Crystal structure without the crystals

X-ray diffraction is a powerful analytical technique but has a drawback that limits its applicability: the target needs to be available as a crystal. This paper describes a new X-ray analysis protocol that does not require crystallization of the sample itself. Instead, crystalline 'sponges' known as metal organic frameworks are used to soak up a drop of a liquid guest containing the target molecule. The sponges contain pores that recognize the target molecules and bind them in an ordered array, enabling the crystallographic structure analysis of the absorbed guest along with the host framework. The method is demonstrated with the absolute structure determination of a scarce natural product, miyakosyne A, using little more than a trace, 5 μg of sample.