Hydrothermal synthesis of copper complexes of 4′-pyridyl terpyridine: From discrete monomer to zigzag chain polymer

Seven copper complexes [Cu(L1)I2] (1), [Cu2(L1)2I2]2[Cu2(μ-I)2I2] (2), [Cu(L2)I2] (3), [Cu2(L2)(μ-I)I(PPh3)] (4), [Cu4(L2)2(μ-I)2I2] (5), {[Cu(L2)I]2[Cu2(μ-I)2I2]}n (6) and [Cu2(L2)(μ-I)2]n (7) have been prepared by reactions of ligands: 4′-(2-pyridyl)-2,2′:6′,2″-terpyridine (L1) and 4′-(3-pyridyl)-2,2′:6′,2″-terpyridine (L2) with CuI in hydrothermal conditions, respectively. By alternating the oxidations states of the metal centers, increasing stoichiometric metal/ligand ratio and introducing a second ligand, the compounds, were successfully developed from mononuclear (1 and 3) to multinuclear (2, 4 and 5) and polymers (6 and 7). The synthesis of these compounds may provide an approach for the construction of coordination compounds of 4′-pyridyl terpyridine with different nuclearity.

Graphical abstractSeveral copper-(4′-pyridyl terpyridine) complexes with different nuclearity have been synthesized by one-pot reactions in hydrothermal conditions. By controlling temperature, stoichiometry, reducing agents or solvents, the compounds had been successfully developed from discrete monomers to zigzag polymeric chains with copper oxidation states of monovalence, mixed-valence and divalence.Figure optionsDownload full-size imageDownload as PowerPoint slide