VOCs Adsorption and Exchange Properties in Bispidine-Based Mn(II) 1D CPs Made of Orthogonally Oriented Linear Chains

The combination of bispidine ligand L1 and Mn(II) produces CP 1-MeCN with a one-dimensional (1D) architecture unprecedented for bispidine-based CPs. Single-crystal X-ray diffraction (SC-XRD) reveals a robust framework of orthogonally oriented ribbon-like chains in the tetragonal space group P4₂2₁2 with solvent-filled perpendicularly intersecting channels that account for about 30% of the unit-cell volume. Volatile organic compound (VOC) exchange on SC proceeds via clean SC-to-SC transformations with nitrobenzene (NB), chlorobenzene (ClBz), and 1,2-dichlorobenzene (DCB), but not with toluene (Tol). The corresponding microcrystalline powder, 1-MeCN^Pwd, and its thermally generated evacuated amorphous phase, 1-amorph^Pwd, were tested as well. In particular, 1-amorph^Pwd adsorbs ca. 1.6-1.9 mmol/g of aromatic NB, ClBz, and DCB (but only 0.7 for Tol) and up to 2.5 mmol/g of MeCN, under saturated vapor conditions at r.t. Although these uptake capacities are comparable to those of previously reported bispidine-based CP sorbents, the preservation of the orthogonal chain packing motif upon guest uptake and the distinct interaction mechanism with the tested VOCs highlight a different role of chain topology and packing in governing sorption and offer new design criteria for the development of novel VOC-capturing materials.