Alkaline-earth metal derivatives

Although the ion pairs of a-substituted benzyl anions and the corresponding cations are chiral species, which, in addition, often bear a pyramidal and hence stereogenic carbon atom, in most cases rapid racemization of the alkali and alkaline earth metal derivatives occurs in solution... 

The structural information on the alkaline earth metal derivatives of the heavier group 14 elements is markedly limited. The first silyhnagnesium compound to be structurally characterized was (Me3Si)2Mg (DME), which is monomeric with distorted tetrahedral geometry of the Mg atom and Si-Mg bond length of 2.630(2)... 

For vinyl monomers two methods can be used to initiate polymerization, both involve alkali metal derivatives, or more rarely alkaline-earth metal derivatives, and differ only by the mechanism of formation of the primary carbanionic... 

French chemist Louis-Nicolas Vauquelin Rare alkaline-earth metal derived from the mineral beryl of which emeralds and aquamarines are crystals. 

With the development and detailed characterization of the bis(bistrimethylsilyl)amides of the heavy alkaline earth metals, the transamination regime has become an attractive route to prepare a variety of alkaline earth metal derivatives, including organometallics. The attractiveness of the route is due to the good stability and excellent solubility of the metal amides in a variety of solvents (eqnation 5). 

In addition, variable amounts of alkaline and alkaline earth metal derivatives are detected by atomic adsorption analysis. X-ray studies have shown that the structures of active Mn02 are quite complex they are either amorphous or of moderate crystallinity (variable proportions of p- and y-Mn02). 

Alkaline earth metal derivatives can also be prepared from the tellurol and [Me3Si)2N]2M(THF)2 (M = Ca, Sr, Ba) in hexane and crystallize from THF with 4 ligands (M = Ca, Sr) or 5 (M = Ba). The magnesium compound is prepared from Bu2Mg and the tellurol as a THF complex of tetrahedral structure. The Mg derivative substitutes CP2MCI2 to give the group IV tellurides . ... 

Composite Oxyalkoxides. Composite oxyalkoxides can be prepared by reaction of tetraalkyl titanates and alkaline-earth metal hydroxides. These oxyalkoxides and their derivatives can be hydroly2ed and thermally decomposed to give alkaline-earth metal titanates such as barium titanate (150). 

In general, the alkah and alkaline-earth metal salts of the B q- and B22-halogenated derivatives have excellent thermal, oxidative, and hydrolytic stabihties. 

The most fundamental issues of the structures of heavier group 14 element-centered anionic derivatives R3EM (R = alkyl, aryl, silyl E = Si, Ge, Sn, Pb M = alkali or alkaline earth metals) turned out to be the questions of their aggregation states (monomeric, dimeric, or oligomeric), nature of the E-M bond (covalent or ionic), and configuration of the anionic centers E (tetrahedral, pyramidal, or planar). The most important experimental techniques that are widely used to clarify these questions are NMR spectroscopy and X-ray diffraction analysis. 

Surprisingly, when the same disiladigermetene 73 was reduced with alkaline earth metals (Mg, Ca) instead of alkali metals, strikingly different prodncts were obtained Mg or Ca derivatives of l,3-disila-2,4-digermabicyclo[1.1.0]butane-2,4-dianions 76 and 76 Ca (Scheme 2.69). ... 

Diazotization of the aminosulfonic acid and subsequent coupling onto the sodium salt of 2-hydroxy-3-naphthoic acid initially affords the monoazo compound in the form of its soluble sodium salt. Subsequent reaction with chlorides or sulfates of alkaline earth metals or with a manganese salt, frequently in the presence of a dispersion agent, or rosin or its derivatives, at elevated temperature yields the insoluble BONA pigment lake. 

Only a few group 1 and 2 metal derivatives of selenolates have been structurally characterized. They are prepared with the same methods used for the thiolates.155,158 At present there are no crystal structures of lithium terphenyl selenolates. However, the potassium and rubidium salts, which are dimeric, have been structurally characterized.155 They are isomorphous, both to each other and to the closely related thiolate analogues.1533 Currently, there are no reported terphenylselenolates reported for the alkaline-earth metals. 

S. Fery-Forgues, M.-T. Le Bris, J.-P. Guette, and B. Valeur, First crown ether derivative of benzoxazinone anew fluoroionophore for alkaline earth metals recognition, J. Chem, Soc., Chem, Commun. 5, 384-385 (1988). 

PTFE, FEP and PFA are attacked only by alkaline metals and their organic derivatives elemental fluorine and chlorine trifluoride alkali and alkaline earth metals with their oxides and carbonates above 350°C. The other halogens, aqua regia, nitrosulfuric acid mixtures, oleum (fuming sulfuric acid) and solvents are without significant effects. 

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