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Abstract: Two dioxomolybdenum(VI) complexes, [Mo2O4(HBAP)2L] (1) and [MoO2(HMBI)] (2) (HBAP=((E)-2-(2-hydroxybenzylidene)amino)phenol, HMBI=((E)-N′-(2-hydroxy-3-ethoxybenzylidene)isonicotinohydrazide) and L=(4,4′-dipyridyl)), have been synthesized and structurally characterized by elemental analysis, 1H NMR spectroscopy and X-ray single crystal diffraction analysis. In complex (1), a 1D-chain is formed through C⋯H⋯O hydrogen-bonding interactions. In complex (2), a dimer is formed through O⋯H⋯N hydrogen-bonding interactions. This dimer is extended into a 1D chain through secondary C⋯H⋯O hydrogen-bonding interactions, in addition to π–π stacking interactions. Electrochemical measurements showed that both complexes undergo an irreversible reduction in DMF solution. The thermogravimetric analyses clearly indicate that the complexes have high thermal stability. [Copyright &y& Elsevier]

The first dual component pseudocryptand-type [2]pseudorotaxanes were designed and prepared via the self-assembly of synthetically easily accessible bis(meta-phenylene)-32-crown-10 pyridyl, quinolyl, and naphthyridyl derivatives with paraquat. The formation of the pseudocryptand structures in the complexes remarkably improved the association constant by forming the third pseudobridge via H-bonding with the guest and π-stacking of the heterocyclic units. [ABSTRACT FROM AUTHOR]

Abstract: Two new cobalt(II) and zinc(II) coordination networks constructed from an anthracene based bis imidazole ligand, 9,10-bis(imidazol-1-ylmethyl)anthracene ligand (L), are reported. The compounds {[Co (HBTC2−) (L) (H2O)2]·H2O}∞(1) and {[Zn (HBTC2−) (L) (H2O)2]·H2O}∞(2) were synthesized under solvothermal conditions and structurally characterized by single X-ray diffraction analysis and thermogravimetric analysis. Both 1 and 2 have a one-dimensional covalently bonded (1D) zigzag chain structure that is linked into infinite two-dimensional (2D) sheets by inter-chain π···π stacking and hydrogen bonding. [Copyright &y& Elsevier]

Six new zinc phosphite hybrids are prepared under a variety of reaction conditions from the primary building blocks, trimethylenedipyridine, zinc acetate, and phosphorous acid. Neutral guest molecules are incorporated into several of the structures. Under hydrothermal conditions at 130 °C, an anionic framework structure, 1, templated on trimethylenedipyridinium, is obtained while a neutral ladder structure, 2, is formed at room temperature. These reactions are done at an initial pH of 4.7-5.0. When the reaction is done at an initial pH of 7.8-8.0, a neutral layered motif is obtained with 1 ,3-dipyridylpropane pillars and neutral guests in the interstitial space. Structures with water, phenol, and catechol as the guests, compounds 3, 4, and 5, respectively, are reported. The use of catechol as a template results in the breakup of the ZnPO sheet structure common to both 3 and 4. When amino acids, including alanine, were added to the reaction medium, a neutral three-dimensional framework, 6, is obtained with no incorporation of the potential template. The syntheses and structures of these new materials are reported. [ABSTRACT FROM AUTHOR]

Abstract: 1,2-Bis[N-(N′-alkylimidazolium)ethane salts form complexes presumed to be pseudorotaxanes with crown ether and cryptand hosts. The association constants of 1,2-bis[N-(N′-butylimidazolium)]ethane bis(hexafluorophosphate) with dibenzo-24-crown-8 and a dibenzo-24-crown-8-based pyridyl cryptand were estimated as 24 (±1) and 348 (±30)M−1, respectively, in acetonitrile at 25°C. The pseudorotaxane-like structure of the 1:2 complex of the N′-methyl analog with the cryptand was observed by X-ray crystallography. Replacement of the ethylene spacer with propylene and butylene spacers resulted in K a values an order of magnitude smaller. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of two manganese(II) complexes formally each featuring two cis-tetracyanoethylenide radical anionic ligands (TCNE•/-) are reported. In each case, tris(pyrazol-1-ylmethyl)amine serves as a capping ligand, blocking three facial coordination sites. Crystal structures show that the two TCNE anions in each molecule exhibit an intramolecular stacking interaction that forms what can be considered a coordinated (TCNE2)2- moiety. These molecules are presumed to be structural models of some of the local bonding in the family of amorphous, ferrimagnetic, M[TCNE]2·y(solvent) coordination polymer magnets. Magnetic measurements indicate that the (TCNE2)2- bridge is diamagnetic and not a good mediator of magnetic exchange, a result that might explain the observed lower ordering temperatures in some of the polymer magnets. [ABSTRACT FROM AUTHOR]