Study of the aqueous reactions of metallic ions with benzenetetracarboxylate ions: Part 2. Crystal structures of compounds of the type M(H2O)5(μ-C6H2(COO)4)M(H2O)5 (M=Mn and Co) and a novel mixed-metallic Mn–Co dimeric compound

The reactions of barium 1,2,4,5-benzenetetracarboxylate with CoSO4 produced the dinuclear species Co(H2O)5(μ-C6H2(COO)4)Co(H2O)5 which was characterized by crystallographic methods. The results have shown that the compound belongs to the monoclinic C2/c space group and it crystallized with six molecules of water in the lattice. The crystal is stabilized by a very elaborate H-bonded 3D network. The molecule contains an inversion center. The average Co–OH2 distance is 2.0710(8) Å and the sixth Co–O bond is 2.0356(7) Å. The reaction of MnCl2 with benzenetetracarboxylate ions produced a similar dinuclear species, Mn(H2O)5(μ-C6H2(COO)4)Mn(H2O)5·H2O (2). The crystallographic results have shown that there are two independent molecules, which each contains an inversion center. This compound crystallized with only one molecule of water, and again the H-bonding system is very elaborate. The aqueous reaction of K2Mn(C6H2(COO)4)·3H2O with CoSO4 produced a compound containing two dinuclear species {Mn(H2O)5(μ-C6H2(COO)4)Mn(H2O)5}{Co(H2O)5(μ-C6H2(COO)4)Co(H2O)5}·2H2O, which was characterized by X-ray diffraction methods. The results have shown that the latter compound is isomorphous with the Mn(II) compound. One of the Mn(II) dimer in 2 has been replaced by a Co(II) dimer.