Structural Systematics of Rare Earth Complexes. XIV Hydrated 1 : 1 Adducts of Lanthanoid(III) Nitrates with 2,2′:6′,2″-Terpyridine

Abstract

Room-temperature single-crystal X-ray structure determinations are recorded for (hydrated) lanthanoid(III) nitrate/2,2′:6′,2″-terpyridine (‘tpy’) (1 : 1) complexes; all are of the form Ln(NO₃)₃/tpy/H₂O(1 : 1 :x), [(tpy)Ln(O₂NO)₂(OH₂)_y](NO₃)(.z H₂O), and form two series of compounds. For Ln = La(-)Gd, the complexes are [(tpy)Ln(O₂NO)₂(OH₂)₃](NO₃), the lanthanoid atom being ten-coordinate; crystals are triclinic, P 1, a ≈ 11·8, b ≈ 11·3, c ≈ 8·9 Å, α ≈ 75, β 69, γ ≈ 89°, Z = 2 f.u., conventional R on |F| 0·045, 0·062 for N_o 4513, 2710 independent ‘observed’ (I > 3σ(I)) diffractometer reflections for Ln = La, Gd respectively. For Ln = Tb(-)Lu, a different form is found: monoclinic, P 2₁/c, a ≈ 8·8, b ≈ 11·5, c ≈ 23·8 Å, β ≈ 111°, Z = 4, R 0·055, 0·037, 0·056 for N_o 2427, 3079, 1857 for Ln = Tb, Lu, Y respectively, the form of the complex being [(tpy)Ln(O₂NO)₂(OH₂)₂](NO₃).2H₂O, with nine-coordinate lanthanoid. Crystallization of the Ln = La adduct from methanol yields an adduct of La(NO₃)3/tpy/MeOH (1 : 1 : 2) [(tpy)La(O₂NO)₃(HOMe)₂] stoichiometry with 11-coordinate lanthanum. Crystals are triclinic, P 1, a 12·361(2), b 12·244(3), c 7·753(2) Å, α 96·56(2), β 103·22(2), γ 91·16(2)°, Z = 2, R 0·037 for N_o 6597.