Iron complexes of bridging azo ligands in aqueous solution: changes in the thermal switching mechanism on coordination and oxidation state of metal centres. Issue 6 (19th January 2023)

• Record Type: Journal Article
• Authors: Bardají, Manuel; Font-Bardia, Mercè; Gallen, Albert; Garcia-Cirera, Beltzane; Ferrer, Montserrat; Martínez, Manuel
• Is Part Of: Dalton transactions. Volume 52:Issue 6(2023)
• Page Start: 1720
• Page End: 1730
• Publication Date: 2023-01-19
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt03790d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Isocyanide-appended azo derivatives have been designed as photoactive building blocks in assembly reactions; the rotation/inversion mechanistic tuning of the thermal cis -to- trans isomerisation has been analysed. Abstract : Three azobenzenes CN(C6 H4 )-NN-(C5 H4 N) (py-iso ), CN(C6 H4 )-NN-(C6 H4 )CN (cyano-iso ) and CN(C6 H4 )-NN-(C6 H4 )NC (iso–iso ) with good coordinating groups (pyridine, phenylcyano or phenylisocyano) at the ends of the diazenyl unit have been synthesized and fully characterised. These compounds have been used as ligands in the synthesis of water-soluble metallic species by coordination to {Fe II (CN)5 3− } units, either in one or two of the anchoring groups of the derivatives. Both the azo derivatives and their complexes are photochemically active with respect to their trans -to- cis isomerisation process. Their cis -to- trans reverse thermal reaction has been thoroughly studied as a function of the donor groups, solvent, temperature and pressure, in order to gain insight into the rotation or inversion mechanisms involved in the process. A comparison of the isomerisation mechanism between the iron complexes and the corresponding free ligands revealed an interesting fine tuning of the process on coordination of the {Fe II (CN)5 3− } moieties, which may even produce, in some cases, non-photoswitchable species containing typically photoactive units.