Zn, Mn, and Fe hexammine and hexakis(methylamine) polychalcogenides – Ionic compounds by solvothermal syntheses

Solvothermal reactions of the less-noble metals Mn, Fe, and Zn with elemental sulfur or/and selenium in liquid ammonia or methylamine give a series of polyselenides and polysulfides, namely [Mn(NH3)6]Se3 (1), [Mn(MeNH2)6]Se4 (2), [Mn(NH3)6]S6 (3), [Fe(NH3)6]S6 (4), [Zn(NH3)6]S6 (5), [Mn(NH3)6]Se6 (6), [Fe(NH3)6]Se6 (7) and two mixed sulfideselenides [Mn(MeNH2)6](S5)0.15(S1.57Se2.43)0.85 (8) and [Mn(NH3)6](S2.71Se2.29) (9). All compounds represent ionic structures with octahedral [M(NH2R)6]2 + (M = Mn, Fe, Zn; R = H, CH3) complex cations and various polychalcogenide anions in the form of chains consisting of three to six sulfur and/or selenium atoms. The hexachalcogenides 4–7 are isostructural. In the structure of 8 S52 − and (S/Se)42 − anions are present in 15%: 85% ratio on one crystallographic site. 9 contains a (S/Se)52 − mixed chalcogenide anion. Generally, N–H∙∙∙S/Se bonding is weak, which facilitates the observed disorder of the polychalcogenide chains in the hexachalcogenides 4–7. The structures of 1–8 show a packing of cations and anions of the simple rock-salt structure type while 9 adopts the PtS structure type.