Structural and magnetic studies on mono- and polynuclear chromium ascorbate complexes

Polynuclear chromium ascorbate complexes were isolated and physicochemically analyzed in a comparative manner with their mononuclear analog (1). Characterization by elemental analysis, electronic, vibrational, 13C-n.m.r and mass spectroscopies, and variable temperature magnetic susceptibility studies, allowed structural proposals for the binuclear, [Cr2(μ-OH)2(H2O)(C6H7O6)3(OH)] · 4H2O (2), and trinuclear, [Cr3(μ-O)3(H2O)6(C6H7O6)3] · 4 H2O (3) complexes. The pseudo-octahedral Cr III centers were suggested to be connected through hydroxo bridges in (2) and in (3) by oxo bridges forming a hexocyclic ring.