Tetrakis diborane

C7H704Rh, Rhodium(I), dicarbonyl(2,4-pentanedionato)-, 34 128 C7HgN4, Bis(l-pyrazolyl)methane, bpm, complex with nickel(ll), 34 139 CgH5FeKN20, Ferrate(ll), carbonyldicyano-(cyclopentadienyl)-, potassium, 34 172 CgH23Ns, Tetraethylenepentamine, tetren, complex with nickel(ll), 34 147, 148 CgH24B2N4, Diborane(4), tetrakis(dimethyl-amino)-, 34 1... 

Boron tribromide Boron bromide (8) Borane, tribromo- (9) (10294-33-4) Bromobis(dimethylamino)borane Borane, bromobis(dimethylamino)- (8) Boranediamine, 1-bromo-N,N,N, N -tetramethyl- (9) (6990-27-8) Tetrakis(dimethylamino)diboron Diborane(4), tetrakis(dimethylamino)- (8) Diborane(4)tetramine, octamethyl- (9) (1630-79-1)... 

Tetrakis(acetato)di- U-amido-diborane is a white crystalline compound which is not too sensitive to moisture. It can be stored in a nitrogen atmosphere in a refrigerator for long periods without decomposition. It is sparingly soluble in most organic solvents and slowly dissolves in glacial acetic acid and acetic anhydride. Monoclinic and triclinic crystalline forms were obtained by recrystallization from acetic anhydride and glacial acetic acid, respectively.1 The infrared spectrum recorded (Beckman i.r.-12) by the KBr pellet technique contains major absorption bands (at frequencies cm.-1) 3280(s), 3230(s), 3100(s), 1740(w,sh),... 

Tetrakis(dimethylamino)diboron Diborane(4)tetramine, octamethyl- (1630-79-1), 77, 177... 

Neopentanediol (0.093 mol), 100 ml diethyl ether and tetrakis(dimethylamino)diborane were mixed, cooled with an ice bath, and 76 ml 2.46 M anhydrous hydrogen chloride (0.187 mol) in ether added. The mixture came to ambient temperature and stirred overnight. The solution was filtered, the solvent evaporated and the product isolated in 23% yield. Residue precipitate was extracted twice with 200 ml benzene increasing the overall yield to 74%. The solid was re-crystallized in benzene/light petroleum and had a mp = 161-162°C. H-NMR data supplied. 

A fairly extensive metathetical chemistry of diboron compounds has been developed which provides the means for synthesis of specific derivatives from more commonly available starting materials such as tetrachloro-diborane(4) and the tetrakis(dialkylamino)diboron derivatives. Thus, reactions involving hydrolysis, aminolysis, alcoholysis, transamination, etc., are available for interconversions of diboron compounds by pathways analogous to those known in monoboron chemistry. Examples of such reactions include the following ... 

Reactions of this type are somewhat less satisfactory for preparation of mixed diboron derivatives containing boron-carbon bonds. Thus, while tetrakis(dimethylamino)diborane(4) is readily hydrolyzed to tetrahydroxy-diborane(4) in aqueous acid, l,2-bis(dimethylamino)-l,2-diethylborane(4) reacts with formation of hydrogen and cleavage of the boron-boron bond 14). Reaction of the dibutyl analog with a twofold excess of water gave the dimethylamine adduct of the boroxole... 

At the other extreme, the most stable derivatives of the B2X4 type appear to be the tetrakis(dialkylamino) compounds. Thus, tetrakis(dimethylamino)-diborane(4) is stable at its boiling point of 206° C 17). The compound decomposes at 300° C to form bis(dimethylamino)borane and involatile residues containing B—C bonds. It is reported that tetra(A -methylanilino)-borane(4) is pyrolyzed at 300° C by a different mechanism to yield N-methylaniline 18). 

The fully aromatic species are usually quite resistant to hydride reduction. Attempted reduction of l,2-dimethyl-5-nitroimidazole with tributyltin hydride failed to yield 1,2-dimethylimidazole <90JCS(Pl)9l9>, but the apparent reduction of 5-iodo-l-methylimidazole to l-methylimidazole by phenylsulfonylacetonitrile and sodium hydride with tetrakis(triphenylphosphine)palladium(0) as catalyst may be an example <92S552>. Lithium aluminum hydride (but not diborane) is able to convert 2-(but not 4-)fluoroimidazoles into the hydrogen species <84JOCi95i>. 

B2Fe20gCgHg, Iron, hexacarbonyl[p-[hexa-hydrodiborato(2—)]]di-. 29 269 B2Hg, Diborane(6), 27 215 B2NgRuC5gHgg, Ruthenium(II), (t) -1,5-cyclooctadiene)tetrakis(hydrazine)-, bis-[tetraphenylborate(l-)], 26 73 B2NgRuCg( H7g, Ruthenium(II), (ti -1,5-cyclooctadiene)tetrakis(methylhydra-zine)-, bis[tetraphenylborate(l-)],... 

Seeking to answer the question of dissociation for the more reactive tetrakis(dimethylamino)ethylene (1), Wiberg and Buchler studied its reactions with a variety of Lewis acids In no case was an adduct of the ylid halves isolated. Diborane and boron trifluoride yielded salts with the structure 31. Zinc chloride gave a 1 1 complex, and trimethylboron failed to yield any complex at temperatures up to 150°. Though the results with the first three Lewis acids are inconclusive with regard to a dissociation equilibrium, the last experiment certainly inspires serious doubt about its existence even at elevated temperatures. Powerful evidence to support Wiberg and Buchler s... 

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