Title: Heterospin Systems Constructed from [Cu2Ln]3+ and [Ni(mnt)2]1-,2- Tectons: First 3p-3d-4f Complexes (mnt = maleonitriledithiolato)
Authors: Madalan, Augustin M ×
Avarvari, Narcis
Fourmigué, Marc
Clérac, Rodolphe
Chibotaru, Liviu
Clima, Sergiu
Andruh, Marius #
Issue Date: Feb-2008
Publisher: American Chemical Society
Series Title: Inorganic Chemistry vol:47 issue:3 pages:940-950
Abstract: Unprecedented heterospin complexes have been obtained as crystalline compounds, by combining the binuclear complexes [{CuL1(2)}Ln(O2NO)3] (L1 = N,N’-propylene-di(3-methoxysalicylideneiminato; L2 = N,N’-ethylene-di(3-methoxysalicylideneiminato; Ln = Gd3+, Sm3+, Tb3+), with the mononuclear [CuL1(2)] and the nickel dithiolene complexes [Ni(mnt)2]q– (q = 1, 2; mnt = maleonitriledithiolate), as follows: 1∞[{CuL1}2Ln(O2NO){Ni(mnt)2}]•Solv•CH3CN (Ln = Gd3+, Solv = CH3OH (1), Ln = Sm3+, Solv = CH3CN (2)) and [{(CH3OH)CuL2}2Sm(O2NO)][Ni(mnt)2] (3) with [Ni(mnt)2]2–, and [{(CH3CN)CuL1}2Ln(H2O)][Ni(mnt)2]3•2CH3CN (Ln = Gd3+ (4), Sm3+ (5), Tb3+ (6)) and [{(CH3OH)CuL2}{CuL2}Gd(O2NO){Ni(mnt)2}][Ni(mnt)2]•CH2Cl2 (7) with [Ni(mnt)2]•–Trinuclear, almost linear, [CuLnCu] motifs are found in all the compounds. In the isostructural 1 and 2, two trans cyano groups from a [Ni(mnt)2]2– unit bridge two trimetallic nodes through axial coordination to the Cu centers, thus leading to the establishment of infinite chains. 3 is an ionic compound, containing discrete [{(CH3OH)CuL2}2Sm(O2NO)]2+ cations and [Ni(mnt)2]2– anions. Within the series 4-6, layers of discrete [CuLnCu]3+ motifs alternate with stacks of interacting [Ni(mnt)2]•– radical anions, for which two overlap modes, providing two different types of stacks, can be disclosed. The strength of the intermolecular interactions between the open shell species is estimated through extended Hückel calculations. In the compound 7, [Ni(mnt)2]•– radical anions coordinate through a CN group one of the Cu centers of a trinuclear [Cu2Gd] motif, whereas also discrete [Ni(mnt)2]•– units are present, overlapping in between, but also with the coordinated ones. Furthermore, the [Cu2Gd] moieties dimerize each other upon linkage by two nitrato groups, both acting as chelate toward the gadolinium ion from a unit, and monodentate toward a Cu ion from the other unit. The magnetic properties of the gadolinium containing complexes have been determined. Ferromagnetic exchange interactions within the trinuclear [Cu2Gd] motifs occur. In the compounds 4 and 7, the [Ni(mnt)2]•– radical anions contribution to the magnetization is clearly observed in the high temperature regime and most of it vanishes upon temperature decrease, very likely because of the rather strong antiferromagnetic exchange interactions between the open shell species. The extent of the exchange interaction in the compound 7, which was found to be antiferromagnetic, between the coordinated Cu center and the corresponding [Ni(mnt)2]•– radical anion, bearing mostly a 3p spin type, was estimated through CASSCF/CASPT2 calculations. In the case of the terbium containing complex 6, a non-classical single molecule magnet behaviour is likely to occur.
ISSN: 0020-1669
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Quantum Chemistry and Physical Chemistry Section
× corresponding author
# (joint) last author

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