Organometallic Polymers Assembled from Cation-π Interactions: Use of Ferrocene as a Ditopic Linker Within the Homologous Series [{(Me3Si)2NM}2⋅(Cp2Fe)]∞ (M=Na, K, Rb, Cs; Cp=cyclopentadienyl)

Addition of ferrocene to solutions of alkali metal hexamethyldisilazides M(HMDS) in arenes (in which M=Na, K, Rb, Cs) allows the subsequent crystallization of the homologous series of compounds [{(Me3Si)2NM}2⋅ (Cp2Fe)]∞ (1–4). Similar reactions using LiHMDS led to the recrystallization of the starting materials. The crystal structures of 1–4 reveal the formation of one‐dimensional chains composed of dimeric [{M(HMDS)}2] aggregates, which are bridged through neutral ferrocene molecules by η5‐cation–π interactions. In addition, compounds 3 and 4 also contain interchain agostic MC interactions, producing two‐dimensional 44‐nets. Whereas 1 and 2 were prepared from toluene, the syntheses of 3 and 4 required the use of tert‐butylbenzene as the reaction media. The attempted crystallization of 3 and 4 from toluene resulted in formation of the mixed toluene/ferrocene solvated complexes [{(Me3Si)2NM)2}2⋅ (Cp2Fe)x⋅(Tol)y]∞ (in which M=Rb, x=0.6, y=0.8, 5; M=Cs, x=0.5, y=1, 6). The extended solid‐state structures of 5 and 6 are closely related to the 44‐sheets 3 and 4, but are now assembled from a combination of cation–π, agostic, and π–π interactions. The charge‐separated complex [K{(C6H6)2Cr}1.5(Mes)][Mg(HMDS)3] (15) was also structurally characterized and found to adopt an anionic two‐dimensional 63‐network through doubly η3‐coordinated bis(benzene)chromium molecules. DFT calculations at the B3 LYP/6–31G* level of theory indicate that the binding energies of both ferrocene and toluene to the M(HMDS) dimers increases in the sequence Li