Triel Bonds within Anion···Anion Complexes

The ability of two anions to interact with one another is tested in the context of pairs of TrX4- homodimers, where Tr represents any of the triel atoms B, Al,...

Evaluation of Ar tagging toward the vibrational spectra and zero point energy of X-HOH, X-DOH, and X-HOD, for X=F, Cl, Br

In this study, we theoretically evaluated the effect of argon tagging toward the binding energy and vibrational spectra of water halide anion complexes, Ar.X-HOH, Ar.X-HOD, and Ar.X-DOH (X=F, Cl, Br)....

Why halides enhance heterogeneous metal ion charge transfer reactions

Halide-induced rate enhancements are correlated with the desorption barriers of aqueous metal–anion complexes on electrodes, which can guide electrode and electrolyte selection to enhance redox kinetics of metal ion charge transfer reactions.

Obtaining and Research of Palladium Complexes with 4-aminopiridine

The obtaining and investigation of various complex compounds of the biologically active aromatic heterocyclic ligands with platinum and palladium are of interest due to their potential medical applications. To that end, 4-amino pyridine containing cyclic and exocyclic nitrogen atoms has been used. The main aim of this work is to clarify which nitrogen atom of the ligand composes stronger and more stable bond. For that purpose, the synthesis of palladium salts with ligand has been accomplished within a wide interval of pH (3-12) and temperature (50-800C). The cation-anion and neutral complex compounds have been obtained depending on stoichiometric ratio of the reacting components, temperature and pH and was further studied. As a result of IR-spectroscopic investigation of synthesized complexes, the acquired information demonstrated that the pyridine nitrogen atom of the ligand is protonated and composes outer sphere as monocharged cation. However, tetraacidoanion is formed in the inner sphere. In the alkaline medium the ligand is monodentately coordinated with palladium through nitrogen atom of pyridine. The exocyclic nitrogen atom of the ligand does not participate in the coordination regardless of pH of the medium and stoichiometric ratio of the taken compounds. As a result of investigation of the thermal stability of the complexes it was determined that the neutral complexes are decomposed without melting at higher temperature than cation-anion complexes. It has been found that one of the factors that affects thermal stability is the steric structure of the complexes. The initial biological probes were accomplished and the correlation between their biological activities, composition and structures of complexes were determined. Despite the fact of taking the same medium and ligand, the cation-anion complexes indicate completely different biological activities than neutral ones.

Photoelectron spectroscopy and computational investigations of the electronic structures and noncovalent interactions of cyclodextrin-closo-dodecaborate anion complexes χ-CD·B12X122− (χ = α, β, γ; X = H, F)

We report a joint negative ion photoelectron spectroscopy and computational study on the electronic structures and noncovalent interactions of a series of cyclodextrin-closo-dodecaborate dianion complexes, χ-CD·B12X122− (χ = α, β, γ; X = H, F).

Solid State and Solution Study on the Formation of Inorganic Anion Complexes with a Series of Tetrazine-Based Ligands

Four molecules (L1–L4) constituted by an s-tetrazine ring appended with two identical aliphatic chains of increasing length bearing terminal morpholine groups were studied as anion receptors in water. The basicity properties of these molecules were also investigated. Speciation of the anion complexes formed in solution and determination of their stability constants were performed by means of potentiometric (pH-metric) titrations, while further information was obtained by NMR and isothermal titration calorimetry (ITC) measurements. The crystal structures of two neutral ligands (L3, L4) and of their H2L3(ClO4)2∙2H2O, H2L4(ClO4)2∙2H2O, H2L3(PF6)2, and H2L3(PF6)2∙2H2O anion complexes were determined by single crystal X-ray diffraction. The formation of anion–π interactions is the leitmotiv of these complexes, both in solution and in the solid state, although hydrogen bonding and/or formation of salt-bridges can contribute to their stability. Evidence of the ability of these ligands to form anion–π interactions is given by the observation that even the neutral (not-protonated) molecules bind anions in water to form complexes of significant stability, including elusive OH− anions.