Crystallographic pressure-lapse snapshots of a porous material responding to gas loading were used to investigate the stepwise uptake of carbon dioxide and acetylene molecules into discrete confined spaces. Based on the data, a qualitative statistical mechanical model was devised that reproduces even subtle features in the experimental gas sorption isotherms.

Coordination polymers (CPs) have garnered much attention in the past several years for the relative facility of their synthesis and potential benefit in diverse applications such as gas separation, energy storage, drug delivery and as novel bio-imaging compounds. To date there have been relatively few reports of CP assembly from peptide-based precursors. CPs generated from biomolecules offer several potential advantages over their synthetic counterparts including extensive structural diversity, intrinsic chirality and the capacity for introduction of catalytic or similar biological functionalities. Here we describe the construction of CPs utilizing protein cage nanoparticles (PCN) as secondary building units. The dodecameric Dps protein cage from the hyperthermophilic archeon Sulfolobus solfataricus was modified for metal binding by chemical ligation of metal-chelating functionalities to the cage exterior. Treatment of modified PCN with transition metals results in the rapid formation of PCN-metal assemblies. These assemblies are characterized by a combination of dynamic light scattering, electron microscopy, small angle X-ray scattering and gas sorption studies.

A series of tripodal imidazole frameworks (TIFs) are reported based on a tripodal, cavity-containing tris(imidazole) derivative. In the case of [Co(3)Cl(6)(1)(2)]·n(solvent) (TIF-1) which possesses a doubly interpenetrated framework structure, the material exhibits rigid, permanent porosity and selectively absorbs CO(2). The non-interpenetrated [Co(1)(2)(H(2)O)(2)]Cl(2)·4H(2)O (TIF-2) also absorbs gases and vapours fully reversibly exhibiting a reversible phase change in the process and considerable conditioning and hysteresis. The very highly hydrated [Co(1)(2)]Cl(2)·22H(2)O (TIF-3) irreversibly dehydrates to the layered structure [Co(1)(2)]Cl(2)·H(2)O (TIF-4). A nickel analogue [Ni(1)(2)]Cl(2)·22H(2)O (TIF-5) closely related to TIF-3 is also reported along with two isostructural, non-porous materials [MCl(2)(1)] (M = Mn, TIF-6; M = Cd, TIF-7) based on d(5) and d(10) Mn(II) and Cd(II). Some of the materials may be prepared by mechanochemical as well as solution based methods. We liken TIF-1 to a gas cylinder, TIF-2 to a sponge and TIF-3 to a fragile soda can that is crushed on emptying to give TIF-4.

Crystallographic pressure‐lapse snapshots of a porous material responding to gas loading were used to investigate the stepwise uptake of carbon dioxide and acetylene molecules into discrete confined spaces. Based on the data, a qualitative statistical mechanical model was devised that reproduces even subtle features in the experimental gas sorption isotherms.

A robust, porous, catenated coordination polymer based on a neutral, flexible imidazole-derived tripodal ligand (a 'tripodal imidazole framework', TIF) reversibly absorbs vapours and gases, particularly CO2.