[Structural and spectral study of a novel lanthanide 2-hydroxynicotinic acid coordination polymer].

A novel lanthanide 2-hydroxynicotinic acid coordination polymer 1 {[LaL(HL) (H2O)3]1/3 (SO4)2/3 (H3O)2 H2O} (H2 L = 2-hydroxynicotinic acid) has been synthesized under hydrothermal condition and characterized by crystal X-ray diffraction, IR, UV, TGA, two-dimensional infrared (2D IR) correlation spectroscopy with magnetic and thermal perturbation. In 1, La ions are connected by 2-hydroxynicotinic acid through both carboxylate oxygen atoms and oxygen atoms from hydroxyl group in pyridine to generate a 2D layer in the ab plane, these layers are further connected by weak interactions to form a 3D framework along c axis. The response of out-of-plane bending vibrations of N-H and C-H are remarkable in the 2D IR correlation spectra under magnetic perturbation, this may attributes to the inducement of pi-electron cloud deformation under magnetic perturbation, v4 vibrations from SO4(2-) was also sensitive to magnetic perturbation. In addition, stretching vibrations from N-H are sensitive to thermal perturbation.