University Honors

Metal-Organic Frameworks (MOFs) are a class of crystalline porous materials composed of metal clustered interconnected by organic linkers. These materials can function as tunable hosts capable of selectively interacting with guest molecules for gas sorption and separation. In this study, a series of partitioned-acs (pacs) MOFs were synthesized using the pore-space partition (PSP) strategy to divide their porous cavities with pyridine-based trimodal ligands. Multiple mixed-metal trimers, carboxylate linkers, and pore-partitioning ligands such as 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT), Tri(pyridine-4-yl)amine (TPA), and tris(pyridin-4-ylmethyl)amine (TPMA), were employed to synthesize pacs MOFs to demonstrate precise control over pore size and geometry within the pacs platform for gas sorption and separation. Tailoring the partitioning ligand enabled dramatic molecular selectivity. Vapor-phase selectivity for benzene over cyclohexane increased from 4.5 in CoV-BDC-TPT to 482.5 in CoV-FA-TPA, showcasing effective pore space partition. Building upon this tunability, pacs utilizing the flexible ligand TPMA were synthesized with dicarboxylate ligands of varying length to systematically compress the pore space of the material. Single crystal X-ray diffraction revealed that geometric compression resulted in a coordination transition of TPMA from a tritopic spiral structure to a ditopic configuration. This response significantly altered the pore space dimensions and surface areas of the material. Gas sorption studies showed strong structure and property correlations, with the compressed CoV-BCP-TPMA exhibiting enhanced C2H2/CO2 selectivity. These results demonstrate that PSP-enabled geometric control can govern pore architecture, and selective hydrocarbon separations.