606927-83-7Relevant academic research and scientific papers
Imido-titanium/molybdenum heterobimetallic systems. Switching from η6-arene to fischer-type aminocarbene complexes by tuning reactivity conditions
Lorber, Christian,Vendier, Laure
, p. 1127 - 1136 (2010/05/01)
Two types of bimetallic titanium/molybdenum systems are described: the first possesses unprecedented η6-arene-imido groups, while the second has Fischer-type aminocarbene ligands bridging the two metals. The (η6-arene)-Mo imido-Ti complex Ti[=N(η6-Ar)Mo(CO) 3]Cl2(NHMe2)2 (2; Ar = 2, 6-'Pr 2-C6H3) has been prepared through the reaction of (η6-ArNH2)Mo(CO)3 (3) and TiCl 2(NMe2)2. The alternative route from 2 and Ti(NMe2)4/Me3SiCl also afforded 1, but it was contaminated with a small amount of Ti(=NAr)Cl2(NHMe 2)2 (1). The reaction between the dimeric complexes {Ti(μ-NAr)(NMe2)2}2 and Mo(CO)6 gave complex mixtures of products, among which the Fischer-type aminocarbene complex [(CO)5Mo{=C(NMeCH2NMe2)O}Ti(=N 2,6-Pri2-C6H3)(NMe 2)(NHMe2)] (4) could be characterized. The formation of 4 resulted from the nucleophilic attack of the amido -NMe2 to the carbonyl that afforded the titanoxy aminocarbene linker between the Mo and the Ti centers, followed by a subsequent C-H activation of a methyl group of the aminocarbene and C,N coupling with an amido ligand on titanium. Treatment of Ti(NMe2)4 with 1 equiv of Mo(CO)6 produced the titanoxy aminocarbene [(CO)5Mo{=C(NMe2)O}Ti(NMe 2)3] (5), while in the presence of 1 equiv of ArNH 2 the imido complex [(CO)5Mo{=C(NMe2)O} Ti(=N-2, 6Pr'2-C6H3)(NMe2)(NHMe 2)2] (6) is formed. The molecular structures of 1-6 have been determined by X-ray diffraction.
A general and facile one-step synthesis of imido-titanium(IV) complexes: Application to the synthesis of compounds containing functionalized or chiral imido ligands and bimetallic diimido architectures
Lorber, Christian,Choukroun, Robert,Vendier, Laure
, p. 4503 - 4518 (2007/10/03)
One-pot reactions of Ti(NMe2)4 with a wide range of primary alkyl, aryl, and silylamines RNH2 in the presence of excess chlorotrimethylsilane produced the corresponding imido-titanium(IV) complexes [Ti(=NR)Cl2(NHMe2)2] (1a-j), in which R = tBu, 1-adamantane, Ph3C, Ph3Si, Ph, 2,6-iPr2-C 6H3, 2,6-Cl2-C6H3, 2,6-Br2-4-Me-C6H2, C6F5, and 3,5-(F3C)2-C6H3. This general synthesis, which starts from commercially available reagents, represents a simple and direct route to imido complexes. Reaction of complexes 1 with pyridine afforded the six-coordinate tris-pyridine adducts [Ti(=NR)Cl 2(Py)3] (2). Another advantage of this method is its tolerance to other functional groups; complexes that contain halides, ether, dialkylamino, cyano, ethynyl, olefin, and nitro substituents on the imido moiety have been prepared. The use of enantiomerically pure primary amines affords the first group of titanium complexes that contain chiral imido groups, and the use of diamines produces diimido complexes. Alternatively, CH3I has been used as an alkylating agent to generate titanium-imido complexes of the type [Ti(NR)I2(THF)2]2. All compounds were fully characterized by spectroscopic methods (IR, 1H NMR, 13C NMR) and elemental analysis. Some of the compounds were also analyzed by single-crystal X-ray diffraction studies. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
