Metalation of a Mesoporous Three-Dimensional Covalent Organic Framework.

Constructing metalated three-dimensional (3D) covalent organic frameworks is a challenging synthetic task. Herein, we report the synthesis and characterization of a highly porous (SABET = 5083 m2 g-1) 3D COF with a record low density (0.13 g cm-3) containing π-electron conjugated dehydrobenzoannulene (DBA) units. Metalation of DBA-3D-COF 1 with Ni to produce Ni-DBA-3D-COF results in a minimal reduction in the surface area (SABET = 4763 m2 g-1) of the material due to the incorporation of the metal within the cavity of the DBA units, and retention of crystallinity. Both 3D DBA-COFs also display great uptake capacities for ethane and ethylene gas.

A ruthenium porphyrin-based porous organic polymer for the hydrosilylative reduction of CO2 to formate.

A ruthenium porphyrin-based porous organic polymer (POP) was synthesized, characterized, and used to reduce CO2 to a formate salt. We demonstrate that Ru-BBT-POP can be utilized to reduce CO2 to a silyl formate and then converted to potassium formate with a respectable turnover number and frequency.

Mechanistic investigations into the cyclization and crystallization of benzobisoxazole-linked two-dimensional covalent organic frameworks.

Although many diverse covalent organic frameworks (COFs) have been synthesised over the past decade, our fundamental understanding of their nucleation and growth during the crystallization process has progressed slowly for many systems. In this work, we report the first in-depth mechanistic investigation detailing the role of nucleophilic catalysts during the formation of two distinct benzobisoxazole (BBO)-linked COFs. The BBO-COFs were constructed by reacting 1,3,5-tris(4-formylphenyl)benzene (TFPB) and 1,3,5-tris(4-formylphenyl)triazine (TFPT) C 3-symmetric monomers with a C 2-symmetric o-aminophenol substituted precursor using different nucleophiles (e.g. NaCN, NaN3, and NaSCH3). Our experimental and computational results demonstrate that the nucleophiles help initiate an oxidative dehydrogenation pathway by producing radical intermediates that are stabilized by a captodative effect. We also demonstrate that the electron deficient TFPT monomer not only aids in enhancing the crystallinity of the BBO-COFs but also participates in the delocalization of the radicals generated to help stabilize the intermediates.

Synthesis of Benzobisoxazole-Linked Two-Dimensional Covalent Organic Frameworks and Their Carbon Dioxide Capture Properties.

Developing novel synthetic strategies to construct crystalline polymeric materials with excellent chemical stability and high carbon capture capacity has become a challenging process. Herein, we report the synthesis of two novel 2D benzobisoxazole-linked covalent organic frameworks (BBO-COFs) utilizing C3-symmetric formyl- and C2-symmetric o-aminophenol-substituted molecular building blocks. The BBO-COFs exhibit excellent water stability, high surface areas, and great CO2 uptake capacities. This general synthetic method affords the opportunity to prepare ordered BBO-based polymeric materials for carbon capture, chemical sensing, and organic electronic applications.

The effects of verbal instruction and shaping to improve tackling by high school football players.

We evaluated verbal instruction and shaping using TAG (teaching with acoustical guidance) to improve tackling by 3 high school football players. Verbal instruction and shaping improved tackling for all 3 participants. In addition, performance was maintained as participants moved more quickly through the tackling procedure.