Nephelauxetic effect in metal ion paramagnetic shielding of spin-paired d6 transition-metal complexes

1985 ◽  
Vol 24 (10) ◽  
pp. 1599-1601 ◽  
Author(s):  
Nenad Juranic
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Metal Ion ◽  
Nephelauxetic Effect

Synthesis and infrared spectra of some transition metal complexes of α-amino acid esters

1967 ◽  
Vol 20 (4) ◽  
pp. 675 ◽  
Author(s):  
RW Hay ◽  
LJ Porter
Keyword(s):  
Amino Acid ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Infrared Spectra ◽  
Metal Ion ◽  
Amino Acid Esters ◽  
Visible Spectra ◽  
Metal Ratio ◽  
Acid Esters

A variety of transition metal complexes of a-amino acid esters have been synthesized, and characterized by analysis, conductivity measurements, and infrared spectra. The complexes can be broadly divided into two groups: (a) complexes in which only a metal-nitrogen bond occurs with the α-amino group of the ester, and (b) complexes in which chelate ring formation occurs via secondary donor groups on the ligand. These latter complexes are found with methyl L-histidinate, methyl γ-glutamate, and methyl L-cysteinate. With the exception of a methyl tryptophanate complex, the infrared spectra show that there is no interaction between the carbonyl group of the ester and the metal ion. The visible spectra of aqueous solutions of the esters and copper(II) at a ligand/metal ratio of 5 : 1 have maxima in the 600-650 mμ range at pH 7 consistent with copper-nitrogen bonding only.

Transition metal complexes of thiabendazole

1971 ◽  
Vol 24 (7) ◽  
pp. 1369 ◽  
Author(s):  
C Kowala ◽  
KS Murray ◽  
JM Swan ◽  
BO West
Keyword(s):  
Electrical Conductivity ◽  
Transition Metal ◽  
Transition Metals ◽  
Metal Complexes ◽  
Organic Solvents ◽  
Transition Metal Complexes ◽  
Metal Ion ◽  
Magnetic Moments ◽  
Anthelmintic Activity ◽  
Metal Chlorides

Complexes of thiabendazole with transition metals (Co2+, Cu2+, Fe2+, Fe3+, Mn2+, Ni2+, and Zn2+) containing one, two, or three molecules of ligand per metal ion are described. Their spectra and magnetic moments are reported. In general, the complexes are insoluble or only slightly soluble in water or most organic solvents. Only complexes of metal chlorides are sufficiently soluble in methanol to show electrical conductivity. It is suggested that most of the insoluble complexes are of polymeric character. � The anthelmintic activity of all complexes is only slightly higher than that of thiabendazole.

scholarly journals Synthesis, Characterization, Biological Activity and DNA Binding Studies of Metal Complexes with 4-Aminoantipyrine Schiff Base Ligand

2012 ◽  
Vol 9 (1) ◽  
pp. 389-400 ◽  
Author(s):  
B. Anupama ◽  
M. Padmaja ◽  
C. Gyana Kumari
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Schiff Base Ligand ◽  
Metal Ion ◽  
Spectral Studies ◽  
Significant Activity ◽  
Central Metal ◽  
Binding Studies

A new series of transition metal complexes of Cu(II),Ni(II),Co(II), Zn(II) and VO(IV) have been synthesized from the Schiff base ligand (L) derived from 4-amino antipyrine and 5- bromo salicylaldehyde. The structural features of Schiff base and metal complexes were determined from their elemental analyses, thermogravimetric studies, magneticsusceptibility, molar conductivity, ESI-Mass, IR, UV-VIS,1H NMR and ESR spectral studies. The data show that the complexes have composition of ML2type. The UV-VIS, magnetic susceptibility and ESR spectral data suggest an octahedral geometry around the central metal ion. Biological screening of the complexes reveals that the Schiff base transition metal complexes show significant activity against microorganisms. Binding of Co(II) complex with calf thymus DNA (CT DNA) was studied by spectral methods.

scholarly journals Structural Properties and Reactive Site Selectivity of Some Transition Metal Complexes of 2,2′(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)dibenzoic Acid: DFT, Conceptual DFT, QTAIM, and MEP Studies

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Fritzgerald Kogge Bine ◽  
Nyiang Kennet Nkungli ◽  
Tasheh Stanley Numbonui ◽  
Julius Numbonui Ghogomu
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Structural Properties ◽  
Transition Metal Complexes ◽  
Metal Ion ◽  
Density Functional ◽  
Conceptual Dft ◽  
Distorted Octahedral Geometry ◽  
Chemical Hardness ◽  
Central Metal

Herein is presented a density functional theory (DFT) study of reactivity and structural properties of transition metal complexes of the Schiff base ligand 2,2′(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)dibenzoic acid (hereafter denoted EDA2BB) with Cu(II), Mn(II), Ni(II), and Co(II). The quantum theory of atoms-in-molecules (QTAIM), conceptual DFT, natural population analysis (NPA), and molecular electrostatic potential (MEP) methods have been used. Results have revealed a distorted octahedral geometry around the central metal ion in each gas phase complex. In the DMSO solvent, a general axial elongation of metal-oxygen bonds involving ancillary water ligands has been observed, suggestive of loosely bound water molecules to the central metal ion that may be acting as solvent molecules. Weak, medium, and strong intramolecular hydrogen bonds along with hydrogen-hydrogen and van der Waals interactions have been elucidated in the complexes investigated via geometric and QTAIM analyses. From the chemical hardness values, the complex [Co(EDA2BB)(OH2)2] is the hardest, while [Cu(EDA2BB)(OH2)2] is the softest. Based on the global electrophilicity index, the complexes [Ni(EDA2BB)(OH2)2] and [Cu(EDA2BB)(OH2)2] are the strongest and weakest electrophiles, respectively, among the complexes studied. In conclusion, the reactivity of the complexes is improved vis-à-vis the ligand, and stable geometries of the complexes are identified, alongside their prominent electrophilic and nucleophilic sites.

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