Syntheses, characterization and the liquid-phase formation enthalpy changes of two new one-dimensional ribbon-like lanthanide supermolecular polymers

Two novel one-dimensional ribbon-like mixed-ligand supermolecular polymers, [Ln(5-nip)(phen)(NO3) (DMF)]n (Ln = Pr (1) and Ho (2)), assembled into two-dimensional networks by strong π–π stacking interactions, have been synthesized by reactions of lanthanide (III) salts with 5-nitroisophatha acid (5-H2nip) and 1,10-phenanthroline (phen) in DMF solvent. They possessed high thermal stabilities and their liquid-phase formation enthalpy changes were determined in DMF solvent at 25.15 °C using an RD496-III type microcalorimeter, which were ΔrHmθ(1)=−9.21kJmol−1, and ΔrHmθ(2)=−11.02kJmol−1, respectively.

Graphical abstractTwo new mixed-ligand supermolecular polymers of Pr(III) and Ho(III) have been synthesized. The results of single-crystal X-ray diffraction reveal that they crystallize isomorphously in the monoclinic space group P2(1)/n and consist of one-dimensional ribbons featuring dinuclear units. The one-dimensional ribbons are assembled into two-dimensional networks by strong π–π stacking interactions with a distance of ca. 3.31 Å for 1 and ca. 3.27 Å for2. Their liquid-phase formation enthalpy changes were determined in DMF solvent at 25.15 °C using an RD496-III type microcalorimeter.Figure optionsDownload full-size imageDownload as PowerPoint slide