Three-dimensional supramolecular H-bonding network in the compounds containing hexamethylenetetramine and aquated Ni(II) or Cd(II) salts

Abstract

To investigate the interactions between hydrogen bond donor and acceptor giving rise to three dimensional networks, compounds [Ni(H 2O) 6](ClO 4) 2 · 2{(CH 2) 6N 4} · 2H 2O ( 1), [Ni(H 2O) 6]Cl 2 · 2{(CH 2) 6N 4} · 4H 2O ( 2) and [Cd(H 2O) 4{(CH 2) 6N 4} 2](ClO 4) 2 · 2H 2O ( 3) (where (CH 2) 6N 4 = hexamethylenetetramine) have been prepared and their crystal structures were investigated. In all three complexes, the metal coordination is octahedral. The hexamine molecules are complexed in the cadmium compound, 3 but are free in the nickel salts, 1 and 2. The supramolecular structures of 1 and 2 show R 4 4 ( 16 ) motif linking the cationic moieties with hexamine which are in turn interwoven with anionic moieties via water molecules. In contrast the supramolecular structure of 3 shows R 2 2 ( 12 ) motif.