Modulating p-hydroxycinnamate behavior as a ditopic linker or photoacid in copper(ii) complexes with an auxiliary pyridine ligand. Issue 18 (25th April 2018)

• Record Type: Journal Article
• Authors: Soldevila-Sanmartín, Joan; Calvet, Teresa; Font-Bardia, Merce; Domingo, Concepción; Ayllón, José A.; Pons, Josefina
• Is Part Of: Dalton transactions. Volume 47:Issue 18(2018)
• Page Start: 6479
• Page End: 6493
• Publication Date: 2018-04-25
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt00645h
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : p -Hydroxycinnamate behaves either as a ditopic linker or as a photoacid in copper(ii ) complexes with a suitable auxiliary pyridine ligand. Abstract : The reaction of copper(ii ) acetate monohydrate with p -hydroxycinnamic acid (HpOHcinn) and different pyridine derivatives (4- tert -butylpyridine, 4- t Bupy; 4-acetylpyridine, 4-Acpy; 3-phenylpyridine, 3-Phpy; 4-phenylpyridine, 4-Phpy) was essayed in methanol solvent at room temperature. The crystal structures of the resulting compounds were elucidated. Their analysis shows that the choice of pyridine ligands determines different coordination modes of the pOHcinn ligand and the Cu(ii ) coordination, nuclearity and geometry. The pOHcinn acts as a monodentate carboxylate ligand in combination with 4- t Bupy or 4-Phpy, yielding monomers and dimers, associated by hydrogen bonds into supramolecular networks in which the phenol group plays a key role. Conversely, in combination with 4-Acpy or 3-Phpy, the phenol group coordinates directly to the Cu(ii ), acting as a ditopic ligand and yielding 2D coordination polymers. The compound containing 3-Phpy shows interesting MeOH–H2 O reversible exchange behavior. Not only has the pyridine auxiliary ligand had a tremendous effect on the coordination mode of pOHcinn, but also its reactivity is influenced. Particularly, in the case of the compound containing 4-Phpy, it undergoes a photoinduced process, in which the phenol group deprotonates and coordinates to Cu(ii ) as a phenoxy ligand. This yields a coordination polymer in which two different dimers alternate, bridged by the resulting pOcinn ligand. The magneto-structural correlation of this compound is also discussed.