From 1D to 3D: dimensional control of low-coordinate lanthanide coordination polymers with SMM behavior and white-light emission

Abstract

The self-assembly of 1,1′,1′′-((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(pyridin-4(1H)-one) (TTP) ligand with Dy(III) ions affords three lanthanide coordination polymers: [Dy(TTP)₂(H₂O)]Cl₃·C₃H₆O·7H₂O (1), [Dy(TTP)₂](CF₃SO₃)₃·2H₂O (2), and [Dy(TTP)₂(H₂O)](CF₃SO₃)₃·2H₂O (3). The structural dimensionality of complexes 1–3 varies from one-dimensional (1D) to three-dimensional (3D) depending on the reaction conditions and crystallization methods. Complexes 1 and 3 consist of a 1D polymeric chain and a 3D framework, respectively, formed from seven-coordinate Dy(III) ions and TTP linkers. The Dy(III) ion in complex 1 adopts an intermediate geometry between a capped trigonal prism and a capped octahedron, while that in complex 3 shows a pentagonal bipyramidal geometry. Complex 2 exhibits a two-dimensional (2D) network, where the Dy(III) ion adopts a six-coordinate octahedral coordination geometry. Magnetic studies revealed that complex 1 exhibits slow magnetic relaxation at a zero static field, while this behavior in complexes 2 and 3 is field-induced, occurring only under a static field. Solid-state luminescence investigations demonstrated that complexes 1–3 exhibit excitation-dependent emissions, with their emission color tunable from yellow to white across different excitation wavelengths. The magnetic properties and yellow emissions of the products are determined by the coordination environments and geometries around the Dy(III) ions.