Syntheses, crystal structures and properties of tetra­kis­(3-methyl­pyridine-κN)bis­(iso­thio­cyanato-κN)manganese(II) and tetra­kis­(3-methyl­pyridine-κN)bis­(iso­thio­cyanato-κN)iron(II)

The reaction of Mn(NCS)(2) or Fe(NCS)(2) with 3-methyl­pyridine (C(6)H(7)N) leads to the formation of two isostructural compounds with compositions [Mn(NCS)(2)(C(6)H(7)N)(4)] (1) and [Fe(NCS)(2)(C(6)H(7)N)(4)] (2). IR spectroscopic investigations indicate that only terminally coordinated thio­cyanate anions are present. This is confirmed by single-crystal structure analysis, which shows that their crystal structures consist of discrete centrosymmetric complexes, in which the metal cations are octa­hedrally coordinated by two N-bonded thio­cyanate anions and four 3-methyl­pyridine ligands. X-ray powder diffraction (XRPD) proves that pure samples have been obtained. Thermogravimetric measurements show that decomposition starts at about 90°C and that the two coligands are removed in one step for 1 whereas for 2 no clearly resolved steps are visible. XRPD measurements of the residue obtained after the first mass loss of 1 show that a new and unknown crystalline compound has been formed.