A valence tautomeric cobalt-dioxolene complex with an anchoring group for prospective chemical grafting to metal oxides

Here, we synthesized a valence tautomeric cobalt-dioxolene complex featuring a protected anchoring group. At room temperature, the complex reveals a nearly pure low-spin-Co(iii)-catecholate state in the solid state, but a nearly pure high-spin-Co(ii)-semiquinonate state in toluene solution. Thermal switchability of the complex in solution and in the solid state is investigated.

Unconventional Method for Fabricating Valence Tautomeric Materials: Integrating Redox Center within a Metal-Organic Framework

Due to the structural advantages displayed by Metal-Organic Frameworks (MOFs), integrating Valence Tautomerism (VT) systems within MOFs could be an effective strategy in order to break through the constraints of the traditional ones. Herein, we report the first successful integration of a VT system into a MOF termed VT-MOF-1. The structural characteristics of VT-MOF-1, such as dinuclear cobalt-catechol clusters and solvent-accessible pores, are both innovative and novel, potentially yielding new vitality within VT field. In addition, VT-MOF-1 exhibits specific behaviors responsive to temperature and different solvent molecules as n-butanol, tert-butanol, and isopropyl alcohol. The entropy values and configurations of the solvent molecules might be responsible for the tunable sensing behaviors.

Spatially controlled positioning of coordination polymer nanoparticles onto heterogeneous nanostructured surfaces

Prussian Blue Analog (PBA) nanoparticles were formed on a heterogeneous nanostructured surface made of an ordered nanoperforated titanium oxide thin film deposited on a gold layer. The study of the nanocomposite film by grazing-incidence wide angle X-ray scattering, infrared spectroscopy, scanning electron microscopy and atomic force microscopy shows that the PBA particles are precisely positioned within all the perforations of the oxide film over very large surface areas. Further investigation on the formation of the PBA particles demonstrates a decisive role of a heterogeneous nucleation of the coordination polymer driven by well-adjusted surfaces energies and reactant concentrations in the spatial positioning of the PBA particles. Thanks to the well-controlled positioning of the particles within the ordered nanoperforations, the latter were successfully used as nano crucibles for the local transformation of PBA into the corresponding metal alloy by heat treatment. The thin film heterostructure thus obtained, made of ferromagnetic islands isolated by diamagnetic walls, opens interesting perspectives for the design of magnetic storage devices.