Linear tri- and tetra-chromium(II) chains supported by four bis(2-pyridyl)formamidinium ligands

Reactions of bis(2-pyridyl)formamidinium ion, DpyF–, with CrCl2 lead to [Cr3(DpyF)4][PF6]2 and [Cr4(DpyF)4Cl2]Cl2, both of which are structurally characterized by X-ray crystallography; the latter contains two Cr–Cr quadruple bonds even though no such bonds were preformed in the starting material (CrCl2).