Tracking Coordination Environment and Reaction Intermediates in Homogeneous and Heterogeneous Epoxidation Catalysts via Ti L-Edge Near-Edge X-ray Absorption Fine Structures.

Ti-based molecules and materials are ubiquitous and play a major role in both homogeneous and heterogeneous catalytic processes. Understanding the electronic structures of their active sites (oxidation state, local symmetry, and ligand environment) is key to developing molecular-level structure-property relationships. In that context, X-ray absorption spectroscopy (XAS) offers a unique combination of elemental selectivity and sensitivity to local symmetry.

Cyclooctatetraenide-based single-ion magnets featuring bulky cyclopentadienyl ligand.

We report a family of organometallic rare-earth complexes with the general formula (COT)M(Cp) (where (COT) = cyclooctatetraenide, (Cp) = 1,2,4-tri(-butyl)cyclopentadienide, M = Y(iii), Nd(iii), Dy(iii) and Er(iii)). Similarly to the prototypical Er(iii) analog featuring pentamethylcyclopentadienyl ligand (Cp*), (COT)Er(Cp) behaves as a single-ion magnet. However, the introduction of the sterically demanding (Cp) imposes geometric constraints that lead to a simplified magnetic relaxation behavior compared to the (Cp*) containing complexes.

Orienting dilute thin films of non-planar spin-1/2 vanadyl-phthalocyanine complexes.

The molecular orientation as well as the electronic and magnetic properties of vanadyl-phthalocyanine (VOPc) diluted into titanyl-phthalocyanine (TiOPc) thin films on Si(100) and polycrystalline aluminum substrates have been investigated by soft X-ray absorption spectroscopy (XAS), X-ray linear dichroism (XLD) and X-ray magnetic circular dichroism (XMCD). On the bare substrates the films grow with a standing-up geometry. By contrast, on template layers of 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA), they assume a lying-down orientation.

Amyloid-beta-copper interaction studied by simultaneous nitrogen K and copper L edge soft X-ray absorption spectroscopy.

We study the interaction between amyloid β (Aβ) peptides and Cu and Zn metal ions by using soft X-ray absorption spectroscopy. The spectral features of the peptides and Cu are simultaneously characterized by recording spectra at the N K-edge and at the Cu L edges. In the presence of the peptides, the Cu L edge shows a fingerprint of monovalent Cu(I), caused by the interaction with the peptides.

Exceptionally High Blocking Temperature of 17 K in a Surface-Supported Molecular Magnet.

Single-molecule magnets (SMMs) are among the most promising building blocks for future magnetic data storage or quantum computing applications, owing to magnetic bistability and long magnetic relaxation times. The practical device integration requires realization of 2D surface assemblies of SMMs, where each magnetic unit shows magnetic relaxation being sufficiently slow at application-relevant temperatures. Using X-ray absorption spectroscopy and X-ray magnetic circular dichroism, it is shown that sub-monolayers of Dy @C (CH Ph) dimetallofullerenes prepared on graphene by electrospray deposition exhibit magnetic behavior fully comparable to that of the bulk.