Room temperature dissolution of metal powders by thiourea: a novel route to transition metal isothiocyanate complexes

A new synthetic route to isothiocyanate containing materials is presented. Five isothiocyanate 4-methylpyridine (γ-picoline) compounds were prepared by refluxing metal powders (Fe, Co, Ni and Cu) with thiourea in γ-picoline. The isothiocyanate ligand is generated in situ by the isomerization of thiourea to NH4+SCN− at reflux temperatures. The complexes [Fe(NCS)2(pic)4]·pic (1), [Co(NCS)2(pic)4]·pic (2), [Ni(NCS)2(pic)4] (3), [Cu(NCS)2(pic)4]·2/3pic·1/3H2O (4), [Cu(NCS)(pic)2]x (5) (where pic=γ-picoline) were characterized by X-ray crystallography; the structural data for compounds 1–3 and 5 are presented.