Manganocene

Manganocene or bis(cyclopentadienyl)manganese(II) is an organomanganese compound with the formula [Mn(C5H5)2]n. It is a thermochromic solid that degrades rapidly in air.

[2] It may be prepared in the manner common for other metallocenes, i.e., by reaction of manganese(II) chloride with sodium cyclopentadienide: In the solid state below 159 °C, manganocene adopts a polymeric structure with every manganese atom coordinated by three cyclopentadienyl ligands, two of which are bridging ligands.

Above 159 °C, the solid changes color from amber to pink and the polymer converts to the structure of a normal sandwich complex, i.e., the molecule Mn(η5-C5H5)2.

[2] The ionic character of manganocene gives it an unusual pattern of reactivities compared to metallocenes of other transition metals in the same row.

[2] Manganocene polymerizes ethylene to high molecular weight linear polyethylene in the presence of methylaluminoxane or diethylaluminium chloride as cocatalysts.

NFPA 704 four-colored diamond Health 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroform Flammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuel Instability 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g. hydrogen peroxide Special hazards (white): no code