Electronic investigation of light-induced reversible coordination of Co(II)/spiropyran complex

Herein, synthesis and characterization of a cobalt (II) complex using a spiropyran as its ligand was described. Solid complex (CoMC) was obtained using a novel ultraviolet radiation-induced precipitation technique, FTIR-ATR spectroscopy demonstrated the binding sites involved in the coordination. Computational calculations were crucial to understand the experimental results, demonstrating the frontiers orbitals in tetrahydrofuran. Moreover, mass spectrometry revealed a 1:2 Co(II):ligand stoichiometry. By means of UV–vis absorption spectroscopy, complexation was confirmed and photochromic and the solvatochromic characteristics of the complex and the free ligand were studied. These results showed that the complex did not present a would be expected pattern regarding its solvatochromic properties, while the free ligand did. Reversibility experiments exposed a high resistance to photodegradation of the complex in isopropanol, comparing to the other solvents tested. [Display omitted] •Complex precipitated through novel ultraviolet induced process.•Ligand and complex presented well pronounced solvatochromic properties.•Isopropanol reduced drastically the complex photodegradation characteristic.