Zinc complexes amines

Tacticity of VIA A is influenced by solvent,90 9 the presence of amines (Table 8.3)90 and complcxation. PYIAA appears more isotactic when formed in a nonhydrogen-bonding solvent,90 95 Polymerization of MAA in CHCh in the presence of 14 or 15 also yields a more isotactic polymer90 Polymerization of zinc complexes of MAA also yields more isotaclic polymers,9 >... 

The zinc complexes of bis(2-pyridylmethyl)amine have been studied by X-ray crystallography and 13C NMR. The structures of [ZnL2](C104)2 and [ZnL2]Cl2-6II20 have been determined and 13C NMR demonstrated to be applicable to distinguishing the isomers.109... 

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... 

Hexadentate ligands l,12-bis(2-pyridyl)-5,8-dioxa-2,ll-diazadodecane and l,12-bis(2-pyridyl)-5,8-dithia-2,ll-diazadodecane have pyridine, amine, and ether or thioether donors offering an N402 or N4S2 donor set. The X-ray structures of the zinc complexes are distorted octahedral with the zinc center encapsulated by the ligand.898... 

Figure 3.4 Multistage imine formation and metal complexation produces a diverse library of amine-, salicylaldehyde- and salicylaldimine-zinc complexes.

Brand U. and Vahrenkamg H. Zinc complexes of the new N, N, S ligand N-(2-mercaptoisobutyl) (picolyl) amine, Inorganica chimica Acta. 308 (2001) pp. 17-23. 

Finally, as a result of infra- or intermolecular (see Intermolecular) coordination, a large variety of association modes is observed when the amine residue contains electron-donating atoms in appropriate position. Two extremely rare examples of monomeric three-coordinate zinc complexes have been obtained by the reaction of R2Zn (R = Me, Et) with V-(2-diphenylphosphinophenyl)-2,6-diisopropylaniltne in Et20 at - 35 As shown in Figure 44, the molecular... 

Zinc complexes, consisting of amine, amino alcohol, alcohol, sulfide, or phosphine as ligand, catalyzed 1,4-addition of Grignard reagents to a,) -unsaturated carbonyl compounds [447,448]. An optically active ligand on zinc achieved asymmetric 1,4-addition, the best result is presented in Eq. (204) [448]. 

Figure 8 Zinc complexes featuring tridentate bis(pyrazolyl)amine ligands...

The reactivity of zinc complexes supported by a variety of tridentate amine donor ligands (Fig. 44) with diphenyl 4-nitrophenyl phosphate in 20% (v/v) acetonitrile-water, and with 2,4-dinitrophenyl diethyl phosphate in 1 % (v/v) in methanol-water, has been investigated. 5 For the former reaction, the second-order rate constant for the hydrolysis of 2,4-dinitrophenyl diethyl phosphate correlates linearly with the —AH value for the formation of the [(ligand)Zn(OH2)]2 + complex from free chelate ligand and aqueous zinc ion. This indicates that in this series of complexes, faster hydrolysis of 2,4-dinitrophenyl diethyl phosphate corresponds to weaker chelate... 

Fig. 44 (top) Tridentate amine donor ligands and (bottom) phosphate triester hydrolysis reactions promoted by zinc complexes of these ligands. 

Mononuclear zinc complexes of A, A /,A ///-tris(3-aminopropyl)amine ligands having either hydrogen atoms or methyl groups as the substituents on the coordinating nitrogen atoms exhibit slight catalytic activity for the hydrolysis of the phosphotriester 2,4-dinitrophenyl diethyl phosphate.233 A zinc hydroxide complex is proposed as the reactive species that promotes phosphotriester hydrolysis. 

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