Platinum complexes interactions

The term 7r,7r-transfer has been proposed for 7r-allyl ligand transfer from one transition metal to another. Such processes differ from those giving a-allyl derivatives 160), which are termed Tr.a-transfer processes. The latter have been studied in detail 161) for 7r-allylnickel, -palladium, and -platinum complexes interacting with metallic mercury. It has been shown that binuclear 7r-allylpalladium complexes rapidly react with mercury in... 

Amino- or halogeno-platinum complexes interact with DNA in different ways. The interaction with cis-[Pt(NH3)2Cl2] is localized on the N(7) (G) and 0(6) (G) sites, forming a chelate without H liberation, while the K2PtCl4 interaction differs in that there is no H liberation before saturation of the N(7) (G) sites. Solid complexes were characterized as [Pt(DNA)Cl2]. Complexes cis-[PtA2], cis- and trans-[Pt(AH)Cl2],... 

Over the last few years, significant advances in the depth of understanding of the conformational features of the polynucleotide—platinum complex interaction have come from both solution (CD, NMR) and solid-state (X-Ray) studies on oligonucleotide fragments, particularly dinucleotide complexes. Excellent summaries of the status of model studies and their relationship to the molecular mechanism of cisplatin can be found in references [82 and 141]. These complement the earlier reviews [83, 84]. The features outlined do in fact confirm some of those expected from model studies, although there has not been an extensive comparison with the trans-isomcr. 

Organonickel derivatives also offer cases of the -coordination of the substituted hydrotrisfpyrazol- l-yl)borate ligand. For the palladium and platinum complexes, the M(II) M(IV) (M = Pd, Pt) transformation is facile. Organopalla-dium chemistry offers anew type of agostic interactions, C—H - - - Pd, where the C—H bond belongs to one of the pyrazolate rings. Cyclopalladation of various pyrazol-l-ylborates and -methanes does not modify their structure. 

Hydrogen bonding between an SiOH group and fluorine occurs in the platinum complex 44 [prepared by hydrolysis of a bis(alkylidene)-silacyclopropane] in which the SbF6 anion hydrogen bonds to the platinum-containing cation (O - F distance 2.77(2) A) (249). The platinum complex 45 is not reported (250) to form hydrogen bonds, and a more recent study (210) has confirmed that there do not appear to be any OH OH or OH tt interactions. 

There are many examples of platinum(II) interacting with metals such as lead(II) or thallium(I) but few where the same metals interact with platinum(O). Catalano et al. have reported a series of metallocryptands such as the one shown in (11) that act as hosts for thallium(I)72 and lead(II).73 They have also reported an unsupported thallium(I) interaction with the platinum in [Pt(PR3)3] (R = Ph or R3 = Ph2py).74 The Pt Tl separations in the cryptands (2.791-2.795 A) are slightly shorter than those in the unsupported complexes (2.865-2.889 A).72,74... 

In this section we summarise the manner in which i -metals. Fig. 6, and where possible specifically the platinum complexes of concern here, interact with biological molecules. Some radio-tracer studies have been carried out on the distribution of platinum complexes in whole bacteria grown in media inocculated with the metal ion. The results are summarised in Table 11. It is noteworthy that the bacteriocidal complex [PtClg]2- was taken up almost entirely by the cytoplasmic protein whereas the filamentous forming neutral species, [Pt(NHs)2Cl4], was... 

Kinetics and mechanisms of substitution at Pt(IV) are occasionally mentioned in relation to those complexes which may have anti-tumor properties. An article on molecular modeling of interactions between platinum complexes and nucleotides or DNA includes a brief mention of Pt(IV) (178). 

Taquet A, Labarbe R, Houssier C (1998) Calorimetric investigation of ethidium and netropsin binding to chicken erythrocyte chromatin. Biochemistry 37(25) 9119—9126 Temple MD, McEadyen WD, Holmes RJ, Denny WA, Murray V (2000) Interaction of cisplatin and DNA-targeted 9-aminoacridine platinum complexes with DNA. Biochemistry 39(18) 5593-5599 Terasaki T, Iga T, Sugiyama Y, Hanano M (1984) Interaction of doxorubicin with nuclei isolated from rat liver and kidney. J Pharm Sci 73(4) 524—528... 

Roos IA, Arnold M. Interaction of an anti-tumour active platinum complex with DNA. J ClinHematol... 

For example, in 1963 the photochemistry of magnesium phthalocyanine with coordinated uranium cations was studied in pyridine and ethanol and indicated the occurrence of PET to the uranium complex . A rapid photoinduced electron transfer (2-20 ps) followed by an ultrafast charge recombination was shown for various zinc and magnesium porphyrins linked to a platinum terpyridine acetylide complex . The results indicated the electronic interactions between the porphyrin subunit and the platinum complex, and underscored the potential of the linking para-phenylene bisacetylene bridge to mediate a rapid electron transfer over a long donor-acceptor distance. 

An attractive suggestion for the mechanism for multiple exchange, in the light of current knowledge, is the involvement of dimeric platinum complexes (53), the hydrocarbon interacting with both platinum atoms ... 

Firstly, reactions of phosphines 14-19 with Pt( 1,5-cod)Cl2 were studied. Notably, using this precursor, under the applied conditions, each of the monophosphines form cis-Pt(phosphine)2Cl2 as the major product (Table 10.5 Figure 10.3A below). These results suggest that the geometry of the platinum complexes does not refer necessarily to attractive ligand-ligand interactions [49]. 

Heavier metal ions and metal complexes can find sites on nitrogen atoms of the nucleic acid bases. Examples are the platinum complex cisplatin and the DNA-cleaving antibiotic neocarzinostatin (Box 5-B). Can metals interact with the n electrons of stacked DNA bases A surprising result has been reported for intercalating complexes of ruthenium (Ru) and rhodium (Rh). Apparent transfer of electrons between Ru (II) and Rh (III) over distances in excess of 4.0 nm, presumably through the stacked bases, has been observed,181 as has electron transfer from other ions.181a Stacked bases are apparently semiconductors.182... 

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