The porous Hoffman-type 3D lattice Fe(pz)[Ni(CN)] exhibits thermally induced spin-crossover (SCO) behavior that is dependent on the solvent guest species occupying the pores. Here, in situ Fe K-edge X-ray absorption spectroscopy (XAS) and both non-resonant and resonant Kβ X-ray emission spectroscopy (XES) methods are used to probe this framework under two solvent environments that yield different extremes of spin crossover temperature: acetonitrile and toluene. While the acetonitrile pore environment engenders an SCO response around room temperature, toluene guests stabilize the high spin state and effectively suppress SCO behavior throughout the ambient temperature range. The multipronged X-ray spectroscopy approach simultaneously confirmed this spin crossover behavior and provided new local coordination and electronic structural insights of the framework under these two solvent environments. Extended X-ray absorption fine structure analysis revealed spin state and solvent guest-dependent differences in coordination bond lengths and structural disorder. Resonant XES measurements produced high-resolution XAS spectra with distinct pre-edge and edge features, whose assignment was established using both simple ligand field theory and time-dependent density-functional theory calculations and further supported by their observed resonance behavior in the 2D RXES plane. Edge feature variation with the Fe spin state was interpreted to reveal changes in specific metal-linker bond covalency.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.inorgchem.2c00774 | DOI Listing |
Phys Rev Lett
December 2024
Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany.
Superdiffusion is surprisingly easily observed even in systems without the integrability underpinning this phenomenon. Indeed, the classical Heisenberg chain-one of the simplest many-body systems, and firmly believed to be nonintegrable-evinces a long-lived regime of anomalous, superdiffusive spin dynamics at finite temperature. Similarly, superdiffusion persists for long timescales, even at high temperature, for small perturbations around a related integrable model.
View Article and Find Full Text PDFNat Commun
January 2025
Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada.
Landau-Zener tunneling, which describes the transition in a two-level system during a sweep through an anti-crossing, is a model applicable to a wide range of physical phenomena. Realistic quantum systems are affected by dissipation due to coupling to their environments. An important aspect of understanding such open quantum systems is the relative energy scales of the system itself and the system-environment coupling, which distinguishes the weak- and strong-coupling regimes.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Materials Science and Engineering, Yonsei University, Seoul, 03722, Republic of Korea.
Nature
January 2025
Max-Planck-Institut für Quantenoptik, Garching, Germany.
JACS Au
December 2024
Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, IPCM, F-75005 Paris, France.
Metallogels built in a bottom-up approach by metal coordination and supramolecular interactions have important potential for the elaboration of smart materials. In this context, we present here the formation of supramolecular coordination polymers driven by the complexation of cobalt(II) or zinc(II) ions with polyoxometalate-based hybrids displaying two terpyridine ligands in a linear arrangement. Thanks to the electrostatic interactions between the polyoxometalate cores and metal nodes, the polymer chains self-assemble into fibers that physically cross-link to form gels above a critical concentration.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!