Synthesis, structure and characterisation of Ln5O(OPri)13 with Ln = Nd, Gd or Er

The molecular and basically isostructural oxo-alkoxides Ln(5)O(OPri)(13) (Pr-i = 2-propyl) with Ln = Nd (1) and Gd (2) were synthesized by metathesis of LnCl(3) and KOPri, in combination with stoichiometric hydrolysis, in 2-propanol-containing solvents. Er5O(OPri)(13) 3 was obtained as co-product to an erbium aluminium 2-propoxide with an Er : Al ratio of ca. 3 : 1, from the reaction of 15KOPr(i) + H2O + Al(OPri)(3) with 5ErCl(3), in toluene-2-propanol. The solid state structures of 1-3 were obtained by single-crystal X-ray diffraction. The characterisations were made with differential scanning calorimetric measurements, UV-Vis and FT-IR spectroscopy. The molecule contains an M5O fragment with the configuration of a square pyramid and the oxo-oxygen atom slightly above the basal plane. FT-IR measurements showed that the molecular structure of the alkoxide was retained, to a large extent, when dissolved in toluene-2-propanol (2 : 1) or hexane. Investigations by UV-Vis and FT-IR spectroscopy showed that Ln(5)O(OPri)(13) reacted with Al-4(OPri)(12) (Ln : Al = 1 : 3) in toluene-2-propanol to form LnAl(3)(OPri)(12) within 2 hours at 80 degreesC.