Syntheses, crystal structures and magnetic properties of cyano- and phenoxide-bridged Fe(iii)Mn(iii) tetramers containing fac-Fe(iii) tricyanides and Mn(iii) Schiff bases

Hyun Young Kwak, Dae Won Ryu, Hyoung Chan Kim, Eui Kwan Koh, Beong Ki Cho, Chang Seop Hong

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Three cyanide-linked Fe(iii)Mn(iii) bimetallic clusters, [(Tp)Fe(CN) 3]2[Mn(acphen)]2 [1; acphen = N,N′-ethylenebis(2-hydroxyacetophenylideneiminato) dianion], [(Tp)Fe(CN)3]2[Mn(5-Bracphen)]2 [2; 5-Bracphen = N,N′-ethylenebis(5-bromo-2-hydroxyacetophenylideneiminato) dianion], and [(Tp)Fe(CN)3]2[Mn(salen)]2·6H 2O [3; salen = N,N′-ethylenebis(salicylidineiminato) dianion], were prepared by self-assembling a facial [(Tp)Fe(CN)3]- [Tp = hydrotris(pyrazolyl)borate] precursor and respective Mn(iii) Schiff bases. X-Ray crystal structure analyses revealed that each complex is composed of a central Mn(iii) dimer doubly linked by phenoxides of the tetradentate N 2O2 Schiff bases and the terminal [(Tp)Fe(CN) 3]- groups connecting to the center through cyanides. Using the spin Hamiltonian H = -2J1(SFe1·S Mn1 + SMn1a·SFe1a) - 2J 2(SMn1·SMn1a), where J1 stands for the exchange coupling constant between Fe(iii) (SFe = 1/2) and Mn(iii) (SMn = 2) through cyanides and J2 between Mn(iii) ions via phenoxides, the best fits corresponded to J1 = 2.61 cm-1 and J2 = 0.85 cm-1 for 1, J1 = 2.50 cm-1 and J2 = 1.30 cm-1 for 2, and J 1 = -2.15 cm-1 and J2 = 0.55 cm-1 for 3. The phenoxide routes transmit ferromagnetic interactions in all cases, while ferromagnetic or antiferromagnetic couplings occur through the cyanide linkage. Although the geometric parameters relevant to the magnetic Fe-CN-Mn pathways are analogous to each other their magnetic natures are varied across the compounds, which supports that a degree of orbital overlap is quite sensitive to a subtle structural change in the present system.

Original languageEnglish
Pages (from-to)1954-1961
Number of pages8
JournalDalton Transactions
Issue number11
DOIs
Publication statusPublished - 2009

ASJC Scopus subject areas

  • Inorganic Chemistry

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