Metal complexes with N-heterocyclic carbene (NHC) ligands have been widely used in catalytic chemistry and are now increasingly considered for the development of new chemical tools and metal based drugs. Ruthenium complexes of the type (p-cymene)(NHC)RuCl₂ interacted with biologically relevant thiols and selenols, which resulted in the inhibition of enzymes such as thioredoxin reductase or cathepsin B. Pronounced antiproliferative effects could be obtained provided that an appropriate cellular uptake was achieved. Inhibition of tumor cell growth was accompanied by a perturbation of metabolic parameters such as cellular respiration.

The induced magnetic field of C_2N (N = 3-14) carbon rings was dissected to contributions from out-of-plane and in-plane π orbitals revealing two concurrent long-range shielding or deshielding cones as a manifestation of the dual aromatic and antiaromatic character of C_4n+2 and of C_4n rings respectively. Aromaticity based on the magnetic criterion was evaluated with regard to bonding pattern and geometrical characteristics elucidating the influence of bond length and bond angle alternation on out-of-plane and in-plane magnetic response. Ground state polyynic geometries of C_4n+2 rings exhibit comparable shielding cones to annulenes, decreasing magnetic response with regard to ring size and similar π_out and π_in diatropicity. Transition state cumulenic rings display increased aromaticity expressed by a constant very strong magnetic response and augmented π_out diatropicity with regard to π_in. The variations of the induced magnetic field are explained on the basis of frontier orbital interactions through rotational excitations, which enable further rationalization of the aromatic/antiaromatic behavior.

A direct correlation between π- and spherical aromaticity of the aromatic structures was established by showing that they shared a characteristic shielding cone, resulting from a specific orientation of the applied field. Herein, we revealed the presence of a related long-range shielding cone in spherical aromatic species that was demonstrated through C₂₀, C₃₂, C₅₀, and C₆₀ Hirsh aromatic fullerenes. It was found that while for planar aromatics, the cone is reserved only for a perpendicularly applied field, for spherical aromatic compounds, the three-dimensional cage allows the formation of a shielding cone according to the given orientation of the external field.