Author: Sami Hietala

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AUTHOR

Sami Hietala

Rapid self-healing and anion selectivity in metallosupramolecular gels assisted by fluorine-fluorine interactions.

Simple ML2 [M = Fe(II), Co(II), Ni(II)] complexes obtained from a perfluoroalkylamide derivative of 4-aminophenyl-2,2′,6,2′-terpyridine spontaneously, yet anion selectively, self-assemble into gels, which manifest an unprecedented rapid gel strength recovery, viz. self-healing, and thermal rearrangement in aqueous dimethyl sulfoxide. The key factor for gelation and rheological properties emerges from the fluorine–fluorine interactions between the perfluorinated chains, as the corresponding hydrocarbon derivative did not form metallogels. The perfluoro-terpyridine ligand alone formed single crystals, while its Fe(II), Co(II) or Ni(II) complexes underwent rapid gelation leading to highly enta…

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Bipyridine based metallogels: an unprecedented difference in photochemical and chemical reduction in the in situ nanoparticle formation

Metal co-ordination induced supramolecular gelation of low molecular weight organic ligands is a rapidly expanding area of research due to the potential in creating hierarchically self-assembled multi-stimuli responsive materials. In this context, structurally simple O-methylpyridine derivatives of 4,4′-dihydroxy-2,2′-bipyridine ligands are reported. Upon complexation with Ag(I) ions in aqueous dimethyl sulfoxide (DMSO) solutions the ligands spontaneously form metallosupramolecular gels at concentrations as low as 0.6 w/v%. The metal ions induce the self-assembly of three dimensional (3D) fibrillar networks followed by the spontaneous in situ reduction of the Ag-centers to silver nanopartic…

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Subcomponent Self-Assembly A Quick Way to New Metallogels

Subcomponent self-assembly, introduced by the Nitschke group,[1] is a process which allow complex structures to be generated from simple building blocks (generally aldehydes and amines). In this bottom-up approach, the building blocks spontaneously self-assemble around templates (usually metal ions) leading to a simultaneous covalent (C=N) and dative (N– metal) bonds formation. The method has been successfully used to construct well-defined metal-organic macrocycles, helicates, catenanes, rotaxanes, grids,[2] and cages.[3] Our field of interest lies not in building-up of defined structures but in designing gelator molecules for a formation of supramolecular gels as functional nanomaterials.…

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CCDC 1500638: Experimental Crystal Structure Determination

Related Article: Rajendhraprasad Tatikonda, Kia Bertula, Nonappa, Sami Hietala, Kari Rissanen, Matti Haukka|2017|Dalton Trans.|46|2793|doi:10.1039/C6DT04253H

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