Significant Enhancement of C H /C H Separation by a Photochromic Diarylethene Unit: A Temperature- and Light-Responsive Separation Switch

A dual temperature- and light-responsive C H /C H separation switch in a diarylethene metal-organic framework (MOF) is presented. At 195 K and 100 kPa this MOF shows ultrahigh C H /C H selectivity of 47.1, which is almost 21.4 times larger than the corresponding value of 2.2 at 293 K and 100 kPa, or 15.7 times larger than the value of 3.0 for the material under UV at 195 K and 100 kPa. The origin of this unique control in C H /C H selectivity, as unveiled by density functional calculations, is due to a guest discriminatory gate-opening effect from the diarylethene unit.