Nanostructuration of PEDOT in Porous Coordination Polymers for Tunable Porosity and Conductivity

A series of conductive porous composites were obtained by the polymerization of 3,4-ethylenedioxythiophene (EDOT) in the cavities of MIL–101­(Cr). By controlling the amount of EDOT loaded into the host framework, it was possible to modulate the conductivity as well as the porosity of the composite. This approach yields materials with a reasonable electronic conductivity (1.1 × 10⁻³ S·cm^–1) while maintaining high porosity (<i>S</i>_BET = 803 m²/g). This serves as a promising strategy for obtaining highly nanotextured conductive polymers with very high accessibility for small gas molecules, which are beneficial to the fabrication of a chemiresistive sensor for the detection of NO₂

Confinement of Single Polysilane Chains in Coordination Nanospaces

Understanding the intrinsic properties of single conducting polymer chains is of interest, largely for their applications in molecular devices. In this study, we report the accommodation of single polysilane chains with hole-transporting ability in porous coordination polymers (PCPs), [Al­(OH)­(L)]_<i>n</i> (<b>1a</b>; L = 2,6-naphthalenedicarboxylate, channel size = 8.5 × 8.5 Ų, <b>1b</b>; L = 4,4′-biphenyldicarboxylate, channel size = 11.1 × 11.1 Ų). Interestingly, the isolation of single polysilane chains increased the values of carrier mobility in comparison with that in the bulk state due to the elimination of the slow interchain hole hopping. Moreover, even when the chains are isolated one another, the main chain conformation of polysilane could be controlled by changing the pore environment of PCPs, as evidenced by Raman spectroscopy, solid-state NMR measurements, and molecular dynamics simulation. Hence, we succeeded in varying the conducting property of single polysilane chains. Additionally, polysilanes have a drawback, photodegradation under ultraviolet light, which should be overcome for the application of polysilanes. It is noteworthy that the accommodation of polysilane in the nanopores did not exhibit photodegradation. These results highlight that PCP–polysilane hybrids are promising candidates for further use in the field of molecular electronics

Lanthanide-Based Porous Coordination Polymers: Syntheses, Slow Relaxation of Magnetization, and Magnetocaloric Effect

Two lanthanide-containing structurally analogous porous coordination polymers (PCPs) have been isolated with the general molecular formula [Ln₂(L₁)₂(H₂O)₄(ox)]_<i>n</i>.4<i>n</i>H₂O (where L₁ = fumarate, ox = oxalate; Ln = Dy (<b>1</b>), Gd (<b>2</b>)). Thermogravimetric analysis (TGA) and TG-MS measurements performed on <b>1</b> and <b>2</b> suggest that not only the solvated water molecules in the crystal lattice but also the four coordinated water molecules on the respective lanthanides in <b>1</b> and <b>2</b> are removed upon activation. Due to the removal of the waters, <b>1</b> and <b>2</b> lost their crystallinity and became amorphous, as confirmed by powder X-ray diffraction (PXRD). We propose the molecular formula [Ln₂(L₁)₂(ox)]_<i>n</i> for the amorphous phase of <b>1</b> and <b>2</b> (where Ln = Dy (<b>1′</b>), Gd (<b>2′</b>)) on the basis of XANES, EXAFS, and other experimental investigations. Magnetization relaxation dynamics probed on <b>1</b> and <b>1′</b> reveal two different relaxation processes with effective energy barriers of 53.5 and 7.0 cm^–1 for <b>1</b> and 45.1 and 6.4 cm^–1 for <b>1′</b>, which have been rationalized by detailed ab initio calculations. For the isotropic lanthanide complexes <b>2</b> and <b>2′</b>, magnetocaloric effect (MCE) efficiency was estimated through detailed magnetization measurements. We have estimated −Δ<i>S</i>_<i>m</i> values of 52.48 and 41.62 J kg^1– K^–1 for <b>2′</b> and <b>2</b>, respectively, which are one of the largest values reported for an extended structure. In addition, a 26% increase in −Δ<i>S</i>_m value in <b>2′</b> in comparison to <b>2</b> is achieved by simply removing the passively contributing (for MCE) solvated water molecule in the lattice and coordinated water molecules