Synthesis and Structural, Magnetic and EPR Characterization of Discrete Finite Antiferromagnetic Chains

Abstract

The synthesis, magnetic and electron paramagnetic resonance (EPR) characterisation of isolated, discrete, {Cr n III } antiferromagnetically coupled chain complexes is reported for n = 6 and 7. Previous studies had reported supramolecular linked {Cr n III } x species. For n = 6, the lowest lying total spin state is diamagnetic with S = 1 and 2 first and second excited states, respectively; for n = 7, the lowest lying total spin state is S = 3/2 with S = 1/2 and 5/2 first and second excited states, respectively. The zero-field splittings of these states are well defined by low-temperature, multi-frequency EPR spectroscopy. 1 Introduction The chemistry and physics of antiferromagnetically coupled rings (AF rings)discrete molecular, cyclic transition-metal clusters with AF coupling between adjacent metal ions-have received much attention. Early examples [1, 2] were Dedicated to Prof Dr Wolfgabg Lubitz on the occasion of his 60th birthday.

Varying spin state composition by the choice of capping ligand in a family of molecular chains: detailed analysis of magnetic properties of chromium(iii) horseshoes

“…668930 and 725125, respectively). 6,7 Crystal data and data collection and refinement parameters for 6 are given in Table 1. Data were collected on an Oxford Diffraction CCD diffractometer (Mo-Ka, l = 0.71069 Å ).…”

“…Ref. 7 reported the determination of a nearest neighbour exchange coupling constant of J = -1.4 meV for 4 with a Zeeman splitting factor of g = 1.98 determined from susceptibility vs. temperature and magnetization vs. field. INS enables low lying energy quantum spin levels to be probed directly at a fixed temperature in zero field.…”