Search

Five heterometallic Zn II 6 -Ln III 3 macrocycles based on a salicylamide imine multidentate unsymmetrical ligand H 2 L [1-(2-hydroxy-3-methoxy-benzamido)-2-(2-hydroxy-3-methoxy-benzylideneamino)-ethane] have been prepared via a coordination-driven self-assembly strategy. Single-crystal X-ray diffraction analysis reveals that the five metallocycles are isomorphic with a formula of [Zn 6 Ln 3 L 6 (OH) 2 (NO 3 ) 4 (H 2 O)]·3NO 3 · nCH 3 CN (ZnLn-1, where Ln = Pr, Nd, Eu, Tb, or Yb; for ZnPr-1, n = 4; for ZnNd-1, ZnEu-1, and ZnTb-1, n = 2; for ZnYb-1, n = 3), where six octadentate ligands L 2- and two in situ-formed μ 2 -OH - ions bridged the alternating Zn II -Ln III -Zn II subunits into a macrocycle. Along with the structural novelty, ZnNd-1 shows distinctive enhanced emission in the visible and near-infrared range upon addition of OAc - . On the basis of ultraviolet-visible spectroscopy, 1 H nuclear magnetic resonance, single-crystal X-ray diffraction, and high-resolution electrospray ionization mass spectrometry, we deduced that this emission enhancement could be attributed to the synergistic effect of TICT and the absent nonradiative transition of μ 2 -OH - induced distinctively by OAc - bridging. Our results demonstrate that the Nd III -containing heterometallic macrocycle can act as a host for anion exchanging and provide a nice example of heterometallic macrocycles with interesting properties and potential applications.

Four tetranuclear heterometallic compounds, [(Tp)Fe(CN)3]2[Ru2(DMBA)4] (1), [(MeTp)Fe(CN)3]2[Ru2(DMBA)4] (2), [((i)BuTp)Fe(CN)3]2[Ru2(DMBA)4] (3), and [(PhTp)Fe(CN)3]2[Ru2(DMBA)4] (4) [DMBA = N,N'-dimethylbenzamidinate, Tp = (hydrotris(pyrazolyl)borate, MeTp = (methyltris(pyrazolyl)borate, (i)BuTp = (2-methylpropyltris(pyrazolyl)borate, and PhTp = (tris(pyrazolyl)phenylborate)] were prepared from the combination of Ru2(DMBA)4(NO3)2 and an appropriate [(RTp)Fe(CN)3](-). Molecular structures of compounds 1-4 were established using single-crystal X-ray diffraction, and all feature a linear Fe-C[triple bond]N-Ru-Ru-N[triple bond]C-Fe array. The magnetic study revealed that the temperature dependence of chi(M)T is mostly attributed to the zero-field splitting of the Ru2 center, indicating the absence of strong spin coupling among three metallic centers. The electronic independence was further confirmed by the vis-NIR spectroscopic studies. Also described are the voltammetric properties of these compounds.

Two new cyano-bridged one-dimensional heterobimetallic coordination polymers, [(bpca)(2)Fe(III)(2)(CN)(6)Cu(H(2)O)(2).1.5H(2)O](n)() (2) and [(bpca)Fe(III)(CN)(3)Cu(bpca)(H(2)O).H(2)O](n)() (3), and a trinuclear complex, [(bpca)(2)Fe(III)(2)(CN)(6)Mn(CH(3)OH)(2)(H(2)O)(2)].2H(2)O (4), have been synthesized using the tailored tricyanometalate precursor (Bu(4)N)[Fe(bpca)(CN)(3)].H(2)O (1) (Bu(4)N(+) = tetrabutylammonium cation; bpca = bis(2-pyridylcarbonyl)amidate anion) as a building block and structurally characterized. In complex 2, the Cu(II) ions are six-coordinated in an elongated distorted octahedral environment, and they are linked by distorted octahedrons of [Fe(bpca)(CN)(3)](-) to form 1D chain of squares. Complex 3 is an unexpected chiral heterobimetallic helical chain complex, in which the helical chain consists of the asymmetric unit of [(bpca)Fe(CN)(3)Cu(bpca)(H(2)O)]. In complex 4, there are two independent trinuclear clusters in one asymmetric unit, and the coordination modes of the two methanol and two water molecules coordinating to the central Mn(II) ion are different (cis and trans). Complex 2 shows metamagnetic behavior with a Neel temperature of T(N) = 2.2 K and a critical field of 250 Oe at 1.8 K, where the cyanides mediate the intrachain ferromagnetic coupling between the Cu(II) and Fe(III) ions. Complex 3 shows ferromagnetic coupling between Cu(II) and Fe(III) ions, the best-fit for chi(M)T versus T using a 1D alternating chain model leads to the parameters J(1) = 7.9(3) cm(-)(1), J(2) = 1.03(2) cm(-)(1), and g = 2.196(3). Complex 4 exhibits ferrimagnetic behavior caused by the noncompensation of the local interacting spins (S(Mn) = 5/2 and S(Fe) = 1/2) which interact antiferromagnetically through bridging cyano groups.