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

Abstract

The structures are reported of 20 1:1 complexes formed between 2,4,6-tri-α-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)(NO 3) 3(H 2O)] · 2C 2H 5OH (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)(NO 3) 3(H 2O)] · Me 2CO ( 2) has been prepared. Eleven co-ordinate [La(tptz)(NO 3) 3(CH 3OH) 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)(NO 3) 3(C 2H 5OH)] · C 2H 5OH ( 18) and [Lu(tptz)(NO 3) 3(H 2O)] · MeCN ( 19), both featuring two bidentate nitrate groups, a monodentate nitrate group and a co-ordinated solvent molecule, and [Lu(tptz)(NO 3) 2(H 2O) 2]NO 3 · 3MeOH ( 20), whose cation contains two bidentate nitrate groups as well as two co-ordinated water molecules. The ytterbium complex [Yb(tptz)(NO 3) 3(C 2H 5OH)] · C 2H 5OH ( 17) is also described.