Synthesis, characterization and luminescence properties of lanthanide(III) compounds with 2,6-di(hydroxymethyl)pyridine and the related 2,6-di(hydroxymethyl-d2)pyridine ligand. X-ray structure of [Sm(2,6-di(hydroxymethyl)pyridine)3](NO3)3

The crystal structure of the compound [Sm(pdm)3](NO3)3 (in which pdm=2,6-di(hydroxymethyl)pyridine) is described. The compound crystallises in the monoclinic space group P21/n with a=7.620(7), b=19.05(1), c=19.96(8) Å and β=94.5(4)°. The nine coordinated Sm-ion is bound to three pdm ligands, each donating a nitrogen and two oxygens, with distances SmN 2.571(11)–2.590(11) and SmO 2.422(10)–2.454(10) Å. Time-resolved measurements of solutions of EuCl3 and pdm and its deuterated analogue pdm-d4 in methanol and deuterated methanol revealed rate constants for depopulation of the excited state that vary from 0.44 to 1.32 ms−1.