Ionothermal syntheses and crystal structures of two cobalt(II)-carboxylate compounds with different topology

Two cobalt-carboxylate compounds, namely, {[PMIM](2)[Co-2(BTC)(2)(H2O)(2)]}(n) (1) (PMIM = 1-propyl-3-methylimidazolium and H3BTC = 1,3,5-benzenetricarboxylic acid) and [CO3(BDC)(3)(IM)(2)](n) (2) (H2BDC = 1,4-benzenedicarboxylic acid and IM = imidazole) have been synthesized under ionothermal reactions. Compound 1 has a 3D anionic framework with (4.6(2))(2)(4(2).6(10).8(3)) topology based on dinuclear cobalt(11) as a secondary building unit. The imidazolium cation [PMIM](+) of the ionic liquid acting as extraframework charge-balancing species occupies the channels of the 3D anionic framework Complex 2 features a 3D neutral framework with (4(12).6(3)) topology constructed of unusual linear trinuclear cobalt(II) as a secondary building unit. The rich ionic environments of the ionic liquid may be particularly helpful in the formation of the frameworks of 1 and 2. The roles of the ionic liquid in ionothermal syntheses and crystallizations of compounds are briefly discussed. (C) 2010 Elsevier B.V. All rights reserved.