Evaluating iodine uptake in a crystalline sponge using dynamic X-ray crystallography

The uptake of gaseous iodine into the crystalline sponge material [(ZnI 2) 3(tpt) 2]·0.7triphenylene·0.3PhNO 2·0.7C 6H 12 1 (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine) has been monitored by dynamic X-ray diffraction and thermogravimetric analysis. The X-ray analyses have enabled the location, quantity, uptake rate, and subsequent chemistry of the iodine upon inclusion into the pores to be determined. An uptake of 6.0 wt % (0.43 I 2 per formula unit) was observed crystallographically over a period of 90 min before crystal degradation occurred. The included iodine molecules interact with the iodine atoms of the ZnI 2 nodes at three different sites, forming coordinated I 3 - ions. The results contrast to recent observations on [(ZnI 2) 3(tpt) 2] without the triphenylene guests which show the presence of I 4 2- ions with low quantities of absorbed iodine.