Dioxin-Linked Covalent Organic Framework-Supported Palladium Complex for Rapid Room-Temperature Suzuki–Miyaura Coupling Reaction

Round 1

Reviewer 1 Report

COFs are considered ideal candidates for the design of heterogenous catalysts due to their abundant functional groups, excellent physical and chemical stability, large specific surface area, and regular pore channels. Moreover, due to their insolubility can be efficiently separated and reused from the reaction system. There are already several reported papers about the catalytic applications of COFs in Suzuki coupling reactions Although all these catalysts show good stability and reusability, they often require high reaction temperatures and, or long reaction times in the catalytic process due to the lack of effective functional ligands to support the metal ions in the COFs.

In this report the authors use a known dioxin-linked COF-318, to prepare the catalysts with good results in the C_C coupling reaction. However, in my opinion some issues should be addressed.

TOF (turnover frequency) = (no. of moles of product/no. of moles of Pd × time (h)) should be determined.

References missed:  See Appl. Nano Mater. 2023, 6, 3, 1714–1723. https://doi.org/10.1021/acsanm.2c04652 or https://doi.org/10.1016/j.jcat.2022.10.019, they should be included in the table.

I also miss some analysis of the morphologies of the material synthesized by high-resolution transmission electron microscopy (HRTEM).

Tga of the material should be also incorporated.

The metals catalyst content ( weight percentage of palladium) should be determined by ICP, for instance.

Have the authors test the Suzuki coupling with chlorides? Please, specify.

The authors should explain the presence of the reduced Pd (0) species during the Pd incorporation process in the COF.

Author Response

We appreciate the helpful comments from the reviewers and have conducted further experiments to address their suggestions. Please see our detailed point-by-point response in the Response Letter. We have submitted a revised version of the manuscript, incorporating all the suggested changes in the Crystals template, along with an updated Supplementary Information file.

We believe that the resubmitted manuscript is now stronger, thanks to the valuable input from the reviewers, and we hope that you share the same opinion.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors present a neat small study embedding a Pd(OAc) catalyst in a known dioxin COF. I have a couple of questions about the characterization of their material.

Page 5, line 192: "no diffraction peaks from the Pd nanocrystal were observed ..." raises some questions:

1. Please show the PXRD of the Pd species.
2. You should be able to estimate (from the masses of the COF and Pd, and assuming 1 Pd bound at any given N, the percentage of N--Pd vs "bare" N sites. This is very important characterization of your material. Scheme 1 shows 50% of N occupied, is this realistic?

Page 8, Line 285:
What do you suggest is happening to the structure of the Pd when it is reduced to Pd(0)? How is the Pd(0) re-oxidised to Pd(II) and will this affect recyclability (5 cycles is somewhat modest)

Author Response

We appreciate the helpful comments from the reviewers and have conducted further experiments to address their suggestions. Please see our detailed point-by-point response in the attached response Letter. We have submitted a revised version of the manuscript, incorporating all the suggested changes in the Crystals template, along with an updated Supplementary Information file.

We believe that the resubmitted manuscript is now stronger, thanks to the valuable input from the reviewers, and we hope that you share the same opinion.

Author Response File: Author Response.pdf