Structures of flexible supramolecular cations (1,4-cyclohexanediammonium 2+)(crown ethers) 2 in [Ni(dmit) 2] − salts

Abstract

Supramolecular dication structures, ( CHDA 2+)(crown ethers) and ( CHDMA 2+)(crown ethers) complexes, were introduced as counter cations to [Ni(dmit) 2] − anions (S=1/2 spin) ( CHDA 2+= trans-1,4-cyclohexanediammonium; CHDMA 2+=1,4-bis(methylammonium)cyclohexane; dmit 2−=2-thioxo-1,3-dithiole-4,5-dithiolate; crown ethers=[12]crown-4, [15]crown-5, or [18]crown-6). The cyclohexane rings, with the –NH 3 + or –CH 2–NH 3 + substituents at trans-1,4-positions, arrange into the crown ethers complexes within the [Ni(dmit) 2] − salts. The cyclohexane rings adopt chair conformations, resulting in sandwich-type ( CHDA 2+ or CHDMA 2+)(crown ethers) 2 structures, through N–H … O hydrogen-bonding interactions within the crystals between the ammonium moieties of cations (–NH 3 + or –CH 2–NH 3 +) and the oxygen atoms of the crown ethers. Formations of π–π dimer structures of [Ni(dmit) 2] − anions were observed in all salts. The selections of the dication structures ( CHDA 2+ or CHDMA 2+) and the crown ethers, due to the various ring sizes, can influence the intra and interdimer interactions of the [Ni(dmit) 2] − anions in the crystals.