Florian Benner

B.S. Chemistry, University of Hamburg, 2015.
M.S. Chemistry, University of Hamburg, 2017.
Florian Benner studied chemistry at the University of Hamburg and received his B.S. degree in Chemistry in 2015. From the same university he received a M.S. degree in Chemistry in September 2017. During his Master studies in the group of Prof. Jürgen Heck, he focused on the synthesis and magnetic properties of C3-symmetric paramagnetic metallocenes to pursue spin-frustrated systems that would be interesting to deposit and probe on metal surfaces. In February 2018 he joined the group of Prof. Selvan Demir at the University of Göttingen and moved with her to Michigan State University in 2019.

The introduction of novel radical bridging ligands into rare earth chemistry, and the in-depth analysis of paramagnetic lanthanide complexes via magnetometry, EPR spectroscopy and computational methods (DFT, CASSCF) are his prevalent research interests. Besides organic radicals, he has a profound interest in heavy p-block chemistry, specifically the stabilization of bismuth-containing Zintl ions via lanthanide ions. The exploration of such novel and particularly reactive compounds is of paramount interest to advance the fundamental understanding of magnetic communication among lanthanide ions. Feel free to get in contact via email: Bennerfl@chemistry.msu.edu.

Outside the lab, Florian enjoys woodworking and hiking the great state of Michigan. After hikes, nothing cools him off like exploring the local draft beer scene, listening to audio books, metal music, and playing Elden Ring!

The dramatic ocean scenery celebrates the first implementation of the bridging ligand 2,2′-bisimidazole into rare earth and magnetochemistry, where this tetranitrogen ligand connects two metallocenium units. The synthesized series consists of three compounds comprising the diamagnetic yttrium, the paramagnetic gadolinium (isotropic) and paramagnetic dysprosium (anisotropic) ions. Excitingly, the dinuclear dysprosium complex features SMM behavior and on the timescale of magnetic hysteresis measurements, open hysteresis loops of up to 5 K. The half-filled f-electron valence shell for trivalent gadolinium ions allows quantification of the magnetic exchange coupling since the orbital singlet affords magnetic behavior that is free of complications arising from spin-orbit coupling. Thus, dc magnetic susceptibility measurements on the respective gadolinium complex revealed weak antiferromagnetic interaction between the metal ions. Due to its comparable ionic size, the yttrium analog served as a diamagnetic surrogate to the lanthanides, enabling the in-depth investigation of the electronic structure of these complexes via spectroscopic methods and density functional theory (DFT) calculations. This provided also profound insight into the redox (in)activity of the bisimidazole bridge, which, in contrast to its annulated 2,2′-bisbenzimidazole analog, showed no reactivity towards reductants or oxidants. This was primarily ascribed to the title compounds lacking accessible ligand-based low-lying π* orbitals, unlike the opposite observation for the respective bisbenzimidazole counterparts. In sum, the fact that the bisimidazole ligand retains and enhances the single-ion anisotropy of the dysprosium ions while providing a wealth of substitution sites for future chemical modification renders this ligand system highly promising for the construction of higher-nuclearity systems. Our cover was selected as the final runner up for the 2023 Chemical Science reader’s favorite outside front cover! See here

The universe scenery showcases on the surface of the asteroid: The structure of the first rare earth metallocene featuring a bisbenzimidazole radical anion determined by X-ray diffraction analysis. The first evidence for the radical nature of the bisbenzimidazole ligand bridge was accomplished by in-depth EPR spectroscopy, shown here through the readout of the unpaired spin by a spaceship producing an EPR spectrum. The cyclic voltammetry indicates electrochemical reduction of the molecule. The magnet illustrates the potential for the bridge for molecular magnet design. The diamagnetic yttrium ions allowed DFT and NMR studies. The discovery introduces bisbenzimidazole radicals into coordination chemistry and the results on hand pave the way to novel functional conductive and magnetic materials containing rare earth metals.

Florian’s Publication List

  1. Construction of intermolecular σ-hole interactions in rare earth metallocene complexes using a 2,3,4,5-tetraiodopyrrolyl anion Delano IV, F.; Benner, F.; Jang, S.; Greer, S. M.; Demir, S.* Chem. Sci. 2024. Advance Article. DOI: 10.1039/D4SC03786C.
  2. Modulation of Fe–Fe distance and spin in diiron complexes using tetradentate ligands with different flanking donors Spielvogel, K. D.; Campbell, E. J.; Chowdhury S.; Benner, F.; Demir, S.; Hatzis, G. P.; Petras, H. R.; Sembukuttiarachchige, D.; Shepherd, J. J.; Thomas, C. M.; Vlaisavljevich, B.; Daly, S. R.* Chem. Commun. 2024. Advance Article. DOI: 10.1039/D4CC02522A.
  3. Polymorphism of a Planar Neutral Radical: Magnetic and Optical Implications Borg, G. C.; Young, H. K. S.; Mills, M.; Mastrandrea, J. W.; Benner, F.; Demir, S.; Lough, A. J.; Boyle, P. D.; Preuss, K. E.* Can. J. Chem. 2024. Just-IN Research Article. DOI: 10.1139/cjc-2024-0051.
  4. Linear, Electron-Rich Erbium Single-Molecule Magnet with Dibenzocyclooctatetraene Ligands Castellanos, E.; Benner, F.; Demir, S.* Inorg. Chem. 2024, 63, 9888–9898. DOI: 10.1021/acs.inorgchem.4c00731.
  5. Isolation of an Organometallic Yttrium Bismuth Cluster and Elucidation of its Electronic Structure Pugliese, E. R.; Benner, F.; Demir, S.* Chem. Commun. 2023, 59, 14791–14794. DOI: 10.1039/D3CC04520J.
  6. From an Isolable Bismolyl Anion to an Yttrium–Bismolyl Complex with μ-Bridging Bismuth(I) Centers and Polar Covalent Y–Bi Bonds Pugliese, E. R.; Benner, F.; Demir, S.* Chem. Eur. J. 2023, 29, e202302687. DOI: 10.1002/chem.202302687.
  7. Pyrrolyl-Bridged Metallocene Complexes: From Synthesis, Electronic Structure, to Single-Molecule Magnetism Delano IV, F.; Benner, F.; Jang, S.; Demir, S.* Inorg. Chem. 2023, 62, 14604–14614. DOI: 10.1021/acs.inorgchem.3c01724.
  8. From unprecedented 2,2′-bisimidazole-bridged rare earth organometallics to magnetic hysteresis in the dysprosium congener Benner, F.; Demir, S.* Inorg. Chem. Front. 2023, 10, 4981–4992. DOI: 10.1039/D3QI00546A.
  9. Magnetic hysteresis and large coercivity in bisbenzimidazole radical-bridged dilanthanide complexes Benner, F.; La Droitte, L.; Cador, O.; Le Guennic, B.; Demir, S.* Chem. Sci. 2023, 14, 5577–5592. DOI: 10.1039/D3SC01562A.
  10. A rare isocyanide derived from an unprecedented neutral yttrium(II) bis(amide) complex Jena, R.; Benner, F.; Delano IV, F., Holmes, D.; McCracken, J.*; Demir, S.*; Odom, A. L.* Chem. Sci. 2023, 14, 4257–4264. DOI: 10.1039/D3SC00171G.
  11. Isolation of the elusive bisbenzimidazole Bbim3–• radical anion and its employment in a metal complex Benner, F.; Demir, S.* Chem. Sci. 2022, 13, 5818–5829. DOI: 10.1039/D1SC07245E.
  12. Taming Salophen in Rare Earth Metallocene Chemistry Castellanos, E.; Benner, F.; Demir, S.* Inorg. Chem. Front. 2022, 9, 1325–1336. DOI: 10.1039/D1QI01331A.
  13. Heteroleptic Rare-Earth Tris(metallocenes) Containing a Dibenzocyclooctatetraene Dianion Pugliese, E. R; Benner, F.; Castellanos, E.; Delano IV, F.; Demir, S.* Inorg. Chem. 2022, 61, 2444–2454. DOI: 10.1021/acs.inorgchem.1c03230.
  14. Organometallic Lanthanide Bismuth Cluster Single-Molecule Magnets Zhang, P.; Benner, F.; Chilton, N. F.; Demir, S.* Chem 2022, 8, 717–730. DOI: 10.1016/j.chempr.2021.11.007.
  15. Cyclopentadienyls and Phospholyls of the Group 3 Metals and Lanthanides Benner, F.; Delano IV, F.; Pugliese, E. R.; Demir, S.* Comprehensive Organometallic Chemistry IV 2022, 4, 98-184. DOI: 10.1016/B978-0-12-820206-7.00064-0.
  16. Slow Magnetic Relaxation in Mono- and Bimetallic Lanthanide Tetraimido-Sulfate S(NtBu)42‒ Complexes Jung, J.; Benner, F.; Herbst-Irmer, R.; Demir, S.*; Stalke, D.* Chem. Eur. J. 2021, 27, 12310–12319. DOI: 10.1002/chem.202101076.