Pyridinium amidates (PYAs) are nitrogen-based, donor-flexible ligands characterized by the ability to adapt to diverse electronic environments by displaying both neutral (L-type) and anionic (X-type) metal bonding contributions.¹ PYA complexes have exhibited exceptional catalytic performance in transition metal-catalyzed reactions, including transfer hydrogenation,² alcohol oxidation,³ ketone arylation,⁴ and water oxidation.⁵ Here, we expanded this family of donor-flexible ligands to include thioamides, which we consider advantageous due to the combination of hard and soft donor atoms, offering a diverse range of coordination modes and electronic properties for a broad range of metals. We will present the first pyridinium thioamidate (PYT) complex synthesis and the specific properties induced by the PYT using spectroscopy, cyclic voltammetry, and X-ray diffraction (XRD), offering a detailed comparison to analogous PYA systems. Our results indicate that PYTs serve as robust ligands that exhibit strong donor properties and show potential for application in transition-metal-catalyzed processes.

[1] J. Race, M. Albrecht, ACS Catalysis, 2023, 13, 9891-9904.

[2] A. Beaufils, P. Melle, N. Lentz, M. Albrecht, Inorganic Chemistry, 2024, 63, 2072-2081.

[3] K. Salzmann, C. Segarra, M. Albrecht, Angewandte Chemie, 2020, 59, 8932-8936.

[4] E. Reusser, M. Albrecht, Dalton Transactions, 2023, 52, 16688-16697.

[5] G. Rodriguez, A. Bucci, R. Hutchinson, G. Bellachioma, C. Zuccaccia, S. Giovagnoli, H. Idriss, A.   Macchioni, ACS Energy Letters, 2017, 2, 105-110.