A homochiral metal-organic framework with amino-functionalized pores

Abstract

A new metal-organic framework [Zn₂(Cam)₂(apyr) ⊃ 2DMF], 4 (apyr = 2-aminopyrazine) has been synthesized by the high temperature equimolar reactions of zinc nitrate with the (+)-camphoric acid (H₂Cam) in neat DMF solution. The crystal structure of 4 was determined by X-ray analyses and found to be a porous cubic network composed of linked zinc camphorate “paddlewheel” secondary building units and apyr pillars. The apyr pillars give amino-functionality to the pores. The extended structure of 4 contains guest DMF molecules trapped within the channels. Compound 4 is potentially porous and thermogravimetric analysis is consistent with the initial loss of guest DMF between 75 and 190°C, with the decomposition of the material at 430°C. The material was found to take up racemic alcohols into its pores, however no enantioselectivity was achieved. Reactivity studies of 4 with acetaldehyde show that the amino groups in the pores can be transformed into imine functionalities via post-synthetic covalent modification.