Magnetic and sorption properties of supramolecular systems based on pentanuclear copper(II) 12-metallacrown-4 complexes and isomeric phthalates: Structural modeling of the different stages of alcohol sorption

Anna V. Pavlishchuk, Sergey V. Kolotilov, Matthias Zeller, Oleksiy V. Shvets, Igor O. Fritsky, Samuel E. Lofland, Anthony W. Addison, Allen D. Hunter

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Abstract

Metathesis of the perchlorate anions in [Cu5(ahpha) 4](ClO4)2·4H2O, where ahpha2- is the dianion of 3-amino-3-hydroximinopropane hydroxamic acid, with m- and p-phthalates resulted in formation of [Cu5(ahpha) 4(m-C8H4O4)(H2O)] ·9H2O (1), [Cu5(ahpha)4(m-C 8H4O4)(H2O)]·2MeOH· DMF (1a) and [Cu5(ahpha)4(p-C8H 4O4)(H2O)2]2· 14H2O (2). Molecules in the structures of 1, 1a and 2 are held together by noncovalent interactions, and the lattices contain voids filled with water molecules. Compounds 1 and 1a differ in the mode of m-phthalate coordination, solvent type, and crystal lattice content. Desolvated 1 and 2 sorb gaseous MeOH and EtOH. Whereas the MeOH sorption capacity was very similar for 1 and 2 (about 0.14 cm3/g at PPS-1 = 0.9, where P is the current methanol pressure and PS the saturation vapor pressure of methanol at 293 K), the capacity of 2 to sorb EtOH was about 1.5 times as high as that of 1. To a certain extent, the structures of 1 and 1a can be considered as models of compounds that can form at different stages during alcohol sorption by desolvated 1. The ÏMT vs. T data for 1 and 2 could be fitted with a model based on the Hamiltonian H(CuII 5) = -2J1(S1·S2 + S 1·S3 + S1·S4 + S 1·S5) - 2J2(S2·S 5 + S2·S3 + S3·S 4 + S4·S5), where S1 represents the spins of the central CuII ions and S 2-S4 correspond to the spins of the peripheral Cu II ions. The best fits corresponded to J1 = -129(3) cm-1, J2 = -66(1) cm-1 and zJ′ = -2.5(2) cm-1 at gCu = 2.12(1) for 1, and J1 = -163(3) cm-1, J2 = -78(1) cm-1 and zJ′ = -1.5(1) cm-1 at gCu = 2.05(1) for 2. Three complexes were obtained starting from a pentacopper 12-metallacrown-4 and isomeric benzenedicarboxylates. The structures of the complexes determined by XRD may be considered as models of intermediates that form during the interaction of these non-rigid sorbents with alcohols.

Original languageEnglish (US)
Pages (from-to)4826-4836
Number of pages11
JournalEuropean Journal of Inorganic Chemistry
Issue number31
DOIs
StatePublished - Nov 1 2011

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All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry

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