Beryllium, Dimethyl

CHLORIDE see DTC600 N>4-DIMETHYL-N -BENZYL-N -(a-PYRIDYL)ETHYLENEDIAMINE see TMP750 DIMETHYL BERYLLIUM see DQR200 DIMETHYLBERYmUM-l,2-DIMETHOXYETHANE see DQR289... 

Dimethyl beryllium is a white solid which sublimes at 200 C and reacts violently with air and water. It is isostructural with SiS2, the crystal being built of infinite chains (a) in which Be forms tetrahedral bonds (Be-C, I -93 A) to four methyl... 

In boron and beryllium there are fewer electrons than available orbitals. The outer orbitals can be filled, for example, in dimethyl beryllium, by a mechanism whereby one carbon atom orbital overlaps with an orbital from each of two neighboring beryllium atoms. The resulting high-molecular-weight chain of dimethyl beryllium thus has three center bonds, which leads to an absurd structural formula when valences are represented in the normal way. Boron hydrides and some aluminum compounds have similar structures ... 

Figure 2-1. Dimethyl beryllium. Left Schematic representation of the overlapping orbitals. Right Normal valence bond method of writing the structure.

In class /, it is possible to distinguish between bridge and spiro structures. Spiro structures occur frequently in inorganic raacromolecules, e.g., in beryllium hydride (p. 4), dimethyl beryllium (p. 41), palladium chloride (p. 46), and silicon disulfide,... 

There is a dearth of structural information about the mixed organometallic compounds. Lithium aluminum tetraethyl is isostructural with dimethyl-beryllium (42), as one might expect after noting that the ratio of metal atoms to alkyl groups is the same in the two compounds. The structure of LlA1(C2H5)4 is shown in Fig. 7 the relevant bond distances and angles are... 

Beryllium and certain compounds Cadmium and certain compounds Carbon tetrachloride Chlorambucil Cyclophosphamide Dimethylcarbamoyl chloride Dimethyl sulphate Ethylene oxide Iron dextran... 

The zinc complex formed with V,V -diphenylformamidinate is structurally analogous to the basic zinc acetate structure, as [Zn4(/i4-0)L6], and the basic beryllium acetate structure. It is prepared by hydrolysis of zinc bis(diphenylformamidinate).184 Mixed metal zinc lithium species were assembled from dimethyl zinc, t-butyl lithium, V.iV -diphenylbenzamidine and molecular oxygen. The amidinate compounds formed are dependent on the solvent and conditions. Zn2Li2 and... 

A polymeric structure is exhibited by "beryllium dimethyl," which is actually [Be(CH3)2] (see the structure of (BeCl2) shown earlier), and LiCH3 exists as a tetramer, (LiCH3)4. The structure of the tet-ramer involves a tetrahedron of Li atoms with a methyl group residing above each face of the tetrahedron. An orbital on the CH3 group forms multicentered bonds to four Li atoms. There are numerous compounds for which the electron-deficient nature of the molecules leads to aggregation. 

Complexes of beryllium with phosphonate ligands have been extensively researched, mainly by potentiometry. The ligands investigated are as follows methylphosphonate (259, 260) chloromethyl-phosphonate (259) 2-aminopropane-l-phosphonate (259) methylene-diphosphonate (130, 260, 261) hexamethylenediphosphonate (259) l-hydroxyethane-l,l-diphosphonate (261) 1,1-dimethyl-1-amino-... 

Fig. 27. 9Be NMR spectra for the system beryllium(II)- l,2-dimethyl-3-hydroxypyri-din-4-one (HL), pH range between 2 and 8. The [Be(H20)4]2+ ion is taken as reference (8 = 0) BeL+ occurs at S ca. 4 and BeL2 occurs at ca. 7.5 ppm (38.0 MHz, H20). Reproduced with permission from Ref. (170). Copyright 1992, The Royal Society of Chemistry.

Limited theoretical studies (31, 89) on the electron-deficient beryllium derivatives have been interpreted to imply that extensive Be—Be bonding occurs. If such bonding does occur, the increased bond length observed in the phenylethynyl(methyl)beryllium trimethylamine adduct takes on additional significance since the Be—Be distance in this derivative is increased by almost 0.3 A over that observed in dimethyl-and diethylberyllium. Moreover, if cyclic trimers are formed, then increased metal-metal distances would be likely, thus reducing the probability of stabilization of the bridged system by Be—Be bonding. Additional studies will be required both on structures and of spectroscopic properties of the species to answer these questions. 

NMR has been used to study ligand exchange in non-coordinating solvents for a series of Be(C104)2-4L (L = trimethyl phosphate, DMSO, DMA, DMF, NMA, 1,1,3,3-tetramethylurea, dimethyl methylphosphonate and dimethyl phenylphosphonate) complexes. 3H NMR studies show that the mode of activation for exchange on beryllium varies from dissociative to associative depending upon L and the nature of the non-coordinating solvent.127 128... 

LB = Lewis base bht = 2,6-di(f-butyl)-4-methylphenoxide bo = l-metalla-2,6-dioxo-3-aza-4,5-diphenylcyclohex-3-ene CBD = Chronic beryllium disease dbp = 2,6-di(t-butyl)phenoxide dfhd = 1,1,1,2,2,3,3,7,7,7-decafluorohept-ane-4,6-dionato dmmhd = 2,6-dimethyl-2-methoxyheptane-... 

PHOSPHOROUS ACID, BERYLLIUM SALT see BFSOOO PHOSPHOROUS ACID DIMETHYL ESTER see DSG600 PHOSPHOROUS ACID, TRIPHENYL ESTER see TMU250... 

Delpuech et al. (106) examined the tetrahedral solvates of the beryllium cation with trimethyl phosphate (TMPA), dimethyl methyl phosphonate (DMMP), N,iV-dimethylamido-0,0 -dimethyl phosphate (DMADM P), bis-A,iV-dimethylamido-0-methyl phosphate (TMDAMP), and hexamethylphosphorotriamide (HMPT) by NMR including that of Be. The kinetics of ligand exchange ... 

C12H1604 2,2-dimethyl-3-hydroxy-3-(p-methoxyphenyl)pr 64284-35-1 486.15 42.555 2 24390 C12Hlfi8 40l3 beryllium oxide acetate 19049-40-2 604.15 53.976 1,2... 

The dimethyl compounds of the metals from beryllium to cadmium are all very volatile liquids, the beryllium, magnesium, and zinc derivatives exploding when treated with water, the cadmium decomposing slowly under the same conditions. 

Beryllium diethyl, Be(CgH5)2, prepared in a similar manner to the preceding compound, is a colourless liquid, B.pt. 93° to 95° C. at 4 mm. or 110° C. at 15 mm. It distils at 180° to 240° C. at ordinary pressure, with considerable decomposition, and when solidified in carbon dioxide-ether freezing mixture white crystals are formed, which melt on warming to — 13° to —11° C. It resembles the corresponding dimethyl derivative in oxidisability and inflammability. With water it yields... 

The mercury may be replaced from mercury dimethyl by sodium, magnesium, zinc, or aluminium under suitable condition with formation of organometallic compounds of these metals with mercury diethyd, the reaction takes place with sodium, magnesium, cadmium, beryllium, zinc, aluminium, bismuth, and tellurium with mercury di-n-propyl, the metals sodium, beryllium, zinc and aluminium react, and sodium also reacts with mercury di-n-octyl. 

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