Streamlined In Situ X‑ray Crystallography of Gas Sorption State as Realized\nthrough the De Novo Development of a Novel Crystal Mount

In\nsitu X-ray crystallography of gas sorption states is a powerful\napproach to gain profound insights into the nature of gas sorption\nphenomena, and its implementation is quite skillful. To broaden the\nrange of implementation choices and also to further facilitate and\ngeneralize in situ X-ray crystallographic analysis under a gas atmosphere,\nwe have carried out the de novo design and development of a novel\ncrystal mount (NCM), which encompasses the following four features:\n(1) the NCM is designed to be as compact as possible in order not\nto interfere with the incident X-ray beam of a laboratory diffractometer.\n(2) The inside of a capillary fixed to the NCM is easily evacuated\nby a vacuum pump. (3) A target gas is also easily introduced into\nthe capillary containing a single crystal. (4) Gas pressure is freely\nadjustable up to 3.9 atm. As a case study, the NCM was subjected to\nin situ X-ray crystallography under a CO<sub>2</sub> atmosphere, and\nwe fully succeeded in analyzing the CO<sub>2</sub> sorption state\nof a dipeptide-based molecular crystal. The present de novo development\nof an NCM with versatility and ease of handling would open new opportunities\nfor in situ X-ray crystallography.