Density functional theory study of the magnetic coupling interaction in a series of binuclear oxalate complexes

Abstract

Magnetic couplings in oxalate-bridged binuclear complexes, namely five isomers of [(VO) 2 (ox) (SCN) 6 ] 4-, trans-(equatorial, equatorial), cis-(equatorial, equatorial), trans-(axial, axial), cis-(axial, axial), and (axial, equatorial), as well as [Cr 2 [Ni 2 (ox) 5 ] 6-, and [Cu 2 (ox)(C 12 H 8 N 2 ) 2 ] 2? , were calculated with the broken symmetry approach. Predominant antiferromagnetic coupling is found in almost all investigated complexes, except in [CrFe(ox)(SCN) 8 ] 4-. The best agreement with experimental values for the exchange coupling constants were obtained at the B3LYP level of theory, whereas the non-hybrid functionals gave the best trend for the investigated vanadium complexes. The linear relationship between coupling constant and (e 2 -e 1 ) 2 as well as linear dependence of J and the square of overlap integral of magnetic orbitals was estimated.

An oxalate-bridged oxidovanadium(IV) binuclear complex that improves the in vitro cell uptake of a fluorescent glucose analog

“…In all cases listed in the table, the magnetic exchange coupling constant (J) is small and compatible with weak antiferromagnetic coupling. Other relative arrangements of the VO 2+ groups in oxalate-bridged dimers, and their magnetic interaction, have been the subject of theoretical studies [15].…”

“…In the coordination chemistry of transition metals such as vanadium, much attention has been devoted to oxalate-containing (C 2 O 4 2or ox 2 ) complexes due to their interesting structural, catalytic [13,14] and magnetic features. [15,16]. The bioinorganic relevance of vanadiumoxalate chemistry, in its turn, has been addressed in a variety of levels [16][17][18].…”

Eight novel metal diphosphonates based on 2-(4-pyridinyl)-1-hydroxyl-1,1-ethylidenediphosphonate: syntheses, structures, and magnetic properties

“…Therefore, the susceptibility data can be analyzed by using a linear trinuclear copper(II) model. Considering the inter-trimer exchange (zj9), a good fit was obtained in the temperature range 25-300 K with the parameters: g = 2.26, J = 25.58 cm 21 , zj9 = 20.27 cm 21 .…”

“…8 Building unit of structure 7 with atomic labeling scheme (50% thermal ellipsoids). Symmetry codes: A: 21 + x, y, z; B: x, 21 + y, z; C: 1 2 x, 1 2 y, 1 2 z; D: 2 2 x, 1 2 y, 1 2 z; E: 1 2 x, 2 2 y, 1 2 z. K, the magnetic moment per Mn 2 is 8.63 cm 3 K mol 21 , close to the theoretical value (8.37 cm 3 K mol 21 ) for spin only value for a pair of S = 5/2 spins with g = 2.0. Fitting of the x M 21 -T using the Curie-Weiss law x M = C/(T-h) gives the Curie constants C = 8.88 cm 3 K mol 21 and negative Weiss constant h = 28.68 K (Fig.…”

“…The susceptibility data above 30 K were fitted to the Curie-Weiss law with the Curie and Weiss constants of 3.8 cm 3 K mol 21 and 245 K, respectively (Fig. S15, ESI3).…”