Magnetostructural and EPR Studies of Anisotropic Vanadium <i>trans</i>-Dicyanide Molecules

Saber, Mohamed R.; Thirunavukkuarasu, Komalavalli; Greer, Samuel M.; Hill, Stephen; Dunbar, Kim R.

doi:10.1021/acs.inorgchem.0c01595

Cited by 10 publications

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References 66 publications

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“…The field-dependent reduced magnetization data at temperatures between 1.8 and 4.5 K reveal nonsuperimposable isofield lines due to the presence of ZFS interactions ( SI Appendix , Fig. S24 ) ( 51 ). Fits using ANISOFIT2.0 led to estimates of the axial ( D = −17 cm −1 ) and rhombic ( E = ±3.8 cm −1 ) ZFS parameters for [FeNi] ‒ with g = 2.26.…”

Section: Resultsmentioning

confidence: 99%

Cooperative redox and spin activity from three redox congeners of sulfur-bridged iron nitrosyl and nickel dithiolene complexes

Quiroz

Saber

Vali

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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The synthesis of sulfur-bridged Fe–Ni heterobimetallics was inspired by Nature’s strategies to “trick” abundant first row transition metals into enabling 2-electron processes: redox-active ligands (including pendant iron–sulfur clusters) and proximal metals. Our design to have redox-active ligands on each metal, NO on iron and dithiolene on nickel, resulted in the observation of unexpectedly intricate physical properties. The metallodithiolate, (NO)Fe(N 2 S 2 ), reacts with a labile ligand derivative of [Ni II (S 2 C 2 Ph 2 )] 0 , Ni DT , yielding the expected S-bridged neutral adduct, FeNi , containing a doublet {Fe(NO)} 7 . Good reversibility of two redox events of FeNi led to isolation of reduced and oxidized congeners. Characterization by various spectroscopies and single-crystal X-ray diffraction concluded that reduction of the FeNi parent yielded [FeNi] − , a rare example of a high-spin {Fe(NO)} 8 , described as linear Fe II (NO – ). Mössbauer data is diagnostic for the redox change at the {Fe(NO)} 7/8 site. Oxidation of FeNi generated the 2 [FeNi] + ⇌ [Fe 2 Ni 2 ] 2+ equilibrium in solution; crystallization yields only the [Fe 2 Ni 2 ] 2+ dimer, isolated as PF 6 − and BArF − salts. The monomer is a spin-coupled diradical between {Fe(NO)} 7 and Ni DT + , while dimerization couples the two Ni DT + via a Ni 2 S 2 rhomb. Magnetic susceptibility studies on the dimer found a singlet ground state with a thermally accessible triplet excited state responsible for the magnetism at 300 K (χ M T = 0.67 emu·K·mol −1 , µ eff = 2.31 µ B ), and detectable by parallel-mode EPR spectroscopy at 20 to 50 K. A theoretical model built on an H 4 chain explains this unexpected low energy triplet state arising from a combination of anti- and ferromagnetic coupling of a four-radical molecular conglomerate.

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Section: Resultsmentioning

confidence: 99%