Significant Enhancement of C2H2/C2H4 Separation by a Photochromic Diarylethene Unit: A Temperature‐ and Light‐Responsive Separation Switch

A dual temperature‐ and light‐responsive C₂H₂/C₂H₄ separation switch in a diarylethene metal–organic framework (MOF) is presented. At 195 K and 100 kPa this MOF shows ultrahigh C₂H₂/C₂H₄ 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 C₂H₂/C₂H₄ selectivity, as unveiled by density functional calculations, is due to a guest discriminatory gate‐opening effect from the diarylethene unit.