Facile Synthesis of Metallosalphen-Based 2D Conductive Metal-Organic Frameworks for NO Sensing: Metal Coordination Induced Planarization.

As an emerging class of promising porous materials, the development of two-dimensional conductive metal organic frameworks (2D c-MOFs) is hampered by the few categories and tedious synthesis of the specific ligands. Herein, we developed a nonplanar hexahydroxyl-functionalized Salphen ligand (6OH-Salphen) through a facile two-step synthesis, which was further applied to construct layered 2D c-MOFs through in situ one pot synthesis based on the synergistic metal binding effect of the N O pocket of Salphen. Interestingly, the C -symmetry of ligand endows Cu-Salphen-MOF with periodically heterogeneous pore structures.

Entanglement of Square Nets in Covalent Organic Frameworks.

Two entangled 2D square covalent organic frameworks (COFs) have been synthesized from 4,4',4″,4‴-(9,9'-spirobi[fluorene]-2,2',7,7'-tetrayl)-tetrabenzaldehhyde (SFTB) and -phenylenediamine (PPA) and benzidine (BZD) to form COF-38, [(SFTB)(PPA)], and its isoreticular form COF-39, [(SFTB)(BZD)]. We also report the single-crystal electron diffraction structure of COF-39 and find that it is composed of mutually entangled 2D square nets (). These COFs represent the first examples of entangled 2D COF structures, which, as we illustrate, were made possible by our strategy of using the distorted tetrahedral SFTB building unit.