Tetraamido complexes

Several interesting bleach catalysts are described in recent patent literature and are currently under evaluation. Fe-TAML (tetraamido macrocyclic ligand), for example, was selected from a large number of similar tetraamido complexes, and has excellent dye transfer inhibition properties, as it selectively destroys many dyes dissolved in the wash liquor [37]. The catalyst is being tested in several applications, such as effluent bleaching, the pulp and paper industry, desulfurization of diesel, and decontamination [38]. 

In this paper, author reported the reactivity of newly synthesized Fem-superoxo and MnIV-peroxo complexes with nitric Oxide (NO) to follow nitric oxide dioxygenation reactions. Reactions of nonheme Fem—superoxo and Mnlv—pcroxo complexes bearing a common tetraamido macrocyclic igand (TAML), namely [(TAML)Fem(02)]2" and [(TAML)MnIV(02)]2% with NO afford the Fem-N03 complex [(TAML)Fem(N03)]2- and the Mnv-oxo complex [(TAML)Mnv(0)]" plus N02, respectively. 

Chanda, A. Popescu, D. L. Tiago de Oliveira, F. Bominaar, E. L. Ryabov, A. D. Miinck, E. Collins, T. J. High-valent iron complexes with tetraamido macrocyclic ligands ... 

The spirocyclic tetraamido Zr complex 12 was prepared at room temperature in 82% yield by the transamination reaction of Me3SiNH-(CH2)2-HN-SiMe3 with Zr(NMe2)4. The latter, in turn, was obtained by the metathesis of ZrCl4-2THF with four equivalents of LiNMe2 (Eq. 7). Recrystallization of 12 in hexane at -75 °C yielded the pure crystalline product. 

Attempts to achieve macrocycles that are capable of stabilizing highly oxidized transition metal complexes has led to the design of noninnocent ligands. The structures of high-valent chrominm(V) oxo species with the two tetraamido N ligands (36) and (37) were determined. Both stmctnres were found to contain distinctly nonplanar amide gronps, and in (36) all fonr amides are nonplanar. 

An example of a tetrahedral tetraamido V(IV) complex, bis(A,iV -bistrimethylsilylethylenediamine)vana dium(IV) was reported (Fig. 9) [63,] which had reversible oxidation and quasireversible reduction features in its CV at 0.41 and —1.51V versus Ag/AgCl/THF respectively. A second, irreversible ligand-based oxidation was observed at 1.34 V. A related bimetallic complex forms when VCl3(THF)3 is treated with dimethylhydrazine (Fig. 10) where three N2Me2 units bridge the two V atoms which are joined by... 

Horwitz et al. developed nonheme iron complexes with tetraamido macrocyclic ligands (TAML) that are efficient for the dye bleaching reactions with HjOj in water from neutral to basic Pinacyanol chloride as a reference,... 

The monoanionic CCC pincer ligand 7 was introduced by Hollis [15] (Figure 9.3). Metallation of the ligand precursor was achieved by deprotonation with tetraamido zirconium(IV) complexes. Modifications were done by Chianese [16] who used stronger donating benzimidazolin-2-ylidene moieties in 8, and by... 

Liao RZ, LiXC, Siegbahn PEM. Reaction mechanism of water oxidation catalyzed by iron tetraamido macrocyclic ligand complexes—a DPT study. Em J Inorg Chem. 2014 728-741. 

Collins TJ, Slebodnick C, Uffelman ES. 1990. Cr(V)-oxo complexes of macrocyclic tetraamido-N ligands tailored for highly oxidized middle transition metal complexes. Inorg Chem 29(18) 3433-3436. 

A number of other recent studies have reported the use of EPR to examine the reaction mechanisms of nonheme iron complexes for catalytic oxidation, including iron complexes bearing a tetraamido macro-cycle, a 2,6-diacylpyridine ligand, a salen type ligand and the porphyrin macrocycle (Scheme in these studies, EPR was used as a... 

---