Influence of the counteranion on the formation of polymeric networks by metal complexes of hexamethylenebis(acetamide)

An investigation into the anion dependence of the network-forming ability o f metal complexes of hexamethylenebis(acetamide), CH3CONH(CH2)(6)NHCOCH3 (H MBA), has resulted in the X-ray characterization of the compounds [Co(HMBA) (3)] [Co(NCS)(4)], 1, [Nd(HMBA)(3)] [Nd(NO3)(6)].2CHCl(3), 2, [Co(HMBA)(3)] [HgCl4] 3, and [Mn(HMBA)(3)]- [HgBr4].3CHCl(3), 4. The structures of compou nds 1, 3, and 4 each comprise cationic frameworks formed by the bridging ac tion of HMBA ligands binding octahedrally to the cobalt or manganese center s and, in the cases of 3 and 1, the formation of tetrahedral HgX42- anions by transfer of the respective halide ions from Co or Mn to Hg. Complete ani on (NO3-) transfer between Nd centers is also a key factor in the structure of 2, which forms a cationic 3-D network of HMBA-bridged octahedrally coor dinated Nd centers with occluded [Nd(NO3)(6)](3-) anions. These types of in ter-metal-anion transfer, with consequent complex counteranion formation, a ppear to facilitate the network-forming ability of the metal-HMBA cationic arrays.