000150585 001__ 150585 000150585 005__ 20251208074743.0 000150585 0247_ $$2doi$$a10.1021/acs.inorgchem.4c04191 000150585 0248_ $$2sideral$$a142677 000150585 037__ $$aART-2024-142677 000150585 041__ $$aeng 000150585 100__ $$0(orcid)0000-0002-6517-1236$$aBartolomé, Juan 000150585 245__ $$aSingle-Molecule Magnet Behavior and Spin Structure of an Fe<sup>III</sup><sub>7</sub> Cartwheel Cluster Revealed by Sub-Kelvin Magnetometry and Mössbauer Spectroscopy: The Final Pieces of the Puzzle 000150585 260__ $$c2024 000150585 5203_ $$aThe spin frustration and other magnetic properties of the “cartwheel” heptanuclear cluster [FeIII7O3(O2CtBu)9(Me-dea)3(H2O)3] (Me-deaH2 = N-methyldiethanolamine) have been previously investigated; we present here a Mössbauer spectroscopic study and sub-Kelvin magnetization and ac susceptibility measurements which enable a complete magnetic picture of this frustrated cluster. 57Fe Mössbauer spectra above 150 K showed three doublets in a 1:3:3 ratio, which could be assigned by their respective quadrupole splittings to the central Fe(1) and the peripheral Fe(2) and Fe(3). The field dependence of the corresponding magnetic sextets at 3 K showed that the spins on the central Fe(1) and the three peripheral Fe(2) sites with O5N coordination are oriented mutually coparallel, while these are antiparallel to the spins on the peripheral Fe(3) sites with O6 coordination, resulting in an overall S = 5/2 ground state. This provides experimental confirmation of the previously proposed spin ground state structure. Upon cooling to sub-Kelvin temperatures, a crossover to spin blocking with TB ≈ 0.21 K could be observed. This single-molecule magnet behavior had been expected but had not been observable with a conventional SQUID. The anisotropy barrier, of 3-fold symmetry, can be described in terms of the parameter D/kB = −0.47 K and a fourth-order perturbation; the latter enables thermally activated quantum tunneling through the excited sublevel mz = ± 3/2, with an activation barrier of U/kB = 1.9 K. 000150585 536__ $$9info:eu-repo/grantAgreement/ES/MICINN/PID2022-138492NB-I00$$9info:eu-repo/grantAgreement/ES/MICINN-AEI/PRTR-C17.I1$$9info:eu-repo/grantAgreement/ES/DGA-FSE/E12-23R-RASMIA$$9info:eu-repo/grantAgreement/ES/DGA/E09-17R-Q-MAD$$9info:eu-repo/grantAgreement/ES/AEI/AEI PID2022-140923NB-C22$$9info:eu-repo/grantAgreement/ES/AEI/AEI PID2022-140923NB-C21$$9info:eu-repo/grantAgreement/ES/AEI/CEX2023-001286-S$$9info:eu-repo/grantAgreement/ES/AEI/CEX2023-001263-S 000150585 540__ $$9info:eu-repo/semantics/openAccess$$aAll rights reserved$$uhttp://www.europeana.eu/rights/rr-f/ 000150585 590__ $$a4.7$$b2024 000150585 592__ $$a0.958$$b2024 000150585 591__ $$aCHEMISTRY, INORGANIC & NUCLEAR$$b6 / 42 = 0.143$$c2024$$dQ1$$eT1 000150585 593__ $$aChemistry (miscellaneous)$$c2024$$dQ1 000150585 593__ $$aPhysical and Theoretical Chemistry$$c2024$$dQ1 000150585 593__ $$aInorganic Chemistry$$c2024$$dQ1 000150585 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000150585 700__ $$aBartolomé, Elena 000150585 700__ $$0(orcid)0000-0001-6284-0521$$aLuis, Fernando 000150585 700__ $$aBurzurí, Enrique 000150585 700__ $$0(orcid)0000-0001-7289-5649$$aCamón, Agustin 000150585 700__ $$aFiloti, George 000150585 700__ $$aAko, Ayuk M. 000150585 700__ $$aBraun, Jonas 000150585 700__ $$aMereacre, Valeriu 000150585 700__ $$aAnson, Christopher E. 000150585 700__ $$aPowell, Annie K. 000150585 773__ $$g63, 51 (2024), 24262-24273$$pInorg. chem.$$tInorganic Chemistry$$x0020-1669 000150585 8564_ $$s4433933$$uhttps://zaguan.unizar.es/record/150585/files/texto_completo.pdf$$yVersión publicada$$zinfo:eu-repo/date/embargoEnd/2025-12-08 000150585 8564_ $$s3088450$$uhttps://zaguan.unizar.es/record/150585/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada$$zinfo:eu-repo/date/embargoEnd/2025-12-08 000150585 909CO $$ooai:zaguan.unizar.es:150585$$particulos$$pdriver 000150585 951__ $$a2025-10-17-14:37:01 000150585 980__ $$aARTICLE