A calix[4]arene-based bipyridine podand as versatile ligand for transition metal cations

Article abstract of DOI:10.1002/1099-0682(200203)2002:4<901::AID-EJIC901>3.0.CO;2-9

The calix[4]arene-based podand 1 which incorporates two 2,2′-bipyridine units and two benzyl units in alternate positions at the lower rim has been subjected to complexation studies with copper(I), copper(II), cobalt(II), nickel(II), and zinc(II). The reaction of 1 with Cu(MeCN)₄PF₆, afforded the expected mononuclear Cu^I complex. With cobalt(II), nickel(II), and zinc(II) chloride, 1 gave dinuclear tetrahedral complexes in which each bipyridine unit is associated to two chlorine atoms around the metal centre. With Zn^II, replacing the chloride ion for the trifluoromethanesulfonate ion resulted in the formation of the mononuclear complex species. The complexes thus obtained were fully characterised, notably by NMR techniques and, for the dinuclear cobalt, nickel and zinc species, by X-ray crystal structure analyses. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.