Manganocene
 | |
| Identifiers | |
|---|---|
73138-26-8  | |
| ECHA InfoCard | 100.149.777 |
| PubChem | 24199707 |
| Properties | |
| C10H10Mn | |
| Molar mass | 185.13 g·mol−1 |
| Appearance | amber solid < 159 °C, pink > 159 °C |
| Melting point | 175 °C (347 °F; 448 K) |
| Boiling point | 245 °C (473 °F; 518 K) |
| Hazards | |
| EU classification (DSD) |
 Xn  F |
| R-phrases | R11, R14, R20/21/22, R36/37/38 |
| S-phrases | S16, S26, S36/37/39 |
| NFPA 704 | |
| Flash point | 52 °C (126 °F; 325 K) |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
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. Although the compound is of little utility, it is often discussed as an example of a metallocene with ionic character.[1]
Synthesis and structure
It may be prepared in the manner common for other metallocenes, i.e., by reaction of manganese(II) chloride with sodium cyclopentadienide:
- MnCl2 + 2 CpNa → Cp2Mn + 2 NaCl
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.[1]
References
- 1 2 Richard A. Layfield "Manganese(II): the black sheep of the organometallic family" Chem. Soc. Rev., 2008, vol. 37, pp. 1098-1107.doi:10.1039/B708850G