Dataset for 'Structural and Magnetization Dynamics of Borohydride-Bridged Rare-Earth Metallocenium Cations'

<strong>Data for paper published in </strong><em><strong>Inorganic Chemistry</strong></em><strong> (14th June, 2023)</strong> <br> Experimental data on all compounds in paper, including: X-ray crystallography data in .cif and .checkcif formats for all compounds. NMR spectroscopy data for yttrium and lutetium compounds. FTIR spectroscopy data for all compounds. Magnetic measurement data for all dysprosium compounds. <br> CIF files can be accessed with graphical interface using Mercury sotware https://www.ccdc.cam.ac.uk/solutions/software/free-mercury/ <br> <strong>Abstract</strong> <br> The structure and magnetic properties of the bimetallic borohydride-bridged dysprosocenium compound [{(h5-Cpttt)(h5-CpMe4t)Dy}2(m:k2:k2-BH4)]+[B(C6F5)4]– ([<strong>3Dy</strong>][B(C6F5)4]) are reported along with the solution-phase dynamics of the isostructural yttrium and lutetium analogues (Cpttt is 1,2,4-tri(<em>tert</em>-butyl)cyclopentadienyl, CpMe4t is tetramethyl(<em>tert</em>-butyl)cyclopentadienyl). The synthesis of [<strong>3M</strong>][B(C6F5)4] was accomplished in the 2:1 stoichiometric reactions of [(h5-Cpttt)Dy(h5-CpMe4t)(BH4)] (<strong>2M</strong>) with [CPh3][B(C6F5)4], with the metallocenes <strong>2M</strong> obtained from reactions of the half-sandwich complexes [(h5-Cpttt)M(BH4)2(THF)] (<strong>1M</strong>) with KCpttt (M = Y, Dy, Lu). Crystallographic studies show significant lengthening of the M×××B distance on moving through the series <strong>1M</strong>, <strong>2M</strong> and <strong>3M</strong>, with essentially linear {M×××B×××M} bridges in <strong>3M</strong>. Multinuclear NMR spectroscopy indicates restricted rotation of the Cpttt ligands in <strong>3Y</strong> and <strong>3Lu</strong> in solution. The single-molecule magnet (SMM) properties of [<strong>3M</strong>][B(C6F5)4] are characterized by Raman and Orbach processes, with an effective barrier of 533(18) cm–1 and relaxation via the second-excited Kramers doublet. Whereas quantum tunneling of the magnetization (QTM) was not observed for [<strong>3M</strong>][B(C6F5)4], it was, surprisingly, found in its magnetically dilute version, which has a very similar barrier of <em>U</em>eff = 499(21) cm–1. Consistent with this observation, slightly wider openings of the magnetic hysteresis loop at 2 K are found for [<strong>3M</strong>][B(C6F5)4] but not for the diluted analogue. The dynamic magnetic properties of the dysprosium SMMs and the role of exchange interactions in <strong>3Dy</strong> are interpreted with the aid of multireference ab initio calculations.