Supramolecular Maleate Adducts of Copper(II) 12-Metallacrown-4: Magnetism, EPR, and Alcohol Sorption Properties

Anna V. Pavlishchuk, Sergey V. Kolotilov, Matthias Zeller, Samuel E. Lofland, Mikhail A. Kiskin, Nikolay N. Efimov, Elena A. Ugolkova, Vadim V. Minin, Vladimir M. Novotortsev, Anthony W. Addison

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

With maleate, [Cu5(ahpha)4]2+ gives two complexes, [Cu5(ahpha)4(DMF)2](MalH)2·2DMF (1) and [Cu5(ahpha)4(MalH)2] (2) (ahpha2– is 3-amino-3-hydroximinopropane hydroxamate; MalH2 is maleic acid). Both 1 and 2 contain non-oligomerized [Cu5(ahpha)4]2+ metallacrown blocks; in 1, two MalH are bound to [Cu5(ahpha)4]2+ only via H-bonds, while in 2, they coordinate to Cu2+. The X-band EPR of 1 was observed at 20 K, 100 K, and 295 K. The EPR at 20 K was of an S = 1/2 ground state, while at room temperature anisotropic |ΔMs| = 1 and |ΔMs| = 2 resonances around 3200 G (g ≈ 2.19) and 1600 G (g ≈ 4.25) were observed for the Cu5 system, due to partial occupation of an S = 3/2 state. The room temperature EPR of 1 was simulated as the weighted sum of the spectra of its various S = 1/2, 3/2, and 5/2 states. Its magnetic behavior was fitted with a χMT vs. T model using a spin Hamiltonian accounting for central–peripheral (J1), peripheral–peripheral (J2) Cu2+–Cu2+ and intercrown (zJ′) spin interactions, yielding J1 = –156(4) cm–1, J2 = –63(1) cm–1, and zJ′ = –4.5(3) cm–1. For sorption of methanol and ethanol vapors at 293 K by a desolvated polycrystalline sample of 1, the shape of the adsorption and desorption isotherms indicated a “gates opening” phenomenon.

Original languageEnglish (US)
Pages (from-to)4866-4878
Number of pages13
JournalEuropean Journal of Inorganic Chemistry
Volume2017
Issue number41
DOIs
StatePublished - Nov 9 2017

All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry

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