期刊
CHEMISTRY-A EUROPEAN JOURNAL
卷 25, 期 64, 页码 14583-14597出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/chem.201902551
关键词
coordination chemistry; iron; magnetic anisotropy; manganese; single-chain magnets; slow magnetic relaxation
资金
- Russian Science Foundation [18-13-00264]
- Ministry of Science and Higher Education within the State assignment FSRC Crystallography and Photonics RAS in part of designing computer codes for calculations of magnetic characteristics of highly anisotropic exchange spin systems in the section Analy
- Russian Science Foundation [18-13-00264] Funding Source: Russian Science Foundation
Reactions of [Mn(H(2)dapsc)Cl-2]H2O (dapsc=2,6-diacetylpyridine bis(semicarbazone)) with K-3[Fe(CN)(6)] and (PPh4)(3)[Fe(CN)(6)] lead to the formation of the chain polymeric complex {[Mn(H(2)dapsc)][Fe(CN)(6)][K(H2O)(3.5)]}(n)1.5n H2O (1) and the discrete pentanuclear complex {[Mn(H(2)dapsc)](3)[Fe(CN)(6)](2)(H2O)(2)}4 CH(3)OH3.4 H2O (2), respectively. In the crystal structure of 1 the high-spin [Mn-II(H(2)dapsc)](2+) cations and low-spin hexacyanoferrate(III) anions are assembled into alternating heterometallic cyano-bridged chains. The K+ ions are located between the chains and are coordinated by oxygen atoms of the H(2)dapsc ligand and water molecules. The magnetic structure of 1 is built from ferrimagnetic chains, which are antiferromagnetically coupled. The complex exhibits metamagnetism and frequency-dependent ac magnetic susceptibility, indicating single-chain magnetic behavior with a Mydosh-parameter phi=0.12 and an effective energy barrier (U-eff/k(B)) of 36.0 K with tau(0)=2.34x10(-11) s for the spin relaxation. Detailed theoretical analysis showed highly anisotropic intra-chain spin coupling between [Fe-III(CN)(6)](3-) and [Mn-II(H(2)dapsc)](2+) units resulting from orbital degeneracy and unquenched orbital momentum of [Fe-III(CN)(6)](3-) complexes. The origin of the metamagnetic transition is discussed in terms of strong magnetic anisotropy and weak AF interchain spin coupling.
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