The cavity of a [2+3] organic molecular cage was partitioned and functionalized by inserting inner-directed P![[double bond, length as m-dash]](http://www.rsc.org/images/entities/char_e001.gif)
O bonds, which shows CO2 capture and CH4 exclusion due to the size-matching and polarity effects. Computational results demonstrate that the successful segmentation via polar PO bonds facilitates the CO2 molecules to reside selectively inside the cavity.
![Graphical abstract: Cavity partition and functionalization of a [2+3] organic molecular cage by inserting polar P [[double bond, length as m-dash]] O bonds](http://hg.y866.cn/compound/lib/scimg/usr/1/C6CC02801B.jpg)
