Auxiliary Atomic Relay Center Facilitates Enhanced Magnetic Couplings in Blatter’s Radical

Abstract

<div>The recent accomplishments in obtaining the strong ferromagnetic exchange interactions in organic diradicals have made the field quite fascinating and even more promising towards its technological applications. In this context, herein we report a unique combination of remarkably strong ferromagnetic exchange interactions coupled with the molecular rigidity utilizing super-stable Blatter’s radical as a spin source. The planar analogues of the parent Blatter’s radical obtained by annulation with a chalcogen coupled to nitronyl nitroxide (NN) are investigated using density functional theory (DFT) along with the wave function based multi-configurational self-consistent field (MCSCF) methods e.g. CASSCF/NEVPT2. The calculations reveal phenomenal modulation in exchange couplings upon annulation such that remarkably strong ferromagnetic interactions are realized especially for a certain class of the Blatter - nitronyl nitroxide diradicals. The modulation of spin spin interactions is rationalised by variation in spin density distribution and molecular torsional angles. We demonstrate that annulation in OMMs opens an additional coupling pathway via auxiliary X-atom acting as atomic relay center which strongly manipulates the magnitude of exchange couplings.</div>

Tuning the magnetic properties of a diamagnetic di-Blatter's zwitterion to antiferro- and ferromagnetically coupled diradicals

“…47 Later on, we witnessed an appreciable enhancement in ferromagnetic exchange couplings by utilizing oxygen-functionalized planar analogues of Blatter's radical. 48 The superior air and moisture stability and thermally robust properties of Blatter's radical also led Wudl and group to synthesize stable benzotriazinyl diradicals. 49,50 Thereafter, Zheng et al proposed the synthesis of Blatter's diradicals by coupling the two monomers of Blatter's radical.…”

Auxiliary Atomic Relay Center Facilitates Enhanced Magnetic Couplings in Blatter’s Radical

“…Further, a mandatory course to multireference methods is performed using symmetry-adapted methods such as CASSCF and CASSCF–NEVPT2 to achieve an appropriate quantitative description of the exchange couplings. An initial version of this manuscript was deposited in ChemRxiv on January 2, 2021 …”