The undecanuclear complex in [Fe-11(III)(mu(4)-O)(3)(mu(3)-O)(4)(L)(3)(mu-O2CCMe3)(12)]Cl center dot 5MeCN has been synthesized and characterized by single-crystal X-ray crystallography. Mossbauer spectroscopy and bulk susceptibility studies reveal that the complex has an S = 13/2 spin ground state and exhibits single-molecule-magnet behavior.