Syntheses, Structures, and Magnetic Properties of Low-Dimensional Heterometallic Complexes Based on the Versatile Building Block [(Tp)Cr(CN)3]−
journal contributionposted on 05.09.2011, 00:00 by Min-Xia Yao, Zheng-You Wei, Zhi-Guo Gu, Qi Zheng, Yan Xu, Jing-Lin Zuo
Using the tricyano precursor (Bu4N)[(Tp)Cr(CN)3] (Bu4N+ = tetrabutylammonium cation; Tp = tris(pyrazolyl)hydroborate), a pentanuclear heterometallic cluster [(Tp)2Cr2(CN)6Cu3(Me3tacn)3][(Tp)Cr(CN)3](ClO4)3·5H2O (1, Me3tacn = N,N′,N′-trimethyl-1,4,7-triazacyclononane), three tetranuclear heterometallic clusters [(Tp)2Cr2(CN)6Cu2(LOEt)2]·2.5CH3CN (2, LOEt = [(Cp)Co(P(O)(OEt)2)3], Cp = cyclopentadiene), [(Tp)2Cr2(CN)6Mn2(LOEt)2]·4H2O (3), and [(Tp)2Cr2(CN)6Mn2(phen)4](ClO4)2 (4, phen = phenanthroline), and a one-dimensional (1D) chain polymer [(Tp)2Cr2(CN)6Mn(bpy)]n (5, bpy = 2,2′-bipyridine) have been synthesized and structurally characterized. Complex 1 shows a trigonal bipyramidal geometry in which [(Tp)Cr(CN)3]− units occupy the apical positions and are linked through cyanide to [Cu(Me3tacn)]2+ units situated in the equatorial plane. Complexes 2–4 show similar square structures, where CrIII and MII (M = CuII or MnII) ions are alternatively located on the rectangle corners. Complex 5 consists of a 4,2-ribbon-like bimetallic chain. Ferromagnetic interactions between CrIII and CuII ions bridged by cyanides are observed in complexes 1 and 2. Antiferromagnetic interactions are presented between CrIII and MnII ions bridged by cyanides in complexes 3–5. Complex 5 shows metamagnetic behavior with a critical field of about 22.5 kOe at 1.8 K.