Semiempirical calculations on the interaction between dimethyltin(IV) and DNA model system

Abstract The interaction between a dinucleotide triphosphate duplex (DD), mimicking the DNA molecule, and the dimethyltin(IV) cation is studied by the semiempirical PM3 method. The results show that the interaction can occur involving the tin atom and the electron-donor centres of DD, requiring in some cases the presence of water molecules. In particular, the binding of the dimethyltin(IV) moiety with two adjacent phosphate oxygen atoms is allowed by the presence of water molecules coordinating to the tin atom. In this case the tin environment shows a geometry in agreement with 119 Sn Mossbauer and X-ray data.

Ab initio study of the tautomeric forms of some quinolinediones

Abstract 7,8-dihydroquinoline-4,5 (1 H ,6 H )-dione ( 1 ) and 7,8-dihydroquinoline-2,5-(1 H ,6 H )-dione ( 2 ) in their tautomeric oxo and hydroxy forms have been studied by ab initio Hartree-Fock calculations; tautomerization energies predict a more stable hydroxy structure having an intramolecular hydrogen bond for compound 1, whereas the oxo form is slightly-preferred for compound 2. Fourier Transform-Infra Red (FT-IR) spectra in CHCl 3 solution indicate that the predicted most stable tautomers in the vapour phase remain as such.

Ab initio study of lithiated N-methylpyridones