Synthesis and crystal structures of two coordination polymers and a binuclear cadmium(II) complex containing 3- and 4-aminobenzoate ligands.

Abstract

Due to their wide range of coordination modes and versatile conformations when binding to metal atoms, multicarboxylate ligands are of interest in the design of metal-organic frameworks (MOFs). Three Cd(II) complexes, namely catena-poly[diammonium [[chloridocadmium(II)]-di-μ-chlorido-[chloridocadmium(II)]-bis(μ-3-aminobenzoato)-κ(3)N:O,O';κ(3)O,O':N]], {(NH4)[CdCl2(C7H6NO2)]}n, (I), catena-poly[[[aquacadmium(II)]-bis(μ-4-aminobenzoato)-κ(3)N:O,O';κ(3)O,O':N] monohydrate], {[Cd(C7H6NO2)2(H2O)]·H2O}n, (II), and di-μ-acetato-κ(4)O:O'-bis[(4-aminobenzoato-κ(2)O,O')(2,2'-bipyridine-κ(2)N,N')cadmium(II)], [Cd2(CH3COO)2(C7H6NO2)2(C10H8N2)2], (III), with different stuctural forms are reported. Complex (I) has a one-dimensional ladder structure, with strong N-H···O and weak N-H···Cl hydrogen bonds linking the cations and anions in the three-dimensional supramolecular structure. Complex (II) has a one-dimensional chain structure. Extensive O-H···O and N-H···O hydrogen bonds between the anionic ligands and the solvent water molecules and π-π stacking interactions between the centroids of the benzene rings lead to the three-dimensional supramolecular structure. Complex (III) is a binuclear molecule which is extended into a three-dimensional supramolecular structure via strong N-H···O and weak C-H···O hydrogen bonds.