Structures of 2,4,6-tri-α-pyridyl-1,3,5-triazine complexes of the lanthanoid nitrates:: A study in the lanthanoid contraction

The structures are reported of 20 1:1 complexes formed between 2,4,6-tri-cz-pyridyl-1,3,5-triazine (tptz) and the nitrates of yttrium and the lanthanoids (La-Lu except Pm). The complexes can be divided up into a series of structural types. The majority of the characterised complexes belong to the isostructural family [Ln(tptz)(NO3)(3)(H2O)]center dot 2C(2)H(5)OH (Ln = Y (3), La-Yb (4-16)), which have three bidentate nitrate groups as well as a co-ordinated water molecule, and the metal ion is 10 co-ordinate, whilst a similar lanthanum complex [La(tptz)(NO3)(3)(H2O)]center dot Me2CO (2) has been prepared. Eleven co-ordinate [La(tptz)(NO3)(3)(CH3OH)(2)] (1), which has three bidentate nitrate groups as well as two co-ordinated methanol molecules, is also reported. By varying the solvent used, three different lutetium complexes can be obtained; [Lu(tptz)(NO3)(3)(C2H5OH)]center dot C2H5OH (18) and [Lu(tptz)(NO3)(3)(H2O)]center dot MeCN (19), both featuring two bidentate nitrate groups, a monodentate nitrate group and a co-ordinated solvent molecule, and [Lu(tptz)(NO3)(2)(H2O)(2)]NO3 center dot 3MeOH (20), whose cation contains two bidentate nitrate groups as well as two co-ordinated water molecules. The ytterbium complex [Yb(tptz)(NO3)(3)(C2H5OH)]-C2H5OH (17) is also described. (c) 2005 Elsevier Ltd. All rights reserved.