Miquel Barceló-Oliver

Bio: Miquel Barceló-Oliver is an academic researcher from University of the Balearic Islands. The author has contributed to research in topics: Chemistry & Supramolecular chemistry. The author has an hindex of 19, co-authored 62 publications receiving 1086 citations. Previous affiliations of Miquel Barceló-Oliver include Spanish National Research Council & University of Zurich.

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...

Rationalization of noncovalent interactions within six new MII/8-aminoquinoline supramolecular complexes (MII = Mn, Cu, and Cd): A combined experimental and theoretical DFT study

Abstract: To examine the influence of the metal ions and their counterions on crystalline networks, we have designed and synthesized six MX2/8-aminoquinoline (8-aq) (M = MnII, CuII, CdII and X = Cl–, Br–, I–, NO3–, SCN–) complexes, having the formulas [Mn(8-aq)2 I2]·(1), [Mn(8-aq)2(H2O)2](8-aq)3·Br2 (2), [Mn(8-aq)2(SCN)2] (3), [Cu(8-aq)2Cl(H2O)]·Cl·H2O (4), [Cu(8-aq)2(NO3)(H2O)]·NO3 (5), and Cd(8-aq)2I2 (6). Single-crystal X-ray diffraction analyses showed that all of the complexes have a distorted octahedral geometry, in which each 8-aq molecule acts as a bidentate ligand and coordinates to the central metal ion with its common coordination mode, to form an N,N′ chelating motif. Remarkably, the influence of the counterion on the geometry of the complex is very significant since both I– and SCN– anions are coordinated to the metal ion in compounds 1, 3, and 6, adopting a cis configuration, while a single anion occupies an axial position in compounds 4 and 5 (Cl– and NO3–, respectively) and the other counterion is n...

Use of metalloligands [CuL] (H2L = salen type di-Schiff bases) in the formation of heterobimetallic copper(II)-uranyl complexes: photophysical investigations, structural variations, and theoretical calculations.

Abstract: Five heterobimetallic copper(II)–uranium(VI) complexes [(CuL1)UO2(NO3)2] (1), [{CuL1(CH3CN)}UO2(NO3)2] (2), [{CuL1(CH3COCH3)}UO2(NO3)2] (3), [{CuL2(CH3CN)}UO2(NO3)2](4), and [{CuL2(CH3COCH3)}UO2(NO3)2][{CuL2}UO2(NO3)2] (5) have been synthesized by reacting the Cu(II)-derived metalloligands [CuL1] and [CuL2] (where, H2L1 = N,N′-bis(α-methylsalicylidene)-1,3-propanediamine and H2L2 = N,N′-bis(salicylidene)-1,3-propanediamine) with UO2(NO3)2·6H2O in 1:1 ratio by varying the reaction temperature and solvents. Absorption and fluorescence quenching experiments (steady-state and time-resolved) indicate the formation of 1:1 ground-state charge transfer copper(II)–uranium(VI) complexes in solution. X-ray single-crystal structure reveals that each complex contains diphenoxido bridged Cu(II)–U(VI) dinuclear core with two chelated nitrato coligands. The complexes are solvated (acetonitrile or acetone) in the axial position of the Cu(II) in different manner or desolvated. The supramolecular interactions that depend up...

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

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.

Copper complexes as anticancer agents

Abstract: Metal-based antitumor drugs play a relevant role in antiblastic chemotherapy. Cisplatin is regarded as one of the most effective drugs, even if severe toxicities and drug resistance phenomena limit its clinical use. Therefore, in recent years there has been a rapid expansion in research and development of novel metal-based anticancer drugs to improve clinical effectiveness, to reduce general toxicity and to broaden the spectrum of activity. The variety of metal ion functions in biology has stimulated the development of new metallodrugs other than Pt drugs with the aim to obtain compounds acting via alternative mechanisms of action. Among non-Pt compounds, copper complexes are potentially attractive as anticancer agents. Actually, since many years a lot of researches have actively investigated copper compounds based on the assumption proposal that endogenous metals may be less toxic. It has been established that the properties of copper-coordinated compounds are largely determined by the nature of ligands and donor atoms bound to the metal ion. In this review, the most remarkable achievements in the design and development of copper(I, II) complexes as antitumor agents are discussed. Special emphasis has been focused on the identification of structure-activity relationships for the different classes of copper(I,II) complexes. This work was motivated by the observation that no comprehensive surveys of copper complexes as anticancer agents were available in the literature. Moreover, up to now, despite the enormous efforts in synthesizing different classes of copper complexes, very few data concerning the molecular basis of the mechanisms underlying their antitumor activity are available. This overview, collecting the most significant strategies adopted in the last ten years to design promising anticancer copper(I,II) compounds, would be a help to the researchers working in this field.