Ethane, 1,2-dimethoxy-, compound with

Perhaps because of inadequate or non-existent back-bonding (p. 923), the only neutral, binary carbonyl so far reported is Ti(CO)g which has been produced by condensation of titanium metal vapour with CO in a matrix of inert gases at 10-15 K, and identified spectroscopically. By contrast, if MCI4 (M = Ti, Zr) in dimethoxy-ethane is reduced with potassium naphthalenide in the presence of a crown ether (to complex the K+) under an atmosphere of CO, [M(CO)g] salts are produced. These not only involve the metals in the exceptionally low formal oxidation state of —2 but are thermally stable up to 200 and 130°C respectively. However, the majority of their carbonyl compounds are stabilized by n-bonded ligands, usually cyclopentadienyl, as in [M(/j5-C5H5)2(CO)2] (Fig. 21.8). 

A few other examples of chain-forming coordination polymers are mentioned. A polymer 31 was obtained under inert conditions by the reaction of 4,4, 5,5 -tetramethyl-2,2 -bisphosphinine with naphthalene/Na in dimethoxy-ethane [85]. The bisphosphinine is reduced two-fold. In the deep purple oxygen-sensitive crystals the chain is held together by electrostatic interactions through alternation between three and one Na(I) cations. The reaction of pentaphosphaferrocene with CuX (X = Cl, Br, I) was used to prepare yellow-brown crystals of one- and two-dimensional poljmiers in which the phospha-ferrocene units are connected by CuX units [86]. One-, two- and three-dimensional tubes were prepared by employing dimetal building units [87]. For example, a one-dimensional tube was obtained from a Rh2 compound with malonic acid and linkers such as tra 5-l,2-bis(4-pyridyl)ethylene. 

A mixture of 12.6 g of benzoyl chloride in 100 cc of ethylene chloride is added dropwise to a suspension of 25.6 g of 3ethylene chloride and 21.8 g of triethylamine within 18 minutes at room temperature while stirring. The mixture is stirred at room temperature for a further 14 hours, 200 cc of water are added, the organic phase is separated and concentrated to an oil in a vacuum. Upon adding ether/dimethoxy ethane to this oil, crude 6-ben zoy I-3absolute ethanol with the addition of a small amount of coal, the compound has a melting point of 125°C to 127°C (decomp.). Displacement of the halogen with hydrazine leads to the formation of endralazine. 

Using dilatometry in parallel with cyclic voltammetry (CV) measurements in lmolL 1 LiC104 EC-l,2-dimethoxy-ethane (DME), Besenhard et al. [87] found that over the voltage range of about 0.8-0.3 V (vs. Li/Li+), the HOPG crystal expands by up to 150 percent. Some of this expansion seems to be reversible, as up to 50 percent contraction due to partial deintercalation of solvated lithium cations was observed on the return step of the CV. It was concluded [87] that film formation occurs via chemical reduction of a solvated graphite intercalation compound (GIC) and that the permselective film (SEI) in fact penetrates into the bulk of the HOPG. It is important to repeat the tests conducted by Besenhard et al. [87] in other EC-based electrolytes in order to determine the severity of this phenomenon. 

Summary In recent years trimethylsilylphosphanes proved to be versatile starting compounds in the syntheses of phosphaalkenes and phosphaalkynes. The tris(trimethylsilyl) derivative, for example, reacts with acyl chlorides in a molar ratio of 1 1 give the corresponding [l-(trimethylsiloxy)-alkylidene]trimethylsilylphosphanes first. From a subsequent hexamethyldisiloxane elimination catalyzed by solid sodium hydroxide at 110-120 C many phosphaalkynes have been obtained so far. In order to understand the underlying reaction mechanism, studies on the chemical behavior of [l-bis(l,2-dimethoxy-ethane-0,0 )fithoxy-2,2-dimethylpropylidene]trimethylsilylphosphan prepared by lithiation of the related trimethylsiloxy derivative are being started. 

When bright yellow, solid bis(trimethylsilyl)mercury is treated with trimethylsilyl-lithium in 1,2-dimethoxy ethane (DME), color changes occur and either a three- or a four-coordinated anionic silyl-Hg compound may be isolated according to the stoichiometry ... 

Figure 9-5. Structures of complexes of a AgBF4 2-dimethoxy ethane complex, b AgBF4 , 2-dimethoxy ethane-ethylene adduct where 1,2-dimethoxy ethane is a model compound of poly(ethylene oxide) [15]. The silver ion is coordinated by two oxygen atoms from 1,2-dimethoxy ethane and two F atoms from the anion to make silver-polymer complexes, when AgBF4 is complexed with 1,2-dimethoxy ethane. One of the two F atoms bound to the silver ion is replaced by an ethylene molecule, when one ethylene molecule approaches the complex in an ethylene environment.

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