A cobalt σ‐alkane complex, [Co(Cy₂P(CH₂)₄PCy₂)(norbornane)][BAr^F₄], was synthesized by a single‐crystal to single‐crystal solid/gas hydrogenation from a norbornadiene precursor, and its structure was determined by X‐ray crystallography. Magnetic data show this complex to be a triplet. Periodic DFT and electronic structure analyses revealed weak C−H→Co σ‐interactions, augmented by dispersive stabilization between the alkane ligand and the anion microenvironment. The calculations are most consistent with a η¹:η¹‐alkane binding mode.

Mechanically chelating ligands have untapped potential for the engineering of metal ion properties. Here we demonstrate this principle in the context of Co^II‐based single‐ion magnets. Using multi‐frequency EPR, susceptibility and magnetization measurements we found that these complexes show some of the highest zero field splittings reported for five‐coordinate Co^II complexes to date. The predictable coordination behaviour of the interlocked ligands allowed the magnetic properties of their Co^II complexes to be evaluated computationally a priori and our combined experimental and theoretical approach enabled us to rationalize the observed trends. The predictable magnetic behaviour of the rotaxane Co^II complexes demonstrates that interlocked ligands offer a new strategy to design metal complexes with interesting functionality.

(E)- and (Z)-3-Ferrocenylmethylidene-1,3-dihydro-2H-indol-2-ones 1 have been structurally modified in order to explore SAR against a range of kinases. Of note is the submicromolar to low micromolar inhibition of DYRK3 and 4 by a number of complexes. Screening using Xenopus embryos showed some of the compounds to have potent antiangiogenisis activity.