Formation and Crystal Structures of [{Li(THF)[HNC(NMe2)2]}2{Fe3(CO)11}] and [Li(THF){HNC(NMe2)2}{Fe(CO)4(C(O)NMe2)}]2

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AbstractThe reaction of tetramethylguanidine, HN=C(NMe2)2 (1), with lithium powder in THF generated a colorless precipitate without visible evolution of dihydrogen. Treatment of this product with [Fe(CO)5] produced a brown oil, which is very soluble in toluene. The orange red compound [{Li(THF)[HNC(NMe2)2]}2{Fe3(CO)11}] (2), which forms an infinite chain, and the colorless dimeric complex [Li(THF){HNC(NMe2)2}{Fe(CO)4(C(O)NMe2)}]2 (3) could be isolated from this solution. The oxygen atom of the carbamoyl part in 3 is connected to two Li+ ions with formation of a Li2O2 ring. Crystals of 2 and 3 were obtained by fractional crystallization from toluene/n‐pentane and characterized by IR spectroscopy and X‐ray analyses.