Gas sorption of nano-porous supramolecules formed by multi-hydrogen bonded coordination capsules

Abstract

[{Re^I(CO)₃(Hbim)}₃(tpta)]₂ (1, Hbim⁻ = 2,2′-biimidazolate monoanion, tpta = 2,4,6-tripyridyl-1,3,5-triazine) was prepared as a nano-space supramolecule by using a new group of H-bonded coordination capsules. The hamburger bun-shaped half unit [{Re^I(CO)₃(Hbim)}₃(tpta)] contains six intermolecular H-bonds of Hbim⁻ ligands with complementary dual NH⋯N types, and three [Re^I(CO)₃(Hbim)] are coordinated by bridging tridentate tpta. Interestingly, mechanical grinding easily would convert single crystals of 1 to an amorphous state with minor crystallinity while maintaining the nano-space pores. The ground sample can reversibly uptake and release small molecules such as CO₂ and (CH₂Cl)₂.