Both experimental and theoretical, our research explores the magnetic properties of molecular compounds, particularly those based on transition metals and lanthanides.
Studies on molecular systems with transition metals and lanthanides have become an important part of our research. This topic has been strongly promoted by our cooperation with Prof. Dr. Helmut Sitzmann and his colleagues based at the University of Kaiserslautern-Landau. Within this cooperation, we have been dealing mostly with transition metal complexes that comprise bulky alkylcyclopentadienyl ligands. The cyclopentadienyl (Cp) ligand with sterically demanding alkyl substitutions on the ring can stabilize unusual oxidation states of the metal centres and has played an outstanding role in the research of molecular single-ion magnets. We have focused mainly on dinuclear complexes with various bridging ligands (hydrides, nitrides, halogenides) and analysis of their magnetic properties using magnetometry and DFT methods.
As regards magnetic studies on molecular compounds, we combine both experimental approach and calculations from first principles, above all SQUID magnetometry, PPMS measurements, and DFT calculations. We employ also 57Fe Mössbauer spectroscopy, which is available to us in cooperation with the Laboratory of Mössbauer spectroscopy at the MFF UK. Importantly, we are capable to handle and carry out magnetic measurements on highly sensitive samples that must be mounted in a glovebox under strictly inert atmosphere (< 1ppm O2, <1 ppm H2O).
Recently, we have established within our department a fully equipped chemical laboratory with a glovebox, a Schlenk line and special equipment for the synthesis of highly sensitive coordination/organometallic compounds. Our synthetic efforts are now directed to novel transition metal complexes, including redox-active ligands, and single-molecule magnets.
In the dinuclear organometallic complex [Cp‴Cr(μ-H)]2, where Cp‴ = tri(tert-butyl)-cyclopentadienide, CrII ions interact through hydride bridges and a direct metal-metal bond, which results in a very strong antiferromagnetic coupling of J12 = −206(1) cm–1. The fit of temperature-dependent product of DC magnetic susceptibility and temperature, decomposed into components of the complex (AFM), paramagnetic impurity (PAR) and temperature-independent paramagnetism (TIP) is shown on the right, the measured susceptibility is shown in the inset. The magnetic study was performed in collaboration with Prof. Dr. Helmut Sitzmann (University of Kaiserslautern-Landau), for more details see Smytschkow et al.
