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]

Abstract

Reactions of N15C5 (2,3-naphtho-15-crown-5) with nickel maleonitriledithiolate sodium complex, Na2[Ni(mnt)2] (mnt = maleonitriledithiolate) using different molar ratios (2 : 1 and 4 : 1) afforded two structurally different complexes [Na(N15C5)2]2[Ni(mnt)2] (1) and [Na(N15C5)]2[Ni(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.