Room Temperature Magnetic Switchability Assisted by Hysteretic Valence Tautomerism in a Layered Two-Dimensional Manganese-Radical Coordination Framework

Publication

Reference: Lannes Anthony, Suffren Yan, Tommasino Jean Bernard, Chiriac Rodica, Toche François, Khrouz Lhoussain, Molton Florian, Duboc Carole, Kieffer Isabelle, Hazemann Jean-Louis, Reber Christian, Hauser Andreas, Luneau Dominique (2016). Room Temperature Magnetic Switchability Assisted by Hysteretic Valence Tautomerism in a Layered Two-Dimensional Manganese-Radical Coordination Framework. J. Am. Chem. Soc., 138, 16493 - 16501.

Names

Title: Room Temperature Magnetic Switchability Assisted by Hysteretic Valence Tautomerism in a Layered Two-Dimensional Manganese-Radical Coordination Framework
Abstract: The manganese-nitronyl-nitroxide two dimensional coordination polymer {[Mn2(NITIm)3]ClO4}n (1) (NITImH = 2-(2-imidazolyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-3-oxide-1-oxyl) undergoes an unusual hysteretic thermoinduced valence tautomeric transition near room temperature, during which the manganese(II) ions are oxidized to manganese( III) and two of the three deprotonated radicals (NITIm-) are reduced to their diamagnetic aminoxyl form (denoted NITImRed 2-). Upon cooling, the high-temperature species {[MnII 2(NITIm)3]ClO4}n (1HT) turns into the low-temperature species {[MnIII 2(NITImRed)2(NITIm)]ClO4}n (1LT) around 274 K, while on heating the process is reversed at about 287 K. This valence tautomeric phenomenon is supported by temperature-dependent magnetic susceptibility measurements, differential scanning calorimetry (DSC), crystal structure determination, UV-vis absorption, X-ray absorption (XAS) and emission (XES) and Electron Paramagnetic Resonance (EPR) spectroscopies in the solid-state.
Keywords: Chemistry, material science
Content: materials sciences, chemistry

Doi

10.1021/jacs.6b10544

Identifiers

Experiment/Spectra