2,6-Bis(azaindole) pyridine: reactivity with iron(III) and copper(II) salts

1-[6-(1H-Pyrrolo[2,3-b] pyridin- 1-y1) pyridin-2-y1]-1H-pyrrolo[ 2,3-b] pyridin-7-ium tetrachloridoferrate(III), (C19H14N5)[FeCl4], (II), and [2,6-bis(1H-pyrrolo[2,3-b]pyridin- 1-y1-kappa N-7)pyridine- kappa N] bis(nitrato-kappa O) copper(II),[ Cu(NO3)(2)(C19H13N5)], (III), were prepared by self- assembly from FeCl3 center dot 6H(2)O or Cu(NO3)(2) center dot 3H(2)O and 2,6-bis(1H- pyrrolo[2,3- b] pyridin-1-y1)-pyridine [commonly called 2,6- bis( azaindole) pyridine, bap], C19H13N5, (I). Compound (I) crystallizes with Z' = 2 in the P (1) over bar space group, with both independent molecules adopting a trans-trans conformation. Compound (II) is a salt complex with weak C-H center dot center dot center dot Cl interactions giving rise to a zigzag network with pi-stacking down the a axis. Complex (III) lies across a twofold rotation axis in the C2/c space group. The Cu-II center in (III) has an N3O2 trigonal - bipyramidal environment. The nitrate ligand coordinates in a monodentate fashion, while the bap ligand adopts a twisted tridentate binding mode. C-H center dot center dot center dot O interactions give rise to a ribbon motif.