Novel Aryltitanium(IV) Complexes Containing η³-NCN-Pseudofacial- and η³-NCN-Meridional-Bonded [C₆H₃(CH₂NMe₂)₂-2,6]^- (Abbreviated as NCN) Ligands. The Crystal Structures of [TiCl₂(η³-fac-NCN)(O-i-Pr)], [TiCl(η³-mer-NCN)(O-i-Pr)(OTf)] Containing an η¹-O-Bonded Triflate Anion, and the Seven-Coordinated [Ti(η³-mer-NCN)(O-i-Pr)(O

Abstract

Titanium(IV) derivatives of the chelating monoanionic aryldiamine ligand [C 6 H 3 (CH 2 -NMe 2 ) 2 -2,6] -(abbreviated as NCN) are prepared by treating [TiCl 3 (OR)] (R ) i-Pr, C 6 H 4 -OMe-4) with [Li(NCN)] 2 . [TiCl 2 (NCN)(O-i-Pr)] is smoothly methylated by methyllithium in toluene to give [TiClMe(NCN)(O-i-Pr)] and [TiMe 2 (NCN)(O-i-Pr)]. Enhancement of the Lewis acidity of the titanium center has been studied by substituting chloro ligands for triflato ligands to give [TiCl(NCN)(O-i-Pr)(OTf)] and [Ti(NCN)(O-i-Pr)(OTf) 2 ]. X-ray studies of the dichloride and triflate complexes feature η 3 -pseudofacial and η 3 -meridional bonding modes for the NCN ligand, respectively. These different NCN bonding modes are explained in terms of the trans influence of the alkoxy and triflato ligands. A rare example of an organo titanium(IV) complex with a seven-coordinate titanium center is observed in the bis(triflate) complex as a result of bidentate O,O′-bonding mode of the triflato anion to one titanium center that is unprecedented in early transition metal chemistry. The triflato ligands exhibit a strong covalent bonding to titanium both in the solid state and in solution; the latter is demonstrated by the observation that cationic species are not formed upon addition of Lewis bases like THF, acetonitrile, and 1,2-bis(dimethylamino)ethane.

A Bis(ortho-amine)aryl−Gold(I) Compound as an Efficient, Nontoxic, Arylating Reagent

“…To our knowledge this is the first demonstration of an organogold compound to cleanly transfer its organic group to other d 10 6 in Et 2 O at -20°C (Scheme 1) afforded the bis(ortho-amine)arylgold(I) compound [Au(NCN)(PPh 3 )] (2) in good (68%) to excellent yields (quantitative). The gold atom in 2 is η 1 -C bonded to C ipso of the pincer moiety and is transcoordinated to the PPh 3 ligand (Figure 1).…”

“…9 Other (early) transition metals can also be incorporated by use of 2. For example, the synthesis of titanium(IV) derivative 7 10 and iron(III) compound [FeCl 2 -(NCN)] (8) 11 was achieved on small scales. Moreover, using 2 only one chloride ligand can be selectively substituted.…”

Synthesis and Reactivity of Titanium(IV)−Salen Complexes Containing Oxygen and Chloride Ligands

“…An alternative method for preparing symmetrically disubstituted titanium salen complexes is through ligand substitution. For example, when 3 was treated with TMSOTf (2 equiv), the two aryloxide ligands were each silylated and replaced by OTf (eq 3) . The 1 H NMR spectrum of the product Ti(salen)(OTf) 2 ( 5 ) in CD 3 CN indicates a single set of salen resonances shifted downfield from H 2 salen, 2 and 3 .…”

Stereospecific Synthesis of Chiral Titanium Complexes Bearing a Bifunctionalized Cyclopentadienyl-Terpenoid Ligand Derived from α-Pinene

“…For complex 3, the more relevant spectroscopic feature is the downfield shift for the fluorine atoms of the triflate group (at −77 ppm), in the 19 F NMR spectrum, that points to a covalently bound OTf ligand. 42 For 4 and 5, both the 1 H and 13 C{ 1 H} NMR spectra show the expected resonances for the respective alkyl substituents.…”