Tetralithio Metalla‐aromatics with Two Independent Perpendicular Dilithio Aromatic Rings Spiro‐fused by One Manganese Atom

Herein, we present the realization of a class of unprecedented aromatic structures 2: metalla‐aromatics with two independent and perpendicular aromatic rings spiro‐fused by a transition‐metal spiro atom, of which their corresponding organic analogues are impossible. Tetralithio spiro manganacycles 2 are readily synthesized from 1,4‐dilithio‐1,3‐butadienes 1 and MnCl2 in the presence of lithium. The aromaticity of 2 is supported by experimental measurements (X‐ray structural analysis, NMR) and theoretical analyses (NICS, ACID, MOs). The spiro atom Mn in 2 uses its 3dxz and 3dxy orbitals to form the two perpendicular manganacycles, which are two independent 6π aromatic systems. Theoretical analyses reveal that the Li cations play an indispensable role in governing their geometric and electronic structures and hence their aromaticity. Therefore, this work contributes not only to enrich the concept of aromaticity, but also to deepen the understanding of the fundamental chemical bonding. Spiro mangana‐aromatics: A novel class of aromatic structures has been realized: metalla‐aromatics with two independent and perpendicular 6π aromatic rings spiro‐fused by a transition‐metal spiro atom. The aromaticity was confirmed by both experimental characterizations and theoretical analysis.