No abstract

The investigation on the catalytic properties of porous organic cages is still in an initial stage. Herein, the reaction of cyclohexanediamine with 5,15-di[3',5'-diformyl(1,1'-biphenyl)]porphyrin affords a porphyrin tubular organic cage, PTC-1(2H). Transient absorption spectroscopy in solution reveals much prolonged triplet lifetime of PTC-1(2H) relative to monomer reference, illustrating the unique photophysical behavior of cagelike photosensitizer. The long triplet lifetime ensures high-efficiency singlet oxygen evolution according to homogeneous photo-bleach experiment, electron spin-resonance spectroscopy, and aerobic photooxidation of benzylamine. Furthermore, microporous supramolecular framework of PTC-1 (2H) is able to promote the heterogeneous photo-oxidation of various primary amines with conversion efficiency above 99% under visible light irradiation. These results indicate the great application potentials of porous organic cages in heterogeneous phase.

Ar obust 2,2'-bipyridine (bpy)-derived biological hydrogen-bonded framework (HOF-25) has been realized depending on guanine-quadruplex with the assistance of p-p interaction, which reacts with Re(CO) 5 Cl to give ap ost-functionalizedH OF-25-Re.X-raya bsorption fine structure spectroscopic study on HOF-25-Re confirms the covalent attachment of Re(bpy)(CO) 3 Cl segments to this HOF.R obust and recycled HOF-25-Re bearing photocatalytic Re(bpy)-(CO) 3 Cl centers displays good heterogeneous catalytic activity towards carbon dioxide photoreduction in the presence of [Ru(bpy) 3 ]Cl 2 and triisopropanolamine in CH 3 CN under visible-light irradiation, with both high CO production rate of 1448 mmol g À1 h À1 and high selectivity of 93 %. Under the same conditions,t he experimental turnover number of HOF-25-Re (50) is about 8times as that of the homogeneous control Re(bpy)(CO) 3 Cl. The sustainably regenerated HOF-25-Re via crystallization and post-modification processes shows recovered photocatalytic performance.

A linear tetracene trimer linked by phenyl groups has been prepared for the first time. The triplet quantum yield formed via intramolecular singlet fission can reach up to 96% in this trimer, which is enhanced significantly compared with that in the dimer. This can be attributed to the stronger electronic coupling between tetracene subunits and more delocalized excitons in the trimer.