Manganese(II), lead(II) and cadmium(II) coordination complexes containing a tetrazole-based acylamide ligand: synthesis and the influence of the metal ions on the structures.

Three new manganese(II), lead(II) and cadmium(II) coordination complexes have been prepared by reaction of N-(1H-tetrazol-5-yl)cinnamamide (HNTCA) with divalent metal salts (MnCl2 , PbCl2 and CdCl2 ) in a mixed-solvent system, affording mononuclear to trinuclear structures namely, bis(methanol-κO)bis[5-(3-phenylprop-2-enamido)-1H-1,2,3,4-tetrazol-1-ido-κ2 N1 ,O]manganese(II), [Mn(C10 H8 N5 O)2 (CH3 OH)2 ], (1), bis[μ-5-(3-phenylprop-2-enamido)-1H-1,2,3,4-tetrazol-1-ido]-κ3 N1 ,O:N2 ;κ3 N2 :N1 ,O-bis{aqua[5-(3-phenylprop-2-enamido)-1H-1,2,3,4-tetrazol-1-ido-κ2 N1 ,O]lead(II)}, [Pb2 (C10 H8 N5 O)4 (H2 O)2 ], (2), and hexakis[μ2 -5-(3-phenylprop-2-enamido)-1H-1,2,3,4-tetrazol-1-ido-κ3 N1 ,O:N2 ]tricadmium(II), [Cd3 (C10 H8 N5 O)6 ], (3). The structures of these three compounds reveal that the nature of the metal ions and the side groups of the organic building blocks have a significant effect on the structures of the coordination compounds formed. Intermolecular hydrogen bonds link the molecules into two-dimensional [complex (1)] and three-dimensional hydrogen-bonded networks. Complexes (2) and (3) show significant fluorescence, while complex (1) displays no fluorescence.