Tris dichloride complex

The fact that the metallocene complexes 1 and 2 are active for olefin polymerization was, of corrrse, of no surprise Kaminsky and Sirm had discovered in the mid-1970s that MAO obtained from partial hydrolysis of tri-methylaluminum (TMA) could activate metallocene dichloride complexes to very efficient olefin... 

Production of Hj Nd by the photodecomposition of water solves the problem of conversion and. storage of. solar energy. The tris(bipyri-dine)ruthenium(II) dichloride complex Ru(bPy),]Cb can theoretically pho-... 

More useful than the preceding methods is cleavage of alkoxides by acetyl chloride or bromide. One, two, three, or four alkoxyls can be replaced by chloride or bromide. Benzoyl chloride gives poor yields, however. The tri- and tetrachlorides, which are stronger Lewis acids than mono- and dichlorides, coordinate with the alkyl acetate formed and yield distillable complexes (46,55,56). 

The first non-heteroatom-substituted carbene complex was prepared by Schrock in 1974 [392] (Figure 3.4). Treatment of tris(neopentyl)tantalum dichloride with neopentyllithium led to the formation of neopentane and (2,2-dimethyl-1-propylidene)tris(neopentyl)tantalum. This carbene complex reacts violently with water or oxygen, but can be sublimed (80 °C) and stored indefinitely at room temperature under argon. 

The monomers dealt with can be polymerized by various mechanisms, not only by ROMP. For example, a rapid polymerization of norbornadiene occurs using a homogeneous catalytic system consisting of nickel acetylacetonate or a nickel-phosphine complex, such as nickel bis-(tri-n-butylphosphine) dichloride (NiCl2(TBP)2) or nickel bis-(tricyclohexylphosphine) dichloride (NiCl2(TBP)2). Nickel acetylacetonate as catalyst is known to initiate rather a classical vinyl polymerization (7). The classical vinyl polymerization... 

P-31 NMR was a powerful tool in studies correlating the structure of tertiary-phosphine-rhodium chloride complexes with their behavior as olefin hydrogenation catalysts. Triphenylphosphine-rhodium complex hydrogenation catalyst species (1) were studied by Tolman et al. at du Pont and Company (2). They found that tris(triphenylphosphine)rhodium(I) chloride (A) dissociates to tri-phenylphosphine and a highly reactive intermediate (B). The latter is dimerized to tetrakis(triphenylphosphine)dirhodium(I) dichloride (C). 

Presumably, a new kind of rearrangement process takes place in the reaction of dicyclopentadienyltungsten dichloride with tris(trimethylsilyl)silyllithium (equation 3473). Silyl complexes formed as intermediates spontaneously rearrange with formation of silylcyclopentadienyl complexes, but the mechanism of this process is not yet clear. 

Dimethyltitanocene (213), called the Petasis reagent, can be used for alkenation of carbonyls (aldehydes, ketones, esters, thioesters and lactones). This reagent is prepared more easily than the Tebbe reagent by the reaction of titanocene dichloride with MeLi. However, this reagent may not be a carbene complex and its reaction may be explained as a nucleophilic attack of the methyl group at the carbonyl [67], Alkenylsilanes are prepared from carbonyl compounds. Tri(trimethylsilyl)titanacyclobutene (216), as a... 

Several internal olefins were also tried in the reaction shown in eq 1. When the reaction of both cis-or trans-2-butene were run at 230°C, they gave a low (10%) yield of the. 2,3-bis (dichlorophosphino)butane as evidenced by a single 31p nmr peak at 193.6 ppm and a symmetrical l C-NMR spectra. When the reaction temperature is raised to 250°C, both cis-and trans-2-butene yield a compound which has the same 31p and 13c-NMR spectra as 6, indicating a l,2-bis(dichlorophosphino)butane product. Along with this rather complex isomer product change, there is an increase in the amount of butylphosphonous dichloride formed. 

Bis[4-methoxyphenyl] tellurium dichloride formed 1 1 complexes with tributyl-, triphenyl-, and tris[4-methoxyphenyl]phosphane selenides, and 1 1 and 2 1 complexes with 1,2-bis[diphenylphosphano]ethane P,P-diselenide6. 

Sarsfield reported the only three known examples of uranyl bis(imino-phosphorano)-methanides reported to date.52,53 Treatment of the tris-THF adduct of anhydrous uranyl dichloride with one molar equivalent of 2 resulted in the isolation of dimeric 101 when the recrystallisation was carried out in dichloromethane, but monomeric 102 when recrystallised from THF. Both 101 and 102, when treated with two and one equivalents, respectively, of potassium bis(trimethylsilyl)amide afford 103. Complexes 101-103 all exhibit uranyl-methanide contacts in the solid state and these represent noteable examples of out-of-equatorial-plane uranyl coordination. A DFT study concluded that the methanide centre coordinates to the uranyl centre with an orbital of p-type character by a highly polarised cr-type interaction. 

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