• Title/Summary/Keyword: dinuclear

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Metal-Dinitrosyl Complexes(Ⅳ) : Synthesis and Characterization of Symmetric and Asymmetric Dinuclear Molybdenum and Tungsten Complexes (금속-디니트로실 착물 (제 4 보) : 몰리브덴과 텅스텐의 대칭 및 비대칭 이핵 착물의 합성과 특성)

  • O, Sang O;Mo, Seong Jong
    • Journal of the Korean Chemical Society
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    • v.38 no.7
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    • pp.485-495
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    • 1994
  • Several new symmetric and asymmetric homo and hetero dinuclear complexes of the type $[Cl(dppp)(NO)_2M({\mu}-pyz)M'(NO)_2(dppp)Cl][ClO_4]_2$ and $[Cl(phen)(NO)_2M({\mu}-pyz)M'(NO)_2(dppp)Cl][ClO_4]_2$(M,M'= Mo or W; phen = 1,10-phenanthroline; dppp = 1,3-bis(diphenylphosphino)propane; pyz = 1,4-pyrazine) were synthesized in three-steps starting from $[M(NO)_2Cl_2]_n(M = Mo, W)$. The final products were purified by eluting it through silica gel column ($2{\times}20$ cm) with acetone as the eluent. Characterization of these complexes and some related complexes was accomplished through UV-vis., $^1H$-NMR, $^{13}C$-NMR and IR spectroscopies as well as elemental analysis. The infrared spectra indicate that the NO groups occupy cis-positions of the octahedral. The $^1H$ and $^{13}C-NMR$ data for the new compounds revealed a dimeric structures with bridged pyz.

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Synthesis, Crystal structure, and Magnetic Properties of Dinuclear Iron(III) Complexes with Methoxo Bridges

  • Shin, Jong-Won;Han, Jeong-Hyeong;Rowthu, Sankara Rao;Kim, Bong-Gon;Min, Kil-Sik
    • Bulletin of the Korean Chemical Society
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    • v.31 no.12
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    • pp.3617-3622
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    • 2010
  • The reaction of stoichiometric amount of $FeCl_2{\cdot}4H_2O$, (2-pyridylmethyl, 3-pyridylmethyl)amine (2,3-pyma) and sodium azide/sodium thiocyanate in methanol under aerobic conditions affords the dinuclear Fe(III) complexes, [(2,3-pyma) $(N_3)_2Fe({\mu}-OCH_3)_2Fe(N_3)_2$(2,3-pyma)]${\cdot}CH_3OH$ (1) and [(2,3-pyma)$(NCS)_2Fe({\mu}-OCH_3)_2Fe(NCS)_2$(2,3-pyma)] (2) in good yield. Two bis-methoxy-bridged diiron(III) complexes are isolated and characterized. The coordination geometries around iron(III) ions in 1 and 2 are the same tetragonally distorted octahedron. The iron(III) ions are coordinated by two nitrogens of a 2,3-pyma, two nitrogens of two azide/thiocyanate ions, and two oxygens of two methoxy groups. Both compounds are isomorphous. The structures of 1 and 2 display the C-$H{\cdots}\pi$ and/or $\pi-\pi$ stacking interactions as well as hydrogen bonding interactions, respectively. Compounds 1 and 2 show significant antiferromagnetic couplings through the bridged methoxy groups between the iron(III) ions in the temperature range from 5 to 300 K ($H=-2JS_1{\cdot}S_2$, J=-19.1 and $-13.9\;cm^{-1}$ for 1 and 2).

Synthesis and Characterization of Dinuclear Ni(II) Complexes with Tetraazadiphenol Macrocycle Bearing Cyclohexanes

  • Kim, Ki-Ju;Jung, Duk-Sang;Kim, Duk-Soo;Choi, Chi-Kyu;Park, Ki-Min;Byun, Jong-Chul
    • Bulletin of the Korean Chemical Society
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    • v.27 no.11
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    • pp.1747-1751
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    • 2006
  • The dinuclear tetraazadiphenol macrocyclic nickel(II) complexes [$Ni_2$([20]-DCHDC)]$Cl_2$ (I), [$Ni_2$([20]-DCHDC)]$(ClO_4)_2{\cdot}2CH_3CN $ (II(b)) and [$Ni_2$([20]-DCHDC)$(NCS)_2$] (III) {$H_2$[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,$0^{4,9}$,$1^{12,16}$,$0^{19,24}$]ditriacontane-2,10,12,14,16(32),17,27(31), 28,30-decane-31,32-diol} have been synthesized by self-assembly and characterized by elemental analyses, conductances, FT-IR and FAB-MS spectra, and single crystal X-ray diffraction. The crystal structure of II(b) is determined. It crystallizes in the monoclinic space group P2(1)/c. The coordination geometries around Ni(II) ions in I and II(b) are identical and square planes. In complex III each Ni(II) ion is coordinated to $N_2O_2$ plane from the macrocycle and N atoms of NCS- ions occupying the axial positions, forming a square pyramidal geometry. The nonbonded Ni…Ni intermetallic separation in the complex II(b) is 2.8078(10) $\AA$. The FAB mass spectra of I, II and III display major fragments at m/z 635.1, 699.4 and 662.4 corresponding to [$Ni_2$([20]-DCHDC)(Cl + 2H)]$^+$, [$Ni_2$([20]-DCHDC)$(ClO_4\;+\;2H)]^+$ and [$Ni_2$([20]-DCHDC)(NCS) + 6H]$^+$, respectively.

Preparation and Characterization of Dinuclear and Trinuclear Metal Complexes, $[(PPh_3)_2(CO)M({\mu}-E)M(CO)(PPh_3)_2]X_2$ (M=Rh, Ir; E=Pyrazine, 4,4'-Bipyridyl, $X=SO_3CF_3$; $E=Pd(CN)_4$, $Pt(CN)_4$, X=none)

  • Ko Jaejung;Lee Myunggab;Kim Moonsik;Kang Sang Ook
    • Bulletin of the Korean Chemical Society
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    • v.13 no.2
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    • pp.158-162
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    • 1992
  • Hydrocarbon solution of $(PPh_3)_2(CO)MOSO_2CF_3(M=Rh$, Ir)reacts rapidly with Pyrazine or 4,4'-bipyridyl to yield dinuclear metal complexes $[(PPh_3)_3(CO)M({\mu}-pyrazine)M(CO)(PPh_3)_2](SO_3CF_3)_2$ (I: M= RhH; III: M=Ir) or [$(PPh_3)_2$(CO)M(${\mu}$-44'-bipyridyl)M(CO)$(PPh_3)_2](SO_3CF_3)_2$, (II: M=Rh; IV: M=Ir), respectively. Compounds, I, II, III, and IV were characterized by $^1H-NMR$, $^{13}C-NMR$, $^{31}P-NMR$, and infrared spectrum. Ethanol solution of $(PPh_3)_2(CO)MOSO_2CF_3$ (M=Rh, Ir) also reacts with $(TBA)_2$M'$(CN)_4$ (M'=Pd, Pt) to yield trinuclear metal complexes [$(PPh_3)_2$(CO)dM-NCM'$(CN)_2$CN-M(CO)$(PPh_3)_2]$ (V : M=Rh, M'=Pd; VI : M=Rh, M'=Pt; VII: M=Ir, M'=Pd; VIII: M=Ir, M'=Pt). The trinuclear metal complexes V, VI, VII, and VIII are bridged by the cyanide groups. The infrared spectrum of V, VI, VII, and VIII supports the presence of the bridged cyanide and terminal cyanide group.

Molecular Wire World Having Metal Complexes

  • Choi, Chang-Shik
    • Rapid Communication in Photoscience
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    • v.3 no.3
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    • pp.42-47
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    • 2014
  • Development of molecular and supramolecular systems showing efficient photoinduced energy or electron transfer are of current research interest due to their applications in various chemical and biological processes. Various polypyridine metal complexes including Ru(II), Ru(III), Os(II), Pt(II), Fe(II), Re(I), Ir(III) and so on as a metal center introduce for expanding some more understanding of molecular-scale photoelectronics. Their complexes are concisely classified by the types of relay ligands as follows; (a) metal-direct ligand-metal system; dinuclear or trinuclear systems, (b) metal-nonconjugated ligand-metal system and metal-nonconjugated ligand system having flexible/rigid ligand, (c) metal-conjugated ligand-metal system, and (d) conjugated ligand-metal-conjugated ligand system and metal-self assembly ligand-metal system. It is pointed out that the role played by the relay ligands is important in constructing the metal complexes.

Influence of Jahn-Teller Distortion on the Magnetic Coupling in Oxalato-Bridged Copper(II) Dimers: An Orbital Interpretation of the Superexchange Mechanism

  • Kang, Dae-Bok
    • Bulletin of the Korean Chemical Society
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    • v.26 no.12
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    • pp.1965-1968
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    • 2005
  • Extended H$\ddot{u}$ckel molecular calculations have been used to analyze how the magnitude of exchange coupling is influenced by the structural distortions in a series of dinuclear six-coordinate copper(II) complexes bridged by the planar bis-bidentate oxalate anion. Copper(II) ions have distorted octahedral surroundings, one being axially elongated and the other compressed. The magnetic interaction is strong in the former complexes and very weak in the latter. This is interpreted as resulting from a switching of magnetic spin orbitals due to the structural distortions (bond elongation or compression) of the copper sites.

Spin Exchange Coupling in Dimethoxo-Bridged Dichromium(III) Complexes: A Density Functional Theory Study

  • Kang, Dae-Bok
    • Bulletin of the Korean Chemical Society
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    • v.29 no.5
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    • pp.963-968
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    • 2008
  • For the [$Cr_2(H_2tmp)_2Cl_4$] compound, simplified models with two bridging methoxo ligands have been studied. The influence of the bridging Cr-O-Cr bond angles on the exchange coupling between metal atoms in the model compound has been analyzed by means of density functional calculations with the broken-symmetry approach. Coupling constant calculated for the full structure is in good agreement with the experimentally reported value, confirming the validity of the computational strategy used in this work to predict the exchange coupling in a family of related dinuclear Cr(III) compounds. The calculations indicate a good correlation between the calculated coupling constant and the sum of the squared energy gap of three pairs of metal $t_{2g}$ OMSOs with a limited variation of the Cr-O-Cr angle. The spin density distribution and the mechanism of magnetic coupling interactions are discussed.

Synthesis and Characterization of C-meso and C-racemic Isomers of a Reinforced Tetraaza Macrocycle and Their Copper(II) Complexes

  • Jeong, Gyeong Rok;Kim, Juyoung;Kang, Shin-Geol;Jeong, Jong Hwa
    • Bulletin of the Korean Chemical Society
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    • v.35 no.7
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    • pp.2043-2048
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    • 2014
  • Two isomers of a new tetraaza macrotricycle 2,2,4,9,9,11-hexaazamethyl-1,5,8,12-tetraazatricyclo[$10.2.2^{5.8}$]-octadecane ($L^2$) containing additional N-$CH_2CH_2$-N linkages, C-meso-$L^2$ and C-racemic-$L^2$, have been prepared by the reaction of 1-bromo-2-chloroethane with C-meso-$L^1$ or C-racemic-$L^1$ ($L^1$ = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). Both C-meso-$L^2$ and C-racemic-$L^2$ react with copper(II) ion to form $[Cu(C-meso-L^2)]^{2+}$ or $[Cu(C-racemic-L^2)]^{2+}$ in dehydrated ethanol, but do not with nickel(II) ion under similar conditions. Crystal structure of [Cu(C-racemic-$L^2$)($H_2O$)]$(ClO_4)_2$ shows that the complex has distorted square-pyramidal coordination geometry with an apically coordinated water molecule. Unexpectedly, the Cu-N distances [2.016(3)-2.030(3) ${\AA}$] of [Cu(C-racemic-$L^2$)($H_2O$)]$(ClO_4)_2$ are longer than those [1.992(3)-2.000(3) ${\AA}$] of [Cu(C-racemic-$L^1$)($H_2O$)]$(ClO_4)_2$. As a result, $[Cu(C-racemic-L^2)(H_2O)]^{2+}$ exhibits weaker ligand field strength than $[Cu(C-racemic-L^1)(H_2O)]^{2+}$. The copper(II) complexes readily react with CN- ion to yield the cyano-bridged dinuclear complex $[Cu_2(C-meso-L^2)_2CN]^{3+}$ or $[Cu_2(C-racemic-L^2)_2CN]^{3+}$. Spectra and chemical properties of $[Cu(C-meso-L^2)]^{2+}$ and $[Cu_2(C-meso-L^2)_2CN]^{3+}$ are not quite different from those of $[Cu(C-racemic-L^2)]^{2+}$ and $[Cu_2(C-racemic-L^2)_2CN]^{3+}$, respectively.

Detection of Superoxide Anion and Singlet Oxygen in the Decomposition of Several Peroxovanadium(V) Complexes

  • Kanamori, Kan;Hata, Kaori;Shimoyama, Toshiyuki;Hayakawa, Shingo;Tajima, Hirotaka;Matsugo, Seiichi
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.412-414
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    • 2002
  • Several peroxovanadium(V) complexes with an organic chelate ligand decompose spontaneously, depending on the nature of the chelate ligand. The self-decomposition reactions of the dinuclear peroxovanadium(V) complex with 2-oxo-l,3-diaminopropane-N,N,N',N'-tetraacetate (dpot) and the peroxovanadium(V) complexes with N-carboxymethylhistidinate (cmhist) and histamine-N,N-diacetate (histada) accompany the reduction of vanadium(V) to vanadium(IV). This implies that the peroxide anion acts as a reducing agent and thus the peroxide is oxidized in the decomposition process of the peroxovanadium(V) complexes. The oxidized dioxygen species have been characterized spectrophotometrically. Superoxide anion has been detected in 2-3 % yields using the reduction of cytochrome c method and chemiluminescence method utilized MCLA as a fluorescer. Singlet oxygen has also been detected in higher yields on the basis of chemiluminescence of tryptophan.

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Different Dimensional and Structural Variations in Coordination Compounds of Cadmium, Manganese and Nickel Constructed from the Ligand 2,2'-Bipyidine-3,3',6,6'-tetracarboxylic Acid (H4bptc)

  • Xiang, Jing;Yang, Tian-Tian;Fu, Lu-Lu;Luo, Ya;Wu, Jia-Shou
    • Bulletin of the Korean Chemical Society
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    • v.34 no.9
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    • pp.2597-2603
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    • 2013
  • The reactions of hydrated $CdCl_2$, $MnCl_2$, and $NiCl_2$ with 2,2'-bipyidine-3,3',6,6'-tetracarboxylic acid ($H_4bptc$) afforded the mononuclear [$Cd^{II}(H_2bptc)(H_2O)_3]{\cdot}H_2O$ (1), linear $\{[Cd(H_2bptc)(H_2O)]{\cdot}3H_2O\}_n$ (2), 3-D heterobimetallic $[NaCd(Hbptc)(H_2O)]$ (3), layer $[Mn(H_2bptc)(H_2O)]_n$ (4) and a dinuclear compound $[Ni_2(H_2bptc)-(H_2O)_2]{\cdot}6H_2O$ (5). These compounds have been characterized by elemental analysis, IR, and their structures have been determined by X-ray crystallography. The thermal stabilities of 1-3 were measured by thermogravimetric analysis (TGA) and their solid state luminescence properties together with the free ligand $H_4bptc$ were investigated at room temperature.