Juan J. Fiol

Bio: Juan J. Fiol is an academic researcher from University of the Balearic Islands. The author has contributed to research in topics: Ligand & Non-covalent interactions. The author has an hindex of 21, co-authored 69 publications receiving 1307 citations. Previous affiliations of Juan J. Fiol include Spanish National Research Council.

Complexes of Zinc(II) with N-Imidazolyl- and N-Pyrazolylpyrimidine Donor Ligands: Synthesis, Crystal Structures, and Theoretical Study

Abstract: The synthesis and crystal-structure determination of three zinc(II) complexes with 2-(1H-imidazol-1-yl)pyrimidine(imipyr) and 2-(1H-pyrazol-1-yl)pyrimidine (pyrapyr) ligands are reported. Complexes [Zn(imipyr)2Cl2] (1) and[Zn(pyrapyr)2Cl2] (2) are mononuclear systems, and [Zn2(pyrapyr)2(Cl)4] (3) is a dinuclear complex with two chlorido bridging ligands. In complex 3, the coordination numbers of the two differently coordinated Zn ions are four and six. All complexes were characterized by X-ray crystallography. A high-level theoretical study was performed to rationalize the interesting noncovalent interactions observed in the solid state. All three structures show a peculiar π stacking, which is characterized by the absence of π–π ring-plane overlapping. In this slipped stacking mode, the rings are antiparallely displaced, and alternating C···N interactions are established. Moreover, complex 3 forms infinite 1D columns by means of double anion–π interactions with pyrapyr. The atoms-in-molecules (AIM) theory proposed by Bader was used to characterize the anion–π and π–π interactions observed in the solid state. A high-level ab initio study (RI-MP2/def2-TZVP level of theory) was performed to analyze the anion–π binding affinity of the pyrapyr ligand coordinated to the transition metal atom. Finally, a CSD search demonstrates that the structure of 3 is quite unique, because dinuclear Zn complexes that contain one tetracoordinate and one hexacoordinate metal center are rare, whereas this combination is common in trinuclear, linear complexes. With bridging chlorido ligands, this simultaneous tetra- and hexacoordination is unprecedented.

New Chlorido(dimethyl sulfoxide)iridium(III) Complexes with N6‐Substituted Adenines – Kinetic N(7) versus Thermodynamic N(9) Coordinated Adenine Isomers

Abstract: New chlorido(dimethyl sulfoxide)iridium(III) complexes with N 6 -substituted adenine derivatives: [Ir III Cl 4 (DMSO-κS){H-AdeC x -κN(7)}]·nH 2 O [x = 3, n = 3 for 1; x = 4, n = 0.5 and 3 for 2a and 2b, respectively; x = 5, n = 0 for 3; x = 10, n = 0.33 for 4] and [Ir III Cl 4 (DMSO-κS){H-AdeC x -κN(9)}] [x = 3 for 5; x = 4 for 6, x = 5 for 7; x = 10 for 8] have been synthesized and characterized by spectroscopic techniques and by single-crystal X-ray diffraction studies (1, 2b and 5). In all cases, iridium shows octahedral geometry and is coordinated to four chlorido ligands and one S atom from dimethyl sulfoxide (DMSO-κS). The coordination sphere of the metal is completed by the N 6 -substituted adenine molecule. Two different coordination modes are observed: (i) the ligand is protonated at N(1) and coordinated through N(7) (complexes 1-4); (ii) the adenine is protonated at N(3) and coordinated through N(9) (complexes 5-8). The kinetic/thermodynamic mechanisms that yield the different coordination products have been studied by using DFT calculations. Electrophoretic mobility studies and atomic force microscopy (AFM) investigation of the interaction between complexes 1, 5, 8 and plasmid pBR322 DNA have been performed.

CH/π hydrogen bonds in crystals

Abstract: The nature and characteristics of the CH/π interaction are discussed by comparison with other weak molecular forces such as the CH/O and OH/π interaction. The CH/π interaction is a kind of hydrogen bond operating between a soft acid CH and a soft base π-system (double and triple bonds, C6 and C5 aromatic rings, heteroaromatics, convex surfaces of fullerenes and nanotubes). The consequences of CH/π hydrogen bonds in supramolecular chemistry are reviewed on grounds of recent crystallographic findings and database analyses. The topics include intramolecular interactions, crystal packing (organic and organometallic compounds), host/guest complexes (cavity-type inclusion compounds of cyclodextrins and synthetic macrocyclic hosts such as calixarenes, catenanes, rotaxanes and pseudorotaxanes), lattice-inclusion type clathrates (including liquid crystals, porphyrin derivatives, cyclopentadienyl compounds and C60 fullerenes), enantioselective clathrate formation, catalytic enantioface discriminating reactions and solid-state photoreaction. The implications of the CH/π concept for crystal engineering and drug design are evident.

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 receptor chemistry: highlights from 2010

Abstract: This critical review covers advances in anion complexation in the year 2010. The review covers both organic and inorganic systems and also highlights the applications to which anion receptors can be applied such as sensing, anion transport, control of molecular motion and gelation (179 references).