Spectroscopic, Magnetic, and Electrochemical Studies of a Dimeric N-Substituted-Sulfanilamide Copper(II) Complex. X-ray and Molecular Structure of the Cu₂(sulfathiazolato)₄ Complex

Abstract

A copper(II) complex of formula Cu(2)(stz)(4) (stz(-) = sulfathiazolato) has been synthesized and characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic system, space group P2(1)cn with a = 10.595(7) Å, b = 14.274(3) Å, c = 29.65(1) Å, and Z = 4. The structure consists of dinuclear copper(II) units which contain four sulfathiazolato ligands bridging the metal ions through a nonlinear NCN group. The copper atoms are four-coordinated, the chromophore being CuN(4). The Cu.Cu bond distance is 2.671(2) Å. Magnetic susceptibility data in the temperature range 7-300 K show the occurrence of intramolecular antiferromagnetic coupling with 2J = -61.5 cm(-1). This low exchange energy value has been analyzed and rationalized through extended Hückel calculations. EPR spectra at X- and Q-band frequencies show the signals corresponding to a dinuclear entity, being the zero-field splitting parameter, D = 0.230 cm(-1).

Development of novel copper(II) complexes of benzothiazole-N-sulfonamides as protective agents against superoxide anion. Crystal structures of [Cu(N–2-(4-methylbenzothiazole)benzenesulfonamidate)2(py)2] and [Cu(N–2-(6-nitrobenzothiazole)naphthalenesulfonamidate)2(py)2]

“…In complex 2 the tetrahedrality value, s, of 1.18°indicates that the copper ion adopts a nearly square planar geometry [46]. The Cu-N bond distances lie in the range of 1.952(2)-2.028(4) Å , which are normal lengths for Cu-N py , Cu-N sulfonamido , and Cu-N thiazole coordination bonds [28,29,30]. The Cu-N thiazole [1.96(2) av Å ] in 2 is shorter than the Cu-N sulfonamido in 1 [2.028(4) Å ].…”

“…To this end, we have synthesized a variety of mono-and dinuclear compounds and studied them extensively [24,25,26,27,28,29,30,31,32,33]. Recently we have also become interested in ternary sulfonamide complexes with SODlike activity.…”

New MnII Complexes with an N/O Coordination Sphere from TripodalN-Centered Ligands − Characterization from Solid State to Solution and Reaction with Superoxide in Non-Aqueous and Aqueous Media

“…[14] Moreover, it provides a simple means of investigating the reactivities of complexes towards superoxide in aqueous buffers and of assessing the effect of additional compounds (e.g., chelators). [14,15,23,42,43] The X/XO assay has proven that complexes 1 and 2 react with superoxide in aqueous solution. Experiments performed in the presence of excess chelators (BSA, EDTA) have shown that the complexes are partially decoordinated in the IC 50 concentration range.…”

Supramolecular Architectures and Magnetic Properties of Self‐Assembled Windmill‐Like Dinuclear Copper(II) Complexes with Purine Ligands

“…[13] The interaction between the spins of both metal atoms through the ligand leads to splitting in two electronic states, giving rise to a singlet (S = 0) and a triplet (S = 1). [15] (Hypox = 7H-hypoxanthine, ox = oxalate anion).…”