Platinate complexes

The metallic character of the cation-deficient partially oxidized tetracyano-platinate complexes is of considerable interest because of their unusual anisotropic electrical properties. The method used in the preparation of these compounds is a modification of the procedure used by Levy1 and gives a higher yield of pure product than the syntheses previously described in the literature2 5 (only the potassium compound has been reported to date). 

In addition to the partially oxidized tetracyanoplatinates, bis(oxalato)platinate-(II) can be nonstoichiometrically oxidized by chemical oxidants13 to form highly lustrous needlelike crystals containing platinum in the 2.36 oxidation state. These complexes have not been characterized to the extent of the tetracyano-platinate complexes however, the oxalato complexes are reported to be highly conducting.13 The starting material is bis(oxalato)platinate(II), which can be prepared in 30% yields from hexachloroplatinate(lV) and potassium oxalate.9... 

In this set of experiments you will synthesize both cis- and trans-platin complexes and study their substitution kinetics in DMSO. The primary focus of the chapter is on c/.v-platin biological reactivity you will investigate the binding of c/.v-platin to DNA adducts by NMR and molecular mechanics methods and assess drug cytotoxicity using a Chinese hamster ovary (CHO) cell line. 

In this experiment, we will study the kinetics of the first Cl- substitution in the cis- and /rara.v-platin complexes by DMSO solvent. Temperature dependence studies will enable the calculation of activation parameters (see Experiment 4.7). DMSO has been chosen for two reasons. First, the substitution kinetics are faster than in aqueous media and are more amenable for study in the teaching laboratory. Second, many drugs like cis- and irara.v-platin that have low aqueous solubility are dissolved in DMSO for cytotoxicity assays. Lippard s group first pointed out that, for the platinum(II) complexes, substitution is relatively rapid in DMSO and requires caution in interpreting cytotoxicity results. We too will use DMSO as a carrier solvent in Experiment 6.5. The results obtained in this kinetics experiment will alert you to the limitations of your cytotoxicity assay. 

Platinic derivatives of a similar nature are formed by oxidizing the platinum in any of the platinous derivatives. With the metal in the quadrivalent state, the complex is capable of holding six molecules or radicals, while a maximum of four external acid radicals may attach to the complex as a whole. Thus we have the following series of platinic complexes —... 

In the course of our research, which focused on the synthesis of pentachloro or pentafluorophenyl-containing Pd or Pt complexes, we developed synthetie procedures for the preparation of square-planar Pt(II) or Pd(II) anionic complexes i.e. palladate or platinate complexes) containing from one to four perhalophenyl groups per metal center. The study of the reactivity of these complexes revealed that because of their anionic nature, they have an excess of electron density around the metal center (probably located on the d orbital) and they can react with Lewis acids giving rise to neutral reaction products. When the Lewis acid is a metal complex or a metal salt, polynuclear derivatives with metal-metal bonds of a donor-acceptor nature are obtained. Most of the work presented in this account has been carried out by reacting the platinate substrates with silver derivatives, which afford polynuclear complexes containing Pt Ag bonds. Our first paper in this field ap-... 

As can be seen, some mononuclear platinate complexes act as bidentate ligands towards the silver center by using not only the platinum center but also another atom bonded to the platinum (Figs. 5, 6, and 7). In addition, the use of dinuclear platinate substrates with the appropriate silver complexes allows the corresponding trinuclear derivatives, in which the anionic platinum complex acts as a bidentate chelating ligand, to be obtained. These complexes can thus be prepared according to Eq. (6). 

Cation-deficient partial oxidation has been effected on the Pt(ox)2 system. Oxidation of Pt(ox)2 with either nitric acid (380), chlorine (244, 245), dichromate (244, 245), hydrogen peroxide (394), or tetracyanodihaloplatinate-(IV) (244, 245, 273) yields copper colored needless of the Pt(ox)2 ion. Oxygen readily oxidizes aqueous solutions of H2Pt(ox)2 to the violet Hi.64-Pt(ox)2(H20)a (273). Table IX lists a variety of partially oxidized bis (oxalato)-platinate complexes. 

Orgel LE (1956) An electronic interpretation of the trans effect in platinous complexes. J Inorg Nucl Chem 2 137-140... 

Avichechter, D., Schechter, B., Amon, R., 1998, Functional polymers in drug delivery carrier-supported CDDP (cis-platin) complexes of polycarboxylates - effect on human ovarian carcinoma. React. Funct. Polym. 36 59-69. 

Dicationic RhCp and IrCp complexes with labile solvent ligands react with tetraalkynylplatinates to afford heterobimetallic complexes with bridging alkynyl groups (754, Scheme 101). The two alkynyl ligands of the platinate complex are turned to become cr-bonded to Rh (or Ir) and vr-bonded to Pt, indicated via cr-7r-cr-rearrange-ment of the ligand, and 754 reacts with Pt(G6Fs)2(THF)2 to form 755. 

Li S, Huang H, Liao H, Zhan J, Guo Y, Zou BY, et al. Phase 1 clinical trial of the novel platin complex dicycloplatin clinical and pharmacokinetic results. Int J Clin Pharmacol Ther 2013 51(2) 96-105. 

Based on a calix[4]pyrrol Kohnke et al. designed a wso-para-anUine derivative trans-coordinated to a Pt(II) centre (45). Platin complexes are commonly used as anticancer drugs and have recently received renewed attention. In this context the presented calix[4]pyrrole-tra i-Pt(II) complex was designed as a drug delivery vehicle. In order to evaluate the potential for the assisted Pt-delivery to DNA nucleobases the complex was tested with adenosine monophosphate as a model... 

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