A new series of lanthanide based complexes with bis(hydroxy)benzoxaborolone ligand: Synthesis, crystal structure, magnetic and optical properties.
Reactions, in hydro thermal conditions, between a lanthanide chloride and the sodium salt of 2 carboxyphenylboronic acid leads to a series of lanthanide based complexes with general chemical formula [Ln2(C7H5O2)4(C7O4H6B)2·4H2O] (hereafter symbolized by [Ln(o cpb)]) with Ln = Eu Dy. During the synthetic process, 2 carboxyphenylboronate ligand decomposes leading to benzoate (C7H5O2) and bis(hydroxy)benzoxaborolone (C7O2H6B). Crystal structure was solved on the basis of the Tb derivative. It crystalizes in the triclinic system, space group P-1 (n°2) with a = 9.3329(13) Å, b = 16.012(2) Å, c = 16.212(2) Å, = 107.789(5)°, = 90.226(5)°, = 97.585(5)°, V = 2284.16(52) Å3 and Z = 2. Crystal structure can be described on the basis of di lanthanides complexes surrounded by the ligands. Compounds that constitute these series are thermally stable up to 190°C. Solid state luminescent properties have been studied in details. Dy derivative magnetic properties have also been explored. It presents a Single Molecule Magnet behavior. Single crystals of the sodium salt of 2 carboxyphenylboronic acid with chemical formula [Na(C7O4H6B)(H2O)]∞ have also been obtained during this study. This compound crystalizes in the orthorhombic system, space group P212121 (n°19) with a = 4.5881(13) Å, b = 6.5905(16) Å, c = 29.644(8) Å, V = 897.0(4) Å3 and Z = 4. Crystal structure is 2D and can be described as zig zag chains of sodium 2 carboxyphenylboronate bound to each other by coordination water molecules.