Bringing an important macrocycle into a polyoxometalate matrix: Synthesis, crystal structure, spectroscopy and electrochemistry of [Co < sup > III < /sup > (transdiene)(Cl) < inf > 2 < /inf > ] < inf > 2 < /inf > [Mo < inf > 6 < /inf > O < inf > 19 < /inf > ], [Ni < sup > II < /sup > (transdiene)][W < inf > 6 < /inf > O < inf > 19 < /inf > ] ·DMSO·DCM and [Zn < sup > II < /sup > (transdsiene)(Cl)] < inf > 2 < /inf > [W < inf > 6 < /inf > O < inf > 19 < /inf > ]

Abstract

Three polyoxometalate based ion pair solids (1-3), in which Co III (d6), NiII (d8) and Zn II (d10) complexes of a tetra-aza macrocycle, Me 6-trans-[14]-diene act as the cationic moieties, have been reported. The title complexes, formulated as [Co (C16H32N 4)(Cl)2]2[Mo6O19] (1), [Ni(C16H32N4)][W6O 19]·DMSO·DCM (2) and [Zn(C16H 32N4)(Cl)]2[W6O19] (3) (C16H32N4 = Me6-trans-[14]-diene), are the first crystallographic paradigms where transition metal complexes of a Schiff condensed tetra-aza macrocycle have been associated with an isopolyanion, [M6O19]2- (M = Mo(vi) and W(vi)). Compounds 1-3 have been characterized through routine spectroscopic analyses including elemental analysis and their structures have been unambiguously determined through single crystal X-ray crystallography. The molecules of compound 1 assemble obeying P1 (#2) space symmetry, whereas those of compounds 2 and 3 follow the higher symmetrical ensemble P21/c (#14). The ESR spectral studies of compounds 1-3 have revealed their diamagnetic (low-spin) nature. The last part of this article describes the electrochemical properties of the title compounds. © The Royal Society of Chemistry 2011.