Zinc complexes applications

Simultaneous detenuination of Cu and Zn in the form of coloured PAR complexes is performed at pH 10 in the presence of pyrophosphate which binds the admixtures of Al, Fe and Mn into the inactive complexes. The measurements of the change in the optical density are made at 520 and 550 nm before and after the destmction of the complexes by EDTA, or at 530 nm before and after the destruction of the copper complexes by the thioglycolic acid and the destmction of the zinc complexes by EDTA. The detection limit for Cu is 2-5, for Zn - 3 p.g/diW. The application of these methodics at pH 8 enables one to determine simultaneously Cu and Zn at high excess of the latter. 

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... 

Blue luminescence of zinc complexes of pyridyl-containing complexes is an area of current interest.277 Design of blue luminescent materials is of relevance to display applications, as blue-light-emitting diodes, and to this end Che examined solution luminescence of zinc pyridylamine complexes.73,278 Che and co-workers studied the complex Zn40(7-azaindoyl)6 which has a blue emission at 433 nm in the solid state.279,280 In an attempt to improve on stability Wang et al. examined compounds with neutral 7-azaindole and an A-functionalized pyridyl derivative.281 In contrast with other metal complexes of the neutral 7-azaindole (32), Zn(7-azaindole)2(OAc)2 is a blue luminescent compound and a A-(2-pyridyl) 2-azaindole (33) and its complexes were also... 

For applications in ring-opening catalysis of chiral lactides, pyrazolylborates have been suitably modified to yield chiral zinc complexes. An example of such a chiral pre-catalyst is the highly sterically encumbered tris(indazolyl)bo-rate methylzinc complex 107, introduced by Chisholm et al., whose C -symmetric structure is shown in Figure 53.165... 

Matsukura, T. and Tanaka, H. (2000). Applicability of zinc complex of L-camosine for medical use. Biochemistry (Moscow) 65, 817-823. 

Chiral zinc complex 43 with imine-oxazoline ligand also co-polymerizes CHO and GO2 in an asymmetric manner/ This zinc complex exhibited higher catalytic activity [TOF = 4.2mol (mol of Zn) h ] and slightly lower enantioselectivity (72% ee of the diol unit) than a mixture of 32a and ethanol, giving a co-polymer with > 99% carbonate linkage, and/n= 14,700 gmol and = 1.35. The same complex is also applicable to asymmetric... 

Mass spectrometry has found various applications in the chemistry of zinc-carbon bonds. The availability of a variety of ionization techniques has made possible the identification of different types of organozinc compounds—volatile, neutral, ionic, dimeric, polymetallic, solvent-containing etc. In the majority of the reported cases, molecular species have been observed. The experimental results demonstrated that Zn—C bonds are rather weak and easily cleaved upon or after ionization. It is obvious, however, that expanding mass spectrometry-based methods of analysis of zinc complexes will greatly benefit this field of chemistry, as well as facilitate applications of organozinc compounds to material sciences. 

Co-ordination of the ligand to the zinc activates it towards nucleophilic attack by ammonia and the product is the zinc complex of a conjugated dianionic tetraaza macrocycle (Fig. 8-35). This ligand is of some interest in forming a very stable lithium complex, derivatives of which have found some application in photoaddressable devices. 

Very thorough and comprehensively referenced surveys of the coordination chemistry of zinc are available. In each of these multivolume compendia, there is an article devoted to zinc complexes, but there are also numerous mentions of zinc complexes in the introductory volumes and in the volumes on applications and uses. " Thermodynamic data (A//f, A, AGf also some A values for e.g. ZnX2 + 2L) are available... 

ZINPLEX 15, a Zinc Complexing Agent, is an active modifying agent for the following industrial areas of application ... 

T. Matsukura and H. Tanaka, Application of zinc complex of carnosine for medical use. Biochemistry Moscow, 65 (2000) 961-968. 

The applications of these ligands have been limited to the work by Nakazawa et al.244 who found tris(pyrazolyl)methane titanium complexes to be high-activity catalysts for the polymerization of olefins, and the use of tris(pyrazolyl)methane zinc complexes to model zinc-containing enzymes, such as dihydrorootase and carbonic anhydrase.245 The structure of the free ligand HC(Me2pz)3 has also been reported.246... 

Additional work has described the use of copper, zinc and rare earth metals for halogenation reactions of chelating substrates. These reactions include another application of ligand 6, which in a screening revealed high enantioselectivities for zinc, scandium and copper complexes, with the former one as the best. Hence, preformed zinc complexes of 6 showed good performances in chlorination and fluorination reaction of 3-keto phosphonates [43] (Scheme 14). 

Because of space limitations, we will only briefly discuss the most basic application in the area of porphyrin optical spectra. Much work has already been done in this area, both with TDDFT and related methods. The TDDFT applications include free base porphin and its ss-octahalogenated derivatives, the porphyrinato-porphyrazinato-zirconiumhV) complex, NiP, NiPz, NiTBP, and NiPc, zinc phthalocyanine, chlorophyll a, zinc complexes of porphyrin, tetraazaporphyrin, tetrabenzoporphyrin, phthalocyanine, phenylene-linked free-base and zinc porphyrin dimers, metal bis(porphyrin) complexes a series of porphyrin-type molecules, and many more. We refer to ref. 75 for an extensive discussion of TDDFT calculations on the spectra of porphyrins and porphyrazines, as well as their interpretation. For further theoretical work on porphyrines, we mention ref. 76 and other papers in that special issue. 

Sherwin-Williams Chemical continues to develop molybdate-based smoke suppressants, used mainly in PVC compounds. In addition to its standard product, Kemgard 911C, a molybdenum/zinc complex, the company has introduced Kemgard PZC, which shows whiter colour and improved stability in plenum cable applications. 

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