Glyoxime ligands

Examples of the use of noncarbonyl anions can be found in the work of Schrauzer and Windgassen on cobalt complexes bearing the dimethyl-glyoximate ligand (23, 24)... 

The hydrosilylation of butadiene proceeds with palladium compounds even in the absence of phosphines. Other ligands, such as glyoxime, benzonitrile, and 1,5-cyclooctadiene, can be used as effective ligands for the hydrosilylation of butadiene (65, 67). The reaction of trichlorosilane and dichlorosilane with isoprene proceeded regioselectively and stereo-selectively to give Z-l-trichlorosilyl-2-methyl-2-butene (67) (65, 66, 68). No reaction of trimethylsilane with isoprene took place, and this shows the lower reactivity of trialkylsilane. 

K[RuClj(H-dmg)2] and K[RuClj(H-dpg)2] (dmg and dpg=monoanions of dime-thyl-glyoxime and diphenylglyoxime) are made from K [Ru(H30)Cl5] and the ligands. As [complex]/PhIO/water they epoxidised cyclohexene, probably via a Ru (0)C1(H-L)3 species [640],... 

The complexes with unsubstituted and either alkyl- or aryl-substituted glyoximes have been prepared by the reaction of nickel(II) salts with the appropriate ligand in aqueous or ethanolic solution or an aqueous-ethanolic mixture. In most cases, the reaction is promoted by addition of ammonia as base and/or refluxing temperature. 

Replacement of the hydrogen bonds in oxime complexes with boron bridges leads to macrocyclic complexes such as those from dimethyl glyoxime (equation 59).201,202 This kinetic template technique has been used for the encapsulation of metals inside cage ligands.203 204... 

Linear NO, nitride (N), linear NNR, NS, NSe, P Ligands which can be subdivided into a combination of 1VE and 2VE donations e.g. Tj3-allyl, ri3-cyclopropenyl, bidentate alkenyls, acyls, carboxylates, dithiocarbamates, amidates, fi-diketonates, salicylates, glyoximates... 

Since the recognition of Vitamin B12 and the existence in Nature of Co—C bonds, there has been much study of model systems. These have been mainly complexes of dimethyl and other glyoximes (the so-called cobaloximes), and Schiff base and macrocyclic ligand complexes. The methyl complex [Co(CH3)(NH3)5]2+ may be regarded as the simplest model it has electronic characteristics very similar to those of [Co(NH3)6]3+.31 The main interest has centered on the reduction of Co1 species and on the formation of Co—C bonds and their reactions. 

A large number of mixed ligand complexes of cobalt(III) are known in which one ligand is either bipyridyl or phenanthroline and the other ligands are, for example, dimethyl glyoxime (569), 8-hydroxyquinoline... 

Bis (dimethylglyoximato) cobalt complexes are of interest as models of vitamin Bi2. The cobalt atom in the square planar ligand field of the four sp -hybridized nitrogen atoms of dimethyl-glyoxime has a pronounced tendency to form stable organo-cobalt derivatives, in analogy to the cobalt atom in the... 

Halogen oxidation of planar complexes, particularly of the nickel triads that contain bidentate glyoximes or macrocyclic ligands, such as, phthalocyanines, substituted porphyrins, or tetraazaannulenes, leads to highly conducting substances that may possess chains of metal atoms as well as chains of polyhalides ... 

Ni(ii) forming 4 coplanar bonds. Planar diamagnetic complexes include the Ni(CN)4 ion, which has been studied in the and other salts (Ni-C, 1-85 A), and molecules such as (a) and (b). The numerous complexes with bidentate ligands include the thio-oxalate ion, (c), molecules of the types (d) ) and (e), and the glyoximes, (0> notable for the short intramolecular hydrogen bonds. Many divalent metals form phthalocyanins, M(ii) replacing 2 H in C32H18N8 (Fig. 27.9). 

Among the more widely studied 2,3-C-disubstituted ligands related to ethylenediamine are sbn and stien (Table 3). These ligands can exist in meso and racemo forms and the properties e.g. solubility) of transition metal complexes (especially Co" ) with the two forms of this type of ligand are often sufficiently different as to allow amine isomer separation to be achieved without separation of the amine mixture. Meso and racemic 5bn are prepared together by the reduction of dimethyl-glyoxime and can be separated by fractional crystallization of the dihydrochloride salts. There are, however, stereospecific synthetic routes available for the meso and racemo forms of stien (Table 6). 

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