Propeller-like heterotrinuclear CuII–LnIII–CuII compounds – Physicochemical properties

•Bimetallic heterotrinuclear CuIISmIIICuII and CuIIEuIIICuII compounds.•A propeller with diversity for right- and left-handed stereoisomers.•Gaseous products.

The new heterotrinuclear compounds [Cu2Ln(L)2(NO3)(H2O)2](NO3)2·3H2O (where Ln = Sm (1), Eu (2) and L = C19H18N2O4Br2 is the deprotonated form of N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine,) have been synthesized and characterized by FTIR, TG-FTIR, TG/DSC and single crystal X-ray analyses. The complexes of 1 and 2 are isostructural. In the trinuclear compounds two terminal copper(II) ions are coordinated by imino and phenolate oxygen atoms, whereas the central lanthanide(III) ion is bound to the phenolate and methoxy oxygen atoms of the Schiff base ligands. The first change in mass estimated from TG curve corresponds to the loss of water molecules. The decomposition of the Schiff base ligand starts above 200 °C. The final decomposition solid products are CuO and Ln2CuO4. The TG-FTIR results show that the main gaseous products in whole decomposition process of complexes are water (H2O), carbon dioxide (CO2), carbon monoxide (CO), nitric oxides (NOx) and bromomethane (CH3Br).

Graphical abstractThe new bimetallic heterotrinuclear isostructural complexes [Cu2Ln(L)2(NO3)(H2O)2](NO3)2·3H2O (where Ln = Sm (1), Eu (2) and L = C19H18N2O4Br2 have been synthesized and characterized by FTIR, TG-FTIR, TG/DSC and single crystal X-ray analyses. In the compounds the phenolate oxygen atoms function as bridging atoms between Cu(II) and Ln(III) metal ions. Clusters present in the analyzed crystals have shape of a propeller with diversity for right- and left-handed stereoisomers. The complexes are stable at room temperature. The main gaseous products in whole decomposition process of complexes are water (H2O), carbon dioxide (CO2), carbon monoxide (CO), nitric oxides (NOx) and bromomethane (CH3Br).Figure optionsDownload full-size imageDownload as PowerPoint slide