Enabling Solvated Single-Crystal-to-Single-Crystal Transformation that Forms a Porous Molecular Crystal by Intermolecular Multiphenyl-Embrace Interactions and Substituent Effects

Tubular complexes, [{Ru2(CO)4(P(C6H4R)3)2}(1,4-O2CC6H4CO2)]3 (R = H, 4; p-Me, 5), were found to adopt a staggered conformation in the solid state. The complexes align themselves in one-dimensional (1-D) channels occluded with organic solvent molecules. A single-crystal-to-single-crystal transformation with both incarceration and liberation at specific sites that forms a porous molecular crystal occurs for one solvated crystals of complex 4 but not for two solvated crystals of complex 5. The data suggest that in the presence of an appropriate R substituent, the intermolecular multiphenyl-embrace interactions between adjacent P(C6H4R)3 groups of different molecules along the channel direction help form close solvent pockets to trap organic solvent molecules and serve as a multiple-point glue to connect adjacent 1-D channels, which ensures lattice stabilization during the air-drying process of the crystal.