Comparative Magnetic Studies in the Solid State and Solution of Two Isostructural 1D Coordination Polymers Containing CoII/NiII-Curcuminoid Moieties

Dielectric behavior of curcuminoid polymorphs on different substrates by direct soft vacuum deposition

Our work examines the structural-electronic correlation of a new curcuminoid, AlkCCMoid, as a dielectric material on different substrates. For this purpose, we show a homemade sublimation method that allows the direct deposition of molecules on any type of matrix. The electronic properties of AlkCCMoid have been evaluated by measurements on single crystals, microcrystalline powder, and sublimated samples, respectively. GIWAXS studies on surfaces and XRD studies on powder have revealed the existence of polymorphs and the effect that substrates have on curcuminoid organization. We describe the dielectric nature of our system and identify how different polymorphs can affect electronic parameters such as permittivity, all corroborated by DFT calculations.

Single molecule magnets of cobalt and zinc homo- and heterometallic coordination polymers prepared by a one-step synthetic procedure

The synthesis of 1D cobalt and zinc monometallic and heterometallic coordination polymers (CPs) was carried out applying one-pot synthetic methods by using either supercritical carbon dioxide or ethanol as the solvent. A collection of four 1D CPs were thus obtained by the combination of a metal (or a mixture of metals) with the linker 1,4-bis(4-pyridylmethyl)benzene. The used metallic complexes were zinc and cobalt hexafluoroacetylacetonate, which can easily incorporate pyridine ligands in the coordination sphere of the metal centre. Independently of the used solvent, the precipitated phases involving Zn(ii), i.e., homometallic CP of Zn(ii) and bimetallic CP of Zn(ii)/Co(ii), were isostructural. Contrarily, homometallic CPs of Co(ii) were precipitated as an isostructural phase of Zn(ii) or with a different structure, depending on the used solvent. All the structures were resolved by XRD using synchrotron radiation. In addition, the magnetic properties of the new CPs involving Co(ii) were studied. Remarkably, at low temperatures with the application of an external field, they acted as field-induced single molecule magnets.

One-pot synthesis of heterometallic (Zn(ii)/Co(ii)) nodes directing CP magnetic behaviour to single molecule magnets.