Titanium complexes dinitrogen complex

A remarkable process was reported by Mori that forms aniline from dinitrogen (Equation (26)).106 Titanium nitrogen fixation complexes were generated from reactions of titanium tetrachloride or tetraisopropoxide, lithium metal, TMS chloride, and dinitrogen. These complexes generated a mixture of aryl and diarylamines in yields as high as 80% when treated with aryl halide and a palladium catalyst containing DPPF ... 

Bis(cyclopentadienyl)titanium(II) dicarbonyl complexes, preparation and reactivity, 4, 250 Bis(cyclopentadienyl)titanium(II) dinitrogen complexes, preparation and reactivity, 4, 250 Bis(cyclopentadienyl)titanium halides ligand metathesis reactions, 4, 537 olefin polymerization, 4, 538 organic reactions, 4, 540 properties, 4, 530 reductions, 4, 532 synthesis, 4, 510... 

Titanium cyclopentadienyl derivatives form an extensive series of dinitrogen complexes. However, when the titanium-containing precursors are bound to polymers there is no reactivity with dinitrogen comparable to that observed for the analogous derivatives in solution, and fixation is, at best, marginal (202, 220). 

The compound [ (T -CsHs TiCH CiCHg) ] has been characterized (337). Its homologs are well known. Surface anchoring of titanium complexes to Si02 in order to produce heterogeneous, supported dinitrogen complexes has not been successful (202). 

The bis(i7-pentamethylcyclopentadienyl)zirconium dinitrogen complex [tj-C5(CH3)5kZrj(N2)3 (22), in solution reversibly releases its dinitrogen in vacuo over several hours (Section III,E). The solutions remaining are said to consist mainly of [T7-C5(CH3)5][T7-C5(CH3)4CH2]ZrH (23) (33). Permethylzirconocene [tj-C5(CH3 )5l,Zr (24) may exist in these solutions in equilibrium with this hydride tautomer (as in the case of titanium). However, thus far permethylzirconocene has not been isolated as a discrete compound or otherwise characterized. It is very likely that permethylzirconocene is less stable and more prone to form complex metallocene hydrides than permethyltitanocene (16). 

The bis(rj-cyclopentadienyl)titanium(III) aryl complexes form interesting dinitrogen derivatives (Section III,B) the 1-methyl, 17-allyl complex (Tj-C5H5)2Ti(i73-C4H7) is the precursor to a particularly effective homogeneous olefin hydrogenation catalyst (Section VI). Attempts to prepare bis(i7-cyclopentadienyl)titanium(III) monoalkyl complexes were unsuccessful (40). 

Teuben and de Liefde Meijer (64) prepared the first well-characterized titanium dinitrogen complex. They found that toluene solutions of phenyl-dicyclopentadienyltitanium(III) (26) when cooled under N2 gave an intense blue coloration ascribed to the reversible formation of a dinitrogen adduct. 

A bis(i7-cyclopentadienyl)titanium(III) alkyl dinitrogen complex was prepared by reaction of [(i7-C5H5)2TiCl]2 with isopropylmagnesium chlo-... 

There are no dinitrogen complexes of any of these metals that contain a phosphine ligand. The considerable amount of nitrogen-fixing chemistry reported for titanium, and to a lesser extent zirconium, involves alkoxide, cyclopentadienyl, and halide complexes.The catalytic nitriding reactions of titanium will be reviewed in Section 3. 

Titanium(IV) chloride forms a number of different adducts with trans-[ReCl(N2)(PMe2Ph)4] (see Table 1) that are believed to involve dinitrogen bridging between rhenium and titanium. Hydrolysis or treatment of these adducts with ethanol results in the virtual quantitative recovery of the original rhenium-dinitrogen complex. 

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