A photochromic dinuclear compound: aquatetrakis(μ-2,3-diphenylprop-2-enoato)bis(2,3-diphenylprop-2-enoato)ethanolbis(1,10-phenanthroline)dilanthanum(III)

The title dinuclear complex, (aqua-1κO)tetrakis(μ-2,3-diphenylprop-2-enoato-1:2κ²O:O′)bis(2,3-diphenylprop-2-enoato)-1κO;2κO-(ethanol-2κO)bis(1,10-phenanthroline)-1κ²N,N′;2κ²N,N′-dilanthanum(III), [La₂(C₁₅H₁₁O₂)₆(C₁₂H₈N₂)₂(C₂H₅OH)(H₂O)], contains two similar La^III centres with distorted [LaO₆N₂] bicapped triganol–prismatic coordination polyhedra formed by six phenylcinnamate (PCA⁻ or 2,3-diphenylprop-2-enoate) ligands, two 1,10-phenanthroline (phen) ligands, a coordinating ethanol molecule and a coordinating water molecule. The two metal centres are bridged by four μ-PCA⁻ ligands, with the remaining two PCA⁻ ligands coordinated in a monodentate fashion. The noncoordinated carboxylate O atoms on the terminal PCA⁻ ligands form O—H...O hydrogen bonds with the coordinated solvent molecules. Each La centre is also coordinated by a bidentate phen ligand. The PCA⁻ ligands all adopt syn–syn orientations, with the two phenyl rings presenting dihedral angles of about 70°. The compound displays photochromic behaviour both in solution and in the solid state.