Formation of Polymeric Network Arrays by Complexes of Manganese(II) or Cobalt(II) with Alkane Chain Linked Bis(amide) Ligands of Biological Relevance

Bis(amides) of the type CH3CONH(CH2) n NHCOCH3 (n = 2, 4, or 6) react with a range of manganese(II) and cobalt(II) salts to produce polymeric “framework” arrays, five of which have been studied by X-ray crystallography. Hexamethylenebis(acetamide) (HMBA) forms the compound [Co(HMBA)3](CoCl4)·2EtOH in which the HMBA molecules bridge the metal centers, binding octahedrally via the oxygen atoms of the amide groups and forming cationic arrays of large rhomboidal “boxes” containing tetrahedral CoCl4 2- ions. The butylenebis(acetamide) (BBA) complex [Co(BBA)3]Br2 forms a sheet cationic network, but in this case, the counteranions are simple bromide ions. The ethylenebis(acetamide) (EBA) complex [Co(EBA)2(H2O)2]Br2 comprises trans-octahedral [Co(O-amide)4(H2O)2]2+ units interlinked by the bridging action of the EBA ligands to form sheet arrays, with simple bromide counterions. From the reaction of HMBA with manganese(II) bromide two crystalline forms were obtained, [Mn(HMBA)3](MnBr4)·2EtOH, with a structure similar to [Co(HMBA)3](CoCl4)·2EtOH, and a solvent-free form, [Mn(HMBA)3](MnBr4), comprising a cationic sheet array. The preparations of several other transition-metal complexes with these ligands are reported together with relevant spectroscopic data.