Manganese(II) chloride complexes with pyridineN-oxide (PNO) derivatives and their solid-state structures

Abstract

Three manganese(II)N-oxide complexes have been synthesized from the reaction of manganese(II) chloride with either pyridineN-oxide (PNO), 2-methylpyridineN-oxide (2MePNO) or 3-methylpyridineN-oxide (3MePNO). The compounds were synthesized from methanolic solutions of MnCl2·4H2O and the respectiveN-oxide, and subsequently characterized structurally by single-crystal X-ray diffraction. The compounds arecatena-poly[[aquachloridomanganese(II)]-di-μ-chlorido-[aquachloridomanganese(II)]-bis(μ-pyridineN-oxide)], [MnCl2(C5H5NO)(H2O)]nor [MnCl2(PNO)(H2O)]n(I),catena-poly[[aquachloridomanganese(II)]-di-μ-chlorido-[aquachloridomanganese(II)]-bis(μ-2-methylpyridineN-oxide)], [MnCl2(C6H7NO)(H2O)]nor [MnCl2(2MePNO)(H2O)]n(II), and bis(μ-3-methylpyridineN-oxide)bis[diaquadichloridomanganese(II)], [Mn2Cl4(C6H7NO)2(H2O)4] or [MnCl2(3MePNO)(H2O)2]2(III). The MnIIatoms are found in pseudo-octahedral environments for each of the three complexes. CompoundIforms a coordination polymer with alternating pairs of bridgingN-oxide and chloride ligands. The coordination environment is defined by two PNO bridging O atoms, two chloride bridging atoms, a terminal chloride, and a terminal water. CompoundIIalso forms a coordination polymer with a similar metal cation; however, the coordination polymer is bridged between MnIIatoms by both a single chloride and 2MePNO. The distorted octahedrally coordinated metal cation is defined by two bridging 2MePNOtransto each other, two chlorides, alsotransto one another in the equatorial (polymeric) plane, and a terminal chloride and terminal water. Finally, complexIIIforms a dimer with two bridging 3MePNOs, two terminal chlorides and two terminal waters forming the six-coordinate metal environment. All three compounds exhibit hydrogen bonding between the coordinating water(s) and terminal chlorides.