Hexagonal Supramolecular Architectures from Ferrocenium Cations Incorporating [Ni(mnt) 2 ] − Columns: Structures and Properties of [Alkylferrocene][Ni(mnt) 2 ] − Charge‐Transfer Complexes (mnt=maleonitriledithiolate)

The crystal architecture, magnetic properties, and thermodynamic properties of [ n ‐butylferrocene][Ni(mnt) 2 ] ( 1 ), [ tert ‐butylferrocene][Ni(mnt) 2 ] ( 2 ), [1,1′‐diethylferrocene][Ni(mnt) 2 ] ( 3 ), and [1,1′‐diisopropylferrocene][Ni(mnt) 2 ] ( 4 ) were investigated (mnt=maleonitriledithiolate). These complexes exhibit a unique supramolecular structure in which the ferrocenium cations constitute honeycomb‐like assembled structures surrounding columns of the anions. For 1 , the cations form a dimer through a very short intermolecular ferrocene–ferrocene distance of 3.28 Å, which mediates an antiferromagnetic interaction with a singlet–triplet energy gap of 5 K. First‐order phase transitions occur in 1 – 3 at 364, 361, and 350 K, respectively, accompanied by thermal hysteresis.