TY - JOUR

T1 - Structure and Magnetic Properties of Mixed-Ligand Complexes of 3d Metal Hexafluoroacetylacetonates with 3,5- and 3,6-Di-Tert-Butyl-O-Benzoquinones

AU - Fokin, S. V.

AU - Fursova, E. Yu

AU - Letyagin, G. A.

AU - Bogomyakov, A. S.

AU - Morozov, V. A.

AU - Romanenko, G. V.

AU - Ovcharenko, V. I.

N1 - Publisher Copyright: © 2020, Pleiades Publishing, Ltd. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/4/1

Y1 - 2020/4/1

N2 - The reaction of metal hexafluoroacetylacetonates M(hfac)2, where M = Fe, Mn, and Co, with 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) in the inert atmosphere of a dry box is found to yield mixed-ligand complexes [M(hfac)2(3,6-Q)]. When the synthesis is performed under ambient conditions or the [M(hfac)2(3,6-Q)] mother liquor is kept in air in the case of Mn(II) and Co(II), crystals of [M(hfac)2(H2O)2](3,6-Q) aqua complexes precipitate into the solid phase, in which cis-coordinated H2O molecules are hydrogen bonded to o-quinone O atoms. Single crystal X-ray diffraction data for compounds, which correlate with the results of quantum chemical calculations, show that solid [M(hfac)2(3,6-Q)] and [M(hfac)2(H2O)2](3,6-Q), where M = Co(II) and Mn(II), contain initial o-quinone molecules. In the interaction of Fe(hfac)2 with 3,6-Q, there is an intramolecular redox process during which Fe(II) is oxidized to Fe(III) and o-quinone is reduced to the respective semiquinonate radical anion, which leads to the formation of [FeIII(hfac)2(3,6-SQ)]. According to the data of magnetic measurements, a strong antiferromagnetic exchange between high-spin Fe(III) unpaired electrons and SQ provide an almost complete compensation of spin of one of the unpaired electrons of the metal ion by SQ spin. For Co a complex with 3,5-di-tert-butyl-o-benzoquinone [Co(hfac)2(3,5-Q)] is also synthesized and its structure and magnetic properties are studied. The latter prove to be similar to those of [Co(hfac)2(3,6-Q)].

AB - The reaction of metal hexafluoroacetylacetonates M(hfac)2, where M = Fe, Mn, and Co, with 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) in the inert atmosphere of a dry box is found to yield mixed-ligand complexes [M(hfac)2(3,6-Q)]. When the synthesis is performed under ambient conditions or the [M(hfac)2(3,6-Q)] mother liquor is kept in air in the case of Mn(II) and Co(II), crystals of [M(hfac)2(H2O)2](3,6-Q) aqua complexes precipitate into the solid phase, in which cis-coordinated H2O molecules are hydrogen bonded to o-quinone O atoms. Single crystal X-ray diffraction data for compounds, which correlate with the results of quantum chemical calculations, show that solid [M(hfac)2(3,6-Q)] and [M(hfac)2(H2O)2](3,6-Q), where M = Co(II) and Mn(II), contain initial o-quinone molecules. In the interaction of Fe(hfac)2 with 3,6-Q, there is an intramolecular redox process during which Fe(II) is oxidized to Fe(III) and o-quinone is reduced to the respective semiquinonate radical anion, which leads to the formation of [FeIII(hfac)2(3,6-SQ)]. According to the data of magnetic measurements, a strong antiferromagnetic exchange between high-spin Fe(III) unpaired electrons and SQ provide an almost complete compensation of spin of one of the unpaired electrons of the metal ion by SQ spin. For Co a complex with 3,5-di-tert-butyl-o-benzoquinone [Co(hfac)2(3,5-Q)] is also synthesized and its structure and magnetic properties are studied. The latter prove to be similar to those of [Co(hfac)2(3,6-Q)].

KW - 3,5-di-tert-butyl-o-benzoquinone

KW - 3,6-di-tert-butyl-o-benzoquinone

KW - cobalt

KW - hexafluoroacetylacetonate

KW - iron

KW - magnetochemistry

KW - manganese

KW - quantum chemical calculations

KW - single crystal X-ray diffraction analysis

UR - http://www.scopus.com/inward/record.url?scp=85088658400&partnerID=8YFLogxK

U2 - 10.1134/S002247662004006X

DO - 10.1134/S002247662004006X

M3 - Article

AN - SCOPUS:85088658400

VL - 61

SP - 541

EP - 549

JO - Journal of Structural Chemistry

JF - Journal of Structural Chemistry

SN - 0022-4766

IS - 4

ER -