Reaction ofp-Toluenesulfonylamide and M(NMe₂)₄(M = Ti, V):  Generation of Electron-Deficient Imido Complexes of Early Transition Metals

Abstract

p-Toluenesulfonamide (p-TsNH2) was successfully employed as an imido ligand precursor in the synthesis of highly air- and moisture-sensitive titanium(IV) and vanadium(IV) complexes. Reaction of M(NMe2)4 (M = Ti, V) with TsNH2 in toluene afforded [M(micro-NTs)(NMe2)2]2 dimer complexes (M = Ti (1), V (2)). By contrast, the reaction carried out in dichloromethane led to [Ti[micro-N,O-NTs]Cl(NMe2)(NHMe2)2]2 (3) and [Ti[micro-N,O-NTs]Cl2(NHMe2)2]n (4) through solvent activation. The same reaction of M(NMe2)4/TsNH2 conducted in the presence of an excess of trimethylchlorosilane produced [V(=NTs)Cl2(NHMe2)2] (5) and [(Me2HN)Cl2Ti(micro2-N-NTs-kappa2N,O)2TiCl2(NHMe2)2] (6). Alternatively, compound 6 has also been prepared from TiCl2(NMe2)2 and TsNH2. 1 was reacted with trimethylchlorosilane to afford the amide complex [Ti[micro-N,O'-N(SiMe3)Ts-kappa3N,O,O']Cl2(NMe2)]2 (7) in which the tosylimide bond has been silylated. Compounds 1-6 represents the first examples of sulfonylimido complexes for titanium and vanadium.

Titanium–Imido Complexes with Pendant Groups – Synthesis, Characterization, and Evaluation of Their Role as Precatalysts for Ethylene Polymerization

“…The N imido –Ti–Cl angles are in the range 107–115°, and theN imido –Ti–N angles are in the range 94–100°. The distances and angles associated with the titanium center and the ligands are comparable to those found in other [M(=NR)Cl 2 (NHMe 2 ) 2 ] complexes (M = Ti,24,25,27V22,23). The complexes exhibit a short Ti–N imido distance of 1.6979(16) for O 1 , 1.700(2) for S 1 , and 1.701(3) Å for S 2 , and the imido linkage is almost linear [Ti–N imido –C ipso 175.72(14), 174.6(2), and 166.9(2)° in O 1 , S 1 , and S 2 , respectively].…”

“…2.20 Å for the three compounds. The supramolecular structure is characterized by Me 2 N–H ··· Cl intermolecular hydrogen bonds (NH ··· Cl 2.403–2.529 Å, N–H ··· Cl 159.8–148.3°), which is a feature that is common to many related compounds 22,24,27…”

[ONNO]-type amine bis(phenolate)-based vanadium catalysts for ethylene homo- and copolymerization

“…[V] h -1 ), and comparable to other vanadium systems described in the literature [10,18,26,[34][35][36][37][38], keeping in mind that we used only 10 equiv of EtAlCl 2 cocatalyst (and we did not use a reactivator such as ethyl trichloracetate). Selected examples of the best catalysts are reported in Table 1.…”

Titanium, zirconium and hafnium

“…65 Bu)(OAr) 2 ], the former being a catalyst for the homologation of propane. 66 68 Catalytic amounts of [Ti(NMe 2 ) 4 ] promote highly selective transamidation reactions between primary amines and secondary carboxamides, whilst stoichiometric amounts lead to amidine and oxotitanium products. 69 The mixed amide/guanidinate [{(N i Pr) 2 C(NEtMe)} 2 Zr(NEtMe) 2 ] is thermally stable and a potential material in the thin-film synthesis of ZrO 2 .…”