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Structural Systematics of Rare Earth Complexes. XVIII (Hydrated) Mononuclear 1 : 1 Adducts of Lanthanoid( <i>III</i> ) Chlorides with 2,2′-Bipyridine
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1999
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Room-temperature single-crystal X-ray structure determinations are recorded for a number of adducts of hydrated lanthanoid(III) chlorides with 2,2'-bipyridine, ‘bpy’, crystallized from water/ethanol solutions, which contain mononuclear arrays with 1 : 1 Ln/bpy stoichiometry. Extended isomorphous series have been defined pertinent to the heavy end of the Ln series: crystals of LnCl3/bpy/H2O (1 : 1 : 6) ([(bpy)Ln(OH2)6]Cl3), seemingly inclusive of (at least) the range Ln = Ho(-)Lu and Y, are monoclinic, P 21/ n , a ˜ 14·2, b ˜ 7·7, c ˜ 17·4 Å, ß ˜ 91°, Z = 4, with an eight-coordinate LnN2O6 array; conventional R values on | F | were 0·043, 0·029, 0·057 for N o 2435, 3120, 1846 independent ‘observed’ ( I &gt; 3s( I )) diffractometer reflections (Ln = Ho, Lu, Y). Crystals of LnCl3/bpy/H2O (1 : 1·5 : 8) ([(bpy)Ln(OH2)6]Cl3.½bpy.2H2O), seemingly encompassing (at least) the range Ln = Er(-)Lu and Y, are triclinic, P 1, a ˜ 11·7, b ˜ 11·0, c ˜ 10·1 Å, a ˜ 85·8, ß ˜ 74·7, ? ˜ 79·5°, Z = 2, R 0·038, 0·033, 0·048 for N o 3897, 4377, 3130, and contain similar [(bpy)Ln(OH2)6]3+ cations as does HoCl3/bpy/H2O (1 : 2 : 7), [(bpy)Ho(OH2)6]Cl3.bpy.H2O, orthorhombic, Pbca , a 18·02(2), b 20·06(2), c 15·051(9) Å, Z = 8, R 0·057 for N o 3009. By contrast, only sporadic, diverse and unrelated forms are thus far defined among the lighter Ln: EuCl3/bpy/H2O(1 : 1 : 5) ([(bpy)Eu(OH2)4Cl2]Cl.H2O), triclinic, P 1, a 11·506(7), b 11·098(5), c 6·974(8) Å, a 77·35(7), b 85·1(1), ? 89·54(4)°, Z = 2, R 0·063 for N o 4633, also contains a mononuclear [( N , N '-bidentate)Ln(unidentate)6] array. PrCl3/bpy/H2O(1 : 1 : 3)(× 4) is a remarkable compound, being 2[(bpy)Pr(OH2)3Cl3] [(bpy)(H2O)2Cl2Pr(µ-Cl)2PrCl2(OH2)2(bpy)].2H2O, triclinic, P 1, a 13·490(4), b 11·121(2), c 10·162(1) Å, a 96·06(1), ß 90·08(2), ? 96·43(2)°, Z = 2 f.u., R 0·045 for N o 4127, with a mononuclear species of PrCl3/bpy/H2O (1 : 1 : 3) stoichiometry and a binuclear species of 1 : 1 : 2 stoichiometry. A binuclear ethanol solvated array has been characterized for LaCl3/bpy/EtOH (1 : 1 : 2) [(bpy)(EtOH)2Cl2La(µ-Cl)2LaCl2(HOEt)2(bpy)], with eight-coordinate lanthanum; this complex is triclinic, P 1, a 11·426(8), b 10·673(7), c 10·453(7) Å, a 109·60(5), ß 113·10(5), ? 105·80(5)°, Z = 1 dimer, R 0·046 for N o 2786.