• Title/Summary/Keyword: Bridging Complex

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Structural and Spectral Characterization of a Chromium(III) Picolinate Complex: Introducing a New Redox Reaction

  • Hakimi, Mohammad
    • Journal of the Korean Chemical Society
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    • v.57 no.6
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    • pp.721-725
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    • 2013
  • Reaction between 2-pyridinecarboxylic acid (Hpic) and $K_3[Cr(O_2)_4]$ give complex $[Cr(pic)_3].H_2O$ (1) which is characterized by elemental analysis and spectroscopic methods (FT-IR, Raman) and X-ray crystallography. In the crystal structure of 1, chromium atom with coordinated by three nitrogen and three oxygen atoms has a distorted octahedral geometry. Also a water molecule is incorporated in crystal network. Each water molecule acts as hydrogen bond bridging and connects two adjacent complexes by two $O-H{\cdots}O$ hydrogen bonds.

Cr(III)-Tetraaza Macrocyclic Complexes Containing Auxiliary Ligands (Part II); Synthesis and Characterization of Cr(III)-Citrato Macrocyclic Complex

  • Byun, Jong-Chul;Park, Yu-Chul;Youn, Jeung-Su;Han, Chung-Hun;Lee, Nam-Ho
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.634-640
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    • 2005
  • The reaction of cis-[Cr([14]-decane)(OH$_2)_2]^+$ ([14]-decane = rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-teraazacyclotetradecane) with auxiliary ligands {$L_a$ = citrate(cit)} leads to a new dimeric complex cis-[{Cr([14]-decane)($\mu$-cit)}$_2](ClO_4)_2$. This binuclear complex has been structurally characterized by a combination of elemental analysis, conductivity, IR and Vis spectroscopy, mass spectrometry, and X-ray crystallography. Analysis of the crystal structure of cis-[{Cr([14]-decane)($\mu$-cit)})($_2]^+$ reveals that each chromium has a distorted octahedral coordination environment and citrato ligands are monodentate to the two chromium atoms via the carboxyl groups. For dimeric complex the bridging geometry is as follows: Cr$\ldots$Cr = 7.361 $\AA$; Cr-O(average) = 1.958 (8) $\AA$; Cr-N range = 2.108 (9)-2.147(9) $\AA$; N(1)-Cr-N(3) (equatorial position) = 98.0(4)$^{\circ}$; N(2)-Cr-N(4) (axial position) = 166.4(4)$^{\circ}$; O(1)-Cr-N(2) = 98.1(4)$^{\circ}$; O(3)-Cr-N(4) = 96.6(3)$^{\circ}$; O(1)-Cr-O(3) = 90.4$^{\circ}$. The FAB mass spectrum of the dimeric complex displays peak due to the molecular ions cis-[{Cr([14]-decane)($\mu$-cit)})($_2]^+$ at m/z 1053.

Preparation and crystal structure of azido bridged one-dimensional polymeric cadmium(II) complex, [Cd(N3)2(2-ethylimidazole)2]

  • Suh, Seung Wook;Kim, Inn Hoe;Kim, Chong-Hyeak
    • Analytical Science and Technology
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    • v.18 no.5
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    • pp.391-395
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    • 2005
  • The title complex, $[Cd(N_3)_2(2-ethylimidazole)_2]$, I, has been prepared and characterized by X-ray single crystallography. The complex I crystallizes in the monoclinic system, Cc space group with a = 16.200(3), b = 12.926(3), $c=7.007(1){\AA}$, ${\beta}=102.29(3)^{\circ}$, $V=1433.7(5){\AA}^3$, Z = 4, $R_1=0.0239$ and ${\omega}R_2=0.0604$ for 1874 independent reflections. Cd(II) atom has a slightly distorted octahedral coordination geometry, with four end-on (${\mu}-1$,1) bridging azido ligands and two 2-ethylimidazole ligands bonding through nitrogen atom. The central cadmium(II) atoms are run in parallel to the c-axis and are doubly bridged with neighboring cadmium(II) atoms by the end-on (${\mu}-1$,1) bridging azido ligands. Thus, this complex has a one-dimensional zigzag chain structure in which the 2-ethylimidazole is in the cis conformation.

Crystal Structure and Molecular Stereochemistry of Novel Polymeric Cu2(DMP)44(DMSO) as a Platform for Phosphate Diester Binding

  • Rafizadeh, Massoud;Tayebee, Reza;Amani, Vahid;Nasseh, Mohammad
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.594-598
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    • 2005
  • Treatment of a solution of $CuCl_2$ in dimethyl phosphate (DMP) with DMSO under nitrogen atmosphere afforded to a light blue fluorescence powder. Slow evaporation of $H_2O$-DMSO solution of this powder resulted in blue-sky crystals of a new polymeric Cu(II) complex, with a unit cell composed of $Cu_2(DMP)_4$(DMSO), (1). The crystal and molecular structure of the complex acquired crystallographically. Compound (1) crystallizes in the monoclinic space group $P2_1$/n with a = 12.8920(11) $\AA$, b = 13.1966(11) $\AA$, c = 14.7926(13) $\AA$, $\alpha$ = 90$^{\circ}$, $\beta$ = 98.943(2)$^{\circ}$, $\gamma$ = 90$^{\circ}$, V= 2486.1(4) ${\AA}^3$, and Z = 4. A square pyramidal environment for the metal center was established by coordination of oxygen atoms of four bridging DMP ligands in the basal positions and binding a tri-centered oxygen atom of DMSO in the apical disposition of Cu(II). The sixth position was also affected by a weak interaction with the sulfur atom of another DMSO. The phosphorous atom in the bridging DMP was arranged in a deformed tetrahedron with (gg) conformation for methyl esters with $C_{2v}$ symmetry.

Structural Analysis and Single-Crystal EPR Study of Dimeric Cu(I) Complex with TTF Derivative

  • Kwon, Sun-Young;Seo, Young-Joo;Lee, Yang-Joo;Noh, Dong-Youn;Lee, Hong-In
    • Journal of the Korean Magnetic Resonance Society
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    • v.8 no.2
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    • pp.86-95
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    • 2004
  • A Cu(I) complex with an asymmetric TTF derivative (CET-EDTTTF) is prepared from the slow-diffusion method using CET-EDTTTF and Cu(I)Br solutions and characterized by X-ray crystallography and EPR spectroscopy. Structural analysis shows Cu(I) ions are tetrahedrally coordinated to two bridging bromides, one terminal bromide, and one S atom from CET-EDTTTF. Detailed geometrical and EPR analysis identified that the dimmer molecule contains [Cu$_2Br_4]^{2-}$ anion between two [CET-EDTTTF]$^+$ radical cations. Single-crystal EPR investigation of the complex reveals that the ganisotropy is unusually big, compared to those of the previously reported TTF+ cation radicals, implying that there is significant contribution of the Cu d-orbital to the HOMO of the complex.

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