화학공학소재연구정보센터
Inorganic Chemistry, Vol.51, No.4, 2140-2149, 2012
Chiral Cyanide-Bridged Cr-III-Mn-III Heterobimetallic Chains Based on [(Tp)Cr(CN)(3)](-): Synthesis, Structures, and Magnetic Properties
By the reactions of Mn-III Schiff-base complexes with the tricyanometalate building block, [(Tp)Cr(CN)(3)](-) (Tp = Tris(pyrazolyl) hydroborate), two couples of enantiomerically pure chiral cyano-bridged heterobimetallic one-dimensional (1D) chain complexes, [Mn((R,R)-Salcy)Cr(Tp)(CN)(3)center dot 1/4H(2)O center dot 1/2CH(2)Cl(2)](n) (1) and [Mn((S,S)-Salcy)Cr(Tp)(CN)(3)center dot 1/4H(2)O center dot 1/2CH(2)Cl(2)](n) (2) (Salcy = N,N'-(1,2-cyclohexanediylethylene)bis(salicylideneiminato) dianion), [Mn((R,R)-Salphen)Cr(Tp)(CN)(3)](n) (3) and [Mn((S,S)-Salphen)Cr(Tp)(CN)(3)](n) (4) (Salphen = N,N'-1,2-diphenylethylene-bis(salicylideneiminato) dianion), have been successfully synthesized. Circular dichroism (CD) spectra confirm the enantiomeric nature of the optically active complexes. Structural analyses reveal the formation of neutral cyano-bridged zigzag single chains in 1 and 2, and neutral cyano-bridged zigzag double chains in 3 and 4. Magnetic studies show that antiferromagnetic couplings are operative between C-III and Mn-III centers bridged by cyanide. Complexes 1 and 2 are the rare examples of chiral ferrimagnets; while complexes 3 and 4 exhibit a coexistence of chirality and spin-glass behavior in a 1D chain.