Synthesis and structures of novel 1-methylcytosinato-bridged (ethylenediamine)platinum(II) and platinum(III) dinuclear complexes
- Author(s)
- Vesna Djinovic, Mathea Sophia Galanski, Vladimir Arion, Bernhard Keppler
- Abstract
The reaction of [Pt(en)(H2O)2]2+ with 1 equivalent of 1-methylcytosine at an initial pH of 6 ultimately led to the 1-methylcytosinato-bridged (ethylenediamine)platinum(ii) dimer, [(en)Pt(MetCyt-H)2Pt(en)](NO3)2 (1). The species during the reactions prior to formation of 1 have been investigated by using 195Pt NMR spectroscopy. From the reaction mixture the [Pt(en)(MetCyt)2](NO3)2 complex (3) could be isolated and structurally characterized. A rational synthesis of 1 was also achieved by dimerization of [Pt(en)(MetCyt)(H2O)](NO 3)2. According to X-ray structure analysis, the Pt-Pt distance of 2.9816(3) Å in 1 is well comparable with the corresponding value found in the cis-diammineplatinum(ii) analog (2.981(2) Å). Oxidation of 1 with K2S2O8 led to the symmetrically sulfate-capped diplatinum(iii) complex with two ethylenediamine ligands equatorially bound to the two Pt atoms ht-[(SO4)(en)Pt(MeCyt-H) 2Pt(en)(SO4)] (5), as established by X-ray crystallography. When the oxidation was carried out in the presence of HClO 4, the formation of the hydroxido/aqua ht-1-methylcytosinato bridged (en)Pt(iii) dimer ht-[H2O(en)Pt(MetCyt-H)2Pt(en)OH] (ClO4)3 (6) was observed, as supported by elemental and X-ray structure analysis. In the structure of 6, two ethylenediamine ligands are differently bound to the two Pt centers: one of them equatorially while the second one caps the opposite axial site of the diplatinum(iii) core. The Pt-Pt distances in the platinum(iii) dimers are 2.5982(4) in 5 and 2.5569(3) Å in 6.
- Organisation(s)
- Department of Inorganic Chemistry
- Journal
- Dalton Transactions
- Volume
- 39
- Pages
- 3633-3643
- No. of pages
- 11
- ISSN
- 1477-9226
- DOI
- https://doi.org/10.1039/b926133h
- Publication date
- 2010
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104003 Inorganic chemistry
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/c4723673-ef07-4378-a23c-1af7c3c0bc1e