Novel crystal engineering in the crown ether nickel maleonitriledithiolate complexes,synthesis and crystal structures of [Na(N15C5)2]2[Ni(mnt)2] and [Na(N15C5)]2[Ni(mnt)2]

Reactions of N15C5 (2,3-naphtho-15-crown-5) with nickel maleonitriledithiolate sodium complex, Na₂Ni(mnt)₂] (mnt?=?maleonitriledithiolate) using different molar ratios (2?:?1 and 4?:?1) afforded two structurally different complexes Na(N15C5)₂]₂Ni(mnt)₂] (1) and Na(N15C5)]₂Ni(mnt)₂] (2). The sandwich Na(N15C5)₂]⁺ and mono-capped Na(N15C5)]⁺ organic cations are observed in the crystals of 1 and 2, respectively, with the same Ni(mnt)₂]^2? inorganic conteranions. It is these structurally different organic cations that lead to the dissimilar structures. Complex 1 exhibits a one-dimensional (1D) chain-like structure assembled by intercantionic {Na(N15C5)₂]⁺}_∞ π–π stacking interactions and electrostatic interactions, while 2 displays a novel two-dimensional (2D) corrugated sheet-like structure constructed by Na–N interactions which occur between the Na(N15C5)]⁺ inorganic cations and Ni(mnt)₂]^2? inorganic anions.