Synthesis, Characterization and Single Crystal X–ray Crystallography of Nd(III) and Pr(III) Complexes with the Tridentate Schiff Base Ligand N'–(1–(pyridin–2–yl)ethylidene)nicotinohydrazide

Abstract

The use of N'–(1–(pyridin–2–yl)ethylidene)nicotinohydrazide (HL) in lanthanide(III) chemistry has yielded one mononuclear and one dinuclear complexes. The 1:1 Nd(NO3)3.6H2O or Pr(CH3COO)3.6H2O/HL in methanol afforded the complexes [Nd (HL)2(NO3)2(H2O)2].(NO3) (1) and {[Pr(L)(h2–OOCCH3)(H2O)](h1:h2:m–OOCCH3)2[Pr (L)(h2–OOCCH3)(H2O)]} (2). The structures of the complexes were solved by single crystal X–ray crystallography. In the mononuclear complex, the Nd3+ atom is coordinated by two neutral molecules of ligand acting in tridentate fashion, two nitrate anions acting in bidentate manner and two coordinated water molecules yielding a twelve–coordinated Nd atom. In the complex (2) the Pr3+ atoms are doubly bridged by two acetates anions and each metal ion is coordinated by one tridentate monodeprotonated molecule ligand, one bidentate acetate group and one coordinated water molecule. Each Pr3+ atom is nine–coordinated with an environment best described as a tricapped prismatic geometry. Complex 1 crystallizes in the monoclinic space group C2/c with the following parameters: a = 22.7657(8) Å, b = 8.4276(3) Å, c = 18.0831(7) Å, b = 114.851(2)°, V = 3148.2(2) Å3, Z = 4, R1 = 0.032, wR2 = 0.098. Complex 2 crystallizes in the monoclinic space group P21/n with the following parameters: a = 11.5388(6) Å, b = 14.1087(8) Å, c = 12.2833(6) Å, b = 102.211(2)°, V = 1954.45(18) Å3, Z = 2, R1 = 0.029, wR2 = 0.066. The supramolecular structures are consolidated by multiple hydrogen bonds.

Synthesis, Spectroscopic, Characterization and X-ray Structures of Lanthanide(III) Complexes Derived from 1,5-bis(phenyl(pyridin-2-yl)methylene)carbonohydrazide

“…Each ligand form a pair of five membered rings with the metal ions. The bite angles values in the five membered rings are in the range [56.8(1) °-62.0(1)°] and are in accordance with the values reported for similar complexes [52]. The ligand containing N5 bonds to the metal ion through its N5, N6 and O1 atoms generation two five membered rings.…”

Synthesis and Structural Study of the Mixed Copper (II)/lanthanum (III) Complex with the Bicompartmental Ligand H2L = 2,2'-{propane-1,2-diyl bis[Nitrilomethylylidene ]}Bis(6-Methoxyphenol)

“…The separation Δυ = υ1-υ5 is used as a selection criterion between a monodentate nitrate group and a bidentate nitrate group, Δυ increasing with the mode of coordination. The value of Δυ = 111 cm -1 clearly indicates that the nitrate group is bidentate [16]. No band characteristic of an uncoordinated nitrate group is observed at 1380 cm -1 .…”