Study of copper(II) complexes of two diacetyl monooxime thiosemicarbazones: X-ray crystal structure and magneto-structural correlation of [Cu(dmoTSCH)Cl]2·H2O (dmoTSCH = monoanion of diacetyl monooxime thiosemicarbazone)

Cu(II) complexes of the tridentate thiosemicarbazone ligands diacetyl monooxime thiosemicarbazone (dmoTSCH2) and diacetyl monooxime (4-phenyl)thiosemicarbazone (dmoPhTSCH2) have been synthesized. X-ray crystal structures of dmoPhTSCH2 and [Cu(dmoTSCH)Cl]2·H2O (1·H2O) are also reported. The Cu(II) compound 1·H2O is a dinuclear complex, where the Cu(II) centers have a square pyramidal geometry and are bridged by two thiolato ligands. A C2 axis passes through the middle of Cu2S2 rectangle. Variable temperature susceptibility measurement for 1·H2O shows that this compound exhibits a very weak antiferromagnetic behavior (in the solid state) with J1 = −2.97 cm−1, using the Heisenberg isotropic spin Hamiltonian (H = −J1S1·S2). DFT calculations show that the intramolecular magnetic interaction should be ferromagnetic, and the net antiferromagnetic behavior is due to competition with antiferromagnetic intermolecular interactions through hydrogen bonds.

Graphical abstractTwo Cu(II) complexes, [Cu(dmoTSCH)Cl]2·H2O and [Cu(dmoPhTSCH)Cl]2 (dmoTSCH2 = diacetyl monooxime thiosemicarbazone; dmoPhTSCH2 = diacetyl monooxime (4-phenyl)thiosemicarbazone), containing a [Cu2(μ-S)2] core are reported. The Cu(II) complex [Cu(dmoTSCH)Cl]2·H2O exhibits a very weak antiferromagnetic behavior with J1 = −2.97 cm−1, calculated using the Heisenberg isotropic spin Hamiltonian (H = −J1S1·S2). DFT calculations show that the intramolecular magnetic interaction should be ferromagnetic, and the net antiferromagnetic behavior is due to their competition with antiferromagnetic intermolecular interactions through hydrogen bonds.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Cu(II) complexes of two tridentate thiosemicarbazone ligands are reported. ► They contain a [Cu2(μ-S)2] core and show very weak antiferromagnetic behavior. ► DFT calculations show the intramolecular magnetic interaction is ferromagnetic. ► There are also intermolecular antiferromagnetic interactions mediated by H-bonds. ► The net effect of these two interactions is weak antiferromagnetic behavior.