Abstract
The platinum(II) complexes trans-[PtCl&sub2;(Ln)&sub2;]∙xSolv 1-13 (Solv = H&sub2;O or CH3OH), involving N6-benzyladenosine-based N-donor ligands, were synthesized; L(n) stands for N6-(2-methoxybenzyl)adenosine (L&sub1;, involved in complex 1), N6-(4-methoxy-benzyl)adenosine (L&sub2;, 2), N6-(2-chlorobenzyl)adenosine (L&sub3;, 3), N6-(4-chlorobenzyl)-adenosine (L&sub4;, 4), N6-(2-hydroxybenzyl)adenosine (L₅, 5), N6-(3-hydroxybenzyl)-adenosine (L₆, 6), N6-(2-hydroxy-3-methoxybenzyl)adenosine (L₇, 7), N6-(4-fluoro-benzyl)adenosine (L₈, 8), N6-(4-methylbenzyl)adenosine (L₉, 9), 2-chloro-N6-(3-hydroxy-benzyl)adenosine (L&sub1;&sub0;, 10), 2-chloro-N6-(4-hydroxybenzyl)adenosine (L&sub1;&sub1;, 11), 2-chloro-N6-(2-hydroxy-3-methoxybenzyl)adenosine (L&sub1;&sub2;, 12) and 2-chloro-N6-(2-hydroxy-5-methylbenzyl)adenosine (L&sub1;&sub3;, 13). The compounds were characterized by elemental analysis, mass spectrometry, IR and multinuclear (¹H-, ¹³C-, ¹&sup9;&sup5;Pt- and ¹&sup5;N-) and two-dimensional NMR spectroscopy, which proved the N7-coordination mode of the appropriate N6-benzyladenosine derivative and trans-geometry of the title complexes. The complexes 1-13 were found to be non-toxic in vitro against two selected human cancer cell lines (HOS and MCF7; with IC₅&sub0; > 50.0 µM). However, they were found (by ESI-MS study) to be able to interact with the physiological levels of the sulfur-containing biogenic biomolecule L-methionine by a relatively simple 1:1 exchange mechanism (one L(n) molecule was replaced by one L-methionine molecule), thus forming a mixed-nitrogen/sulfur-ligand dichlorido-platinum(II) coordination species.