Synthesis of novel lanthanide acylpyrazolonato ligands with long aliphatic chains and immobilization of the Tb complex on the surface of silica pre-modified via hydrophobic interactions

Abstract

Five new complexes Ln(Q^C17)₃(H₂O)(Solv) (Ln = Y, Solv = H₂O, Ln = Tb, Dy, Sm or Eu, Solv = EtOH) were synthesized with the acylpyrazolonato ligand Q^C17 bearing a long aliphatic C₁₇H₃₅ chain in the acyl moiety, and the crystal structure of Y(Q^C17)₃(H₂O)₂ shows the three aliphatic chains from the coordinated ligands positioned in the same direction, affording plane layers built by Y(Q^C17)₃(H₂O)₂ molecules connected through H-bonding interactions. The layers are stitched to each other like in “hook & loop” tapes. Luminescence of complexes was determined and the complex Tb(Q^C17)₃(H₂O)(EtOH) was immobilized on the surface of silica preprocessed using a C₁₇H₃₅CONH(CH₂)₃Si(OEt)₃ reagent via hydrophobic interactions of long aliphatic chains. Luminescent properties and micromorphology of the obtained hybrid particles and hybrid films were investigated. Intensive green emission of the complex retains after grafting onto the silica surface. Inclusion of the complex on the surface of silica materials occurs as separate molecules, after the disruption of the H-bonding network present in the crystalline phase of the pure terbium sample.