Untitled

Singh, Sudha; Singh, Ramesh; Babbar, Preeti

doi:10.1023/a:1007061109703

Cited by 7 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23 There are also well-known metal complexes with adenine as the primary ligand and halouracil as the secondary ligand. 24 The X-ray structures of uracil and 5-halouracils were solved up to the mid-1970s. [25][26][27][28] Considering the importance of 5-halouracils for medicinal chemistry, it is surprising that their vibrational spectra, taken for low-temperature matrixes and for the polycrystalline state, have been looked into relatively little and that the literature assignments of a number of fundamental vibrations are often in conflict.…”

Section: Introductionmentioning

confidence: 99%

Ar-Matrix IR Spectra of 5-Halouracils Interpreted by Means of DFT Calculations

et al. 2005

View full text Add to dashboard Cite

The infrared low-temperature Ar-matrix spectra of 5-halouracils and unsubstituted uracil were measured and interpreted in terms of the spectra calculated at the DFT/B3PW91/6-311G level followed by a potential energy distribution (PED) analysis. For the PED analysis, the sets of halouracil mode definitions were constructed so that dissimilarities in the interpretations of the different spectra were minimized. Anharmonic frequency calculations enabled more light to be shed on the Fermi resonance (FR) phenomena occurring in the nu(C=O) stretching vibrations region. For each halouracil vibrational spectrum, several FRs manifest themselves in the nu(C=O) stretching vibrations region. We show that the most frequent components participating in these resonances are the nu(C(4)=O(10)) frequency, a beta(N-H) mode frequency, and a beta(C=O) mode frequency. The experimental nu(N-H) frequencies are reproduced by the calculated anharmonic frequencies better than by the scaled harmonic ones, and the nu(C=O) frequencies respond in the opposite manner. The experimental frequencies located below 1500 cm(-1) are reproduced equally well by the two kinds of calculations.

show abstract

Section: Introductionmentioning

confidence: 99%

Ar-Matrix IR Spectra of 5-Halouracils Interpreted by Means of DFT Calculations

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Ternary complexes of various metal ions with nucleobases, nucleosides, nucleotides, and other ligands have been reported by several workers, − as they provide the model for various metal activated reactions in biological systems. Considerably less is known on the interaction between metal ions and the nucleic acid base pairs and mispair. − But no literature is available on the interaction of metal ions with the guanine-cytosine base pair and mispair.…”

Section: Introductionmentioning

confidence: 99%

Nucleic Acid Base Pair and Mispair Interactions with Metal IonsA Thermodynamic Aspect

Tyagi

Gencaslan

2003

J. Chem. Eng. Data

Self Cite

View full text Add to dashboard Cite

Potentiometric equilibrium measurements were made for some metal ions (M(II) = Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ca(II), Sr(II), and Ba(II)) with guanine (A) in a 1:1 (M(II):A) ratio and with cytosine, cytidine, 5-bromocytosine, 5-azacytosine, and 5-fluorocytosine as primary ligands (L) and guanine as secondary ligand in a 1:1:1 (M(II):L:A) ratio at (25.0, 35.0, and 45.0) °C and I = 0.1 mol·dm-3 NaNO3 in aqueous solution. The experimental pH-titration data were analyzed by using a BEST computer program in order to evaluate the formation constants of various intermediate species and their relative distribution. The experimental conditions were selected in such a way that the self-association of the nucleobases and their complexes due to stacking interaction was negligibly small, so that only the neutral monomeric and hydroxo ternary complexes were studied. The enthalpy (Δf H°) and entropy (Δf S°) changes for the formation of binary and ternary complexes were calculated from temperature coefficient data. The δΔf S° values are positive for all the metal ligand systems. The negative δΔf H° values indicate the extra stabilization of most of the ternary complexes by the exothermic enthalpy change (δΔf S° = ΔT S° − ΔB S° and δΔf H° = ΔT H° − ΔB S° where ΔT S°, ΔT H° and ΔB S°, ΔB H° are the entropy and enthalpy values associated with the ternary and binary complexes, respectively). On the basis of IR data for metal complexes with the 5FC−G mispair, it has been proposed that the guanine is bonded to metal ions through N1/C6O and N7, whereas cytosine and its derivatives are bonded through N3 atoms in ternary complexes.

show abstract

“…Recently there has been considerable interest in the study of binary, ternary and quaternary complexes by pH-metric method [1][2][3][4] . Ternary metal complexes in presence of organic and inorganic ligands, amino acids, peptides, proteins, vitamins and enzymes have been recently studied due to their ability as metal systems for metal-protein complexes such as metallo-enzymes.…”

Section: Introductionmentioning

confidence: 99%