David Quiñonero

Bio: David Quiñonero is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: Cooperativity & Ab initio. The author has an hindex of 10, co-authored 10 publications receiving 463 citations. Previous affiliations of David Quiñonero include University of Texas at Austin & University of Barcelona.

Anion−π Interactions in Bisadenine Derivatives: A Combined Crystallographic and Theoretical Study

Abstract: In this manuscript we report a high-level ab initio study of anion−π interactions involving N9-methyl-adenine, N6-methyl-adenine, N9-methyl-hypoxanthine, a dimer of N9-methyl-adenine, and N9,N9‘-trimethylene-bisadenine. DNA bases like adenine are electron-deficient arenes that are well suited for interacting favorably with anions. We demonstrate that these compounds are able to interact favorably with anions. N9-Methyl-adenine, N6-methyl-adenine, and the dimer of N9-methyl-adenine interact with the anion via the six-membered ring more strongly than adenine due to cooperativity effects between the noncovalent π−π and anion−π interactions. This pattern, i.e., coexistence of π−π and anion−π bonding, is observed experimentally in the solid state. Finally, we report the solid-state characterization of two new compounds N6,N6‘-dimethylene-bisadenine hydrochloride and an outer-sphere complex of protonated N9,N9‘-trimethylene-bishypoxanthine with zinc tetrachloride anion, that exhibit interesting anion−π interact...

Coordination Complexes Exhibiting Anion · · ·π Interactions: Synthesis, Structure, and Theoretical Studies

Abstract: The polydentate ligand 2,4,6-tris(dipyridin-2-ylamino)-1,3,5-triazine (dpyatriz) in combination with the Cu(ClO4)2/CuX2 salt mixtures (X− = Cl−, Br−, or N3−) leads to the formation of molecular coordination aggregates with formulas [Cu3Cl3(dpyatriz)2](ClO4)3 (2), [Cu3Br3(dpyatriz)2](ClO4)3 (3), and [Cu4(N3)4(dpyatriz)2(DMF)4(ClO4)2](ClO4)2 (4). These complexes consist of two dpyatriz ligands bridged via coordination to CuII and disposed either face-to-face in an eclipsed manner (2 and 3) or parallel and mutually shifted in one direction. The copper ions complete their coordination positions with Cl− (2), Br− (3), or N3−, ClO4−, and N,N-dimethylformamide (DMF) (4) ligands. All complexes crystallize together with noncoordinate ClO4− groups that display anion···π interactions with the triazine rings. These interactions have been studied by means of high level ab initio calculations and the MIPp partition scheme. These calculations have proven the ClO4−···[C3N3] interactions to be favorable and have revealed ...

Rational Design, Synthesis and Application of a New Receptor for the Molecular Recognition of Tricarboxylate Salts in Aqueous Media

Abstract: A rational design of a tripodal receptor for the molecular recognition of tricarboxylate salts in aqueous media, based on squaramide, has been performed using high-level DFT calculations (RI-BP86/SVP level of theory) in solution using the COSMO treatment, including some preliminary ab initio calculations at the higher RI-MP2/TZVP level of theory, comparing the ability of squaramide to bind carboxylate salts with two widely used guanidinium salts. The tripodal receptor has been synthesized using a new methodology that has been recently reported by some of us, and its capability of recognizing several mono-, di-, and tricarboxylate salts has been studied experimentally by means of microcalorimetry experiments in a very high competitive media, H2O:EtOH 1:3. These experiments give enthalpic and entropic data, which are unfortunately scarce in the literature of molecular recognition of anions. Finally, a fluorimetric ensemble of the receptor with fluorescein has been found to be useful for the fluorimetric det...

Simultaneous Interaction of Tetrafluoroethene with Anions and Hydrogen-Bond Donors: A Cooperativity Study

Abstract: A computational study of the complexes formed by tetrafluoroethylene, C2F4, with anions has been carried out by means of density functional theory (DFT) and second-order Moller-Plesset (MP2) computational methods, up to MP2/aug-cc-pVTZ level. In addition, the possibility of cooperativity in the interaction of anions and hydrogen-bond donors (FH, ClH, and H2O) when interacting with different faces of the C2F4 molecule has been explored. Electron density of the complexes has been analyzed by means of atoms in molecules (AIM) methodology, while natural bond orbital (NBO) methodology has been used to characterize the orbital interaction. In addition, natural energy decomposition analysis (NEDA) has been applied to analyze the source of the interaction. The energetic results indicate that C2F4 is a weaker anion receptor than C6F6, but in combination with the anions, it became a stronger hydrogen acceptor than C2H4. Cooperativity effects are observed in YH·C2F4·X(-) clusters. In C2F4·X(-) complexes the dominant attractive terms are the electrostatic and polarization ones, while in YH·C2F4·X(-) complexes the charge transfer increases significantly, becoming the most important term for most of the FH and ClH complexes studied here.

Energetic vs synergetic stability: a theoretical study.

Abstract: The aim of this manuscript is to define a new concept, namely synergetic stability, which can be useful in systems where the interplay of noncovalent interactions is important. Usually, the stabili...

Aromatic rings in chemical and biological recognition: energetics and structures.

Abstract: This review describes a multidimensional treatment of molecular recognition phenomena involving aromatic rings in chemical and biological systems. It summarizes new results reported since the appearance of an earlier review in 2003 in host-guest chemistry, biological affinity assays and biostructural analysis, data base mining in the Cambridge Structural Database (CSD) and the Protein Data Bank (PDB), and advanced computational studies. Topics addressed are arene-arene, perfluoroarene-arene, S⋅⋅⋅aromatic, cation-π, and anion-π interactions, as well as hydrogen bonding to π systems. The generated knowledge benefits, in particular, structure-based hit-to-lead development and lead optimization both in the pharmaceutical and in the crop protection industry. It equally facilitates the development of new advanced materials and supramolecular systems, and should inspire further utilization of interactions with aromatic rings to control the stereochemical outcome of synthetic transformations.

Anion receptors based on organic frameworks: highlights from 2005 and 2006

Abstract: This critical review covers advances in anion complexation chemistry related to receptors based on organic frameworks in the years 2005–2006. The review covers anion receptors that employ amides and thioamides, pyrroles and indoles, ureas and thioureas, ammonium, guanidinium, imidazolium, and receptors containing hydroxyl groups. There is a discussion of anion templated assembly, followed by a short section outlining modelling studies of these systems. (226 references.)

Squaramides: Bridging from Molecular Recognition to Bifunctional Organocatalysis

Abstract: In this minireview, squaramides are presented from their roots as artificial anion receptors in molecular recognition studies to their recent advances as powerful bifunctional hydrogen-bonding catalysts in asymmetric organocatalysis. The main features of the squaramido functionality and the direct comparison with the analogous ureas and thioureas are also discussed.