Organometallic Polymers Assembled from Cation–π Interactions: Use of Ferrocene as a Ditopic Linker Within the Homologous Series [{(Me 3 Si) 2 NM} 2 ⋅(Cp 2 Fe)] ∞ (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 [{(Me 3 Si) 2 NM} 2 ⋅ (Cp 2 Fe)] ∞ ( 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 η 5 ‐cation–π interactions. In addition, compounds 3 and 4 also contain interchain agostic MC interactions, producing two‐dimensional 4 4 ‐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 [{(Me 3 Si) 2 NM) 2 } 2 ⋅ (Cp 2 Fe) 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 4 4 ‐sheets 3 and 4 , but are now assembled from a combination of cation–π, agostic, and π–π interactions. The charge‐separated complex [K{(C 6 H 6 ) 2 Cr} 1.5 (Mes)][Mg(HMDS) 3 ] ( 15 ) was also structurally characterized and found to adopt an anionic two‐dimensional 6 3 ‐network through doubly η 3 ‐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

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