Tromancenium complexes with steric and electronic modulation

A series of new heteroleptic cationic (eta 7-cycloheptatrienyl)(eta 5-cyclopentadienyl)manganese(I) ("tro-mancenium") sandwich complexes containing the cycloheptatrienyl ligand and various sterically bulky cyclopentadienyl ligands was synthesized in a one-pot two-step procedure via their cymantrene precur-sors by high-power LED photochemistry followed by oxidation. In comparison to their less-substituted congeners which display only partially reversible redox events, these new air-stable tromancenium salts show reversible Mn(I)/Mn(II) and quasi-reversible Mn(I)/Mn(0) redox couples, as intended by the concep-tual design of this work. Full spectroscopic and structural characterization of by 1 H, 13 C, 55Mn NMR, IR, UV-vis spectroscopy, high-resolution mass spectrometry and single crystal structure analysis is reported.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )