Conductive Lanthanide Metal-Organic Frameworks with Exceptionally High Stability

Electrically conductive metal-organic frameworks(MOFs)have been extensively studied for their potential uses in energy-relatedtechnologies and sensors. However, achieving that goal requires MOFsto be highly stable and maintain their conductivity under practicaloperating conditions with varying solution environments and temperatures.Herein, we have designed and synthesized a new series of {[Ln(4)(& mu;(4)-O)(& mu;(3)-OH)(3)(INA)(3)(GA)(3)]-(CF3SO3)(H2O)(6)}( n ) (denotedas Ln ( 4 ) -MOFs, Ln= Gd, Tm, and Lu, INA = isonicotinic acid, GA = glycolic acid) singlecrystals, where electrons are found to transport along the & pi;-& pi;stacked aromatic carbon rings in the crystals. The Ln ( 4 ) -MOFs show remarkable stability,with minimal changes in conductivity under varying solution pH (1-12),temperature (373 K), and electric field as high as 800 000V/m. This stability is achieved through the formation of strong coordinationbonds between high-valent Ln(III) ions and rigid carboxylic linkersas well as hydrogen bonds that enhance the robustness of the electrontransport path. The demonstrated lanthanide MOFs pave the way forthe design of stable and conductive MOFs.