Cobalt as a Probe for Zinc in Metalloenzyme Model Compounds? A Comparison of Spectroscopic Features and Coordination Geometry of Four- and Five-Coordinate Complexes. Crystal and Molecular Structures of [Co(η3-TpPh)(η2-TpPh)], [(η3-TpPh)Zn(anthranilate)], and [(η3-TpPh)M(η2-acac)] (TpPh= Hydrotris(3-phenylpyrazol-1-yl)borate, acac = Pentane-2,4-dionate, and M = Zn, Co)

1997 ◽  
Vol 36 (8) ◽  
pp. 1552-1563 ◽  
Author(s):  
Andreas Kremer-Aach ◽  
Wolfgang Kläui ◽  
Ralf Bell ◽  
Angela Strerath ◽  
Hartmut Wunderlich ◽  
...  
1990 ◽  
Vol 45 (10) ◽  
pp. 1369-1382 ◽  
Author(s):  
Heindirk tom Dieck ◽  
Lutz Stamp

Diazadienes RN = CR′-CR′ = NR (DAD) form molecular complexes with copper(I) halides of composition (DAD)CuX, the structures of which vary from [(DAD)2Cu]+(CuCl2)⁻ with a non-tetrahedral bis(chelated) cation, over [(DAD)CuCl]2 with asymmetrically bridging chloro ligands to planar three-coordinate (DAD)CuCl. The composition of the isolated complexes depends on the relative concentrations or on the solvent. The “soft” coordination geometry of copper is underlined by the structure of the coordination polymer of composition (DAD)2Cu5Cl5, in which Cu atoms of coordination number 2, 3 and 4 and very irregular geometries are encountered and where the DAD ligands are exclusively bridging. Halide ions and sp2-nitrogen donors are very competitive. Bridging DAD ligands are also encountered in (DAD)Cu-Y with the less nucleophilic anions trifluoromethane-sulphonate or perchlorate. Crystal and molecular structures are established for all these coordination geometries and the causes are discussed for the coordination flexibility of copper(I)


1995 ◽  
Vol 48 (11) ◽  
pp. 1887 ◽  
Author(s):  
MI Bruce ◽  
PJ Low ◽  
BW Skelton ◽  
ERT Tiekink ◽  
A Werth ◽  
...  

The crystal and molecular structures of MBr (PPh3)2(η-C5H5).CH2Cl2 (M = Ru and Os) have been determined. A revised synthesis of the bromo osmium complex is given. The coordination geometry about the metal atom is based on a distorted octahedron with one face being occupied by the cyclopentadienyl group [average Ru -C(Cp) 2.214(3), Os-C(Cp) 2.177(3)Ǻ] and the other by the bromide [ Ru -Br 2.5683(8), Os-Br 2.5438(9)Ǻ] and the two phosphorus atoms [ Ru -P 2.323(2), 2.329(1); Os-P 2.290(2), 2.297(2)Ǻ]. Structural parameters are compared with those of the corresponding chloro complexes and differ only minimally. Crystals of MBr (PPh3)2(η-C5H5).CH2Cl2 are triclinic, space group Pī , with unit cell dimensions ( Ru [Os]): a 14.374(5) [14.276(4)], b 14.057(4) [13.959(3)], c 10.012(5) [9.903(3)]Ǻ, α 99.43(3) [99.79(2)], β 105.60(3) [105.74(2)], γ 100.42(3) [100.39(2)]°, V 1868(1) [1817.7(9)] Ǻ3, Z 2. The structures were refined by a full-matrix least-squares procedure to R 0.050 [0.036] for 7365 [5108] reflections with I ≥ 3σ(I).


1985 ◽  
Vol 63 (5) ◽  
pp. 1063-1067 ◽  
Author(s):  
Tristram Chivers ◽  
Richard T. Oakley ◽  
Roger Pieters ◽  
John F. Richardson

The sulphenyl chloride, Ph2CNSCl, prepared insitu from Ph2CNSiMe3 and sulphur dichloride, has been employed in the synthesis of Ph2CNSNSO and Ph2CNSNSNSNCPh2 by reaction with Me3SiNSO and Me3SiNSNSiMe3, respectively. An X-ray structural determination of Ph2CNSNSO shows it to consist of a planar cis-trans chain. The crystals are triclinic and belong to the space group[Formula: see text], a = 9.9078(8), b = 10.0967(9), c = 15.1682(14) Å, α = 78.646(7), β = 71.065(7), γ = 63.449(7)°, V = 1281.5(5) Å3, Z = 4. The final R and Rw values were 0.033 and 0.027, respectively. The π* → π* excitation energies for the RSNSO and RSNSS chromophores are compared for different R groups and discussed in the light of MNDO calculations on the model compounds HSNSX (X = S, O). The thermal decomposition of both Ph2CNSNSO and Ph2CNSNSNSNCPh2 produced S4N4 and Ph2CO or (Ph2CN)2S, respectively.


1978 ◽  
Vol 31 (4) ◽  
pp. 781 ◽  
Author(s):  
R Mason ◽  
GR Scollary

The crystal and molecular structures of two rhodium(I) complexes with long-chain alkyne- or alkene-α,ω-diyldiphosphines have been determined by single-crystal X-ray diffraction techniques. RhCl(CO){But2P(CH2)4C≡C(CH2)4PBut2} crystallizes in the orthorhombic space group Pna21 with a 21.991 (2), b 11.915(1), c 11.890(1) Ǻ and Z 4. The structure was refined by least-squares methods to a conventional R factor of 0.097 for 1768 independent reflections (Mo Kα diffraction data). The rhodium ion is in a square-planar coordination geometry with trans-phosphorus atoms; the unsaturated (alkynyl) group is not bonded to the rhodium. Crystals of RhCl{But2P(CH2)2CH=CH(CH2)2- PBut2} are monoclinic, space group P21/c, a 20.783(12), b 8.580(4), c 14.799(9) Ǻ, β 100.70(2)°, Z 4. The structure analysis has converged to R 0.069 for 1417 reflections (Mo Kα diffractometry); the coordination geometry of the rhodium is again planar with the ethylenic group occupying a single bonding site. The effect of ring size on the rhodium-phosphorus bond lengths is discussed.


Author(s):  
Janjira Kreaunakpan ◽  
Kittipong Chainok ◽  
Nathan R. Halcovitch ◽  
Edward R. T. Tiekink ◽  
Teerapong Pirojsirikul ◽  
...  

The complete molecule of the binuclear title complex, bis[μ-1H-1,2,4-triazole-5(4H)-thione-κ2 S:S]bis{(thiocyanato-κS)[1H-1,2,4-triazole-5(4H)-thione-κS]silver(I)}, [Ag2(SCN)2(C2H3N3S)4], is generated by crystallographic inversion symmetry. The independent triazole-3-thione ligands employ the exocyclic-S atoms exclusively in coordination. One acts as a terminal S-ligand and the other in a bidentate (μ2) bridging mode to provide a link between two AgI centres. Each AgI atom is also coordinated by a terminal S-bound thiocyanate ligand, resulting in a distorted AgS4 tetrahedral coordination geometry. An intramolecular N—H...S(thiocyanate) hydrogen bond is noted. In the crystal, amine-N—H...S(thione), N—H...N(triazolyl) and N—H...N(thiocyanate) hydrogen bonds give rise to a three-dimensional architecture. The packing is consolidated by triazolyl-C—H...S(thiocyanate), triazolyl-C—H...N(thiocyanate) and S...S [3.2463 (9) Å] interactions as well as face-to-face π–π stacking between the independent triazolyl rings [inter-centroid separation = 3.4444 (15) Å]. An analysis of the calculated Hirshfeld surfaces shows the three major contributors are due to N...H/H...N, S...H/H...S and C...H/H...C contacts, at 35.8, 19.4 and 12.7%, respectively; H...H contacts contribute only 7.6% to the overall surface.


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