Thermal Elimination of Ethylene from Cyclobutyl Groups Characterized by X‐ray Crystallography in a Metal–Organic Framework Matrix

Abstract

Methods to synthesize and characterize aromatic molecules with vinyl substituents are sought after yet limited in the literature. Here, we introduce cyclobutyl groups into a metal–organic framework (MOF) matrix that are poised to produce ethylene upon heating. The expulsion of ethylene produces vinyl groups on an aromatic core, which are isolated by the crystalline matrix of the framework. This enables full characterization of the thermolysis by single‐crystal X‐ray diffraction. Further, we modify the vinyl groups by a bromine addition reaction. Importantly, the two transformations happen in a single‐crystal‐to‐single‐crystal manner without changing the overall network structure of the parent framework. New insights into the structural and synthetic chemistry of this important class of compound are generated. Installing reactive vinyl tags in materials by the high temperature thermolysis of cyclobutyl groups is a powerful strategy for altering their physicochemical characteristics.

Photoinduced Electron Transfer in Multicomponent Truxene-Quinoxaline Metal–Organic Frameworks

“…Since photoinduced electron transfer in MOFs typically involves two distinct framework components, we sought to develop radical-based photochromic properties in MUF-7 and MUF-77 (MUF = Massey University Framework). − MUF-7 and MUF-77 are multicomponent MOFs that comprise three different carboxylate ligands linked together by Zn 4 O clusters. The ligand set comprises a tritopic tris­(carboxylate) linker based on a truxene core, such as hexamethyltruyxenetricarboxylic acid (H 3 hmtt), and ditopic linkers based on the 4,4′-biphenyldicarboxylic acid (H 2 bpdc) and 1,4-benzenedicarboxylic acid (H 2 bdc) backbones (Figure A).…”

“…The formulae of MUF-7 and MUF-77 are the same, [Zn 4 O­(hmtt) 4/3 (bpdc) 1/2 (bdc) 1/2 ], but they are topological isomers of one another and differ subtly in the arrangement of the constituent ligands (Figure B,C). They can be distinguished crystallographically: while both are cubic, MUF-7 has a unit cell parameter around 60 Å and belongs to the I -43 d space group, while MUF-77 has a unit cell parameter around 30 Å and belongs to the Pm -3 space group. ,,, In their powder X-ray diffraction (PXRD) patterns, MUF-7 has a shoulder at 2θ = 3.5° and a peak at 5.5°, while MUF-77 has a peak at 2θ = 3.0°, 5.1°, and 6.1° (Cu α radiation). It is important to note that for this work, the substituents on the bdc linker determined whether the MUF-7 or MUF-77 topology is produced.…”