Auf Chinonen basierte Einzelmolekülmagnete
Physikalische Chemie von Molekülen, Flüssigkeiten und Grenzflächen, Biophysikalische Chemie
Zusammenfassung der Projektergebnisse
The aim of this project was to synthesize and investigate mono- and multi-nuclear cobalt(II) complexes with sulfonyl-substituted diamido-type donors as potential building blocks for singleion magnets. Additionally, mononuclear iron(II) and nickel(II) complexes were synthesized and investigated to compare and contrast their properties with their cobalt(II) congeners. The pseudo-tetrahedrally coordinated mononuclear complexes were successfully synthesized and characterized. A thorough spectroscopic, magnetometric and theoretical investigations revealed that the cobalt(II) complexes display extremely high negative values for zero-field splittings, a high energy barrier, as well as slow relaxation of magnetization in the absence of an external magnetic field. The properties of these complexes are robust towards substitution of the sulfonyl moieties, and theoretical calculations show that these complexes likely present the optimum in single-ion magnet behaviour for these kinds of compounds. Mononuclear synthons with additional labile ligands were developed in order to access radical-bridged di- and trinuclear complexes. Such radical bridges should supress under-barrier Raman processes and lead to increase in magnetic relaxation times. Indeed, we have shown that relaxation times can be increased by more than 350-fold by converting the mononuclear synthons into their radical-bridged dinuclear counterparts. These compounds also represent rare examples of airand moisture stable radical-bridged tetra-coordinated metal complexes. One very important result coming out from the spectroscopic investigations is the experimental observation of spinphonon coupling in the systems investigated in this project. The most challenging aspect in this project has been the synthesis of radical-bridged trinuclear complexes. However, the access to the heteroleptic mononuclear synthons as well as the successful synthesis of the ligand have already brought us very close to accessing such complexes. We expect that the highly air- and moisture-stable synthons of single-ion magnets that we have presented here will lead to new strategies for surface-immobilization of single-ion magnets. Additionally, these synthon will also make access to multi-functional magnetic materials possible.
Projektbezogene Publikationen (Auswahl)
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Strong Exchange Couplings Drastically Slow Down Magnetization Relaxation in an Air‐Stable Cobalt(II)‐Radical Single‐Molecule Magnet (SMM). Angewandte Chemie International Edition, 58(29), 9802-9806.
Albold, Uta; Bamberger, Heiko; Hallmen, Philipp P.; van Slageren, Joris & Sarkar, Biprajit
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Iron(II), Cobalt(II), and Nickel(II) Complexes of Bis(sulfonamido)benzenes: Redox Properties, Large Zero-Field Splittings, and Single-Ion Magnets. Inorganic Chemistry, 60(5), 2953-2963.
Bamberger, Heiko; Albold, Uta; Dubnická, Midlíková Jana; Su, Cheng-Yong; Deibel, Naina; Hunger, David; Hallmen, Philipp P.; Neugebauer, Petr; Beerhues, Julia; Demeshko, Serhiy; Meyer, Franc; Sarkar, Biprajit & van, Slageren Joris
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Spin-state control of cobalt(ii) and iron(ii) complexes with click-derived tripodal ligands through non-covalent and fluorine-specific interactions. Dalton Transactions, 50(48), 18097-18106.
Nößler, Maite; Hunger, David; Reichert, Felix; Winkler, Mario; Reimann, Marc; Klein, Johannes; Suhr, Simon; Suntrup, Lisa; Beerhues, Julia; Kaupp, Martin; van Slageren, Joris & Sarkar, Biprajit
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Fluorinated click-derived tripodal ligands drive spin crossover in both iron(ii) and cobalt(ii) complexes. Dalton Transactions, 51(27), 10507-10517.
Nößler, Maite; Hunger, David; Neuman, Nicolás I.; Reimann, Marc; Reichert, Felix; Winkler, Mario; Klein, Johannes; Bens, Tobias; Suntrup, Lisa; Demeshko, Serhiy; Stubbe, Jessica; Kaupp, Martin; van Slageren, Joris & Sarkar, Biprajit
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Electrochemistry and Spin‐Crossover Behavior of Fluorinated Terpyridine‐Based Co(II) and Fe(II) Complexes. European Journal of Inorganic Chemistry, 26(19).
Nößler, Maite; Jäger, René; Hunger, David; Reimann, Marc; Bens, Tobias; Neuman, Nicolás I.; Singha, Hazari Arijit; Kaupp, Martin; van Slageren, Joris & Sarkar, Biprajit
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Spin Crossover and Fluorine‐Specific Interactions in Metal Complexes of Terpyridines with Polyfluorocarbon Tails. Chemistry – A European Journal, 29(46).
Nößler, Maite; Neuman, Nicolás I.; Böser, Lisa; Jäger, René; Singha, Hazari Arijit; Hunger, David; Pan, Yixian; Lücke, Clemens; Bens, Tobias; van Slageren, Joris & Sarkar, Biprajit
