Synthetic and Structural Studies in the Lanthanide Toluene-4-sulfonate Hydrates

Single-crystal X-ray structure determinations at c. 295 K are reported for representative members of the hydrated toluene-4-sulfonates of the lanthanide elements. The early members of the series, represented by lanthanum, cerium and neodymium, are monoclinic tridecahydrates , space group C2/c, a ≈ 32, b ≈ 7.2, c ≈ 35 A, β ≈ 115 o, Z = 8; the cation is a tricapped trigonal prismatic nonaaqualanthanide (III) species, with three toluene-4-sulfonate counter ions and four lattice water molecules per formula/asymmetric unit. The later members of the series, represented by samarium, lutetium and also yttrium, are, in agreement with contemporary work, monoclinic nonahydrates , space group P21/n, a ≈ 25, b ≈ 7.5, c ≈ 17.8 A , β ≈ 99o, Z = 4; the cation is a square prismatic hexaaquabis (toluene-4-sulfonato)lanthanide(III) species with a single toluene-4-sulfonate counter ion and three lattice water molecules. The solid state dehydration reactions of the tridecahydrates are complicated but there is at least one more endothermic step than is observed for the nonahydrates , with both series of compounds appearing to undergo water loss only below 300oC.