文摘
Chiral variants of the prototypal metal鈥搊rganic framework MOF-5, 螞-CMOF-5 and 螖-CMOF-5, have been synthesized by preparing MOF-5 in the presence of l-proline or d-proline, respectively. CMOF-5 crystallizes in chiral space group P213 instead of Fm3虆m as exhibited by MOF-5. The phase purity of CMOF-5 was validated by single-crystal and powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, N2 adsorption, microanalysis, and solid-state vibrational circular dichroism. CMOF-5 undergoes a reversible single crystal-to-single crystal phase change to MOF-5 when immersed in a variety of organic solvents, although N-methyl-2-pyrrolidone (NMP) does not induce loss of chirality. Indeed, MOF-5 undergoes chiral induction when immersed in NMP, affording racemic CMOF-5.