Cobalt-5-aminoisophthalate: [Co(AIPA)(OH2)2] n ·nH2O: a new one-dimensional rail-road polymer with occluded water molecules

Abstract

A new structural form of cobalt-5-aminoisophthalate, [Co(AIPA)(OH2)2]n·nH2O (1) has been synthesized from the reaction of CoCl2·6H2O with 5-aminoisophthalic acid (AIPA-H2) in a 1:1 molar ratio at room temperature by layering aqueous solutions of the starting materials over a period of 2–3 weeks. [Co(AIPA)(OH2)2]n·nH2O (1) has been characterized by elemental analysis, IR spectroscopy, and single crystal X-ray diffraction studies. [Co(AIPA)(OH2)2]n·nH2O (1) crystallizes in triclinic space group P\(\bar{1}\) (a=7.549(2) A, b=8.833(2) A, c=9.080(2) A, α=62.23(3)°, β=75.09(3)°, γ=81.52(3)°). Compound 1 forms a rail-road like 1-D polymeric structure which is held together in the lattice by a variety hydrogen bonds aided by the presence of lattice water molecule. The Co2+ ion is in a severely distorted octahedral geometry with a CoO5N coordination environment.