Heavy metal--nucleotide interactions. VIII. Binding of cis-diammineplatinum(II) and ethylenediamineplatinum(II) to inosine, 1-methylinosine, and 5'-inosine monophosphate in aqueous solution

Journal Article · Wed Apr 28 00:00:00 EDT 1976 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00425a038· OSTI ID:7363435

Chu, G Y.H.; Tobias, R S

The bifunctional electrophiles cis-diammineplatinum(II) and ethylenediamineplatinum(II) form stable complexes with inosine, 1-methylinosine, and 5'-inosine monophosphate over a wide range of pH. These reactions have been characterized primarily through Raman spectrophotometry and /sup 1/H NMR spectroscopy of solutions containing 25 mM nucleoside or nucleotide and varying concentrations of the platinum complex in H/sub 2/O and D/sub 2/O. The reactions with 1-methylinosine and inosine below pH approximately 6 led to the formation of mono and bis complexes where coordination occurs at N-7 of the base. The structure of the bis complex is discussed in terms of ring current effects observed in the /sup 1/H NMR spectra. The perturbations of the ligand vibrations are very similar to those caused by coordination of CH/sub 3/Hg/sup II/ at N-7. Platination at N-7 is observed to increase the rate of exchange of H-8 with solvent protons. Above pH approximately 6, protons are dissociated from N-1, and the pK is 7.2 +- 0.3 in D/sub 2/O, 25/sup 0/, for 25 mM inosine in the presence of an equimolar amount of cis-(H/sub 3/N)/sub 2/Pt/sup II/. This is an increase of over two orders of magnitude compared to inosine alone. Under these conditions coordination occurs at both N-7 and N-1 with the formation of a polynuclear complex. A structure for the polymer is suggested on the basis of the Raman and /sup 1/H NMR spectra, and this involves the stacking of a bipolar complex similar to the stacking of 7-methylinosine. The reactions of cis-(H/sub 3/N)/sub 2/Pt/sup II/ with mononucleotides and with polynucleotides are discussed generally. Raman spectrophotometry provides an especially powerful technique for studying the interactions of ions or molecules with nucleotides in aqueous solution. (auth)

• Research Organization: Purdue Univ., West Lafayette, IN
• OSTI ID: 7363435
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 98:9
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
INOSINE
CHEMICAL REACTION KINETICS
NUCLEOTIDES
PLATINUM COMPLEXES
AMINES
AQUEOUS SOLUTIONS
HEAVY WATER
NUCLEAR MAGNETIC RESONANCE
PH VALUE
PURINES
RAMAN SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
COMPLEXES
DISPERSIONS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
KINETICS
MAGNETIC RESONANCE
MIXTURES
NUCLEOSIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
REACTION KINETICS
RESONANCE
RIBOSIDES
SOLUTIONS
SPECTRA
TRANSITION ELEMENT COMPLEXES
WATER
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)