Adding Time-Domain 161Dy Mössbauer to the Mix: a Multitechnique Investigation of Magnetic Transitions in a {CoIII3DyIII3} Cluster with a Toroidal Moment

Abstract The coordination cluster [CoIII₃DyIII₃(µ₃-OH)₄(O₂C-C₆H₄-p-Me)₆(pmide)₃(H₂O)₃]Cl₂∙10MeCN (1) (where H₂pmide = N-2-pyridylmethyldiethanolamine) crystallizes on a threefold site in the trigonal space group P3c1. The cluster core contains one equilateral Dy₃III triangle and one triangle of diamagnetic CoIII ions to give a shuttlecock-like molecular structure. The magnetic spin structure has been investigated using a multi-technique approach. In addition to the magnetic susceptibility, we report ¹⁶¹Dy Synchrotron Mössbauer Spectroscopy (SMS) which shows an abrupt transition from a non-magnetic to a magnetic state which is in line with the transition observed in complementary measurements. The experimental orientations of the individual axes were independently assessed using torque magnetometry and micro-SQUID measurements and both experiments converged on a spin structure that can be correlated with the crystal structure. The results are also in agreement with those from ab initio CASSCF/SO-RASSI calculations, which also showed that a hydrogen-bonded chloride counterion has a significant effect on the magnetic structure.