High-spin tetranuclear Mn(II)(2)Mn(IV)(2) clusters with unique Mn(ii)-Mn(iv) magnetic exchange: synthesis, structures and magnetism.
Reactions of N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (H(4)edte) with MnCl(2).4H(2)O or FeCl(3).6H(2)O in MeOH or MeCN with different bases yield four butterfly-like tetranuclear clusters with fused defective dicubane M(4)O(6) cores: [Mn(II)(2)Mn(IV)(2)(mu(4)-Hedte)(2)(thme)(2)].MeCN () (H(4)edte = N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine, H(3)thme = 1,1,1-tris(hydroxymethyl)ethane), [Mn(II)(2)Mn(IV)(2)(mu(4)-Hedte)(2)(thme)(2)].2MeOH (), [Fe(III)(4)(mu(4)-Hedte)(2)(N(3))(6)].2MeCN () and [Fe(III)(4)(mu(4)-edte)(2)(N(3))(4)(MeOH)(2)] (). Both and crystallize in the triclinic space group P1[combining macron], while and crystallize in the monoclinic space group P2(1)/c and P2(1)/n, respectively. The hexadentate Hedte(3-) ligand in , and the edte(4-) ligand in acts in a similar mu(4):eta(1):eta(1):eta(1):eta(2):eta(2):eta(3) coordination mode to bridge four metal ions into butterfly-like tetranuclear clusters with fused defective dicubane M(4)O(6) cores. Magnetic studies show that has the spin ground state S(T) = 8 while has the spin ground state S(T) = 0. Within the Mn(4)O(6) cluster core of , both Mn(iv)Mn(ii) and Mn(ii)Mn(ii) ferromagnetic interactions (J(Mn(iv)Mn(ii)) = +2.91 cm(-1) and J(Mn(ii)Mn(ii)) = +7.94 cm(-1)) occur contrary to the Fe(4)O(6) core, where antiferromagnetic exchange exists (J(aptical-Fe(iii)central-Fe(iii)) = -15.4 cm(-1) and J(central-Fe(iii)central-Fe(iii)) = -4.5 cm(-1)).
Zhou
Ai-Ju
AJ
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry/State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275, China.
Liu
Jun-Liang
JL
Herchel
Radovan
R
Leng
Ji-Dong
JD
Tong
Ming-Liang
ML
D018360:Crystallography, X-Ray; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure
D008345:Manganese