Synthesis and Characterisation of Thiophene‐Functionalised Lanthanoid Diketonate Clusters with Solvent‐Modulated Europium Luminescence

The reaction of a thiophene‐containing ligand, ( Z )‐3‐hydroxy‐3‐phenyl‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one (Hhtp), with hydrated lanthanoid chloride salts has resulted in the isolation of two tetranuclear clusters, [Ln 4 (μ 3 ‐OH) 2 {(μ‐O)‐κ 2 ‐htp} 2 {(μ‐O) 2 ‐κ 2 ‐htp} 2 (κ 2 ‐htp) 6 ] [Ln = Nd ( 1 ), Eu ( 2 )] and an erbium pentanuclear cluster, [Er 5 (μ 3 ‐OH) 4 (μ 4 ‐OH){(μ‐O)‐κ 2 ‐htp} 4 (κ 2 ‐htp) 6 ] ( 3 ). The clusters have been characterised by elemental analysis, mass spectrometry, infrared spectroscopy and X‐ray single‐crystal structural determination. The luminescent properties of cluster 2 have been assessed, and, at 25 °C, quenching of luminescent emission was found to predominantly occur. However, incremental addition of selected coordinating solvents was found to promote luminescence at 25 °C, showing a linear relationship at low analyte concentrations.