Titanium tetrabromide

It melts at 39°C and may be purified by vacuum sublimation. The Hquid boils at 233°C to give a monomeric vapor in which the Ti—Br distance is 231 pm. Titanium tetrabromide is soluble in dry chloroform, carbon tetrachloride, ether, and alcohol. Like titanium tetrachloride, TiBr forms a range of adducts with molecules such as ammonia, amines, nitrogen heterocycles, esters, and ethers. 

Tetraacylates are prepared from titanium tetrabromide and excess carboxyUc acid ia an iaert solvent. After solvent removal, the residue is heated to remove hydrogen bromide. 

Titanium tetrabromide [7789-68-6] M 367.5, m 28.3°, b 233.5 , d 3.3. Purified by distn. Distillate forms light orange hygroscopic crystals. Store in the dark under N2 preferably in sealed brown glass ampules. [Olsen and Ryan J Am Chem Soc 54 2215 1932.]... 

The catalytic activity of certain of the Friedel-Crafts catalysts was shown to decrease over a very wide range in the series boron fluoride, aluminum bromide, titanium tetrachloride, titanium tetrabromide, boron chloride, boron bromide and stannic chloride (Fairbrother and Seymour, mentioned in Plesch al., 83). When boron fluoride is added to isobutylene at dry ice temperatures, the olefin is converted to a solid polymer within a very few seconds. The time required for complete polymerization with aluminum bromide hardly extends to a few minutes while reaction times of hours are required with titanium chloride and periods of days with stannic chloride. 

Titanium tetrabromide unites with ammonia, forming octammino-titanic bromide, [Ti(NH3)8]Br4, which has similar- properties to the chloride. 

Aldehydes undergo a Mukaiyama-aldol reaction followed by a Prins cyclization with the highly reactive allylsilane 329 to afford jy -2,6-tetrahydropyrans 330 that feature an oeo-methylene group at C-4 (Equation 140, Table 12). This Mukaiyama-aldol-Prins (MAP) cascade cyclization has been used to form a key bis-tetrahydropyran intermediate during the total synthesis of leucascandrolide A <2001JA8420>. Similarly, titanium tetrabromide mediated MAP reactions afford 4-bromo tetrahydropyrans <20030L3163>. 

Tri-O-acetyl-L-rhamnosyl bromide has been prepared from tetra-0-acetyl-L-rhamnose by the action of titanium tetrabromide in chloroform, ... 

Kayayana Y, Ogawa K, Miura T (2005) Electrochemical reduction of titanium tetrabromide in a hydrophobic room temperature molten salt. Electrochemistry 73(8) 556-578... 

Klemn also reported that zirconium tetrabromide possessed a structure similar to the iodide but with tetragonal distortion. Berdonosov and co-workers (58), apparently unaware of Klemn s report, write that zirconium tetrabromide has a primitive cubic lattice with a= 10.95 0.01 A, and assigned the space group T, by analogy with zirconinm tetrachloride. Zirconium and hafnium tetrabromides seem to be structurally different than titanium tetrabromide. It is observed that titanium tetrabromide is soluble to the extent of 40% in chloroform and 30% in ethylene dichloride and carbon tetrachloride, whereas zirconium and hafnium tetrabromides are soluble to the extent of only 4% in chloroform and 0% in carbon tetrachloride (57). 

TiBr4 TITANIUM TETRABROMIDE 1672 TI2Se THALLIUM SELENIDE 1716... 

TiBr4[g] TITANIUM TETRABROMIDE (GAS) 1673 TI2Te THALLIUM TELLURIDE 1717... 

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