The reaction of the phenol-based ligand 4-methyl-2,6-bis{[(2methylpyridyl)(2-methylthiophenyl)amino]methyl}phenol-(Hpy2th2s), containing pyridine and thiophene substituents, with copper(II) chloride and bromide yields two new dinuclear complexes with the composition [Cu 2 (py2th2s)X 3 ], where X = Cl or Br. In both complexes, the copper(II) ions are pentacoordinate and bridged by the deprotonated phenolate anion and by one halogen anion. Both complexes exhibit geometric asymmetry, as the coordination environment around one of the two copper ions is square-pyramidal, whereas the geometry around the other can be best de- [a] scribed as a distorted trigonal bipyramid. The complexes were characterized by means of X-ray single-crystal diffraction, ligand field and EPR spectroscopy, mass spectrometry, and electrochemically. Magnetic susceptibility measurements indicate an antiferromagnetic coupling between the two metal centers (2J ഠ −200 cm −1 ). The interaction of the complexes with model substrates 3,5-di-tert-butylcatechol and tetrachlorocatechol is reported.

The phenol-based compartmental ligand Hpy2ald contains a tridentate amino arm and a weak donor aldehyde group at the 2 0 and at the 6 0 positions of the phenol ring, respectively. This ligand reacts with cobalt(II) perchlorate, cobalt(II) tetrafluoroborate and manganese(II) perchlorate, yielding dinuclear complexes, where two metal ions are doubly bridged by two deprotonated cresolate moieties. The coordination environment around the metal ions is then completed to a very distorted octahedron by three nitrogen donor atoms from the pendant amino arm and the oxygen atom of the aldehyde group. The crystal structures of the complexes, their spectroscopic and magnetic properties are reported.

The phenol‐based ligand Hpy2ald containing formyl, amine and pyridine functions reacts with copper(II) nitrate, copper(II) bromide and manganese(II) chloride to yield complexes with unexpected structures. In contrast to previously reported coordination compounds with similar ligands, the carbonyl group of the ligand in all complexes does not coordinate to the metal ions. The metal‐to‐ligand ratio is 2:1 in the case of the copper(II) nitrate complex and 1:1 in the case of the copper(II) bromide and manganese(II) chloride complexes. The copper(II) nitrate complex exhibits both donor‐atom and coordination number asymmetry, as one copper ion is pentacoordinate with an N3O2 donor set, and the other one is hexacoordinate with an O6 donor set. In the latter two complexes, the phenol group of the ligand remains protonated and fails to bridge the two metal ions; instead it is semi‐coordinated to only one metal ion. This results in the formation of mononuclear complexes in which copper(II) or manganese(II) ions have a distorted square‐pyramidal surrounding. All complexes were structurally, spectroscopically and magnetically investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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