Acetonitrile complexes

Palladiumdl) chloride-acetonitrile complex is formed by placing a.00 g of PdCl2 in 200 ml of acetonitrile and stirring for 2 days or refluxing for 3 hr. The complex (11.43 g, 97.8%) is collected by filtration, washed, and dried. 

The compound known as 18-crown-6 is one of the simplest and most useful of the macrocyclic polyethers. Its synthesis in low yield was first reported by Pedersen. Greene and Dale and Kristiansen" have reported syntheses of the title compound from triethylene glycol and triethylene glycol di-p-toluenesulfonate. Both of these procedures use strong base and anhydrous conditions and achieve purification by more or leas classical methods. The combination of distillation and formation of the acetonitrile complex affords crown of high purity without lengthy chromatography or sublimation. ... 

A terminal 1,13 diene with interstitial deka(difluoromethylene) chain is converted to the corresponding diepoxide by repeated reacUon with a very large excess of hypofluorous acid-acetonitrile complex [22](equation 14)... 

In 1999, Kiindig and Bruin reported a closely related catalyst system 29a, in which a more readily accessible ligand has been employed [37]. Catalytic activity and stability are strongly dependent upon the nature of the neutral ligand L. While the acetonitrile complex 29b is stable, yet catalytically inactive, complex 29a with L = acrolein is stable only in the solid state, but decomposes as a solution in DCM... 

To determine if CP was indeed lost in the chemical step the potential was held at — 1.7 V for 30s, then a positive-going scan initiated up to 1.5 V. A number of anodic peaks were observed with the largest and most significant at 1.2 V. This was unequivocally attributed to the oxidation of CP to Cl2 on the basis of a second experiment in which tetrabutylammonium chloride was added to the base electrolyte and the potential regime repeated. Hence, the chemical step after the addition of the first electron involves the ejection of the chloride anion. The identity of the species formed subsequent to this process was determined thus O Toole et al. prepared and characterised the hydrido and acetonitrile complexes (as the bipyridine derivatives) and determined their E° values as —1.46 V and —1.25 V, respectively, far removed from the observed value — 1.62 V hence neither of these species were taken as being the product. 

The disubstituted acetonitrile complex has been found to undergo all the reactions cited above for the cyclooctene complex. A particular advantage of these compounds is that it is possible sequentially to replace the ligands to produce the intermediate compound [Os3(CO)10-(CN3CN)X], which may then be further reacted to give a mixed complex [Os3(CO)10XX ]. 

In many instances it is not necessary to isolate the acetonitrile complex or to carry out the reaction in acetonitrile. The use of amine oxide as a means of displacing carbonyl groups in metal carbonyls is well documented, and reaction proceeds smoothly with the carbonyl in the presence of a variety of ligands—e.g., ethylene or pyridine—to yield the monosubstituted derivatives. The advantage of the acetonitrile adducts is the stability of the compounds and the reactivity of the amine oxide toward acidic ligands. 

The host-guest interaction of manganese(II) with a range of ferrocene-containing species, which included the dithia derivative (219), has been investigated in acetonitrile. Complexation gave rise to a bathochromic shift of the lowest-energy ferrocene-centered d-d transitions. 

Combination with bipyridyl hgand in carbon tetrachloride followed by hydrolysis yields a molybdenum oxychloride bipyridyl complex of formula MoOCR(bipy). When mixed with ammonium chloride in acetonitrile and water, an oxychloride-acetonitrile complex, NIRfMoOCRCHsCN], is obtained. 

Cleavage of a Mo L bond. The electrochemical reduction of the acetonitrile complex ds-19 + is an overall two-electron process leading to the cleavage of the Mo—NCMe bond. The CV of cis-[Mo2(cp )2(At-SR)2(CO)3(MeCN)]2+ appeared to be strongly dependent upon the nature of the sulfur substituents and of the... 

Through selective complexation with nitromethane, dimethyl carbonate and dimethyl oxalate, it was possible to isolate [18]crown-6 in 98 % purity from a crude reaction mixture 14a). Although the acetonitrile complex with [18]crown-6 has been known for some time, the structure was determined only recently because of rapid crystal deterioration 14). 

The high level of stereocontrol in the formation of complexes 25 and 27 suggests that compounds of this type may be useful as chiral catalysts. Indeed, several examples of enantioselective catalytic reactions carried out with half-sandwich complexes have been published recently [23, 25]. However, it seemed desirable to have access to complexes of the [21 Ru(solv)2] type, which have two easily removable solvent molecules coordinated to the central metal, in order to provide coordination sites for a substrate to be transformed. Although the chloride ligand could be easily removed from 23 and 25 all attempts to strip off the PPhs were unsuccessful. Therefore a new reaction scheme was developed which precluded the use of phosphine ligands, and the bis (acetonitrile) complex 28 could be obtained in a multi-step protocol via the T1 salt T1 21 (Scheme 1.5.12) [26]. 

Scheme 1,5.12 Multi-step synthesis of the bis(acetonitrile) complex 28.

ACETONITRILE COMPLEXES OF SELECTED TRANSITION METAL CATIONS... 

Acetonitrile Complexes of Selected Transition Metal Cations 129... 

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