Longato, Bruno and Montagner, Diego and Zangrando, Ennio (2006) Mono- and Polynuclear Complexes of the Model Nucleobase 1-Methylcytosine. Synthesis and Characterization of cis-[(PMe2Ph)2Pt{(1-MeCy(−H)}]3(NO3)3 and cis-[(PPh3)2Pt{1-MeCy(−H)}(1-MeCy)]NO3. Inorganic Chemistry, 45. pp. 8179-8187. ISSN 0020-1669

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Abstract

The hydroxo complex cis-[L2Pt(μ-OH)]2(NO3)2 (L = PMe2Ph), in various solvents, reacts with 1-methylcytosine (1-MeCy) to give as the final product the cyclic species cis-[L2Pt{1-MeCy(−H),N 3N 4}]3(NO3)3 (1) in high or quantitative yield. X-ray analysis of 1 evidences a trinuclear species with the NH2-deprotonated nucleobases bridging symmetrically the metal centers through the N3 and N4 donors. A multinuclear NMR study of the reaction in DMSO-d6 reveals the initial formation of the dinuclear species cis-[L2Pt{1-MeCy(−H),N 3N 4}]22+ (2), which quantitatively converts into 1 following a first-order kinetic law (at 50 °C, t1/2 = 5 h). In chlorinated solvents, the deprotonation of the nucleobase affords as the major product (60−70%) the linkage isomer of 1, cis-[L2Pt{1-MeCy(−H)}]33+ (3), in which three cytosinate ligands bridge unsymmetrically three cis-L2Pt2+ units. In solution, 3 slowly converts quantitatively into the thermodynamically more stable isomer 1. No polynuclear adducts were obtained with the hydroxo complex stabilized by PPh3. cis-[(PPh3)2Pt(μ-OH)]2(NO3)2 reacts with 1-MeCy, in DMSO or CH2Cl2, to give the mononuclear species cis-[(PPh3)2Pt{1-MeCy(−H)}(1-MeCy)](NO3) (4) containing one neutral and one NH2-deprotonated 1-MeCy molecule, coordinated to the same metal center at the N3 and N4 sites, respectively. X-ray analysis and NMR studies show an intramolecular H bond between the N4 amino group and the uncoordinated N3 atom of the two nucleobases.

Item Type:	Article
Keywords:	Mono-; Polynuclear; Complexes; Model Nucleobase; 1-Methylcytosine;
Academic Unit:	Faculty of Science and Engineering > Chemistry
Item ID:	7045
Identification Number:	https://doi.org/10.1021/ic060831r
Depositing User:	Diego Montagner
Date Deposited:	23 Mar 2016 09:41
Journal or Publication Title:	Inorganic Chemistry
Publisher:	American Chemical Society
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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