Structural evidence for ligand back-bonding in distortions from octahedral geometry of complexes of d6 ML4 fragments with .pi.-ligands

1991 ◽  
Vol 10 (2) ◽  
pp. 442-447 ◽  
Author(s):  
Donald J. Wink
Author(s):  
Mohammed Al-Amery1 ◽  
Ashraf Saad Rasheed ◽  
Dina A. Najeeb

Five new mixed ligand metal complexes have been synthesized by the reaction of divalent transition metal ions (Hg, Ni, Zn, Cu and Cd) with 2-(naphthalen-l-ylamino)-2-phenylacetonitrile (L1 ) and 1,10-phenanthroline (L2). The coordination likelihood of the two ligands toward metal ions has been suggested in the light of elemental analysis, UV-Vis spectra, FTIR, 1H-NMR, flam atomic absorption, molar conductance and magnetic studies. Results data suggest that the octahedral geometry for all the prepared complexes. Antibacterial examination of synthesized complexes in vitro was performed against four bacterias. Firstly, Gram-negative bacteria namely, Pseudomonas aerugin and Escherichia. Secondly, Gram-positive bacteria namely, Bacillus subtilis, Staphylococcuaurouss. Results data exhibit that the synthesized complexes exhibited more biological activity than tetracycline pharmaceutical.


2012 ◽  
Vol 68 (6) ◽  
pp. m824-m825 ◽  
Author(s):  
Ichraf Chérif ◽  
Jawher Abdelhak ◽  
Mohamed Faouzi Zid ◽  
Ahmed Driss

In the crystal structure of the title compound, (C5H6ClN2)[Cr(C2O4)2(H2O)2]·1.5H2O, the CrIII atom adopts a distorted octahedral geometry being coordinated by two O atoms of two cis water molecules and four O atoms from two chelating oxalate dianions. The cis-diaquadioxalatochromate(III) anions, 2-amino-5-chloropyridinium cations and uncoordinated water molecules are linked into a three-dimensional supramolecular array by O—H...O and N—H...O hydrogen-bonding interactions. One of the two independent lattice water molecules is situated on a twofold rotation axis.


2003 ◽  
Vol 58 (9) ◽  
pp. 916-921 ◽  
Author(s):  
Amitabha Datta ◽  
Samiran Mitra ◽  
Georgina Rosair

Two new bimetallic complexes [Zn(phen)3][Fe(CN)5(NO)] · 2 H2O · 0.25 MeOH, (1) and [(bipy)2(H2O)Zn(μ-NC)Fe(CN)4(NO)] · 0.5 H2O, (2), have been isolated (where phen = 1,10-phenanthroline and bipy = bipyridyl) and characterised by X-ray crystallography [as the 2 H2O · 0.25 CH3OH solvate for (1) and hemihydrate for (2)] infrared spectroscopy and thermogravimetric analysis. Substitution of phenanthroline for bipyridyl resulted in a cyano-bridged bimetallic species rather than two discrete mononuclear metal complexes. The bond angles of Fe-N-O were shown to be practically linear for both 1 [179.2(7)°] and 2 [178.3(3)°], and the Zn atoms have distorted octahedral geometry. The solvent molecules in both crystal lattices take part in forming hydrogen-bonded networks.


2001 ◽  
Vol 79 (3) ◽  
pp. 263-271
Author(s):  
Paul K Baker ◽  
Michael GB Drew ◽  
Deborah S Evans

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of 1-phenyl-1-propyne (MeC2Ph) in CH2Cl2, and in the absence of light, gave the bis(1-phenyl-1-propyne) complex [WI2(CO)(NCMe)(η2-MeC2Ph)2] (1) in 77% yield. Treatment of equimolar quantities of 1 and NCR (R = Et, i-Pr, t-Bu, Ph) in CH2Cl2 afforded the nitrile-exchanged products, [WI2(CO)(NCR)(η2-MeC2Ph)2] (2-5) (R = Et (2), i-Pr (3), t-Bu (4), Ph (5)). Complexes 1, 2, and 5 were structurally characterized by X-ray crystallography. All three structures have the same pseudo-octahedral geometry, with the equatorial sites being occupied by cis and parallel alkyne groups, which are trans to the cis-iodo groups. The trans carbon monoxide and acetonitrile ligands occupy the axial sites. In structures 1 and 2, the methyl and phenyl substituents of the 1-phenyl-1-propyne ligands are cis to each other, whereas for the bulkier NCPh complex (5), the methyl and phenyl groups are trans to one another. This is the first time that this arrangement has been observed in the solid state in bis(alkyne) complexes of this type.Key words: bis(1-phenyl-1-propyne), carbonyl, nitrile, diiodo, tungsten(II), crystal structures.


1974 ◽  
Vol 52 (16) ◽  
pp. 2923-2927 ◽  
Author(s):  
André L. Beauchamp ◽  
Bernard Saperas ◽  
Roland Rivest

The compound cis-Hg(SCN)2(Phen)2 belongs to the triclinic space group [Formula: see text] with a = 13.252(5), b = 11.077(4), c = 8.443(3) Å, α = 105.20(3), β = 83.25 (3), γ = 90.92(3)°, and Z = 2. The structure was solved by the heavy atom method and refined on 1718 independent reflections to an R factor of 0.069. The crystal contains discrete molecules, in which mercury is coordinated to four nitrogen atoms from two phenanthroline molecules and to two sulfur atoms from thiocyanate groups. These donor atoms define a distorted octahedral geometry around mercury. The Hg—N bond lengths are in the range 2.42(2)–2.52(2) Å, whereas the Hg—S bonds are equal to 2.622(8) and 2.582(8) Å. The molecules are packed in layers parallel to the (110) planes and the layers are held together by normal van der Waals interactions. Within the layers, the packing of the complex is characterized by parallel stacking of phenanthroline ligands at distances of ∼3.4 Å. The terminal nitrogen atoms of the thiocyanate groups are uncoordinated.


2012 ◽  
Vol 68 (8) ◽  
pp. m1055-m1055 ◽  
Author(s):  
M. Mobin Shaikh ◽  
Veenu Mishra ◽  
Priti Ram ◽  
Anil Birla

The structure of the centrosymmetric title complex, [Cu(C5H9O2)2(C6H7NO)2], has the CuIIatom on a centre of inversion. The CuIIatom is six-coordinate with a distorted octahedral geometry, defined by the N and O atoms of the chelating 2-(2-hydroxymethyl)pyridine ligands and two carboxylate O atoms from two monodentate pivalate ions. The crystal packing is stabilized by intermolecular C—H...O and intramolecular O—H...O hydrogen-bond interactions.


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