Find in Library

The redox reactions of various lanthanide metals with 3-(4-pyridyl)pyrazole (4-PyPzH) or 3-(3-pyridyl)pyrazole (3-PyPzH) ligands yield the 2D network <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>2</mn></msubsup></mrow></semantics></math></inline-formula>[Eu(4-PyPz)₂(Py)₂] containing divalent europium, the 3D frameworks <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>3</mn></msubsup></mrow></semantics></math></inline-formula>[Ln(4-PyPz)₃] and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>3</mn></msubsup></mrow></semantics></math></inline-formula>[Ln(3-PyPz)₃] for trivalent cerium, praseodymium, neodymium, holmium, erbium, and thulium as well as <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>3</mn></msubsup></mrow></semantics></math></inline-formula>[La(4-PyPz)₃], and the 2D networks <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>2</mn></msubsup></mrow></semantics></math></inline-formula>[Ln(4-PyPz)₃(Py)] for trivalent cerium and thulium and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>2</mn></msubsup></mrow></semantics></math></inline-formula>[Ln₂(4-PyPz)₆]·Py for trivalent ytterbium and lutetium. The 18 lanthanide coordination polymers were synthesized under solvothermal conditions in pyridine (Py), partly acting as a co-ligand for some networks. The compounds exhibit a variety of luminescence properties, including metal-centered 4f–4f/5d–4f emission in the visible and near-infrared spectral range, metal-to-ligand energy transfer, and ligand-centered fluorescence and phosphorescence. The anionic ligands 3-PyPz⁻ and 4-PyPz⁻ serve as suitable antennas for lanthanide-based luminescence in the visible and near-infrared range through effective sensitization followed by emission through intra–4f transitions of the trivalent thulium, holmium, praseodymium, erbium, and neodymium. <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>2</mn></msubsup></mrow></semantics></math></inline-formula>[Ce(4-PyPz)₃(Py)], <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>3</mn></msubsup></mrow></semantics></math></inline-formula>[Ce(4-PyPz)₃], and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>3</mn></msubsup></mrow></semantics></math></inline-formula>[Ce(3-PyPz)₃] exhibit strong degrees of reduction in the 5d excited states that differ in intensity compared to the ligand-based emission, resulting in a distinct emission ranging from pink to orange. The direct current magnetic studies show magnetic isolation of the lanthanide centers in the crystal lattice of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow></mrow><mo>∞</mo><mn>3</mn></msubsup></mrow></semantics></math></inline-formula>[Ln(3-PyPz)₃], Ln = Dy, Ho, and Er.