New Single‐Molecule Magnets by Site‐Specific Substitution: Incorporation of “Alligator Clips” into Fe 4 Complexes

“Alligator clips” suitable for grafting on H‐terminated silicon or gold surfaces have been incorporated into single‐molecule magnets (SMMs) of the Fe 4 family. Tripodal ligands 2,2‐bis(hydroxymethyl)‐10‐undecen‐1‐ol (H 3 L 1 ) and 11‐(acetylthio)‐2,2‐bis(hydroxymethyl)undecan‐1‐ol (H 3 L 2 ) have been used to replace the six methoxide bridges in [Fe 4 (OMe) 6 (dpm) 6 ], affording new Fe 4 derivatives [Fe 4 (L 1 ) 2 (dpm) 6 ] ( 1 ) and [Fe 4 (L 2 ) 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 two SMMs have an S = 5 ground state and an easy‐axis magnetic anisotropy leading to slow relaxation of the magnetization at low temperature, with effective anisotropy barriers of 15.9(2) K in 1 and 15.1(2) K in 2 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)