cyclometallization (Eq. 30) [111]. The formation of Cu [112a], Ag, Au [112b,c], Zn, Cd [113], Co [114], Cr, Mo, and W [115] complexes has been attained by reacting selenourea or selenoamides with the corresponding metal halides or metal carbonyls. 

A further synthesis of metal complexes containing two six-membered aromatic rings, which was limited to chromium, was based on the interaction of phenyl magnesium bromide and chromic chloride, and subsequent hydrolysis of the reaction mixture to the [Cr(C8He)2] cation (107, m, m). 

Dhal PK, Arnold FH (1991) Template-mediated synthesis of metal-complexing polymers for molecular recognition. J Am Chem Soc 113 7417... 

Electrolyses at sacrificial electrodes allow direct synthesis of metal complexes from bare metal electrodes. Systematic studies have been reported and periodically reviewed.22-24 The sacrificial electrode may either be a cathode (Pb, Sn, Hg), or an anode (metals) which is the most usual configuration. The experiments are generally carried out under galvanostatic conditions (10-30 mA cm-2) and so a reference electrode and a potentiostat are not required. Different types of products have been obtained from the simplest complexes to clusters. 

From the seminal work of Lunsford et al. in the early 1980s (DeWilde et al., 1980 Quayle and Lunsford, 1982), ship-in-a-bottle synthesis of metal complexes in the zeolite supercages, encapsulation of catalytically, optically, and/or electrochemically active species within micro- and mesoporous aluminosilicates, has received considerable attention (Alvaro et al., 2003). Site isolation of individual guest molecules, combined with shape and size restrictions imposed by the supercage steric limitations. 

Kamai, G., and Kukhtin, V.A., Polymerization of some unsaturated esters of phosphonocarboxyhc acids, Zh. Obshch. Khim., 24, 1855, 1954 J. Gen. Chem. USSR (Engl. Transl.), 24, 1819, 1954. Kennedy, J., Lane, E.S., and Robinson, B.K., Synthesis of metal-complexing polymers. Part 1. Phosphorylated polymers, J. Appl. Chem., 8, 459, 1958 Chem. Abstr., 53. 3032h, 1959. 

Figure 35 Copper (I)-templated synthesis of metal-complexed [2]-rotaxane (105) bearing...

---