Metallo‐Ligand Based 3d/4f Coordination Polymers: Synthesis, Structure and Magnetic Properties

Abstract

Employment of N,N′‐bis(2‐hydroxy‐4‐carboxyphenyl)oxalamide (H6L) in Cu2+ chemistry afforded the mononuclear complex (Et4N)4[CuL] ⋅ 13H2O (A) which comprises a square planar [CuL]4− complex with several O donor atoms in its periphery. The 1 : 1 reaction between complex A and Ln(NO3)3 ⋅ xH2O (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb, x=6 or 9) in 1 : 4 mixture of ethanol/water in the presence of excess of KCl yielded two families of isomorphous 3d/4f coordination polymers, namely (Et4N)0.5[K0.5(H2O)Ln(H2O)4(CuL)] ⋅ 3H2O [Ln=La(1), Ce(2), Pr(3), Nd(4), Sm(5), Eu(6) and Gd(7)] and [K(H2O)Ln(H2O)4(CuL)] ⋅ ⋅6H2O [Ln=Tb(8), Dy(9), Ho(10), Er(11) and Yb(12)]. The crystal structures of 2–4 revealed the presence of 3D coordination polymers while the crystal structure of 9 the presence of a 2D coordination polymer. In both 3d/4f families, complex A retains its original structure and serves as a “metallo‐ligand”. The magnetic properties of 2–4, 7–9, 11 and 12 are discussed.

The First Tetranuclear Iron(II)‐Gadolinium(III) Carboxylate Complex [Fe2Gd2(piv)10(bpy)2]: Synthesis, Structure Elucidation and Magnetic Properties

“…[1][2][3][4][5][6] A quite big number of 3d-4 f metals complexes has been designed. [7][8][9][10][11][12][13] Some such type complexes have been found to demonstrate single-molecule magnet (SMM) properties. [13][14][15][16][17][18] The understanding of an intramolecular magnetic exchange between paramagnetic 3d-and 4 f-metals is a serious task which is often complicated by the high anisotropy and spin orbital interactions etc.…”

“…The investigations of heterometallic polynuclear complexes based on paramagnetic 3d and 4 f metals have gained increasing and remarkable relevance in view of their variable structural topology, resulting in complicated but fascinating and, sometimes, unusual magnetic properties arising from magnetic exchanges of different nature and energy, strong spin‐orbit coupling and ion magnetic anisotropy [1–6] . A quite big number of 3d–4 f metals complexes has been designed [7–13] . Some such type complexes have been found to demonstrate single‐molecule magnet (SMM) properties [13–18] .…”