Premium
Platinum Complexes with One Monodentate Ligand (1‐Methylbenzimidazole or Antiviral Ribavirin) Flanked by Two cis ‐NMe 2 Groups: Informative Models for Assessing Interligand Interactions
Author(s) -
Cerasino Leonardo,
Natile Giovanni
Publication year - 2006
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600232
Subject(s) - chemistry , nucleobase , denticity , guanine , ligand (biochemistry) , stereochemistry , amine gas treating , platinum , crystallography , diamine , context (archaeology) , crystal structure , dna , organic chemistry , nucleotide , paleontology , biochemistry , receptor , biology , gene , catalysis
Platinum complexes with a tridentate amine ligand (A 3 ) and a nucleobase (L) represent very useful models for investigating nucleobase/ cis ‐amine interactions without the complications arising from nucleobase/nucleobase interferences present in the more frequently used cis ‐A 2 PtL 2 model systems (A 2 = two monodentate amines or a diamine). In this context, the Me 3 dienPtL complexes (Me 3 dien = N1 , N4 , N7 ‐trimethyldiethylenetriamine), previously investigated, were particularly informative. The presence of a methyl group on each terminal nitrogen atom renders the rotation of L about the Pt–L bond slow on the NMR timescale and the two half spaces defined by the coordination plane inequivalent. Thus, guanine and deoxyguanine derivatives were found to have comparable rates of rotation by way of a H‐bond interaction between the O6 atom of the rotating guanine and the NH group of the cis ‐amine. We have now extended the investigation to Me 5 dien complexes (Me 5 dien = N1 , N1′ , N4 , N7 , N7′ ‐pentamethyldiethylenetriamine). The results indicate that the absence of a proton on the terminal nitrogen atoms not only reduces the rate of rotation of L by a factor of 10 10 , but also dramatically increases the difference in the rates between the L ligands mimicking guanine and deoxyguanine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)