The interaction of S,N-coordinated dimethyltin(IV) derivatives with deoxyribonucleic acid: structure and dynamics by 119Sn Mössbauer spectroscopy
✍ Scribed by Renato Barbieri; Friedo Huber; Arturo Silvestri; Giuseppe Ruisi; Mario Rossi; Giampaolo Barone; Adriana Barbieri Paulsen
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 111 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0268-2605
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✦ Synopsis
Complexes
Me 2 SnCl(SPy) and Me 2 SnCl(SPym) (HSPy = 2-mercaptopyridine; HSPym = 2-mercaptopyrimidine), from ethanol solutions, interact with aqueous calf-thymus DNA yielding condensed phases with probable Me 2 Sn(SPy,-SPym) (DNA monomer) stoichiometries of 1:1; the condensation of DNA is inferred originated from electrostatic bonding between complex cations Me 2 Sn(SPy,SPym) and the phosphate oxygen of the phosphodiester groups. Octahedral-or trigonal-bipyramidal tin environments are inferred from the point-charge model treatment of the 119 Sn Mo ¨ssbauer parameter nuclear quadrupole splitting, considering the bonding by S and N, or only S donor atoms from the ligand, as well as possible coordination by H 2 O molecules. The dynamics of tin atoms in the condensed systems Me 2 Sn(SPym) (DNA monomer), in both gel and lyophilized phases, have been investigated by variable-temperature 119 Sn Mo ¨ssbauer spectroscopy, obtaining evidence of a general correspondence as reported in the literature for the lyophilized condensates Alk 2 Sn(DNA monomer) 2 ; possible analogies for Me 2 Sn(SPym) (DNA monomer) and Alk 2 Sn(DNA monomer) 2 in DNA bonding, and structures of tin environments, are discussed. 'Neutral' complexes, such as Me 2 Sn(SPy) 2 , neither induce DNA condensation, nor bind to DNA in solution phases.