Exchange Coupling in Carboxylato-Bridged Dinuclear Copper(II) Compounds: A Density Functional Study

Abstract

A computational study of the exchange coupling is presented for a selected sample of carboxylato-bridged dinuclear copper(II) compounds. Model calculations have been used to examine the influence of several factors on the coupling constants: a) the electron-withdrawing power of the bridging ligands; b) the nature of the axial ligands; c) the number of bridging carboxylato groups; d) some structural distortions frequently found in this family of compounds; and e) the coordination mode of the carboxylato bridge. Coupling constants calculated for some complete structures, as determined by X-ray diffraction, are in excellent agreement with experimental data, confirming the ability of the computational strategy used in this work to predict the coupling constant for compounds for which experimental data are not yet available.

Solvothermal syntheses, characterizations and properties of two new NiII-PMIDA phosphonates

“…The magnetic data are fitted by Curie-Weiss law v m = C m /(T À h) above 12.4 K, obtaining fitted parameters Weiss constant h = À18.47 K and Curie constant C = 5.26 emu K mol À1 . Based on spin Hamiltonian for the parallelogram-like arrangement of four S = 1 Ni(II) centers[28,29], the better fitted parameters of compound 2 are obtained above 18 K: J = À10.21 cm À1 , g = 2.53 and TIP = 0.0008 emu mol À1 . The isothermal magnetization M(T, H) at 4 K for compound 2 is also measured (seeSupporting Information Fig.…”

“…Fan). O-C-O groups in anti-anti coupling mode, which gives rise to a weak antiferromagnetic coupling[25]. Fit of the magnetic data was done above 15 K by using the Curie-Weiss law v m = C m / (T À h): C = 1.08 emu K mol À1 and h = À18.5 K. The negative h further confirmed antiferromagnetic interaction between Ni(II) ions.…”

Magnetic behaviour in metal-organic frameworks—Some recent examples

“…Of the 3d transition metal ions, Cu +2 ions have the largest number of complexes employing the three bridging modes described above when considering compounds that are formed without any other bridges. [22][23][24][25] This creates impediment for a complete interpretation of the magnetic interactions that are formed by the carboxylate bridges.…”

Syntheses, structures and magnetic property of two copper complexes with cyclic dimer and 2D herringbone-like network built from helical motif

“…The magnetic orbital at each copper atom is defined by the short equatorial bonds, and it is of the d x 2 Ày 2 type with possible some mixture of the d z 2 character in the axial position. Theoretical DFT calculations corroborate these general features [15]. In the second case (basal-axial, such as in complex 1), low magnetic coupling should be expected because the magnetic orbitals involved are the d x 2 Ày 2 and d z 2 , respectively.…”