Copper complexes diethyl ether

Aluminium can be deposited from complex organic solutions if sufficient precautions are taken, and such coatings are now being produced commercially in North America. Two of the systems on record are (1) aluminium trichloride and lithium aluminium hydride dissolved in diethyl ether used at 40°C and 50A/m, and (2) aluminium chloride, n-butylamine and diethyl ether used at 20°C and 970 A/m. Deposits of 0-010 mm can be obtained on mild steel or copper at 20°C and 970 A/m using aluminium-wire anodes and nitrogen or argon atmospheres. 

The cobalt complex is usually formed in a hot acetate-acetic acid medium. After the formation of the cobalt colour, hydrochloric acid or nitric acid is added to decompose the complexes of most of the other heavy metals present. Iron, copper, cerium(IV), chromium(III and VI), nickel, vanadyl vanadium, and copper interfere when present in appreciable quantities. Excess of the reagent minimises the interference of iron(II) iron(III) can be removed by diethyl ether extraction from a hydrochloric acid solution. Most of the interferences can be eliminated by treatment with potassium bromate, followed by the addition of an alkali fluoride. Cobalt may also be isolated by dithizone extraction from a basic medium after copper has been removed (if necessary) from acidic solution. An alumina column may also be used to adsorb the cobalt nitroso-R-chelate anion in the presence of perchloric acid, the other elements are eluted with warm 1M nitric acid, and finally the cobalt complex with 1M sulphuric acid, and the absorbance measured at 500 nm. 

In addition to the boron trifluoride-diethyl ether complex, chlorotrimcthylsilanc also shows a rate accelerating effect on cuprate addition reactions this effect emerges only if tetrahydrofuran is used as the reaction solvent. No significant difference in rate and diastereoselectivity is observed in diethyl ether as reaction solvent when addition of the cuprate, prepared from butyllithium and copper(I) bromide-dimethylsulfide complex, is performed in the presence or absence of chlorotrimethylsilane17. If, however, the reaction is performed in tetrahydrofuran, the reaction rate is accelerated in the presence of chlorotrimethylsilane and the diastereofacial selectivity increases to a ratio of 88 12 17. In contrast to the reaction in diethyl ether, the O-silylated product is predominantly formed in tetrahydrofuran. The alcohol product is only formed to a low extent and showed a diastereomeric ratio of 55 45, which is similar to the result obtained in the absence of chlorotrimethylsilane. This discrepancy indicates that the selective pathway leading to the O-silylated product is totally different and several times faster than the unselective pathway" which leads to the unsilylated alcohol adduct. A slight further increase in the Cram selectivity was achieved when 18-crown-6 was used in order to increase the steric bulk of the reagent. 

Benzylzinc requires activation by copper(l) cyanidc/boron trifluoride-diethyl ether complex for rapid carbonyl addition29. Little information is available on the reactivity of benzyltitani-um derivatives30,31. 

The beneficial effect of added phosphine on the chemo- and stereoselectivity of the Sn2 substitution of propargyl oxiranes is demonstrated in the reaction of substrate 27 with lithium dimethylcyanocuprate in diethyl ether (Scheme 2.9). In the absence of the phosphine ligand, reduction of the substrate prevailed and attempts to shift the product ratio in favor of 29 by addition of methyl iodide (which should alkylate the presumable intermediate 24 [8k]) had almost no effect. In contrast, the desired substitution product 29 was formed with good chemo- and anti-stereoselectivity when tri-n-butylphosphine was present in the reaction mixture [25, 31]. Interestingly, this effect is strongly solvent dependent, since a complex product mixture was formed when THF was used instead of diethyl ether. With sulfur-containing copper sources such as copper bromide-dimethyl sulfide complex or copper 2-thiophenecarboxylate, however, addition of the phosphine caused the opposite effect, i.e. exclusive formation of the reduced allene 28. Hence the course and outcome of the SN2 substitution show a rather complex dependence on the reaction partners and conditions, which needs to be further elucidated. 

With this end in view, phenyldimcthylsilyl tri-n-butylstannane was added under the influence of zero-valent palladium compound with high regioselectivity and in excellent yield to the acetylene 386 to give the metallated olefin 387 (Scheme 56). The vinyl lithium carbanion 388 generated therefrom, was then converted by reaction with cerium(lll) chloride into an equilibrium mixture (1 1) of the cerium salts 389 and 390 respectively. However, the 1,2-addition of 389 to the caibonyl of 391, which in principle would have eventually led to ( )-pretazettine, did not occur due to steric reasons — instead, only deprotonation of 391 was observed. On the other hand, 390 did function as a suitable nucleophile to provide the olefinic product 392. Exposure of 392 to copper(II) triflate induced its transformation via the nine membered enol (Scheme 55) to the requisite C-silyl hydroindole 393. On treatment with tetrafluoroboric acid diethyl ether complex in dichloromethane, compound 393 suffered... 

The coordinatively unsaturated complexes are even less soluble in organic solvents such as diethyl ether, benzene, and chloroform than their saturated equivalents. The magnetic moment of copper complexes of tridentate formazans with a 2-hydroxyaryl substituent at N1 is very low (1.44 iB) compared to the expected value of copper(n) complexes with an unpaired electron and strong covalent bonding. The low solubility and magnetic moment suggest that the dimerization occurs with the formation of a saturated dinuclear complex 38. 

Arnold and co-workers also reported the deprotonation of alkoxy imi-dazolium iodides with -butyl lithium to yield lithium alkoxide carbenes (Scheme 3).14 Single crystals of one of the complexes were grown from a diethyl ether solution, and revealed a dimer of LiL with lithium iodide incorporated to form a tetramer of lithium cations (7). The lithium-NHC bond distance of 2.131(6) A is similar to that of the lithium amide carbene 4. Also as in 4 there is distortion of the lithium-NCN bond which has an angle of 152.3°. The C2 carbon resonates at 200 ppm in the 13C NMR spectrum which is a relatively high-frequency, possibly as a result of the incorporated lithium iodide. The lithium salts were able to act as ligand transfer reagents and react with copper (II) chloride or triflate to afford mono- or bis-substituted copper(II) alkoxy carbene complexes. 

A solution of Li[GaH4] in diethyl ether is prepared by the standard methods,J1 and is stored in a needle-valve O-ring flask. The concentration of Li[GaH4]-ether solution is determined by hydrolysis of a known volume of the solution followed by gallium determination by ethylenediamine-tetraace-tic acid, disodium salt using copper-PAN [l-(2-pyridylazo)-2-naphthol copper complex] as the indicator.4 It is assumed that all the gallium is present as the tetrahydrogallate. Only an approximate concentration need be determined since an excess of sodium hydride or potassium hydride is used. 

An oven-dried, 1-L, round-bottomed flask is equipped with a magnetic stirring bar and a rubber septum. The flask is charged with 25.61 g of copper bromide-dimethyl sulfide complex (124 mmol) and 250 mL of dry diethyl ether, and the resulting slurry is cooled to -78°C with a dry ice-acetone bath. The Grignard reagent solution prepared above is added to the copper bromide-dimethyl sulfide slurry via cannula... 

The paper discusses two types of reaction involving metal complexes, and it is postulated that each proceeds by an initial free-radical step. In reactions between metal carbonyls and N2O4—NO2 mixtures, the nature of the product depends upon the phase in which the reaction is carried out. In the liquid phase, where the predominant equilibrium is N204 N0+ + NO3-, metal nitrates or carbonyl nitrates are formed in the gas phase, where the equilibrium is N2O4 2NO2/ nitrites or their derivatives are produced. Reactions of Mn2(CO) o Fe(CO)5, Co2(CO)3, and Ni(CO)4 are discussed. Anhydrous metal nitrates in which the nitrate group is covalently bonded to the metal have enhanced reactivity. This is believed to result from the dissociation M—O—N02 M—O + NO2 This can explain the solution properties of beryllium nitrates, and the vigorous (even explosive) reaction of anhydrous copper nitrate with diethyl ether. 

On the contrary, encapsulation of the larger K" " or NH4 ions should lead to the formation of metallacrown ether sandwich complexes (M+ MC= 1 2). Reaction of diethyl ketipinate H2L 13 with copper(ll) acetate in the presence of calcium nitrate affords green microcrystals 14 after crystallization from tetrahydro-furan/diethyl ether (Scheme 1). 

In an atmosphere of argon, a solution of 13.5 g (88%, 94 mmol) of S.6b and 300 mg (11 mmol) of copper (I) trifluoromethanesulfonate benzene complex (CuOTf) in 120 mL of dry diethyl ether is irradiated in a Pyrex photoreactor with a water cooled quartz immersion well by a high-pressure mercury lamp (HPK 125 W, Fa. Philips). After the reaction is complete (monitored by GLC), the mixture is concentrated in vacuo and purified by column chromatography (cyclohexane/ethyl acetate 2 3) to give 10.5 g (64% from... 

The [3-diketiminato copper complex is a pale yellow solid that is freely soluble in benzene, toluene, chlorobenzene, THF, and acetonitrile while partially soluble in diethyl ether and pentane. In solution, the toluene ligand dissociates. When dissolved in benzene, for example, the NMR spectrum exhibits signals for both LMe Me3cu(benZene) (major species) and [LMe,Me3Cu]2(benzene) (minor species). The copper complex reacts slowly with chloroform and dichloromethane, resulting in a gradual darkening of the solution to purple. 

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