Platinum compounds length

Reconstitution of full-length BRCAl into mouse embryonic fibroblast cells with a disrupted BRCAl led to an increase in resistance to several DNA damaging agents, including the platinum compounds carboplatin and oxaliplatin, the topoisomerase 1 drugs irinotecan and topotecan, and the topoisomerase 11 drugs doxorubicin and etoposide (61). 

Nicked circular PM2 DNA (0.02 mg/mL) was incubated in NaClOt (10 mM) with platinum compounds at 20 C in the dark for 8 d. After dialysis against NaClOt (10 mM) and platinum determination by atomic absorption spectrophotometry, the complexes were absorbed on carbon-coated copper grids and observed using a Philips 301 electron microscope. The average length of control DNA (Ldsa) and of platinum-DNA complexes (Ldna pO were determined from an observation of at least 60 molecules. 

Platinum compounds yield various kinds of carbene complexes [118-137]. For example, if isocyanate platinum compounds react with alcohols or amines, the carbon of the isocyanate bonds to the hetero atom to afford the reactive CXY (X and Y are hetero atoms) group, and the carbene complex yields as shown in eqs. (21.44) [119,127] and (21.45) [120]. On the other hand, as shown in eq. (21.46) [121], the platinum carbene complexes are also obtained by the reaction of cyclic XYC = CXY with platinum compounds on heating for a long time. In these carbene complexes, the cw-isomer is more stable than the /ra/75-isomer as shown in eq. (21.47), the rra/j5-isomers being isomerized to the m-isomer at around 200 C [125]. The Pt-C bond length of these carbene eomplexes is about 2.00 A slightly shorter than 2.16 A, the sum of the covalent radii of the Pt-C bond (Pt= 1.39 A, C = 0.77A). 

Me2CH, were obtained by iodine oxidation of dimeric platinum(II) complexes.419,420 The Pt—Pt bond lengths in the latter two compounds are 2.598(1) A and 2.578(1) A respectively,420 substantially longer than that in the acetate analogue. 

ControUed-potential oxidations of a number of primary, secondary, and tertiary alkyl bromides at platinum electrodes in acetonitrile have been investigated [10]. For compounds such as 2-bromopropane, 2-bromobutane, tert-butyl bromide, and neopentyl bromide, a single Ai-alkylacetamide is produced. On the other hand, for 1-bromobutane, 1-bromopentane, 1-bromohexane, 1-bromo-3-methylbutane, and 3-bromohexane, a mixture of amides arises. It was proposed that one electron is removed from each molecule of starting material and that the resulting cation radical (RBr+ ) decomposes to yield a carbocation (R" "). Once formed, the carbocation can react (either directly or after rearrangement) with acetonitrile eventually to form an Al-alkylacetamide, as described above for alkyl iodides. In later work, Becker [11] studied the oxidation of 1-bromoalkanes ranging from methyl to heptyl bromide. He observed that, as the carbon-chain length is increased, the coulombic yield of amides decreases as the number of different amides increases. 

Palladium, Platinum, (a). Synthetic and Structural Studies. In the last 10 years, primary emphasis has been placed on the reaction chemistry of the 1,1-dithio Pd and Pt complexes. The crystal and molecular structure of the Pd(Et2 Dtc)2 complex has been reported (30). The compound is x-ray isomorph-ous to the Pt(II) analogue, for which the crystal structure was reported previously (12). The expected four-coordinate planar coordination of the Pd(II) ion is characterized by a Pd-S bond length of 2.316(3) A. 

Further, Maxted (36) studied the influence of several sulfur compounds on the activity of platinum black for the hydrogenation of crotonic acid in the liquid phase. He noticed that between 15 and 50°C the toxicity remains constant for a sulfur compound, pointing out the irreversibility of sulfur adsorption. Conversely, the toxicity of various compounds increases with the molecule size. For molecules containing two sulfur atoms, losing all freedom of rotation through this double adsorption, the toxicity is less than for molecules of the same length containing only one atom of sulfur. 

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