Azo- and Hydrazo-Dipyridines in Halidometallate Structures

From reaction mixtures containing 1,2-di(pyridin-y-yl)diazene derivatives (“azopyridines”; y,y’-azpy; y = 2, 3, or 4) and metal precursors such as cu(ii), co(ii), mn(ii), bi(iii), and fe(iii) salts or elemental sn, in aqueous concentrated hx (x = cl, br, i) solutions, we obtained single crystals of the new 1-d pseudo-perovskite structures (4,4’-azpyh2)[cu2cl6], (4,4’-azpyh2)[mncl2(h2o)2]cl2, (4,4’-azpyh2)2 1∞[cu2i4(i3)2](i2) (2,2’- hydpyh2)1 ∞[cu2i4], (4,4’-hydpyh2)1∞[cu2i4], and the 0-d pseudo-perovskite structure (4,4’-hydpyh2)[bii6](i3), along with non-perovskite salt-like structures. some structures contain protonated azopyridinium (azpyh2 2+) dications, obtained through protonation of the starting azopyridines, while others contain hydrazopyridinium (hydpyh2 2+) cations, produced in a reduction-protonation reaction. starting from cu(ii) salts, we found the metal reduced to cu(i) in the presence of iodide, but not for chloride. the azopyridine-containing structures are easily discriminated from hydrazopyridine derivatives by their negligible c–n–n–c torsion angles and unequivocal anti-conformations. the hydrazopyridine moieties showed c–n–n–c torsions ranging from 99 to 133° and the conformations around the hydrazo –hn–nh– moiety are best described as anti-clinal.