Bond valence sum analysis of metal-ligand bond lengths in metalloenzymes and model complexes

1992 ◽  
Vol 31 (9) ◽  
pp. 1585-1588 ◽  
Author(s):  
H. Holden Thorp
Keyword(s):  
Bond Valence ◽  
Model Complexes ◽  
Bond Lengths ◽  
Bond Valence Sum ◽  
Metal Ligand ◽  
Ligand Bond

Crystallographic Distances Based Bond Valence Sum (BVS) Analysis on Nickel(II) Complexes Containing Ni-S and Ni-P Bonds

2012 ◽  
Vol 584 ◽  
pp. 84-87 ◽  
Author(s):  
Arumugam Manohar ◽  
Kuppukannu Ramalingam ◽  
Kottamalai Karpagavel ◽  
Gabriale Bocelli
Keyword(s):  
Metal Ions ◽  
Oxidation State ◽  
Mixed Ligand ◽  
Bond Valence ◽  
Donor Ligands ◽  
Back Bonding ◽  
Bond Valence Sum ◽  
First Time ◽  
Metal Ligand ◽  
Ligand Bond

Bond valence sum (BVS) analysis is used by many researchers to determine the oxidation state of metal ions in solids based on crystallographically determined metal-ligand bond distances. In this paper, bond valence sums (BVS) have been calculated for a series of mixed ligand complexes involving Nickel(II)dithiocarbamates and phosphorous donor ligands. The BVS values are calculated first time for the complexes whose crystal structures have been reported from our laboratory and a few others reported from other laboratories. The calculated values show that the BVS values are higher than the expected formal oxidation state of +2. The higher values observed in the complexes support the fact that the Ni-S, Ni-P bonds are more covalent and the back bonding effects are very highly pronounced.

The Crystal and Molecular Structures of Two Modifications of cis-Dichloro-mer-tris-(dimethylphenylphosphine)hydridoiridium(III)

1988 ◽  
Vol 41 (3) ◽  
pp. 283 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker
Keyword(s):  
Heavy Atom ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Metal Ligand ◽  
Ligand Bond

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a 27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.

SUBSTITUTION EFFECT IN Pr-DOPED YBCO

2006 ◽  
Vol 20 (20) ◽  
pp. 2899-2907
Author(s):  
L. ZHANG ◽  
M. WANG ◽  
Y. Y. XU
Keyword(s):  
Rietveld Refinement ◽  
Reference System ◽  
Structural Changes ◽  
Substitution Effect ◽  
Bond Valence ◽  
X Ray Diffraction ◽  
Dc Magnetization ◽  
X Ray ◽  
Bond Lengths ◽  
Bond Valence Sum

A series of samples of Y 1-x Pr x Ba 2 Cu 3 O y ( YPrBCO ) with 0.05 ≤ x ≤ 0.6 was synthesized and characterized by DC magnetization, X-ray diffraction (XRD), and Rietveld refinement. It is found that besides Pr substitution for Y , a part of Pr substituted for Ba in YBa 2 Cu 3 O y (YBCO), and the amount of Pr in the Y and Ba positions, respectively, is estimated by the refinement with the help of bond valence sum (BVS) calculation. By comparing the correlation of structural changes such as Ba-O (4) and Cu (1, 2)- O (4) bond lengths and superconductivity between our system with the reference system where Pr just replaces Y , structural evidences are found to explain Pr substitution for Ba suppresses Tc more strongly than that for Y .

scholarly journals Metal Complex Geometries in Small-Molecule Crystals

1998 ◽  
Vol 54 (6) ◽  
pp. 1194-1198 ◽  
Author(s):  
A. Guy Orpen
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Metal Complex ◽  
Small Molecule ◽  
Structure Determination ◽  
Complex Geometries ◽  
Bond Lengths ◽  
Structural Database ◽  
Metal Ligand ◽  
Ligand Bond

The origins, scope and utility of compilations of metal–ligand and intraligand bond lengths based on the Cambridge Structural Database are discussed. The limitations on the apparent uncertainty of metal–ligand bond lengths derived from crystallographic data and recent evidence of metal-assisted hydrogen bonding involving ligands are reviewed in the light of the transferability of bond-length values from one crystal structure determination.

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