Amines tripod ligands

Partial hydrolysis of a potentially heptadentate Schiff-base tripodal ligand derived from tris-(2-aminoethyl)amine and 2-hydroxyacetophenone, induced by copper(II) salts, was reported and the final copper(II) complex (377) was characterized.333 Using salicylaldehyde as a co-ligand, with a copper(II) complex (378), catalytic epoxidation was demonstrated 334... 

An unusual unsymmetric tripodal ligand, (2-picolyl)(A-pyrrolidinylethyl)(2-hydroxy-3,5-di-t-butylbenzyl)amine, with three different donor groups attached to the central amine was synthesized by Vahrenkamp and co-workers. The zinc complex of the N30 ligand with an additional phenoxide coordinated was structurally characterized (Figure 15).877... 

Intramolecular coordination site exchange reactions in square-planar platinum(II) complexes [Pt(tbte)Cl]+ of the potentially four-donor-atom tripodal ligand tris[2-(t-butyl-thio)ethyl]amine (tbte) N,S,S-bonded occur through a trigonal bipyramidal five-coordinate intermediate... 

Two iron(III) complexes of unsymmetrically substituted tris(2-pyridylmethyl)amine (tpa, (58)) tripodal ligands, [Fe(59)Cl3] and [Fe(60)Cl3], have been synthesized and structurally characterized." The crystal structure, magnetic susceptibility, Mossbauer spectroscopy and photomagnetism of the iron(II) complex [Fe(bpmae)(2,2 -bisimidazole)](C104)2 2F[20, where bpmae is the unsymmetrical tripod N CH2(2-pyridyl)2 (CH2CH2NH2), have been established." ... 

Hydroxide is rarely found coordinated to Fe " in a mononuclear octahedral complex, but has been demonstrated in the purple salt [Fe(tnpa)(0H)(00CPh)]C104, where tnpa is the tetradentate tripodal ligand tris(6-neopentylamino-2-pyridylmethyl)amine, (203) the hydroxide is cis to the benzoate ligand." ... 

Complexes of the tripodal ligand tris(2-pyridylmethyl)amine are described in the next section. See also structure (377) and ref. 1709. 

The first of two conversions catalyzed by the metalloenzyme tyrosinase is the selective ortho-hydroxylation of a phenol moiety, yielding catechol. Few synthetic systems exist that are capable of selectively performing the same monooxygenase reaction [172-178]. The group of Casella has studied a series of dicopper complexes based on 2,6-disubstituted benzene hgands providing two N3 compartments [179-181] (26a,b) as well as the asymmetrically substituted tripodal amine-based ligand (27) [182]. 

Yang, X.-P. Su, C.-Y. Kang, .-S. Feng, X.-L. Xiao, W.-L. Liu, H.-Q. Studies on lanthanide complexes of the tripodal ligand bis(2-benzimidazolylmethyl)(2-pyridyl-methyl)amine. Crystal structures and luminescence properties. J. Chem. Soc., Dalton Trans. 2000, (19), 3253-3260. 

Chromium(II) forms the trigonal bipyramidal complex [CrBr(Me6tren)]Br with the tripod ligand tris(2-dimethylaminoethyl)amine (Me6tren) (Section 35.3.4.3), and pyrazolyl-substituted ligands also form five-coordinate complex cations (Section 35.3.3.4.v see also Table 42). 

The interesting potential septadentate tripod ligand, obtained by the condensation of 5-chlorosalicylaldehyde with tris(2-aminoethane)amine, has been shown to yield an almost undistorted octahedral Mn111 compound, MnN303, with the apical N atom of the ligand unbound.660... 

The first structurally characterized antimony derivatives of tripodal ligands such as tris(aminoethyl)amines, N[CH2CH2N(R)H]3, named azastibatranes, were obtained from the reaction between tetramines and tris(dialkylami-no)stibine. Thus, treatment of [N(CH2CH2N(Me)H] with Sb(NEt2)3 led to 16a isolated as a colorless oil in 95% yield. 

RuCl(dpp)2] /PhIO (or LiClO) [117] are efficient for the oxidation of cyclohexane and adamantane. Ruthenium] 111) complexes such as [RuCl2(TPA)] and [RuCl-(Me2SO)(TPA)] bearing tripodal ligand TPA (TPA = tris(2-pyridylmethyl)amine) were synthesized, and catalytic oxidation of adamantane with m-chloroperbenzoic... 

The chemistry of tris(2-pyridyl) tripod ligands such as (107)-(113) and their metal derivatives has been recently reviewed.160 These ligands are neutral donors, coordinating in a facial manner to a single metal center through the pyridyl nitrogens. Tris(2-pyridyl)amine (107), which is a pyridine analogue of triphenylamine, and its monosubstituted derivatives can be prepared by sequential condensation of 2-halopyridine with 2-aminopyridine.160... 

Nucleophilic opening of the oxetane cycle by amines calls for rather harsh conditions and works satisfyingly only for a few types of amines (HNMe2, H2NMe, H2NBn) (Equation (7), route a, (71), (72), (74)-(76)). The further transformation to tripod ligands calls for intermediate protection of the NHR groups in the form of their carbobenzoxy derivatives (74), (76). 

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