Mono metal complexes

More often, the preparation of mono-metallic complexes featuring long poly-ynyl ligands MLn (CsC) R has been accomplished by a sequence of crosscoupling reactions between terminal poly-ynyl complexes and 1-halo alkynes and... 

We also tested the reactivity and selectivity of mono metalated complexes (Type V). These catalysts, although reactive, were in general less selective than bimetal-ated compounds with head-to-tail configuration. Finally, preliminary studies of reactivity of doubly metalated compounds with the head-to-head configuration (Type Vllb) showed that these compounds are not promising catalysts for C-H insertion reactions. 

Quite recently we also succeeded in X-ray structure determination of the mono-metallated complex of 1 with (Cp Ru)+ [64]. As in the bis-ruthenium analog the metal was 7 coordinated to one of the benzene rings of 1 on its exo (convex) face. This is the first experimental evidence demonstrating the exo preference of 7 coordination of (Cp Ru)+ to corannulene. Also, another bis-metallated complex, [(Cp Ru)2( 2 / / C2oHio)][SbF6]2 was prepared and characterized by X-ray [64]. 

Ultrasonic absorption is used in the investigation of fast reactions in solution. If a system is at equilibrium and the equilibrium is disturbed in a very short time (of the order of 10"seconds) then it takes a finite time for the system to recover its equilibrium condition. This is called a relaxation process. When a system in solution is caused to relax using ultrasonics, the relaxation lime of the equilibrium can be related to the attenuation of the sound wave. Relaxation times of 10" to 10 seconds have been measured using this method and the rates of formation of many mono-, di-and tripositive metal complexes with a range of anions have been determined. 

Organic Halides. Alkyl halides and aiyl halides, activated by election withdrawing groups (such as NO2) in the ortho or para positions, react with alkyleneamines to form mono- or disubstituted derivatives. Product distribution is controlled by reactant ratio, metal complexation or choice of solvent (16,17). Mixing methylene chloride [75-09-2J and EDA reportedly causes a mnaway reaction (18). 

Returning briefly to CO2 as a ligand in addition to the various mono-C02 complexes referred to above, several bis(rj -CO2) transition-metal adducts are known, e.g. /ran -[Mo( ) -C02)2(PMe3)4] (5) and trans.mer-[Mo( 2-C02)2(PMc3)3(CNPr )].< 22 The first homo-bimetallic bridging-C02 complex has also been structurally characterized by X-ray analysis, viz. [(dppp)(CO)2Re(/x, j 0,0 j C)Re(CO)3(dppp)] (6) [dppp = l,3-bis(diphenyl-phosphino)propanc]. 0 3)... 

Different main-group-, transition- and lanthanide-metal complexes can catalyze the cycloaddition reaction of activated aldehydes with activated and non-activated dienes. The chiral metal complexes which can catalyze these reactions include complexes which enable substrates to coordinate in a mono- or bidentate fashion. 

Inhibitors (Section 5.3), including transition metal complexes and nilroxides, may be used to prepare mono-end-functional polymers. If an appropriate initiator is employed, di-end-functional polymers are also possible. 

The scope of the present paper is limited to those cyclopentadienyl ligands that contain more than two bulky substituents and transition metal complexes derived thereof in order to be able to focus on the specific effects of these ligand systems. A selection of some mono-substituted cyclopentadienyl ligands will be treated also. Among the numerous reviews highlighting special aspects of cyclopentadienyl... 

Formazans and their metal complexes are used as textile dyes by direct application. The in situ reduction of tetrazolium salts has not been used to introduce the dyes to their substrates. Treatment with triaryl mono and bis tetrazolium salts followed by a reducing agent such as ascorbic acid or thioglycolic acid has been claimed as a method of introducing formazans as permanent hair dyes.641 There are some references to their use as therapeutic agents.642 544... 

All of the reactions described above use anionic alkyl metal complexes as stoichiometric reductants. Cationic zirconium catalyst 58 was shown to re-ductively cyclize a variety of 1,5-dienes to give both mono- and bicyclic silane products when H3SiPh was employed as the stoichiometric reductant (Scheme 10) [32]. Poor yields due to competing polymerization processes were observed when less substituted dienes were employed. It is likely that... 

Well-characterized transition metal complexes of vitamin C (ascorbic acid) are rare, and a select number of these exhibit anticancer properties. Hollis et al. have described the first examples to be fully characterized by X-ray crystallography.316 Treatment of [Pt(H20)2L2]2+ (L = NH3, MeNH2 L2 = en, 1,2-chxn) with ascorbic acid gives either the mono- or bisascorbate species of the type cis-[PtL2(C2,Os-ascorbate)] (e.g., (125)) or m-[PtL2(C2-ascorbate)(03-ascorbate)], respectively. Interestingly, in both types of complexes, platinum(II) forms a bond with the C-2 atom of ascorbic... 

The most prevalent metal complex dyes for textile and related applications are metal complex azo dyes. Their colors span the entire spectrum although, as described earlier, they tend to give dull shades. They may be 1 1 dye metal complexes or 2 1 complexes and contain mainly one (mono-azo) or two (disazo) azo groups. 

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