A Distorted pcu Topological Heterometallic Metal-Organic Framework with Right- and Left Chiral Covalent Layers

An unusual heterometallic 3D framework, [Zn2Ca(mip)2(Hmip)2(bpe)]n (1), was synthesized by using an alkali‐earth metal (calcium) and a d10 metal (zinc) under hydrothermal conditions [H2mip = 5‐methylisophthalic acid, bpe = 1,2‐bi(4‐pyridyl)ethene]. Single‐crystal X‐ray analysis shows that complex 1 is a pillared‐grid metal‐organic framework (MOF) with nanosized parallelogram channels fully occupied by dangling Hmip– pendants. The most fascinating structural feature of the complex is that the achiral framework pillared by rod‐like bpe is assembled by opposite chiral covalent sheets arranged alternatingly with single left‐ or right‐handed helical chains. Topologically, the framework can be simplified as a distorted uninodal pcu net with the Schläfli symbol of {412·63}, which is rare representative of an achiral pillared‐layer MOF with chiral sheets comprising only one type of helical chains.