The discovery of ferrocene nearly 70 years ago marked the genesis of metallocene chemistry. Although the ferrocenium cation was discovered soon afterwards, a derivatized ferrocenium dication was only isolated in 2016 and the monoanion of ferrocene has only been observed in low-temperature electrochemical studies. Here we report the isolation of a derivatized ferrocene anion in the solid state as part of an isostructural family of 3d metallocenates, which consist of anionic complexes of a metal centre (manganese, iron or cobalt) sandwiched between two bulky Cp^ttt ligands (where Cp^ttt is {1,2,4-C₅H₂ ^tBu₃}). These thermally and air-sensitive complexes decompose rapidly above −30 °C; however, we were able to characterize all metallocenates by a wide range of physical techniques and ab initio calculations. These data have allowed us to map the electronic structures of this metallocenate family, including an unexpected high-spin S = 3/2 ground state for the 19e⁻ derivatized ferrocene anion.

近70年前发现的二茂铁标志着茂金属化学的起源。尽管很快发现了二茂铁阳离子，但直到2016年才分离出衍生化的二茂铁阳离子，并且仅在低温电化学研究中才观察到二茂铁的单阴离子。在这里，我们报告了固态衍生化二茂铁阴离子的分离，它是3d金属茂的同构结构家族的一部分，该金属结构由夹在两个庞大的Cp ^ttt配体之间的金属中心（锰，铁或钴）的阴离子络合物组成Cp ^ttt是{1,2,4-C ₅ H ₂ ^t Bu ₃}。这些对热和空气敏感的络合物在−30°C以上会迅速分解。但是，我们能够通过各种物理技术和从头算来表征所有金属茂铁。这些数据使我们能够映射此metallocenate家族的电子结构，包括一个意想不到的高自旋小号 = 3/2地面为19状态ë ^-衍生的二茂铁的阴离子。