trans to cis photo-isomerization in merocyanine dysprosium and yttrium complexes

Pramila Selvanathan (1) , Vincent Dorcet (1) , Thierry Roisnel (1) , Kevin Bernot (1) , Gang Huang (1) , Boris Le Guennic (1) , Lucie Norel (1) , Stéphane Rigaut (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

We report the synthesis of two lanthanide complexes including a chelating merocyanine (MC) ligand obtained from the reaction of a bis(pyridinemethyl)amine substituted spiropyran with yttrium(iii) or dysprosium(iii) triflate salts, whose structures were confirmed both in the solid state and in solution by single crystal X-ray diffraction studies and NMR investigations. The obtained merocyanine metal complexes can reversibly undergo a photo-triggered transformation consisting of a partial isomerization of the trans-merocyanine ligand to its cis isomer (cis-MC) providing complexes in which the metal-phenolate bond is retained. SQUID magnetometry experiments in combination with ab initio calculations were used to evidence and rationalize the single-molecule magnet behavior of the dysprosium complex and to probe the changes in the dysprosium ion local environment upon photo-isomerization.

Keywords: photochromism; spiropyran; mercocyanine; lanthanide; single molecule magnet; ab initio calculations

Domains: Chemical Sciences; Coordination chemistry

Pramila Selvanathan, Vincent Dorcet, Thierry Roisnel, Kevin Bernot, Gang Huang, et al.. trans to cis photo-isomerization in merocyanine dysprosium and yttrium complexes. Dalton Transactions, 2018, 47 (12), pp.4139-4148. ⟨10.1039/c8dt00299a⟩. ⟨hal-01744292⟩