An iron(III) phosphonate cluster containing a nonanuclear ring

This communication reports the first example of cyclic ferric clusters with an odd number of iron atoms capped by phosphonate ligands, namely, [Fe-9( mu-OH)(7)( mu- O)(2)(O3PC6H9)(8)( py)(12)]. The magnetic studies support a S = 1/ 2 ground state with an exchange coupling constant of about J approximate to -30 K.