Facile routes to manganese(II) triflate complexes

Manganese(II) chloride reacts with trimethylsilyl triflate (TMS(OTf) where OTf = − OSO2CF3) in a 1:1 mixture of acetonitrile and tetrahydrofuran and after recrystallization affords the linear coordination polymer [MnII(CH3CN)2(OTf)2]n. Each distorted octahedral manganese(II) center in the polymeric chain has trans-acetonitriles and the remaining equatorial coordination positions are occupied by the bridging triflate anions. Dissolving [MnII(CH3CN)2(OTf)2]n in equal volumes of acetonitrile and pyridine followed by recrystallization with diethyl ether yields trans-[MnII(C5H5N)4(OTf)2]. The distorted octahedral geometry of the manganese center features monodentate trans-triflate anions and four equatorial pyridines. Exposure of either [MnII(CH3CN)2(OTf)2]n or [MnII(C5H5N)4(OTf)2] to water readily gives [MnII(H2O)6](OTf)2. XRD reveals hydrogen-bonding interactions between the [MnII(H2O)6]2+ cation and the triflate anion. All three of these species are easily crystallized and provide convenient sources of manganese(II) for further synthetic elaboration.

Convenient routes for the preparation of [Mn(CH3CN)2(CF3SO3)2]n, [Mn(C5H5N)4(CF3SO3)2], and [Mn(H2O)6](CF3SO3)2. Each species is readily crystallized and exhibits distinct triflate vibrational features.Figure optionsDownload as PowerPoint slideHighlights
► Reliable preparative routes for manganese(II) triflates.
► Structures and spectroscopic characterization of these catalyst precursors.
► Caveats regarding susceptibility of the manganese(II) triflates to water.