Abstract
The oxidative addition of a bromoporphyrin onto in situ formed highly active Pd(0) complex allowed us to characterize the Pd(II) intermediate by X-ray crystallography. In addition, after the heterobidentate coordination of Xantphos hemioxide (Xantphos: 4,5-bis(diphenylphosphino)-9,9-dimethyl-xanthene), the oxidized product responsible for Pd(II)-Pd(0) reduction, was also proved. The species isolated by us is the product of oxidative addition, the first step of the suggested catalytic cycle. Earlier only the structure of the dichloro complex of palladium with (P-P(O)) ligand was known. The isolated Pd(P-P(O))X(porphyrinyl) complex can be considered as a new example of catalytic intermediates of important cross-coupling and carbonylation reactions giving further strong proof for their mechanism.
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Data availability
The datasets generated and/or analysed during the current study are available in the Crystallographic Data Centre repository, http://www.ccdc.cam.ac.uk/data_request/cif using reference deposition numbers: 2512487 for 2 and 2,512,488 for 3, as well as 2,512,489 for DPP-Bn, 2,512,490 for DPP-Gly, 2,385,880 for DPP-Gly2 and 2,512,491 for DPP-Ala2. In addition to analytical data (1H and 13C NMR, MS) discussed in Supplementary Information, further details are available from the authors upon request.
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Acknowledgements
The research reported in this paper is part of project no. TKP2021-EGA-17, implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research Development and Innovation Fund financed under the TKP2021 funding scheme. The research was supported by the EU and co-financed by the European Regional Development Fund under the project GINOP-2.3.2-15-2016-00008 and also under the project GINOP-2.3.3-15-2016-00004 to purchase the diffractometer at the University of Debrecen. The Coimbra Chemistry Centre-Institute of Molecular Sciences (CQC-IMS) is supported by national funds from Fundação para a Ciência e a Tecnologia (FCT) through projects UIDB/00313/2025 and UIDP/00313/2025 and LA/P/0056/2020 (https://doi.org/10.54499/LA/P/0056/2020). This research was also funded by project “ECOXOPLAS” n. 15161 (COMPETE2030-FEDER-00882400).
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Open access funding provided by University of Pécs. The authors declare funding by the Ministry of Innovation and Technology of Hungary, by the European Regional Development Fund, and by Fundação para a Ciência e a Tecnologia (FCT, Portugal).
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P.S. carried out the catalytic experiments and isolated the complexes as crystals A.B. determined the crystal structures and wrote the discusssion on XRD R.A. prepared the porphyrins M.M.Pereira reviewed the manuscript L.K. wrote the main text.
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Szuroczki, P., Bényei, A., Aroso, R.T. et al. First time exploration and characterization of key-intermediates in palladium-catalysed coupling reactions. Sci Rep (2026). https://doi.org/10.1038/s41598-026-43634-1
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DOI: https://doi.org/10.1038/s41598-026-43634-1
