Ionothermal Synthesis and Characterization of a Three-dimensional Anionic Zinc-5-sulfoisophthalate Framework Charge-balanced with the 1-Ethyl-3-methylimidazolium

摘要

The ionothermal reaction of Zn(NO_3)_2·6H_2O with 5-sulfoisophthalic acid monosodium salt(NaH_2SIP) and 1,2,4-triazole in 1-ethyl-3-methylimidazolium tetrafluoroborate(EMIM-BF_4) ionic liquid has afforded the compound {(EMIM)[Zn(SIP)]}_n(1).The Zn(Ⅱ) ions are linked by the carboxylate groups of SIP^(3-) ligands to give a two-dimensional layered structure featuring the centrosymmetric dinuclear Zn_2(μ_2-COO)_2 units.The adjacent two-dimensional layers are further linked by the Zn-0 bonds between the Zn(Ⅱ) ions and the sulfonate O atoms to generate a three-dimensional anionic[Zn(SIP)]_n^(n-) framework featuring one-dimensional open channels propagating along the a axis.The imidazolium cations[EMIM]^+ derived from ionic liquid act as extraframework charge-balancing species for the anionic[Zn(SIP)]_n^(n-) framework and occupy the void space of the one-dimensional open channels.The rich ionic environments of the ionic liquid may be particularly helpful in the formation of the ionic compound 1.The roles of the ionic liquid in ionothermal synthesis and crystallization of the compound are briefly discussed.Furthermore,compound 1 displays a photoluminescent emission at 490 nm upon excitation at 406 nm.