Systematic investigation of 2,7-dihydroxy-1,8-naphthyridine dimerization – secondary interactions and tautomeric preferences calculations (original) (raw)
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Multiple hydrogen bonds and tautomerism in naphthyridine derivatives
New Journal of Chemistry, 2004
The behaviour of three 2,7-disubstituted 1,8-naphthyridines able to exhibit tautomerism has been studied by NMR in solution and in two cases in the solid state. The three derivatives studied are 2,7-dihydroxy-(1), 2-acetamido-7-amino-(3) and 2,7-diacetamido-1,8-naphthyridine (4). To explore the problem of secondary interactions, a series of complexes, with up to four simultaneous hydrogen bonds, where the monomers are generated using pyridine and 4-pyridone as building blocks, have been theoretically studied. The calculated interaction energies have been correlated with the number of hydrogen bonds and with attractive and repulsive secondary interactions. Further analysis of the electron density and orbital interactions shows that the secondary interactions, both attractive and repulsive, have a purely electrostatic origin. The X-ray structure of compounds 3 and 4 have been determined. In the solid state these compounds exist in the '' diamino '' tautomers with the N-H proton of the amido groups pointing towards the naphthyridine nitrogen. DFT and GIAO calculations have been essential to disentangle the problem of the structure of these compounds. NJC www.rsc.org/njc P A P E R 700 N e w . J . C h e m . , 2 0 0 4 , 2 8 , 7 0 0 -7 0 7
Journal of Molecular Structure, 2009
Tautomerism and dimerization of 2,7-disubstituted-1,8-naphtyridines has been studied theoretically by quantum chemical methods and experimentally by liquid and solid state NMR and ESI-TOF mass spectral techniques. The heterocomplex formation has been proven in solution by variable temperature 1H NMR and in solid state by 13C CPMAS NMR spectra of a grinded mixture of two congeners. Secondary interactions have been proposed as driving forces in the heterocomplex formation. The energy differences between homo- and heterocomplexes were calculated with recently developed DFT + D methods. The energy data obtained by the quantum chemical methods are in agreement with the concept of secondary interactions and with the experimental observations.
Russian Journal of Physical Chemistry A, 2014
In this paper, the stabilities and hydrogen bond interactions of 4 chloro 1 naphthol, 1 hydrox ynaphthalene and 1,4 dihydroxynaphthalene dimers have been theoretically investigated by means of study on binding energies with nonlocal hybrid three parameter Lee-Yang-Parr, B3LYP, and M06 class func tional calculations. Calculations on dimers aim to provide as a test of the efficacy of M06 calculations for intermolecular interaction calculations and more strongly bound systems. For hydroxyl and halo substi tuted derivatives of naphthalene, total electronic energies, their correction for the zero point vibrational ener gies with some calculated thermodynamic properties and their relative differences are together in order to dis cuss the rotamer structures. Static (hyper) polarizabilities and the electric dipole moments, frontier molecu lar orbital energy gaps and the relationships between them have been interpreted. Generally, they are seen that the calculated geometric parameters and spectral results were in a good agreement with the corresponding experimental data.
Intermolecular interactions of 7-(RCONH)- [1H]-2-oxo-1,8-naphthyridines (R = Me, Et, i-Pr, t-Bu, 1-adamantyl (1-Ad), CF3, and C2F5) containing ADAD quadruple hydrogen bonding motif were studied by liquid and solid state NMR, ESI-MS, IR, and DFT calculations. 1H NMR was used to determine the dimerization constants of i-Pr and 1-Ad congeners in CDCl3. 13C and 15N crosspolarization (CP) magic angle spinning (MAS) NMR data suggest that compounds possess similar solid state structures. Further, mass spectral data reveal that in gas phase both Me and 1-Ad derivatives form also multimers due to lack of competitive solvent interactions. The structures of the gas phase multimers depend on the size of the alkyl group. These results are in agreement with quantum chemical calculations. Geometry optimization and 1H NMR spectra show that in dimers that carry bulky alkyl groups (t-Bu and 1-Ad) certain hydrogen bonds are weaker than in Me, Et, and i-Pr derivatives while strong electron acceptors, CF3 and C2F5, deshields hydrogen bonded protons but creates significant electronic F/O repulsion yielding lowering of the energy of interaction. The influence of steric effect on dimerization of quadruply hydrogen bonded dimers was correlated with the Taft Es values.
Tautomerism in monomers/dimers and association of 2,5-dihydroxy-1,8-naphthyridine was studied at the DFT level recently recommended for studies of noncovalent interactions. Studied dimers are stabilized by double and triple hydrogen-bonding. In some associates the intermolecular proton transfer may take place. Transition state related to the double proton transfer reactions were calculated and discussed in terms of energetics, changes in atomic charges upon association, aromaticity (HOMA), properties of hydrogen bond critical point (QTAIM methodology) and geometry change during this reaction. It was found that double proton transfer is supported by third hydrogen bond or by weak secondary interaction. Some protons in transition states are shared between two basic atoms, while other are covalently bound only to one of them. The said process leads to replacement of secondary interactions of attractive character to repulsive and vice versa. Overall, results suggest that in subjected compound the triple hydrogen-bonded associate may be in equilibrium with double hydrogenbonded dimer.
Spectroscopic and theoretical studies of derivatives of 1,6- and 1,7-naphthyridines
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2003
The solvatochromism in 8-hydroxy-1,6-naphthyridin-5(6H)-one-7-carboxylic acid methyl ester (1), 5-hydroxy-1,7naphthyridin-8(7H)-one-6-carboxylic acid methyl ester (2), and 4-hydroxy-2-methyl-1(2H)-isoquinolone-3-carboxylic acid methyl ester (3), has been studied in solvents of different polarity and hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) ability. The relative stabilities of isomers for these naphthyridine derivatives and their interaction with the solvent are reported. Two intramolecular hydrogen-bonded structures contribute to the ground state of compound 1. Temperature effects on the absorption bands were recorded to analyse the possible equilibrium between covalent and zwitterionic forms. The formation of zwitterionic species was observed only in HBD solvents, from which is inferred the solvent assistance in the proton transference. AM1 and PM3 semi-empirical calculations were used in support of the proposed interpretations.
1,8‐Naphthyridine Revisited: Applications in Dimetal Chemistry
European Journal of Inorganic Chemistry, 2009
The diverse applications of functionalized 1,8‐naphthyridine (NP) ligands is the focus of this microreview. Simpler synthetic routes and the pliant nature of NP‐R steered us towards their utilization in dimetal chemistry. The ongoing research on NP chemistry in our laboratory is highlighted. The topics include the comprehensive study of the ligand disposition around the quadruply bonded Mo2 core,modulation of the metal–metal distance by axial donors in paddlewheel complexes, facile cyclometalation and C–C bond formation at axial sites of the diruthenium(I) core, building metallosupramolecular architectures, and the formation of novel unsupported iridium(II) dimer aided by redox‐active NP‐R ligands.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Journal of the Brazilian Chemical Society, 2016
In this work, semi-empirical AM1 and DFT B3LYP/6-31G** calculations were applied in the study of the interconversion among tautomers of several naphthazarin and 5-amino-8-hydroxy-1,4naphthoquinone β-substituted derivatives bearing electron-donor or electron-withdrawing groups. Using a semi-empirical method, detailed potential energy landscapes for proton transfers were built, from which four tautomers and four transition states of interconversions were identified for each compound. These structures were recalculated without restraints and, using the Boltzmann distribution, the populations for each of the four tautomers and their respective molar fractions were calculated. The calculations showed that the tautomeric equilibrium is shifted to the tautomer where the ring with the substituent has a quinonic nature and is more pronounced when the β-substituent is an electron donor group. For derivatives of 5-amino-8-hydroxy-1,4-naphthoquinone, an equilibrium between an aromatic and a 1,5-naphthoquinonic non-aromatic enamine was observed, being the former the most stable.
Ab Initio Benchmark Study of (2-Pyridone) 2 , a Strongly Bound Doubly Hydrogen-Bonded Dimer
The Journal of Physical Chemistry A, 2004
The 2-pyridone dimer, (2PY) 2 , has two antiparallel N-H‚‚‚O H-bonds analogous to nucleobase dimers. The gas-phase rotational constants and all six intermolecular vibrational frequencies of (2PY) 2 have been previously measured, providing benchmarks for theory. The structure, rotational constants, vibrational frequencies, and binding and dissociation energies of (2PY) 2 were calculated at the correlated level using second-order Møller-Plesset perturbation theory (MP2) with medium to very large basis sets. The MP2 binding energy limit was extrapolated to the complete basis set (CBS) as D e,CBS ) -22.62 ( 0.07 kcal/mol. Higher order correlation energy contributions to D e at the CCSD(T) level are destabilizing (+0.77 kcal/mol). This implies that (2PY) 2 is the most strongly bound doubly hydrogen-bonded dimer known so far. The Hartree-Fock contribution to D e,CBS is only ≈65%. Several medium-size basis sets yield MP2 D e 's within (5% of the CBS value, as well as structure, rotational constants, and intermolecular vibrations in good agreement with experiment. The PW91 density functional method also shows very good performance with regard to all properties calculated, comparable to MP2. The results imply that correlated methods combined with carefully chosen medium-size basis sets may give near-quantitative results for the structures, binding energies, and intermolecular vibrational frequencies of nucleic acid base dimers.
Chemical Physics, 2009
Ab initio calculations at MP2/aug-cc-pVTZ level were used to analyze the interactions between nitrosyl hydride (HNO) dimers and trimers. The structures obtained have been analyzed with the Atoms in Molecules (AIMs) and Natural Bond Orbital (NBO) methodologies. Four minima were located on the potential energy surface of the dimers. Nine different structures have been obtained for the trimers. Three types of interactions are observed, NHÁ Á ÁN and NHÁ Á ÁO hydrogen bonds and orthogonal interaction between the lone pair of the oxygen with the electron-deficient region of the nitrogen atom. Stabilization energies of dimers and trimers including BSSE and ZPE are in the range 4-8 kJ mol À1 and 12-19 kJ mol À1 , respectively. Blue shift of NH bond upon complex formation in the ranges between 30-80 and 14,114 cm À1 is predicted for dimers and trimers, respectively.