Recognition and order of multiple sidechains by a porous framework enhances molecular separation

Porous materials perform molecular sorting, separation and transformation by interaction between their framework structures and the substrates. Proteins also interact with molecules to effect chemical transformations, but benefit from the precise amino acid sequencing along a common polypeptide backbone to maximise their performance. Design strategies that positionally order sidechains over a defined porous framework to diversify the internal surface chemistry would enhance control of substrate processing. Here we show that different sidechains can be ordered over a common porous scaffold through recognition of their distinct chemistries during synthesis . The sidechains are recognised because each one forces the building unit that defines the backbone of the framework into a different conformation in order to form the same structure . This affords hexane isomer separation performance superior to that of the same framework decorated with only a single sidechain. The separated molecules adopt distinct arrangements within the resulting modified pore geometry, reflecting their more strongly differentiated environments precisely created by the ordered sidechains. The development of framework-forming chemistries that recognise, distinguish and thus order multiple sidechain functionality offers tailoring of the internal surfaces within families of porous materials to direct interactions at the molecular level.