Carbodithioato derivatives of weak nitrogenous nucleophiles. I. Electronic structure and ground state properties of Ni(II) amide N-carbodithioates

1989 ◽  
Vol 67 (5) ◽  
pp. 902-909 ◽  
Author(s):  
C. C. Hadjikostas ◽  
G. A. Katsoulos ◽  
M. P. Sigalas ◽  
C. A. Tsipis
Keyword(s):  
Electronic Structure ◽  
Molecular Orbital ◽  
Metal Ion ◽  
Chemical Reactivity ◽  
Frontier Molecular Orbital ◽  
The Novel ◽  
Substitution Reactions ◽  
Square Planar ◽  
Elemental Analyses ◽  
Derivatives Of

Nickel(II) complexes of the general type [Ni(S2CN(COR′)R)2] have been synthesized by the reaction of the appropriate Ni(II) N-alkyldithiocarbamate with acetic anhydride or benzoyl chloride in the presence of triethylamine. The complexes obtained were identified and characterized by elemental analyses, conductivity measurements, and ir and electronic spectra. It was concluded that the bonding mode of the dithiocarbamato ligands to the metal ion is not altered by the acylation reaction, the chromophore remaining square-planar NiS4. Moreover, EHMO-SCCC calculations have been used in the analysis of electronic structure, and related properties of the novel compounds. From the calculated molecular orbital description of the complexes and the frontier molecular orbital approach of chemical reactivity, plausible mechanisms of their formation reactions have been deduced. Keywords: Ni(II) amide N-carbodithioates, N-alkyldithiocarbamates, dithiocarbimates, electrophilic substitution reactions, EHMO-SCCC calculations.

The ?-electronic structure and chemical reactivity of 2- and 4-hydroxyquinolines in aromatic substitution reactions

1972 ◽  
Vol 6 (2) ◽  
pp. 205-208
Author(s):  
V. P. Zvolinskii ◽  
M. E. Perel'son ◽  
Yu. N. Sheinker
Keyword(s):  
Electronic Structure ◽  
Chemical Reactivity ◽  
Aromatic Substitution ◽  
Substitution Reactions

Synthesis and Characterization of Palladium(II) Complexes with Substituted Dihydrobenzoimidazo Quinazoline Derivatives

2017 ◽  
Vol 13 (2) ◽  
pp. 1-15
Author(s):  
Rita Bhattacharjee Virupaiah Gayathri
Keyword(s):  
Metal Ion ◽  
Synthesis And Characterization ◽  
Planar Geometry ◽  
Conductivity Measurements ◽  
Spectral Techniques ◽  
Mass Spectral ◽  
Square Planar ◽  
Elemental Analyses ◽  
Quinazoline Derivatives

A series of palladium(II) halo complexes of the types [PdX 2 L 2 ].nH 2 O {n = 0, X = Cl, L = L 2 , L 4 and L 5 ; X = Br, L = L 2 ; n = 1, X = Cl, L = L 1 and L 3 } and Pd 2 X 4 L 3 [X = Br, L = L 1 , L 3 , L 4   and L 5 ] were prepared where L is 6-R-5,6- dihydrobenzoimidazo quinazoline (R-Diq; where R = ethyl: L 1 / n or i-propyl: L 2 , L 3 / n or i-butyl: L 4 , L 5 ) and characterized by elemental analyses, conductivity measurements, TGA, infrared, electronic, NMR and mass spectral techniques. Based    on these studies monomeric/dimeric structure with a square planar geometry around the metal ion was proposed for all the complexes. Some of the complexes were investigated for anti-microbial activity.

Tuning the thermoelectric performance of π–d conjugated nickel coordination polymers through metal–ligand frontier molecular orbital alignment

2018 ◽  
Vol 6 (40) ◽  
pp. 19757-19766 ◽  
Author(s):  
Xue Yong ◽  
Wen Shi ◽  
Gang Wu ◽  
Shermin S. Goh ◽  
Shiqiang Bai ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Power Factor ◽  
High Mobility ◽  
Frontier Molecular Orbital ◽  
Phonon Coupling ◽  
Thermoelectric Power Factor ◽  
Square Planar ◽  
Electron Phonon Coupling ◽  
Weak Electron ◽  
Metal Ligand

A good frontier molecular orbital alignment between the square planar metal-tetrasulfide fragment and the organic π-conjugated spacers results in a weak electron-phonon coupling, a high mobility and eventually a higher thermoelectric power factor.

scholarly journals Enhanced Antioxidant Activity of Ursolic Acid by Complexation with Copper (II): Experimental and Theoretical Study

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 264
Author(s):  
Mariola Samsonowicz ◽  
Monika Kalinowska ◽  
Kamila Gryko
Keyword(s):  
Antioxidant Activity ◽  
Molecular Orbital ◽  
Ursolic Acid ◽  
Metal Ion ◽  
Chemical Reactivity ◽  
Antioxidant Properties ◽  
Molar Ratio ◽  
Antioxidant Power ◽  
Ferric Reducing Antioxidant Power ◽  
Lowest Unoccupied Molecular Orbital

The copper (II) complex of ursolic acid (Cu(II) UA) was synthesized and discussed in terms of its infrared, UV–visible spectra, quantum-chemical calculations at B3LYP/6-31G(d) level and antioxidant capacity. The copper (II) complex was stable in methanolic solution with the molar ratio metal:ligand 1:1. The data obtained by FT-IR confirmed the metal ion coordination through the carboxylate anion. The antioxidant properties of ursolic acid and its complex with Cu were discussed on the basis of energy of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and values of chemical reactivity parameters. The antiradical properties of ursolic acid and the Cu (II) complex were examined against DPPH• and HO• radicals, and the ferric reducing antioxidant power (FRAP) was examined. The Cu(II) complex showed higher antioxidant activity than ursolic acid, i.e., in DPPH• assay, the EC50 for UA was 47.0 mM, whereas, for Cu(II), UA EC50 = 19.5 mM; the FRAP value for UA was 20.8 µMFe2+, and 35.4 µMFe2+ for Cu(II) UA (compound concentration 3 mM). Although there was no distinct difference in the antioxidant activity against HO• between these two chemicals, they were both better HO• scavengers than DPPH• and showed different kinetics in the reaction with DPPH•.

Substitution reactions at the Ni(III) cation in macrobicyclic complexes – Reaction of metal ion complexes prepared from ligands L1 (17-oxa-1,4,8,11-tetraazabicyclo[6.5.6]nonadecane) and L2 (17-oxa-1,4,8,11-tetraazabicyclo[10.5.2]nonadecane) with chloride ion

2002 ◽  
Vol 80 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Alison M Ingham ◽  
Chao Xu ◽  
T W Whitcombe ◽  
Chengtian Xu ◽  
J N Bridson ◽  
...  
Keyword(s):  
Metal Ion ◽  
Chloride Ion ◽  
Chemical Oxidation ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Substitution Reactions ◽  
Kinetic Measurements ◽  
Acidic Solutions ◽  
Square Planar ◽  
Ether Oxygen

The potentially penta-coordinating ligand L1 has been synthesized by reaction of the bridge bis-(2-(methylsulfonyl)oxyethyl)ether with the tetraazamacrocycle cyclam (cyclam = 1,4,8,11-tetraazatetradecane). The copper(II) complex was characterized initially and subsequent demetallation provided pure L1. Electrochemical and chemical oxidation of the nickel(II) species yields a Ni(III) ion (low-spin d7, rhombic, gxx 2.195, gyy 2.189, gzz 2.027) of sufficient stability in acidic solutions for kinetic measurements to be undertaken of substitution reactions at the sixth site. The isomeric ligand L2, has been synthesized previously, and reactions of the [Ni(L1)(solv)]3+ and [Ni(L2)(solv)]3+ ions with chloride have also been investigated. In both reactions, an unusually high acid dissociation constant is observed, associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound both to the metal centre and hydrogen bonded to the ether. The structure [Ni(L2)](PF6)2 (monoclinic, P21/c, a = 10.699(2), b = 13.244(4), c = 16.603(2) Å, β = 92.10(1)°) converged at R = 0.055 (R' = 0.057) for 325 parameters using 3293 reflections with I > 2σ(I). In this complex, the detachment of the ether O donor to yield a square-planar complex is confirmed. Comparisons are made with substitution rates at other Ni(III) macrocyclic ions.Key words: nickel(III), substitution, macrobicyclic ligand, synthesis, kinetics.

scholarly journals The synthesis and spectroscopic characterization of (+)-demethoxyaspidospermine: Density functional theory calculations of the structural, electronic, and non-linear optic and spectroscopic properties

2019 ◽  
Vol 43 (11-12) ◽  
pp. 531-541 ◽  
Author(s):  
Goncagül Serdaroğlu ◽  
Nesimi Uludağ
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Studies ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Linear Optic ◽  
Non Linear ◽  
Orbital Analysis

(+)-Demethoxyaspidospermine was synthesized via the acylation of aspidospermidine with acetic anhydride, and the structure was determined by elemental analysis and Fourier-transform infrared and nuclear magnetic resonance spectroscopic tools and was supported by the simulated spectroscopic studies. Next, the stable geometries obtained by the conformational analysis performed at the B3LYP/6-31G(d, p) level were used for further investigations carried out in B3LYP and M06-2X functionals, and Hartree–Fock (HF) method, employed by the 6-311++G(d, p) basis set. Also, the natural bond orbital analysis revealed that the most contribution to the lowering of the stabilization energy came from n → π* and π → π* interactions. Moreover, the non-linear optic analysis has shown that the title compound can be a useful agent in the optoelectronic devices because of the optical properties. Also, the chemical reactivity tendency for nucleophilic or electrophilic attack reactions on the compound was evaluated by frontier molecular orbital analysis, and the reactive sites of the compound was shown by highest molecular orbital and lowest unoccupied orbital amplitudes and molecular electrostatic potential diagrams.

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