Coordinative alignment of molecules in chiral metal-organic frameworks

Stop wiggling and hold that pose X-ray crystallography can be the definitive method for determining the structure and chirality of small organic molecules, but orientational disorder in the crystal can limit its resolution. Lee et al. used a chiral metal-organic framework containing formate ligands that can bind and align molecules covalently to reduce this motion (see the Perspective by Öhrström). The structure and absolute configuration—i.e., which spatial arrangement of atoms is the R or S isomer—of several organic molecules can thus be measured. These range from small molecules, such as methanol, to complex plant hormones, such as gibberellins that have eight stereocenters or jasmonic acid, whose absolute configuration had not previously been directly established. Science , this issue p. 808 ; see also p. 754