# A Durable Metal–Organic Framework with a Hydrophobic sp3‐Carbon‐Rich Nanospace Constructed from Flexible Medium‐Sized Ring Ligands

## TL;DR

Scientists created a stable metal-organic framework with a hydrophobic interior that can separate ethanol from water.

## Contribution

A new durable MOF with a hydrophobic sp3-carbon-rich nanospace is synthesized using a flexible medium-sized ring ligand.

## Key findings

- The MOF (CBoard) shows excellent cycling stability during guest adsorption–desorption.
- The hydrophobic nanospace preferentially captures ethanol over water.
- The framework is water-resistant and suitable for ethanol–water separation in dilute solutions.

## Abstract

Despite the high design freedom of metal–organic frameworks (MOFs), flexible ligands that bear sp3‐hybridized carbon atoms in their core are generally avoided as building blocks for MOFs because they may compromise framework stability. Herein, a 2D MOF (CBoard) is reported incorporating a dibenzocyclooctadiene with a flexible medium‐sized ring at the core as a flexible ligand. The moderate flexibility of the incorporated dibenzocyclooctadiene in CBoard reduces the strain induced by external stimuli on the coordination bonds, conferring cyclic stability upon guest adsorption–desorption. Furthermore, the sp3‐hybridized carbon‐rich nanospace endows CBoard with water resistance and surface hydrophobicity. This hydrophobic nanospace preferentially captures ethanol over water, highlighting its potential for applications in ethanol–water separation in dilute aqueous solutions.

A stable 2D metal–organic framework (MOF), which incorporates dibenzocyclooctadiene with a flexible medium‐sized ring core, has been synthesized. The moderate ring flexibility enables excellent cycling stability during repeated adsorption–desorption. The sp3‐carbon‐rich hydrophobic nanospace provided by the medium‐sized rings shows promising performance in the separation of ethanol from aqueous solutions.