Influence of metal coordination and light irradiation on hierarchical self-assembly processes. Issue 3 (2nd November 2018)

• Record Type: Journal Article
• Authors: Kartha, Kalathil K.; Allampally, Naveen Kumar; Politi, Antiope T.; Prabhu, Deepak D.; Ouchi, Hayato; Albuquerque, Rodrigo Q.; Yagai, Shiki; Fernández, Gustavo
• Is Part Of: Chemical science. Volume 10:Issue 3(2019)
• Page Start: 752
• Page End: 760
• Publication Date: 2018-11-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc03875a
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : We unravel the impact of metal coordination and light irradiation on hierarchical self-assembly processes by combined theoretical and experimental results. Abstract : Smart light-responsive supramolecular materials have been extensively investigated in the past decade, but so far the impact of metal coordination on hierarchical supramolecular structures of light-responsive building blocks has remained nearly unexplored. Herein, we unravel the hierarchical self-assembly of a small π-conjugated azo-containing pyridyl ligand that is able to respond to UV-light and metal complexation. The ligand self-assembles in an antiparallel fashion into long twisted fibers, which are then disassembled upon photoisomerization of the azobenzene groups, resulting in shorter rigid rods with a different packing motif. Complexation of Pd(ii ) ions enhances the cooperativity of the aggregation and induces a molecular rearrangement into slipped stacks with subsequent formation of long thin fibers. These are then transformed into thinner, shorter rods upon light irradiation. The observed different light-responsiveness, besides clearing up the influence of metal coordination and light irradiation in self-assembly processes, paves the way towards the design of novel supramolecular photochromic systems.