Pentadentate thioether-oxime macrocyclic and quasi-macrocyclic complexes of copper(II) and nickel(II)

A series of new pentadentate thioether-oximes (TtoxH(2), MeTtoxH(2), OdtoxH (2)) were synthesized along with their Ni(II) and Cu(II) complexes. BF2+-br idging is accomplished by reaction of the I-I-bonded oxime complex with BF3 . OEt2, though when Cu(BF4)(2) is used as the Cu(II) salt, direct macrocycl ization occurs during the metal complexation reaction. Crystallographic stu dies reveal: [Cu(TtoxH)]ClO4 has a N2S3 square-pyramidal geometry, with an I-I-bond forming a quasi-macrocycle. In [Cu(OdtoxH)](ClO4).[Cu(OdtoxH(2))]( ClO4)(2), while retaining the same overall geometry as [Cu(TtoxH)]ClO4, hal f of the cations are singly deprotonated and the remaining half retain both their protons. In addition, there is an unexpected interaction involving a perchlorate oxygen and the dimethylene bridges between the ligand's ether oxygen and thioether sulfurs. [Ni(OdtoxBF(2))]ClO4. H2O has an N2S2O2 octah edral geometry. The ligand occupies the equatorial plane and one of the api cal positions; the coordination sphere is completed by a water oxygen. Cycl ic voltammetry and rotating disk electrode (RDE) polarography reveal that N 2S3 donor sets stabilize both Ni(III) and Ni(I), whereas the Cu(II) complex es stabilize only Cu(I). The copper complexes show axial ESR spectra typica l of tetragonal Cu(II). Nitrogen superhyperfine structure is observed in bo th the room temperature fluid and 77 K cryogenic glass spectra. Macrocycliz ation by BF2+ enforces the in-plane geometry around the metal ion. (C) 2000 Elsevier Science S.A. All rights reserved.