NANOMETER-SIZED MOLECULAR-COMPLEXES

Nanosized molecular complexes synthesized as monodispersed, X-ray stru cturally characterizable chemical entities afford ideal experimental s ystems for the study of the properties of matter at the molecular/soli d state boundary. Representative studies of an undecanuclear, [Fe11O6( OH)(6)(O2CPh)(15)]. 6THF, and two heptadecanuclear; [Fe16MO10(OH)(10)( O2CPh)(20)] where M = Mn2+, Fe2+, complexes are presented. Low tempera ture, high field Mossbauer data give compelling experimental evidence that deviation from simple paramagnetism and onset of superparamagneti c-like behavior can occur in molecular complexes containing 10 to 20 i ron ions participating in pseudo three-dimensional superexchange inter actions.