Luminescent Covalent Organic Frameworks Containing a Homogeneous and Heterogeneous Distribution of Dehydrobenzoannulene Vertex Units

Finding new ways to construct crystalline multiple-component covalent organic frameworks (COFs) has become an important focus. Herein we report the synthesis of three novel COFs containing a homogeneous and heterogeneous distribution of π-conjugated dehydrobenzoannulene (DBA) vertex units. The COFs were synthesized by reacting different ratios of <i>C</i>₃-symmetric DBA catechol monomers with <i>C</i>₂-symmetric pyrene-2,7-diboronic acid (PDBA) to yield three COFs, Py-DBA-COF 1, Py-DBA-COF 2, and Py-MV-DBA-COF. All three materials are highly crystalline and display unique luminescent properties in the solid state

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 (SA_BET = 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 (SA_BET = 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

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 <i>o</i>-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

2D Covalent Organic Frameworks with Alternating Triangular and Hexagonal Pores

2D Covalent Organic Frameworks with Alternating Triangular and Hexagonal Pore

Oligosiloxane-Based Epoxy Vitrimers: Adaptable Thermosetting Networks with Dual Dynamic Bonds

Embedding dynamic covalent bonds into polymer compositions transforms static thermosets into active materials with the reprocessability of thermoplastics and the bulk properties of cross-linked networks. This class of next-generation materials, called covalent adaptable networks, shows significant promise in composites, soft optoelectronics, and robotics. Herein, we synthesized two oligosiloxane-based epoxy networks that provide fast dynamic bond exchange. Oligosiloxane diepoxides were cured with stoichiometric amounts of 1,2-phenylenediacetic acid to generate epoxy acid networks with two dynamic covalent bonding mechanisms. The resulting polymer networks provided access to fast stress-relaxation times (1–10 min) at temperatures of only 130 °C with excellent reprocessability