A flexible iron(ii) complex in which zero-field splitting is resistant to structural variation. Issue 1 (19th October 2015)

• Record Type: Journal Article
• Authors: Zadrozny, Joseph M.; Greer, Samuel M.; Hill, Stephen; Freedman, Danna E.
• Is Part Of: Chemical science. Volume 7:Issue 1(2016:Jan.)
• Page Start: 416
• Page End: 423
• Publication Date: 2015-10-19
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5sc02477c
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : The zero-field splitting parameters D and E in the iron(ii ) complex [Fe(C3 S5 )2 ] 2− are shown to be remarkably resistant to a twist of the inter-ligand dihedral angle ( θ d ) from 90 to 70°. Abstract : The relationship between electronic structure and zero-field splitting dictates key design parameters for magnetic molecules. In particular, to enable the directed synthesis of new electronic spin based qubits, developing complexes where zero-field splitting energies are invariant to structural changes is a critical challenge. Toward those ends, we report three salts of a new compound, a four-coordinate iron(ii ) complex [Fe(C3 S5 )2 ] 2− ([(18-crown-6)K] + (1 ), Ph4 P + (2 ), Bu4 N + (3 )) with a continuous structural variation in a single parameter, the dihedral angle ( θ d ) between the two C3 S5 2− ligands, as a function of counterion ( θ d = 89.98(4)° for1 to 72.41(2)° for3 ). Electron paramagnetic resonance data for1–3 reveal zero-field splitting parameters that are unusually robust to the structural variation. Mössbauer spectroscopic measurements indicate that the structural variation in θ d primarily affects the highest-energy 3d-orbitals (d xz and d yz ) of the iron(ii ) ion. These orbitals have the smallest impact on the zero-field splitting parameters, thus the distortion has a minor effect on D and E . These results represent the first part of a directed effort to understand how spin state energies may be fortified against structural distortions for future applications of qubits in non-crystalline environments.