Cuiying Pei

Gas storage in porous aromatic frameworks (PAFs)

A series of porous aromatic frameworks (PAFs) were synthesized via a Yamamoto-type Ullmann reaction containing quadricovalent Si (PAF-3) and Ge (PAF-4). These PAFs are thermally stable up to 465 °C for PAF-3 and 443 °C for PAF-4, corresponding to a 5% weight loss according to the TG pattern. As PAF-1, they exhibit high surface areas (up to 2932 m2 g−1) and excellent adsorption ability to hydrogen, methane and carbon dioxide. Low pressure gas uptake experiments on PAFs show PAF-3 has the highest heat of adsorption (Qst) of hydrogen (6.6 kJ mol−1) and carbon dioxide (19.2 kJ mol−1), while PAF-4 has the highest Qst for methane adsorption (23.2 kJ mol−1) among PAFs. Gas molecule recognition at 273 K was performed and results show only greenhouse gases such as carbon dioxide and methane could be adsorbed onto PAFs.

Ultrahigh iodine adsorption in porous organic frameworks

We present two porous organic frameworks (POFs), PAF-1 and JUC-Z2, with ultrahigh iodine capture capacity. The iodine vapor uptake of PAF-1 and JUC-Z2 were 1.86 g g−1 and 1.44 g g−1 respectively at 298 K per 40 Pa, which is extremely high for such low pressure sorption conditions. In addition, PAF-1 and JUC-Z2 could adsorb iodine over water with the selectivity of 5.1 and 6.5 respectively. The isosteric enthalpy at zero surface coverage, calculated by a virial equation with the iodine vapor sorption isotherms at 298 K and 313 K of JUC-Z2, reached −51.1 kJ mol−1, which was much higher than the coverage of PAF-1 (−14.9 kJ mol−1). Raman measurement confirmed the polyiodide to be I5− in POFs. Furthermore, solvents with different polarities, such as n-hexane, chloroform, and methanol, were chosen to conduct iodine binding measurements on PAF-1 and JUC-Z2. The formation constant Kf for POFs in n-hexane, chloroform and methanol drastically decreased with the increase in polarity, thus illustrating the important role of solvents in iodine binding.

Synthesis of copolymerized porous organic frameworks with high gas storage capabilities at both high and low pressures

A series of copolymerized porous organic frameworks (C-POFs) were synthesized with monomers of tetrakis(4-bromophenyl)methane and tris(4-bromophenyl)amine in different ratios by a Yamamoto-type Ullmann cross-coupling reaction. These C-POFs exhibit high physicochemical stability, large surface areas and excellent H2, CH4 and CO2 adsorption properties both at low and high pressures.

Site specific supramolecular heterogeneous catalysis by optically patterned soft oxometalate–porous organic framework (SOM–POF) hybrid on a chip

We have designed a supramolecularly bound multi-component catalytic material based on a soft oxometalate (SOM) and a porous organic framework (POF) material, which shows high catalytic conversion efficiency. We have also used this material for site directed supramolecular heterogeneous catalysis with a yield even higher than in the bulk, and with micron-level precision by controllably depositing the material on a glass substrate, making a reactor chip, using a thermo-optical tweezers. Various SOM–POF composites have been prepared in dispersion phase and patterned using thermo-optic tweezers and their catalytic activities have been compared with a benchmark molecular catalyst [PMo12]. This work can lead to further explorations for hybrid materials that are formed out of well-defined molecular level precursors which can be controllably micro-patterned to simultaneously catalyze targeted reactions.

Targeted synthesis of electroactive porous organic frameworks containing triphenyl phosphine moieties

A novel electroactive porous aromatic framework (JUC-Z4-Cl) was designed and synthesized via Yamamoto-type Ullmann cross-coupling reaction with the monomer tris(4-chlorophenyl)phosphine. By simple redox chemical reactions, stable, reductive, porous polytri(p-phenyl)phosphine (JUC-Z4) and polytri(p-phenyl)phosphine oxide (JUC-Z5) could be obtained as off-white powders. The structures of JUC-Z4 and JUC-Z5 were confirmed using magic-angle spinning nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, etc. The microporous architectures exhibit high stability (471°C for JUC-Z4 and 484°C for JUC-Z5) and large surface area (793 and 648 m2 g−1 for JUC-Z4 and JUC-Z5, respectively). JUC-Z4 also exhibits efficient recognition ability of greenhouse gases from dry air.

Correction: Great prospects for PAF-1 and its derivatives

Correction for ‘Great prospects for PAF-1 and its derivatives’ by Cuiying Pei et al., Mater. Horiz., 2015, 2, 11–21.