Toward Templated Metal−Organic Frameworks: Synthesis, Structures, Thermal Properties, and Luminescence of Three Novel Lanthanide−Adipate Frameworks

Three novel praseodymium−adipate frameworks were synthesized hydrothermally. GWMOF-3 ([Pr2(adipic acid)3(H2O)4]·adipic acid·4H2O) and GWMOF-6 ([Pr2(adipic acid)3(H2O)2]·4,4‘-dipyridyl) formed three-dimensional structures,
whereas GWMOF-4 ([Pr2(adipic acid)3(H2O)2]·H2O) produced a more dense, two-dimensional topology. Single-crystal X-ray and powder diffraction, IR spectroscopy, fluorescence spectroscopy, thermogravimetric analysis, and
elemental analysis were employed to characterize all samples. GWMOF-6 represents an innovative step forward
in metal−organic framework synthesis where a neutral molecular species not used in the construction of the framework
is utilized as a structure-directing agent, or template. Furthermore, this template molecule (4,4‘-dipyridyl) is shown
to sensitize the fluorescence of lanthanide metal centers in a europium analogue of GWMOF-6.