Experimental magnetic studies performed on the [{CuLX}2
] system (HL = pyridine-2-
carbaldehyde thiosemicarbazone, X = Cl−, Br−, I−) point to the larger electronegativity in X, the lower
magnitude of the antiferromagnetic interactions. In order to confirm this and other trends observed
and to dip into them, computational studies on the [{CuLX}2
] (X = Cl− (1), I− (2)) compounds are here
reported. The chemical and structural comparisons have been extended to the compounds obtained in
acid medium. In this regard, chlorido ligands yield the [Cu(HL)Cl2
]·H2O (3) complex, whose crystal
structure shows that thiosemicarbazone links as a tridentate chelate ligand to square pyramidal Cu(II)
ions. On the other hand, iodido ligands provoke the formation of the [{Cu(H2L)I2
}2
] (4) derivative,
which contains pyridine-protonated cationic H2L
+ as a S-donor monodentate ligand bonded to
Cu(I) ions. Crystallographic, infrared and electron paramagnetic resonance spectroscopic results are
discussed. Computational calculations predict a greater stability for the chlorido species, containing
both the neutral (HL) and anionic (L−) ligand. The theoretical magnetic studies considering isolated
dimeric entities reproduce the sign and magnitude of the antiferromagnetism in 1, but no good
agreement is found for compound 2. The sensitivity to the basis set and the presence of interdimer
magnetic interactions are debated.
