Ionothermal syntheses of two coordination polymers constructed from 5-sulfoisophthalic acid ligands with 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid as solvent

Two coordination polymers, namely, [Co(IM)6][Co2(SIP)3] (1) (IM = imidazole, H3SIP = 5-sulfoisophthalic acid) and [BMIM]2[Cd2(SIP)3] (2) (BMIM = 1-n-butyl-3-methylimidazolium) were synthesized in ionothermal reactions by using ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate as solvent. Single-crystal X-ray analyses revealed that 1 has an anionic 1D polymeric chain charge balanced by an uncommon [Co(IM)6]2+ cation. Complex 2 features an anionic 2D layer containing unique tetranuclear [Cd4(CO2)6(SO3)2] cluster wherein the four Cd atoms are co-planar. The imidazolium cation [BMIM]+ of the ionic liquid acting as charge compensating agent intercalated into the [Cd2(SIP)2]2n− interlayers in structure 2. The rich ionic environments of the ionic liquid may be particularly helpful in the formation of the anionic frameworks of 1 and 2.