Magnetic blocking in extended metal atom chains: a pentachromium(II) complex behaving as a single-molecule magnet.

Compound [Cr5(tpda)4Cl2] (H2tpda = N(2),N(6)-di(pyridin-2-yl)pyridine-2,6-diamine), an Extended Metal Atom Chain complex featuring two quadruply-bonded {Cr2} units, exhibits field-induced slow relaxation of its magnetization arising from the terminal chromium(II) ion and provides the first example of a chromium(II)-based Single-Molecule Magnet.