- Influence of Host-Guest and Host-Host Interactions on the Spin-Crossover 3D Hofmann-type Clathrates {FeII(pina)[MI(CN)2]2}· xMeOH (MI = Ag, Au)
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The synthesis, structural characterization and magnetic properties of two new isostructural porous 3D compounds with the general formula {FeII(pina)[MI(CN)2]2}·xMeOH (x = 0-5; pina = N-(pyridin-4-yl)isonicotinamide; MI = AgI and x ~5 (1·xMeOH); MI = AuI and x ~5 (2·xMeOH)) are presented. The single-crystal X-ray diffraction analyses have revealed that the structure of 1·xMeOH (or 2·xMeOH) presents two equivalent doubly interpenetrated 3D frameworks stabilized by both argentophilic (or aurophilic) interactions and interligand C=O···HC H-bonds. Despite the interpenetration of the networks, these compounds display accessible void volume capable of hosting up to five molecules of methanol which interact with the host pina ligand and establish an infinite lattice of hydrogen bonds along the structural channels. Interestingly, the magnetic studies have shown that solvated complexes 1·xMeOH and 2·xMeOH display two- and four-step hysteretic thermally driven spin transitions, respectively. However, when these compounds lose the methanol molecules, the magnetic behavior changes drastically giving place to gradual spin conversions evidencing the relevant influence of the guest molecules on the spin-crossover properties. Importantly, since the solvent desorption takes place following a single-crystal-to-single-crystal transformation, empty structures 1 and 2 (x = 0) could be also determined allowing us to evaluate the correlation between the structural changes and the modification of the magnetic properties triggered by the loss of methanol molecules.
- Valverde-Mu?oz, Francisco Javier,Bartual-Murgui, Carlos,Pi?eiro-López, Lucía,Mu?oz, M. Carmen,Real, José Antonio
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- Synthesis and characterization of one, two and three-dimensional Cu(I) polymers supported by bipyridylamide ligands
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Reaction of bipyridylamide ligands N-(3-pyridyl)nicotinamide (3-pna), N-(4-pyridyl)nicotinamide (4-pna) and N-(4-pyridyl)isonicotinamide (4-pina) with Cu(I) salts afforded four coordination polymers. X-ray crystallography analysis showed one-, two- and three-dimensional networks. The correlation between the pyridyl nitrogen donor disposition and dimensionality of the structures was discussed. Reflectance UV–Vis and fluorescence spectroscopic methods were used to characterize the MLCT features of these complexes. Thermal stability of the coordination polymers under nitrogen was also investigated.
- Mugenzi, Clement,Powell, Douglas R.,Gerasimchuk, Nikolay N.,Yang, Lei
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- Unexpected right-handed helical nanostructures co-assembled from l-phenylalanine derivatives and achiral bipyridines
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The construction of chiral supramolecular systems with desirable handedness is of great importance in materials science, chemistry, and biology since chiral nanostructures exhibit fascinating photophysical properties and unique biological effects. Herein,
- Liu, Guofeng,Liu, Jinying,Feng, Chuanliang,Zhao, Yanli
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p. 1769 - 1775
(2017/03/09)
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- INHIBITORS OF RHO ASSOCIATED PROTEIN KINASES (ROCK) AND METHODS OF USE
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Compounds and compositions having activity as inhibitors of Rho-associated proteinkinases (ROCKs), and methods of making and using the subject compounds are disclosed.
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Page/Page column 42
(2013/08/15)
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- Molecular hydrogels from bolaform amino acid derivatives: A structure-properties study based on the thermodynamics of gel solubilization
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Insight is provided into the aggregation thermodynamics associated to hydrogel formation by molecular gelators derived from L-valine and L-isoleucine. Solubility data from NMR measurements are used to extract thermodynamic parameters for the aggregation i
- Nebot, Vicent J.,Armengol, Jose,Smets, Johan,Prieto, Susana Fernandez,Escuder, Beatriu,Miravet, Juan F.
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supporting information; experimental part
p. 4063 - 4072
(2012/05/31)
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