Synthesis, Structure, and Magnetic Properties of a New Chloro-Bridged Dimer [Cu₂(dpt)₂Cl₂]Cl₂ with an Unusual Structure and Ferromagnetic Coupling

Abstract

The complexes [Cu2(dpt)2Cl2]X2 (dpt = dipropylenetriamine; X = Cl, 1; X2 = (Cl)(BPh4), 2) have been prepared and their magnetic properties studied. The crystal structure of complex 1 has been solved. The compound belongs to the C2/c space group with Z = 4, a = 17.201(2) Å, b = 10.873(2) Å, c = 11.835(2) Å, and β = 99.720(10)°. The geometry about each copper approximates that of a distorted square pyramid. The three N-atoms of the dpt ligand and one of the Cl bridging ligands form the base of the pyramid while the other chloro bridging ligand occupies the axial site. The two pyramids share a base-to-apex edge with the basal planes being perpendicular, an arrangement which had not been previously observed for this type of dimers. The chloro counterions are responsible for interdimer interactions through hydrogen bonding forming chains of dimers throughout the lattice. Magnetic susceptibility data show a ferromagnetic coupling between the two Cu(II) centers (J = 42.94 cm-1 for 1 and J = 13.89 cm-1 for 2). Dimer−dimer interaction and ZFS have been considered with the J ‘ parameter (1, J ‘ = −3.92 cm-1; 2, J ‘ = −2.9 cm-1). Extended Hückel calculations on complex 1 clearly reveal that the intradimer magnetic interaction only takes place through the basal chloro bridging ligand (with a CuCl(1)Cu angle of 91.4°) which in turn is consistent with the observed ferromagnetic coupling.

Structural Basis and Mechanism of the Inhibition of the Type-3 Copper Protein Tyrosinase from Streptomyces antibioticusby Halide Ions

“…see Refs. [32][33][34][35][36][37][38][39], and it has also been proposed for both met and half-met hemocyanin (11,26,27,60). We note that exchange of the Cu 2 bridging ligand would affect the magnitude of antiferromagnetic coupling (i.e.…”

Equilibria and catalytic properties of a chloro-bridged Diimine copper(II) complex in the N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) oxidation

“…This result can be justified on the basis of the structural distortion around the copper ions. [36][37][38] For the present complex [Cu 2 (bimpy) 2 For compound 2, the usual Curie-Weiss equation fitted the experimental data.…”

“…This result can be justified on the basis of the structural distortion around the copper ions. [36][37][38] For the present complex [Cu 2 (bimpy) 2 Cl 2 ](ClO 4 ) 2 , (3), a distorted pyramidal coordination geometry is expected in each mononuclear unit that comprises the dimer. In both units, d x 2 -y 2 orbitals are the partially occupied or orbital that is involved in the other half of the bridge.…”

Structural and Magnetic Properties of Monomeric and Dimeric Copper(II) Complexes with Phenyl-N-[(pyridine-2-yl)methylene]methaneamide

“…Current research work concerning the structural and magnetic properties of polynuclear transition metal compounds is aimed at understanding the structural and chemical features governing electronic exchange coupling through multi-atom bridging ligands [1][2][3] and possibilities for magnetic interaction between the two metal ions, leading to the design of molecular magnetic materials. 4 The pyridine-based bridging ligands have been actively utilized as construction units to obtain lots of supramolecular arrays and molecular magnetic materials.…”

“…12, 13 As a part of this program, we have focused on the preparation, characterization and magnetism of copper(II) complexes of [Cu(ppmma)Cl 2 ] 2 and Cu(ppmma)Br 2 together with the X-ray crystal structure determination. In our recent observation, 12 crystal structure determinations of [Cu(dmamhp)X 2 ] 2 complexes (where dmamhp = 2-dimethylaminomethyl-3-hydroxy pyridine) have revealed that both chloride and bromide complexes form dimeric structures, but interestingly, in the present situation, chloride is dimeric while analogous bromide is a monomeric complex.…”