Two new ligands, 2-[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenol (HL) and 2-[(bis(2-pyridylmethyl)amino)methyl]-4-methyl-6-(methylthio)phenol (HSL), were synthesized and were used to prepare the trinuclear copper(II) complex {[CuSL(Cl)]
2Cu}(PF
6)
2·H
2O (
1) and the corresponding binuclear complexes [Cu
2(SL)
2](PF
6)
2 (
2) and [Cu
2L
2](PF
6)
2 (
3).The crystal structure of
1 shows two different coordination environments: two square base pyramidal centers (Cu1 andCu1a, related by a
C2 axes), acting as ligands of a distorted square planar copper center (Cu2) by means of the sulfuratom of the SCH
3 substituent and the bridging phenoxo oxygen atom of the ligand (Cu2-S = 2.294 Å). Compounds
2and
3 show two equivalent distorted square base pyramidal copper(II) centers, bridged in an axial-equatorial fashion bytwo phenoxo groups, thus defining an asymmetric Cu
2O
2 core. A long copper-sulfur distance measured in
2 (2.9261(18)Å) suggests a weak bonding interaction. This interaction induces a torsion angle between the methylthio group and thephenoxo plane resulting in a dihedral angle of 41.4(5)
![](/images/entities/deg.gif)
. A still larger distortion is observed in
1 with a dihedral angle of74.0(6)
![](/images/entities/deg.gif)
. DFT calculations for
1 gave a ferromagnetic exchange between first neighbors interaction, the calculated
Jvalue for this interaction being +11.7 cm
-1. In addition, an antiferromagnetic exchange for
1 was obtained for the secondneighbor interaction with a
J value of -0.05 cm
-1. The Bleaney-Bowers equation was used to fit the experimentalmagnetic susceptibility data for
2 and
3; the best fit was obtained with
J values of +3.4 and -16.7 cm
-1, respectively.DFT calculations for
2 and
3 confirm the nature and the values of the
J constants obtained by the fit of the experimentaldata. ESR and magnetic studies on the reported compounds show a weak exchange interaction between the copper(II)centers. The low values obtained for the coupling constants can be explained in terms of a poor overlap between themagnetic orbitals, due to the axial-equatorial phenoxo bridging mode observed in these complexes.