Diacetoneglucose complexes of manganese(II) and iron(II) and their organometallic derivatization

Homoleptic metal-sugar complexes were obtained in the form of Mn-II- and Fe-II-diacetoneglucose derivatives. The protolysis of [Mn(3)Mes(6)] and [Fe(2)Mes(4)] (Mes = 2,4,6-Me3C6H2) with DAGH (1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose, diacetoneglucose) led to [M(DAG)(2)] [M = Mn (1). Fe (2)]. Although monomeric in solution, they showed a different degree of aggregation in the solid state, iron being monomeric and manganese oligomeric (see magnetic properties). Dimeric complexes from 1 and 2 were obtained in the reaction with 9,10-phenanthroline [phen], leading to [(phen)(2)M(mu-DAG)(2)M(DAG)(2)] [M = Mn (3), Fe (4)]. The organometallic functionalization of I and 2 was achieved via a ligand redistribution reaction mixing them with [Mn(3)Mes(6)] and [Fe(2)Mes(4)], respectively. The reaction led to mixed alkoxo aryl trinuclear complexes in the form of [(Mes)(2)M-2(mu-DAG)(2)M-(mu-Mes)(2)] [M = Mn (5), Fe (6)]. Both have a linear trimetallic skeleton with Mn ... Mn and Fe ... Fe average distances of 2.93 and 2.88 Angstrom, respectively. The crystal data are as follows: complex 5. C60H82Mn3O12, monoclinic, space group P2(1), a = 10.289(5) Angstrom, b = 20.878(5) Angstrom, c = 14.015(5) Angstrom, beta = 93.19(2)degrees, Z = 2: complex 6, C60H82Fe3O12, monoclinic, space group P2(1). a = 9.748(12) Angstrom, b = 26.05(3) Angstrom, c = 12.50(2) Angstrom, beta = 107.50(2)degrees, Z = 2. The data were collected at -123 degrees C. For 5 and 6 the magnetic analysis showed a strong antiferromagnetic coupling between the M(II) centers, with spin frustration leading to an overall S = 5/2 and S = 2 ground state, respectively.