Stable ZnI‐Containing MOFs with Large [Zn70] Nanocages from Assembly of ZnII Ions and Aromatic [ZnI8] Clusters.

Abstract: Two unique ZnI‐containing MOFs {[ZnI8ZnII3(H2O)<italic>x</italic>(HL)12](OH)2<bold>⋅</bold>13 H2O}<italic>n</italic> (<italic>x=</italic>6, <bold>1</bold>; <italic>x=</italic>2, <bold>2</bold>) (HL=tetrazole monoanion) with high‐nuclearity Zn‐cages were prepared successfully. These Zn‐cages are constructed from [ZnI8] clusters with multi‐centered ZnI−ZnI bonds and ZnII ions. [ZnI8] clusters in <bold>1</bold> and <bold>2</bold> display <italic>Oh</italic> and <italic>D</italic>4<italic>h</italic> symmetry, respectively. Importantly, eight [ZnI8] clusters and six ZnII ions form a large [Zn70] nanocage in <bold>1</bold>. To our knowledge, this is the first MOF based on polynuclear Zn‐cages consisting of ZnI and ZnII ions. Compared with reported ZnI‐species, <bold>1</bold> and <bold>2</bold> display high thermal and solvent stabilities. Theoretical investigations based on DFT calculations uncover that effective 4s‐4s orbital overlap and electron delocalization through these a1g+t1u molecular orbitals on [ZnI8] clusters lead to considerable aromatic stabilization, which can explain well the intrinsic stability of <bold>1</bold> and <bold>2</bold>. Interestingly, <bold>1</bold> can behave as a luminescent probe to detect the toxic CrVI ions in aqueous. [ABSTRACT FROM AUTHOR]