Study of the tunable structure and two-dimension correlation infrared spectroscopy of Gd/3-methylbenzoic acid with o-phenanthroline, 2,2′-and 4,4′-bipyridines

Three rare earth compounds with 3-methylbenzoic acid (HMeBA) have been hydrothermally synthesized directly: Gd2(MeBA)6(o-Phen)21 (o-Phen = o-phenanthroline), [Gd2(MeBA)6(2,2′-bpy)]n2 (2,2′-bpy = 2,2′-bipyridine) and Gd (MeBA)3·(4,4′-bpy)0.53 (4,4′-bpy = 4,4′-bipyridine). These crystal structures were determined by single-crystal X-ray diffraction with the following data: 1: monoclinic, Cc; 2: monoclinic, P21/n; 3: Triclinic, P − 1. The compound 1 is a zero-dimensional Bi-nuclear oligomer and ligand -o- phenanthroline participates in the coordination; the compound 2 is a one-dimensional chain and the second ligand -2,2′-bpy participates in coordinating with the Gd ion; in particular, due to the existence of the second ligand -4,4′-bpy which acts as the bridge, the compound 3 is the two-dimensional layer. Additionally, in order to explore the structural characteristic, photo-luminescent and the 2D-IR correlation spectroscopy containing the temperature-induced structural variations and magnetism-induced structural variations are used.

► Three Gd/3-methylbenzoic acid and second ligands compounds have been synthesized.
► The different second ligand leads to different coordination modes of carboxylates.
► The influence of second ligand on the structure of the compounds has been studied.
► 2D-IR correlation spectroscopy for the compounds 1 and 2 is studied.