New Helical Complexes with a Bis(bidentate) Schiff Base Ligand Containing a Flexible Spacer

Neutral complexes with the general empirical formula M(PTs) [M: Mn, Fe, Co, Cu, Zn, and Cd; H2PTs: N,N′-bis(2-tosylaminobenzylidene)-1,3-diaminopropane] were obtained by means of an electrochemical procedure. All complexes were characterised by elemental analyses, mass spectrometry, IR and 1H NMR spectroscopy, and magnetic measurements, where appropriate. Recrystallisation of the cobalt, copper, and zinc complexes yielded single crystals of [Co(PTs)] (1), [Cu(PTs)]·1.5CH3CN (2) and [Zn(PTs)]2·1.5H2O·CH3CN (3). Their X-ray characterisation shows that 1 and 2 are mononuclear tetrahedral single-stranded helical complexes in the solid state, while 3 is a double-helical compound containing a major and a minor groove, with the Schiff base acting as a bis(bidentate) N4 donor.