Syntheses, Structures and Magnetic Properties of Novel Oxamido‐Bridged Tetranuclear Complexes [Cu₃M] (M = Cu, Mn)

Abstract

Three oxamido-bridged tetranuclear complexes with the formulae -5,6:15,16-dibenzo-1,4,8,13-tetraazacylotetradeca-7,13-diene) have been prepared and characterised. Their structures were deduced using X-ray crystallography. All three complexes crystallise in the triclinic system, space group P1 . The three copper ions of the complex ligands and the central metal ions (Cu, Mn) remain in the plane and form a scalene triangle. Three copper ions occupy the vertexes and the M(Cu, Mn) ions are located at the centre. Magnetic susceptibility meas-

Syntheses, structure and magnetic properties of oxamido-bridged trinuclear Cu–M–Cu macrocyclic complexes (M=Cu, Co and Mn)

“…The magnetic properties of complex 3 indicates the neighbouring ions of Cu and Mn, exhibit weak antiferromagnetic intramolecular interaction with J = À13.93 cm À1 (corresponding with reported result [27]), g = 1.96, and R = 2.43 · 10 À3 . N a is set as 120 · 10 À6 m 3 mol À1 .…”

“…The fitting parameters indicate significant anti-ferromagnetic coupling between adjacent copper ions in complex 1. The antiferromagnetic interaction between the copper(II) ions for complex 1 is within other oxamido bridge copper complexes reported previously (J = 210 À 61.8 cm À1 ) [27,29,30]. The magnitude of the antiferromagnetic interaction is due to the better co-planarity overlap between the magnetic orbital central to each copper [33].…”

“…Moreover oxamido bridge is regarded as one of the best bridges, which could transfer magnetic coupling [14][15][16][17][18]. Although most of the reported polynuclear complexes of nearest neighbouring magnetic centers impose antiferromagnetic coupling except Cu II -VO IV , Cu II -Cr III , Cu IIGd III , Ni-Cr III , and low spin Fe III -Cu II system [8,[19][20][21][22][23], and the design and construction of magnetic materials is still a challenge due to the difficulties in selecting proper metal ions and ligands, great efforts have been devoted to this field [24][25][26][27][28]. Investigating relationship with coordination environment, complex structure and electron structure will give the basic and useful information to design and synthesize complexes with expected magnetic behavior, which have been rarely reported [29][30][31].…”

(7,12-Diphenyl-5,6:13,14-dibenzo-8,11-diazonia-1,4-diazacyclopentadeca-7,12-diene-2,3-dione)nickel(II)

“…Among the transition metal complexes of macrocyclic ligands (Wang et al, 2004;Zhang et al, 2003), the oxamide bridge serves as a pathway through which electron spin interaction takes place. The title complex, (I), has such a bridge (Fig.…”

Synthesis, crystal structure of a new tetranuclear Ni 2 II Cu 2 II complex containing a macrocyclic ligand

“…In order to extending this view, we have designed and synthesized a new complex with the macrocyclic oxamido-nickel(II) complex and thiocyanate. This is the first established example involving both bridging N, S-ligand and oxamide ligand [13][14][15]. Here, we described the syntheses, crystal structure and spectroscopic characterization of [(NiL) 2-Cu 2 (l-NSC) 2 (NSC) 2 ].…”