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To investigate the halogen substitution effect on the anionic spin crossover (SCO) complexes, azobisphenolate ligands with 5,5′-dihalogen substituents from fluorine to iodine were synthesized, and their anionic FeIII complexes 1F, 1Cl, 1Br, and 1I were isolated. The temperature dependence of magnetic susceptibility and crystal structure revealed that 1F, 1Cl, and 1Br are all isostructural and exhibit SCO with the rotational motion of the cation and ligands, whereas 1I shows incomplete SCO. Note that 1Cl and 1Br showed irreversible and reversible cooperative SCO transitions, respectively. Short intermolecular contacts between the FeIII complex anions were found despite Coulomb repulsions for all the complexes. The topological analysis of the electron density distributions revealed the existence of X···X halogen bonds, C–H···X, C–H···N, and C–H···O hydrogen bonds, and C–H···π interactions are evident. The dimensionality of intermolecular interactions is suggested to be responsible for the cooperative SCO transitions in 1Cl and 1Br, whereas the disorder due to the freezing of ligand rotations in 1Cl is revealed to inhibit the SCO cooperativity. [ABSTRACT FROM AUTHOR]

To investigate the halogen substitution effect on the anionic spin crossover (SCO) complexes, azobisphenolate ligands with 5,5′-dihalogen substituents from fluorine to iodine were synthesized, and their anionic FeIII complexes 1F, 1Cl, 1Br, and 1I were isolated. The temperature dependence of magnetic susceptibility and crystal structure revealed that 1F, 1Cl, and 1Br are all isostructural and exhibit SCO with the rotational motion of the cation and ligands, whereas 1I shows incomplete SCO. Note that 1Cl and 1Br showed irreversible and reversible cooperative SCO transitions, respectively. Short intermolecular contacts between the FeIII complex anions were found despite Coulomb repulsions for all the complexes. The topological analysis of the electron density distributions revealed the existence of X···X halogen bonds, C–H···X, C–H···N, and C–H···O hydrogen bonds, and C–H···π interactions are evident. The dimensionality of intermolecular interactions is suggested to be responsible for the cooperative SCO transitions in 1Cl and 1Br, whereas the disorder due to the freezing of ligand rotations in 1Cl is revealed to inhibit the SCO cooperativity.

To investigate the π-extension effect on an unusual negative-charged spin crossover (SCO) FeIII complex with a weak N2O4 first coordination sphere, we designed and synthesized a series of anionic FeIII complexes from a π-extended naphthalene derivative ligand. Acetonitrile-solvate tetramethylammonium (TMA) salt 1 exhibited an SCO conversion, while acetone-solvate TMA salt 2 was in a high-spin state. The crystal structural analysis for 2 revealed that two-leg ladder-like cation-anion arrays derived from π-stacking interactions between π-ligands of the FeIII complex anion and Coulomb interactions were found and the solvated acetone molecules were in one-dimensional channels between the cation-anion arrays. A desolvation-induced single-crystal-to-single-crystal transformation to desolvate compound 2' may be driven by Coulomb energy gain. Furthermore, the structural comparison between quasi-polymorphic compounds 1 and 2 revealed that the synergy between Coulomb and π-stacking interactions induces a significant distortion of coordination structure of 2. [ABSTRACT FROM AUTHOR]

Use of a silylamido–magnesium chloride and a magnesium bis-silylamide where the Si–N–Si core is crafted in a cyclic structure, toward magnesium battery application is demonstrated. Reaction between prepared silylamido–magnesium compounds and a Lewis acid in tetrahydrofuran solvent furnishes the desired electrolytes. Embedding the Si–N–Si core into cyclic structure enhances the oxidation potentials of the ‘in situ’ electrolytes (without any purification) against Mg/Mg 2+ compare to the acyclic analogue. Theoretical calculation provides insight into the ionic species present in the electrolyte systems. [ABSTRACT FROM AUTHOR]

A new anionic 8-hydroxyquinolinatopalladate(II) complex with malonate has been synthesized and characterized by elemental analysis, conductivity, FT-IR, UV-Vis and 1H NMR techniques to enhance the development of potential anticancer agents. Cytotoxicity was determined against the human leukemia cells, molt, by MTT assay. The novel antitumor Pd(II) complex was evaluated for its binding to calf thymus DNA (ctDNA) in physiological buffer (pH 7.0) by using absorption spectroscopy, fluorescence titration spectra, ethidium bromide displacement and gel chromatography studies. The results obtained from these analyses indicated that the water-soluble complex can bind to DNA cooperatively through a static quenching procedure at low concentrations. Thermodynamic parameters obtained from fluorescence experiments at different temperatures revealed the hydrogen binding and van der Waals force in the binding process which was supported by Scatchard's plots. [ABSTRACT FROM AUTHOR]

The anionic ruthenium and iron complexes Li[(η5-C5Me5)M(CO)2] (M=Ru (1-Ru), Fe (1-Fe)) were generated by deprotonation of the transition metal hydride (η5-C5Me5)M(CO)2H with n-BuLi in tetrahydrofuran (THF). The reaction proceeded at −45 °C immediately. Reactions of 1 with various electrophiles (Me3SiCl, pTol2HSiCl, Me2SiCl2, MeSiCl3, SiCl4, Me3SiSiMe2Cl, and Ph2GeCl2) afforded the corresponding nucleophilic substitution products (η5-C5Me5)M(CO)2ER3 (E=Si, Ge) via salt-elimination. [Copyright &y& Elsevier]