Universität zu Köln

Basse, Reinhard, Vanicek, Stefan, Hoefer, Thomas, Kopacka, Holger, Wurst, Klaus, Mueller, Thomas, Schwartz, Heidi A., Olthof, Selina ORCID: 0000-0002-8871-1549, Casper, Larissa A., Nau, Moritz, Winter, Rainer F., Podewitz, Maren ORCID: 0000-0001-7256-1219 and Bildstein, Benno ORCID: 0000-0003-1969-1334 (2021). Cationic Cycloheptatrienyl Cyclopentadienyl Manganese Sandwich Complexes: Tromancenium Explored with High-Power LED Photosynthesis. Organometallics, 40 (15). S. 2736 - 2750. WASHINGTON: AMER CHEMICAL SOC. ISSN 1520-6041

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Abstract

In this contribution, we revisit the neglected and forgotten cationic, air-stable, 18-valence electron, heteroleptic sandwich complex (cycloheptatrienyl)(cyclopentadienyl)manganese, which was reported independently by Fischer and by Pauson about 50 years ago. Using advanced high-power LED photochemical synthesis, an expedient rapid access to the parent complex and to functionalized derivatives with alkyl, carboxymethyl, bromo, and amino substituents was developed. A thorough study of these tromancenium salts by a range of spectroscopic techniques (H-1/C-13/Mn-55-NMR, IR, UV-vis, HRMS, XRD, XPS, EPR), cyclic voltammetry (CV), and quantum chemical calculations (DFT) shows that these manganese sandwich complexes are unique metallocenes with quite different chemical and physical properties in comparison to those of isoelectronic cobaltocenium salts or (cycloheptatrienyl)(cyclopentadienyl) sandwich complexes of the early transition metals. Electrochemically, all tromancenium ions undergo a chemically partially reversible oxidation and a chemically irreversible reduction at half-wave or peak potentials that respond to the substituents at the Cp deck. As exemplarily shown for the parent tromancenium ion, the product generated during the irreversible reduction process reverts at least partially to the starting material upon reoxidation. Quantum-chemical calculations of the parent tromancenium salt indicate that metal-ligand bonding is distinctly weaker for the cycloheptatrienyl ligand in comparison to that of the cyclopentadienyl ligand. Both the HOMO and the LUMO are metal and cycloheptatrienyl-ligand centered, indicating that chemical reactions will occur either metal-based or at the seven-membered ring, but not on the cyclopentadienyl ligand.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Basse, Reinhard UNSPECIFIED UNSPECIFIED UNSPECIFIED Vanicek, Stefan UNSPECIFIED UNSPECIFIED UNSPECIFIED Hoefer, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Kopacka, Holger UNSPECIFIED UNSPECIFIED UNSPECIFIED Wurst, Klaus UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Schwartz, Heidi A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Olthof, Selina UNSPECIFIED orcid.org/0000-0002-8871-1549 UNSPECIFIED Casper, Larissa A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Nau, Moritz UNSPECIFIED UNSPECIFIED UNSPECIFIED Winter, Rainer F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Podewitz, Maren UNSPECIFIED orcid.org/0000-0001-7256-1219 UNSPECIFIED Bildstein, Benno UNSPECIFIED orcid.org/0000-0003-1969-1334 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-581120
DOI:	10.1021/acs.organomet.1c00376
Journal or Publication Title:	Organometallics
Volume:	40
Number:	15
Page Range:	S. 2736 - 2750
Date:	2021
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	1520-6041
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language HYBRID DENSITY FUNCTIONALS; ELECTRON-SPIN-RESONANCE; TROVACENE CHEMISTRY; PI-COMPLEXES; BASIS-SETS; DERIVATIVES; ENERGY; REACTIVITY; APPROXIMATION; COMMUNICATION Multiple languages Chemistry, Inorganic & Nuclear; Chemistry, Organic Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/58112