# Expression of concern: Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald–Hartwig and Ullmann type coupling reactions

## TL;DR

The paper addresses a concern regarding a study on copper nanoparticle-based catalysts for chemical reactions.

## Contribution

The paper expresses concerns about the validity or reliability of the findings in the original study.

## Key findings

- The paper raises concerns about the original study's claims.
- It questions the reliability of the reported catalytic performance.
- It suggests potential issues with the experimental data or conclusions.

## Abstract

Expression of concern for ‘Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald–Hartwig and Ullmann type coupling reactions’ by Hojat Veisi et al., RSC Adv., 2021, 11, 22278–22286, https://doi.org/10.1039/D1RA02634H.