Cationic Ti Complexes with Three [N,O]-Type Tetrazolyl Ligands: Ti↔Fe Transmetalation within Fe Metallascorpionate Complexes

Abstract

Herein, we report the synthesis of two novel ionic Ti complexes possessing three [N,O]-type bidentate ligands from the reaction of Fe metallascorpionate ligands possessing extended alcohol groups and TiCl. The reaction of substituted hydroxyphenyl tetrazole and Fe(ClO) in a molar ratio of 3:1 afforded iron scorpionate metalloligands possessing extended arms, which were characterized by IR spectroscopy and ESI-TOF-MS spectrometry. Their molecular structures were also confirmed as neutral Fe-centered scorpionate complexes by X-ray crystallography, in which the extended alcohol groups adopted a tripodal geometry. Moreover, two different crystals of iron scorpionate metalloligand grown from CHCl and CHOH were studied, revealing that, in the latter crystal, the tripod arms are folded and aligned toward the C-rotational axis of the molecule, whereas the tripod arms are unfolded and spread outward from the rotational axis in the former crystal. These metalloligands are solvatochromatic; a bathochromic shift was observed as the solvent polarity increased. From the reaction, the aforesaid Fe complexes were further reacted with TiCl in a molar ratio of 1:1 to produce ionic [TiL][FeCl] (L = substituted hydroxyphenyl tetrazole) complexes from the transmetalation of Ti and Fe. The complexes were characterized by various analytical methods including UV/vis and IR spectroscopies, electrospray time-of-flight mass spectrometry (ESI-TOF-MS), and X-ray crystallography.

Trends in Structure and Ethylene Polymerization Reactivity of Transition-Metal Permethylindenyl-phenoxy (PHENI*) Complexes

“…The solid-state structures of PHENI* complexes are tetrahedral at the metal center, with τ 4 geometry indices of 0.89–0.92 . Measured Ti–I cent * distances are similar to permethylindenyl post metallocene complexes, to the analogous Ti–Cp cent for PHENICS complexes ,, and titanium constrained geometry complexes. , The Ti–O bond lengths and I cent *–Ti–O angles are in the same range as PHENICS complexes. ,, The Ti–O bonds are slightly shorter than in other phenoxy-titanium systems such as phenoxy-tetrazole, phenoxy-imine, phenoxy-amine, , bis-phenoxy, and phenoxy-azo ligands …”

“…44,45 The Ti−O bond lengths and I cent *−Ti−O angles are in the same range as PHENICS complexes. 14,17,18 The Ti−O bonds are slightly shorter than in other phenoxy-titanium systems such as phenoxy-tetrazole, 46 phenoxy-imine, 47 phenoxy-amine, 48,49 bis-phenoxy, 50 and phenoxy-azo ligands. 51 Compared to the indenyl−PHENICS complex reported by Hanaoka et al, Me 2 SB( d t Bu,Me ArO,Ind)TiCl 2 (A), 14 85°(A)).…”

Zn(II)-to-Cu(II) Transmetalation in an Amide Functionalized Complex and Catalytic Applications in Styrene Oxidation and Nitroaldol Coupling

“…It thus provides a common and convenient method for preparing various organo-transition metal complexes, which are otherwise difficult to synthesize via direct metal-ligand self-assembly. Such phenomenon is well documented and has expanded to other types of materials [4][5][6][7][8][9][10][11]. The process usually proceeds through either "direct exchange", where the incoming metal does not alter the topology of the frameworks or through "disruptive exchange" in which the geometry of the transmetalation complex differs from the original structure as a result of the metal exchange.…”

Synthesis and Characterization of Strongly Solvatochromic Molybdenum(III) Complexes

“…In a metal-to-ligand charge transfer (MLCT) arrangement, the degree to which the M–L bond polarization is negated by the charge transfer event directly correlates to the extent of solvatochromism. Therefore, many complexes that possess solvatochromism only report 15–50 nm shifts, but significant solvatochromism (>100 nm shift in λ max ) is less common. − Transition metal complexes that display color changes in different solvents can sometimes be attributed to solvent coordination . What appears to be solvatochromism is complicated by a chemical transformation that alters the d-orbital splitting and may only be tangentially related to solvent polarity.…”