Jump to main content
Jump to site search


Promotion of antiferromagnetic exchange interaction in multinuclear copper(II) complexes via fused oxamato/oxamidato ligands

Author affiliations

Abstract

Treatment of N,N′-bis(2-aminophenyl)oxalamide (bapoxH6, 1) with ethyl oxalyl chloride in THF afforded oxamide-N,N′-bis(o-phenylene oxamic acid ethyl ester) (L1H4Et2, 2), which was converted to 3 (oxamide-(o-phenylene oxamic acid ethyl ester)(o-phenylene-N1-methyloxalamide); L2H5EtMe) and 4 (oxamide-N,N′-bis(o-phenylene-N1-methyloxalamide); L3H6Me2) by the addition of appropriate equivalents of MeNH2. Successive treatment of 2–4 with six equivalents of [nBu4N]OH and two equivalents of CuII salt resulted in the formation of the binuclear complexes [nBu4N]2[Cu2(L1)] (5), [nBu4N]2[Cu2(L2Me)] (6) and [nBu4N]2[Cu2(L3Me2)] (7). Upon addition of one equivalent of [Cu(pmdta)(NO3)2] (pmdta = N,N,N′,N′′,N′′-pentamethyldiethylenetriamine) to 5–7, the trinuclear complexes [Cu3(L1)(pmdta)] (8), [Cu3(L2Me)(pmdta)] (9) and [Cu3(L3Me2)(pmdta)] (10) were obtained, while the addition of two equivalents of [Cu(pmdta)(NO3)2] gave rise to the tetranuclear complexes [Cu4(L1)(pmdta)2](NO3)2 (11), [Cu4(L2Me)(pmdta)2](NO3)2 (12) and [Cu4(L3Me2)(pmdta)2](NO3)2 (13). The identities of compounds 2–4 were established by elemental analyses, NMR and IR spectroscopy, and ESI-MS measurements. For the multinuclear complexes 5–13, elemental analysis and IR spectroscopy were applied to confirm their identities. Furthermore, the solid-state structures of 5–8 and 11–13 were determined by single crystal X-ray diffraction studies. The magnetic behavior of 5–8 and 11–13 was studied by direct current susceptibility measurements as a function of temperature. For the binuclear complexes 5–7, exceptionally large antiferromagnetic exchange interactions with J1,2 values of −378, −397 and −419 cm−1 were determined. Astonishingly, the tendency of these series of magnetic exchange interactions can be smoothly associated with the d–d transitions of 5–7 measured through UV-Vis spectroscopy. The J1,2 value of 8 amounts to −507 cm−1, while for the tetranuclear complexes 11–13, this value is significantly smaller and amounts to −294, −292 and −370 cm−1. The second antiferromagnetic exchange interactions J2,3 and J1,4 are equal due to inversion symmetry and are −100, −135, −80 and −108 cm−1 for 8 and 11–13, respectively, in the expected range. Magneto-structural correlations are used to discuss the variable magnetic exchange interactions of all here reported multinuclear complexes.

Graphical abstract: Promotion of antiferromagnetic exchange interaction in multinuclear copper(ii) complexes via fused oxamato/oxamidato ligands

Back to tab navigation

Supplementary files

Publication details

The article was received on 12 Sep 2018, accepted on 05 Oct 2018 and first published on 16 Oct 2018


Article type: Paper
DOI: 10.1039/C8DT03691H
Citation: Dalton Trans., 2018, Advance Article
  •   Request permissions

    Promotion of antiferromagnetic exchange interaction in multinuclear copper(II) complexes via fused oxamato/oxamidato ligands

    S. Weheabby, M. A. Abdulmalic, M. Atzori, R. Sessoli, A. Aliabadi and T. Rüffer, Dalton Trans., 2018, Advance Article , DOI: 10.1039/C8DT03691H

Search articles by author

Spotlight

Advertisements