Acetonitrile metalation

The dicarbonylbis( 4-l,3-cyclohexadiene)molybdenum(0) (9g) and tungsten (1 lg) complexes are formed only in moderate yields, photochemically. They are readily accessible, however, by thermal reactions of the respective tricarbonyltris(acetonitrile)metal(0) complexes (19) and lg (20). 

R = H, alkyl, aryl, 0-alkyl, Cl, Br, I, C02-alkyl, CONHR, SO2R, NO, CF3 R - = H, alkyl, aryl EWG = CHO, CO-alkyl, C02-alkyl, CO2H, CO2NH2, CO2NR2, CN, alkenyl, Cl, Br HX HCI, HBr solvent acetone, acetonitrile metal salt CuCI, CuBr,... 

Transition metal cations solvated by weakly coordinating solvents are useful precursors for a variety of nonaqueous synthetic applications. The dissociation of acetonitrile ligands opens up vacant coordination sites for catalysis, and allows transition metals to be introduced into extended arrays formed by condensation reactions with polydentate ligandsAlthough salts of homoleptic acetonitrile metal cations with tetrafluoroborate anions have been known since the 1960s, there has been no detailed description of the syntheses and characterization of these compounds. Likewise, there have been general descriptions of the syntheses of trifluoromethanesulfonate salts, but no specific outline for individual metals has been published. In this report, the syntheses of [M (CH3CN)x][BF4]2 (M = Cr,Mn,Fe,Co,Ni,Cu) and [M CHaCNlJlSOsCFsla (M = Mn,Fe,Co,Ni) are described. Two different methods are used to prepare tetrafluoroborate salts (1) the oxidation of metals with nitrosonium tetrafluoroborate, first described by Hathaway et al. and (2) the dehydration of aqueous tetrafluoroborate salts in a Soxhlet extractor with molecular sieves. The oxidation reaction is rapid, anhydrous, and recommended for smaller-scale preparations because of the relatively... 

The nitration of aromatics is an important chemical reaction, and new reagents include iV-nitropyrazole in the presence of a Lewis acid, metal nitrates in trifluoroacetic anhydride, and silver nitrate-boron trifluoride in acetonitrile. Metal salts, especially cerium(iv) acetate, also promote aromatic nitromethyl-... 

Ethylamine, monoethylamine, CH3CH2NH2-B.p. 19 C. Prepared by reduction of acetonitrile or by heating ethyl chloride with alcoholic ammonia under pressure. It is a strong base and will displace ammonia from ammonium salts. Forms a crystalline hydrochloride and also crystalline compounds with various metallic chlorides. 

For LC, temperature is not as important as in GC because volatility is not important. The columns are usually metal, and they are operated at or near ambient temperatures, so the temperature-controlled oven used for GC is unnecessary. An LC mobile phase is a solvent such as water, methanol, or acetonitrile, and, if only a single solvent is used for analysis, the chromatography is said to be isocratic. Alternatively, mixtures of solvents can be employed. In fact, chromatography may start with one single solvent or mixture of solvents and gradually change to a different mix of solvents as analysis proceeds (gradient elution). 

Acetonitrile also is used as a catalyst and as an ingredient in transition-metal complex catalysts (35,36). There are many uses for it in the photographic industry and for the extraction and refining of copper and by-product ammonium sulfate (37—39). It also is used for dyeing textiles and in coating compositions (40,41). It is an effective stabilizer for chlorinated solvents, particularly in the presence of aluminum, and it has some appflcation in... 

Electron donor molecules are oxidized in solution easily. Eor example, for TTE is 0.33V vs SCE in acetonitrile. Similarly, electron acceptors such as TCNQ are reduced easily. TCNQ exhibits a reduction wave at — 0.06V vs SCE in acetonitrile. The redox potentials can be adjusted by derivatizing the donor and acceptor molecules, and this tuning of HOMO and LUMO levels can be used to tailor charge-transfer and conductivity properties of the material. Knowledge of HOMO and LUMO levels can also be used to choose materials for efficient charge injection from metallic electrodes. 

When exposed to ait, the sodium salts tend to take up moisture and form dihydrates. The alkah metal xanthates are soluble ia water, alcohols, the lower ketones, pyridine, and acetonitrile. They are not particularly soluble ia nonpolar solvents, eg, ether or ligroin. The solubiUties of a number of these salts are Hsted ia Table 4. Potassium isopropyl xanthate is soluble ia acetone to ca 6 wt %, whereas the corresponding methyl, ethyl, / -propyl, n-huty isobutyl, isoamyl, and benzyl [2720-79-8] xanthates are soluble to more than 10 wt % (12). The solubiUties of the commercially available xanthates ia water are plotted versus temperature ia Figure 1 (14). 

NOTE - Petrochemical plants also generate significant amounts of solid wastes and sludges, some of which may be considered hazardous because of the presence of toxic organics and heavy metals. Spent caustic and other hazardous wastes may be generated in significant quantities examples are distillation residues associated with units handling acetaldehyde, acetonitrile, benzyl chloride, carbon tetrachloride, cumene, phthallic anhydride, nitrobenzene, methyl ethyl pyridine, toluene diisocyanate, trichloroethane, trichloroethylene, perchloro-ethylene, aniline, chlorobenzenes, dimethyl hydrazine, ethylene dibromide, toluenediamine, epichlorohydrin, ethyl chloride, ethylene dichloride, and vinyl chloride. 

Compound 9 has been prepared by the latter authors using triethylene glycol diiodide and triethylene glycol diamine (see Eq. 4.11) and an alkali metal carbonate in acetonitrile solution. ... 

Although most of the macrocycles that contain phosphorus or arsenic which have thus far been prepared, are primarily transition metals binders, two compounds have been prepared which are essentially crown ethers containing phosphorus. Kudrya, Shtepanek and Kirsanovhave prepared two compounds which are essentially polyoxygen macrocycles but which contain one or two methylphosphonic acid esters as part of the ring. These two macrocycles are shown below as 7d and 17 and are both prepared by the reaction of 2,2 [oxybis(ethyleneoxy)] bisphenolate with methylphosphonic dichloride in a mixture of acetonitrile and benzene. The crystalline monomer 16) and dimer 17) were isolated in 17% and 11% yields respectively as indicated in Eq. (6.13). 

The work of Hyatt on cyclotriveratrylene—derived octopus molecules contrasts with this. Of course, these species have the advantage of ligand directionality absent in the benzene-derived octopus molecules. Except for the shortest-armed of the species (i.e., n = 1), all of the complexing agents (i.e., n = 2—4) were capable of complexing alkali metal cations. Synthesis of these species was accomplished as indicated below in Eq. (7.7). These variations of the original octopus molecules were also shown to catalyze the reaction between benzyl chloride and potassium acetate in acetonitrile solution and to effect the Wittig reaction between benzaldehyde and benzyltriphenylphos-phonium chloride. 

In order to prepare thin fdms of (SN) on plastic or metal surfaces, several processing techniques have been investigated, e.g., the electroreduction of [SsNs]" salts. Powdered (SN) is prepared by the reaction of (NSC1)3 with trimethylsilyl azide in acetonitrile/ The sublimation of (SN) at 135°C and at pressure of 3 x 10 Torr. produces a gas-phase species, probably the cyclic [SsNs] radical, that reforms the polymer as epitaxial fibres upon condensation/... 

Apart from TiO and the lower halides already mentioned, the chemistry of these metals in oxidation states lower than 3 is not well established. Addition compounds of the type [TiCl2L2] can be formed with difficulty with ligands such as dimethylformamide and acetonitrile, but their magnetic properties suggest that they also are polymeric with appreciable metal-metal bonding. However, the electronic spectra of Ti in TiCl2/AlCl3 melts and also of Ti incorporated in NaCl crystals (prepared by... 

Acetonitrile (methyl cyanide, cyanomethane) is frequently used with other solvents such as chloroform and phenol, and particularly with acetic acid. It enables very sharp end points to be obtained in the titration of metal acetates6 when titrated with perchloric acid. 

The polarographic determination of metal ions such as Al3 + which are readily hydrolysed can present problems in aqueous solution, but these can often be overcome by the use of non-aqueous solvents. Typical non-aqueous solvents, with appropriate supporting electrolytes shown in parentheses, include acetic acid (CH3C02Na), acetonitrile (LiC104), dimethylformamide (tetrabutyl-ammonium perchlorate), methanol (KCN or KOH), and pyridine (tetraethyl-ammonium perchlorate), In these media a platinum micro-electrode is employed in place of the dropping mercury electrode. 

The metal catalyst is not absolutely required for the aziridination reaction, and other positive nitrogen sources may also be used. After some years of optimization of the reactions of alkenes with positive nitrogen sources in the presence of bromine equivalents, Sharpless et al. reported the utility of chloramine-T in alkene aziridinations [24]. Electron-rich or electron-neutral alkenes react with the anhydrous chloramines and phenyltrimethylammonium tribromide in acetonitrile at ambient temperature, with allylic alcohols being particularly good substrates for the reaction (Schemes 4.18 and 4.19). 

However, even if electrolytes have sufficiently large voltage windows, their components may not be stable (at least ki-netically) with lithium metal for example, acetonitrile shows very large voltage windows with various salts, but is polymerized at deposited lithium if this reaction is not suppressed by additives, such as S02 which forms a protective ionically conductive layer on the lithium surface. Nonetheless, electrochemical stability ranges from CV experiments may be used to choose useful electrolytes. 

Formation constants of metal complexes in non-aqueous solvents, I — acetonitrile. R. C. Kapoor and J. Kishan, Rev. Anal. Chem., 1981, S, 257-280 (96). 

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