New Single-Molecule Magnets by Site-Specific Substitution: Incorporation of “Alligator Clips” into Fe4 Complexes

“Alligator clips” suitable for grafting on H-terminated siliconor gold surfaces have been incorporated into single-moleculemagnets (SMMs) of the Fe4 family. Tripodal ligands 2,2-bis-(hydroxymethyl)-10-undecen-1-ol (H3L1) and 11-(acetylthio)-2,2-bis(hydroxymethyl)undecan-1-ol (H3L2) have been usedto replace the six methoxide bridges in [Fe4(OMe)6(dpm)6],affording new Fe4 derivatives [Fe4(L1)2(dpm)6] (1) and[Fe4(L2)2(dpm)6] (2) in high yield (Hdpm = dipivaloylmethane).The molecular structures have been unambiguously established by XRD combined with ESI-MS and magnetic characterization techniques, including DC and AC magnetometry and high-frequency EPR spectroscopy. The twoSMMs have an S = 5 ground state and an easy-axis magneticanisotropy leading to slow relaxation of the magnetization atlow temperature, with effective anisotropy barriers of15.9(2) K in 1 and 15.1(2) K in 2.