New dirhodium(II,II) species as building corner connectors for square molecular boxes

The new mixed dirhodium(II,II) complexes, [Rh2(form)2(O2CC6H 4CN)2] (2) and [Rh2(form)2(O2CC5H 4N)2] (3) (form=N,N′-di-p-tolylformamidinate) as building corner connectors for heteronuclear molecular boxes, were synthesized. By exploiting the peculiar equatorial reactivity of [Rh2(form)2(O2CCF3)2(H 2O)2] (1), due to the lability of trifluoroacetates, the synthesis of 2 and 3 was readily achieved by mathematical relations with the exo-functionalized 4-cyanobenzoate and isonicotinate carboxylates, respectively. The X-ray diffraction studies performed on the pyridine adduct of 2, [Rh2(form)2(O2CC6H 4CN)2(Py)2], are reported, together with some preliminary attempts of self-assembly with square-planar platinum(II) and palladium(II) complexes.