In an effort to develop a general synthetic route to ansa-chromocene complexes with diverse ligand frameworks, we investigated ansa-magnesocene compounds as an alternative, potentially more versatile ligand source than ansa-calcocene compounds. The first single-carbon-bridged ansa-chromocene compound, Me2C(C5H4)2CrCO, was isolated from the reaction between Me2C(C5H4)2Mg and CrCl2 in THF under an atmosphere of carbon monoxide. This new ansa-chromocene compound is considerably more air-sensitive and less chemically stable than its ethanediyl-bridged counterparts.

The human species has deeply impacted the geology of our planet, our current environmental conditions now being very different from the stable interglacial conditions of the Holocene Epoch, in which human civilization flowered. Hence, a new epoch has been proposed, the Anthropocene, starting in tandem with the mid-20th-century Great Acceleration of population, industrialization, and globalization. One of the clearest measures of human impact on our planet is energy use, as reflected by rapidly increasing atmospheric carbon dioxide levels. Through this lens, the large-scale historical patterns of human activity show not gradual change but sudden and massive linked changes to geology and ecosystems. This has been driven by growth of the technosphere, a quasi-autonomous and emergent sphere of human-driven processes that interacts with the other Earth spheres. Consequences include the rapid accumulation of unrecycled waste, increasingly threatening the success of this development and hence of humans too.