Organozinc complex

The reaction of CF3I and CgFjI with dialkylzmc in the presence of a Lewis base, such as diglyme or pyridine, quantitatively gives the corresponding fluori-nated organozinc complexes [32] (equation 23) When Rf is C2F5 or iso CjF-j, the pure zinc complexes are not isolated... 

For other examples of three-coordinate organozinc complexes, see ... 

Cationic Organozinc Complexes Bearing Macrocyclic Ligands 343... 

Beyond these fundamental aspects, the great versatility of organozinc compounds can also be seen in the important roles they play in commercial applications. Organozinc complexes have been shown to be excellent catalysts and precatalysts for the polymerization of esters and the co-polymerization of epoxides and carbon dioxide they are also co-catalysts in polyolefin catalysis. 

The introduction of cyano groups in the 3-position of diketimiminate ligands greatly increased the crystallinity of their complexes (Figure 49, 95), due to the formation of one-dimensional coordination polymers. A new f3-oxo-<5-diimine ligand, in turn, allowed the synthesis of a bimetallic organozinc complex 96, by the same methods that had been used for the syntheses of the mononuclear species 92-94.154... 

A theoretical study of the reaction mechanism for addition of organozincate complexes to aldehydes was recently performed using density functional theory.298 It has been suggested that the addition takes place through formation of a four-centered transition state and, therefore, it can be considered a typical nucleophilic reaction. 

Some of the zinc taken up by the intestinal epithelial cells is rapidly transferred to the portal plasma where it associates with albumin, a2 macroglobulin, and amino acids. About 67% of the zinc in plasma is bound to albumin, and about 3% is stored in liver (Stemlieb 1988). Soluble organozinc complexes are passively absorbed across the plasma membrane of the mucosa of the intestinal villi the soluble, nondiffusable complexes are transported in the intestinal products and excreted in feces (NAS 1979). Zinc loss from urine and sweat is usually small (Casey and Hambidge... 

In aquatic environments, Spear (1981) spotlights three research needs (1) development of analytical procedures for measurement of individual dissolved zinc species, notably the aquo ion and zinc chloride, and for nondissolved species that occur in natural waters (2) separation of natural from anthropogenic influences of sediment-water interactions on flux rates, with emphasis on anoxic conditions, the role of microorganisms, and the stability of organozinc complexes and (3) establishment of toxicity thresholds for aquatic organisms based on bioaccumulation and survival to determine the critical dose and the critical dose rate, with emphasis on aquatic communities inhabiting locales where zinc is deposited in sediments. These research needs are still valid. 

It should also be noted that significant progress has been made in the measuring of thermochemical parameters of organozinc complexes. Ionization energies were measured and the dissociation characteristics of ions were determined. The experimental results for gaseous Zn-containing ions were supported by quantum-chemical calculations. 

Complexes MX2 (R-DAB) with M = Zn, Hg and Cd have been isolated with R = Cy, p-MeOC6H4, Bu1.155 Organozinc complexes ZnR2(Bu,-DAB) have been prepared by reaction of ZnR2 and Bu1-DAB.125 The reactivity of these complexes wilt be discussed later (Section 13.5.3.4.7).125... 

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