Physical Properties of Phenol Compound: Semi-empirical Calculation of Substituent Effects [Part One]
- Research Summary
Physical properties of phenol compound such as steric energy, charge
of oxygen, ionization potential, dipole moment, LUMO and bond length have been calculated.
Approach: All molecular geometries were minimized by quantum mechanic especially at (AM1)
method was used to investigate the effect of a variety of substituents on the phenol (H, o-Cl, p-Cl, m-
Cl, o-CH3, m-CH3, p-CH3, o-NH2, m-NH2, o-NO2, m-NO2, p-NO2, 2,4-di-NO2). Global descriptor
such as electronic chemical potential (m), hardness (h), the maximum electronic charge and global
electrophilicity index (w) were determined and used to predict the (pKa) values. Results: The
theoretical results (predictive values) found were in good agreement with experimental values. The
predictive pKa calculated values by AM1 method gave excellent results with experimental values. The
correlation between the predicted values especially global electrophilicity index showed excellent
qualitative agreement with the experimental pKa (R2 = 0.95). Conclusion: The present research was to
calculate the physical properties of phenol derivatives. Then, the calculated values were compared,
quite favorably with experimental values of these properties. In future, we can predict any substituent
of set of a phenol compound and compare its value with the experimental.
- Research link
- key words
AM1, phenol, hardness, pKa , substituent effect
Beneficiation of oil shale by froth flotation: Critical review
- Research Summary
Oil shale beneficiation by froth flotation hasn’t received enough attention in the last two decades. The reason
was the economics of the process as well as its environmental impact. However, the recent surge in oil price and recent
developments in fine grinding technologies may improve the efficiency of oil shale beneficiation by such process.
In this work, oil shale concentration by froth flotation technique was critically reviewed. It was found that most of the
work was conducted by conventional mechanical flotation using non-ionic collector such as kerosene. Flotation has more
pronounced effect on flotation of low grade oil shale; Almost 95% of ash forming minerals were removed to enrich oil
shale concentrate by factor of 2-4 with 60-95 % kerogen recovery and approximately 50-300 % increase in oil yield
(L/tonne) .Oil shale retorting economics showed that beneficiation reduced the capital cost for pyrolysis and fractionation
by 250 % and spent shale disposal by 270%. However, these saving are offset by the cost of beneficiation (grinding,
flotation, and dewatering). Therefore, the key for economical oil shale concentration process is the reduction of fine
grinding costs.
- Research link
- key words
Flotation, Oil shale, oil shale beneficiation
Synthesis and Characterization of Organosilicon(IV) Complexes with Some Schiff-base derivatives
- Research Summary
New Schiff base derived from 2-hydroxy-or 2-methoxy benzaldehyde and phenyl-3-aminophenyl ketone or 2-amino-3-hydroxy pyridine (L1,L2L3 and L4, respectively), have been found to react with the organosilicon(IV) chlorides, RnSiCl4-n (R= Me or Ph, n=1-3) to yield complexes of the general formula [RnSiCl3-n (L1-H), [RnSiCl4-n(L2). n=1-3. [RnSiCl2-n(L3-2H), n=1,2 [Me2PhSi(L3-H)] and [RnSiCl3-n(L4-H), n=1-3. These complexes have been characterized physicochemically and spectroscopically. The molecular mechanic technique were applied to confirm the suggested structures of the complexes by computing the steric energy and the physical properties of each complex
- Research link
- key words
Organosilicon(IV), Schiff base
Reaction of VOCl3 and TaCl5 with the Ligands 1,2-Bis(o-Aminophenylthio)ethane and 1,1,2,2-Tetrakis (o-aminophenyl) Ethene
- Research Summary
The reaction of VOCI: or TaCl5 with crs-(Lr) or trans-1,2-bis(oaminophenylthio)
ethane (L2) and 1,7,2,2-tetrakis(o-aminophenylthio)ethane (L3)
leads to the formation of complexes of the general formula [VOCl3Lr] , [TaC15L1] ,
[V2O2CI6L] and [Ta2C116L3]. The complexes were isolated from the reaction
mixture in a solid form and characterized on the basis of their elemental analyses,
conduCtivity measurements, magnetic nleasurements, infrared and electronic
spectral data. tire results obtained showed that-.the compiexes of VOO have
oitahedral geometry while the complexes of Ta(v) have pentagonal bipyramidal
geometry around the metal with a coordination number of seven.
- Research link
- key words
Oxovanadium(V); Tantalum(V); Thioethene; Complexes.
Synthesis and characterization of gold (III) complexes with bis-(1,4-sodium thioglucolate) butane ligand,
- Research Summary
The new ligand bis-(1,4-sodium thioglycolate)butane (L)
–O2CCH2S(CH2)4SCH2CO2
–, has been prepared from the reaction of
disodium salt of mercaptoacetic acid and 1,4-dichlorobutane. Mono,
di and tetranuclear complexes were obtained by direct reaction of the
bis-(1,4-sodium thioglycolate)butane with H[AuCl4] in 1:1, 1:2, 2:2
and 4:2 metal:ligand molar ratio. The prepared complexes were characterized
by elemental analysis, spectral studies FT-IR and UV-Vis, magnetic
measurement, conductivity measurement and 1H NMR for the ligand.
The electrical conductance data indicate that the complexes of the formula
[Au(L)]Cl, Na[Au(L)2] and [Au3(L)2Cl4][AuCl4] are 1:1 electrolyte and
[Au4(L)2Cl6]Cl2 is 1:2 electrolyte. Electronic spectra and magnetic moment
values indicate the presence of square planner geometry around the
Au(III) ion. Molecular modeling program MM2 is used to determine
the most stable isomer which coincidence with experimental results.
- Research link
- key words
Gold(III) complexes, Bis-(1,4-Sodium thioglucolate)- butane
Synthesis and Characterization of Dinuclear Metal Complexes Stabilized by Tetradentate Schiff Base Ligands
- Research Summary
The synthesis, spectroscopic properties and theoretical calculations of
acetylacetonimine and acetylacetanilidimine Schiff-base ligands, L1H and L2H, respectively and their
dinuclear complexes of the type [M2LnCl2(H2O)2], where n = 1 or 2, M = Co(II), Ni(II), Cu(II), Zn(II)
and Cd(II) are described. Approach: The new tetradentate dianion Schiff base ligand which was used
as stabilizers for the complexes were prepared by condensation of hydrazine with acetylacetone or
acetylacetanilide. The dinuclear complexes of theses ligands were synthesized by treating an ethanolic
solution of the prepared ligand with hydrated metal salts in molar ratio of 1:2 (L:M). Results: The
ligand and their dinuclear metal complexes were characterized by CHN elemental analysis, FT-IR,
UV-Vis, 1HNMR (for the ligands), conductivity, magnetic susceptibility and theoretical calculation by
using MM2 modeling program. Conclusion: The reaction of these ligands in a 1:2 (L:M) afford
dinuclear M(II) metal complexes with tetrahedral arrangement around Co(II), Zn(II) and Cd(II) and
square planar around Ni(II) and Cu(II).
- Research link
- key words
Schiff base, hydrazine, acetoacetanilide, acetyl acetone, dinuclear complexes
Quantum Chemical Calculations (QSAR) of Antipyrine Drug and Its Metabolites
- Research Summary
The electronic properties of antipyrine and its metabolites have been investigated theoretically by the different methods of semi-empirical
(AM1, MNDO/3 and PM3) and ab initio at STO-3G level calculations. These metabolites are of much interest due to their biological and
medical importance. The charges, HOMO, LUMO, hardness (h), electronic chemical potential (μ) and global electrophilicity index (w)
were determined. The metabolites of A4 (according to MNDO/3) and A6 (according to AM1, PM3 and ab initio) have relatively low
LUMO-HOMO differences indicating that these compounds would be the most reactive metabolites
- Research link
- key words
Antipyrine, Metabolism, QSAR, Drug design, HOMO
Synthesis and Characterization of some new semi conducting dinuclear Platinum (II) complexes containing 1,1,2,2-tetrakis-(substituted phenylthio) ethylene
- Research Summary
New homobimetallic complexes of the type, [Pt2LCl4] and [Pt2(L)(L`)4], where, L = 1,1,2,2-
tetrakis-(substituted phenylthio) ethylene, L`= thiophenoxide (TH) or p-aminothiophenoxide (ATH),
have been prepared and characterized by elemental (carbon, hydrogen and nitrogen) analysis, molar
conductance, magentic measurements, IR and UV-visible spectral measutements. The diamagnetic
nature and electronic spectral studies suggest a square plannar environment around Pt (II) in the
complexes. Solid state electrical conductivities of compacted pellets suggest that all of the complexes
behave as typical semiconductors as their conductivities were found to increase with temperature from
303-328 K. The molecular mechanic techniques were applied to confirm the suggested structures of the
complexes by computing the steric energy of each complex.
- Research link
- key words
Dinuclear platinum (II), 1,1,2,2-Tetrakis-(substituted phenylthio) ethylene
Reactions of Pd2+ and Pt2+ with Pyrrolidinedithio Carbamate and Cystine Ligands:Synthesis and DFT Calculations
- Research Summary
Mono- and dinuclear complexes of the type M(cys), M(PTD)2 and M2(PTD)4, where M = Pd(II) or
Pt(II), cys = (SCH2CH(NH2)COOH)2 and PTD = pyrrolidine thiocarbanoyl disulfide, have been prepared
through oxidative addition reaction. They are characterized by microanalyses of metal content,
molar conductance, magnetic measurements, infrared and UV–visible spectral studies. The experimental
infrared data are supported by density functional theory (DFT) calculations using the B3LYP level of
theory and LANL2DZ basis set. The vibrational frequencies of the molecules were computed using the
optimized geometry obtained from the DFT calculations. The diamagnetic nature, the electronic spectral
studies and calculated geometries suggest a distorted square planner environment around Pd(II) and Pt(II)
complexes.
S2C N
n
Mx SCH2
HC
NH2
COOH 2
x K2MCl4 M
PTD=pyrrolidine thiocarbanoyl disulf ide
m PTD
x= 1, m=1, n=2 or x=2, m=2, n=4
- Research link
- key words
mono- and dinuclear complexes; pyrrolidine dithiocarbamate; cystine; DFT (density functional
theory)
Synthesis and characterization of some mixed ligands complexes from o-phthalic acid as primary ligand
- Research Summary
The present investigation involves the synthesis of some new Co(II), Ni(II)
and Cu(II) complexes with phthalic acid and their adducts with monodentate
donor ligands (Benzyl methyl amine) gave 1: 2 adducts while the bidentate
donor ligands (ethylene diamine) form 1:1 adducts. The complexes and
adducts were characterized by their complexes analysis, IR and UV-Vis
spectroscopy, conductivity and magnetic measurements. Conductivity data in
DMSO showed that the complexes and adducts are 1:2 which assigning the
formula Na2[M(L)2] and Na2[M(L)2(L`)] Explanations of the structural
elucidation of these showed a tetrahedral geometry for complexes and
octahedral environment for adducts. The results obtained by physical
measurements are coincided with that of theoretical calculations by computing
the steric energy and the physical properties of each complex.
- Research link
- key words
O-Phthalic acid, metal complexes
Synthesis and Characterization of Ni2+, Cu2+ and Zn2+ Complexes with Benziimidazole-2-thionate, Diphosphene and their Reaction with Iodine
- Research Summary
Nickel, copper or zinc metal react with bis-benzimidazole disulfide (C14H10N4S2) (L1) in refluxing ethanol-toluene to give the complexes
of the type [M(L)2], where M = Ni2+, Cu2+, Zn2+ and L = benzimidazole-2-thionate (C7H5N2S–) through an oxidative addition reaction. The
complexes of type [M(L)2Ph2P(CH2)nPPh2], n= 1, 2 or 3, were prepared by direct reaction of [M(L)2] with diphosphene ligand in (1:1) and
(2:2) molar ratio respectively. The reaction of some of the above complexes with iodine was also carried out. The complexes were
characterized by microanalysis, IR, UV-visible spectroscopy, molar conductivity and magnetic moment and solid state electrical conductivity
measurements. Electronic and magnetic measurements indicate that some of the complexes have square planar geometry and the other
contain tetrahedral and octahedral geometries. Solid state electrical conductivity of compact pellets suggest that the complexes are non
conducting while with the iodinated complexes behave as typical semiconductors as their conductivities were found to increases with
temperature
- Research link
- key words
Synthesis, Characterization, Ni2+, Cu2+, Zn2+, Complexes, Benzimidazole-2-thionate
Synthesis and DFT Calculations of Dinuclear complex of Co2+, Ni2+ and Cu2+ with macrocyclic Schiff base Ligands
- Research Summary
The 20-, 34- and 36-membered macrocyclic of bis (dithiodimine) Schiff base ligands, Bis-N,N’(dithiocarbonyl) terephthliden (L1), Bis-N,N’[1,3(o-aminophenylthio)-propane] terephthylidene (L2) and Bis-N,N-[1,4(o-amino phenylthio)-butane] terephthylidene (L3), have been prepared by a (2+2) condensation of terephthaldehyde with dithiooxamide or 1,3-bis-(o-aminophnylthio)propane,or1,4-bis-(o-aminophenylethio)-butane. Air stable dinuclear complexes of Co2+, Ni2+ and Cu2+ were obtained from reaction of metal salts with L1, L2 and L3 in tetrahydrofuran. Ligands consist of two S2N2 donor sites coordinated with the metal ions. Also, adducts of the cobalt complex with 1,4-phenelyene diamine was also presented. CHN elemental analysis, metal content, molar conductivity,magnetic measurements, proton nuclear magnetic resonance, UV-visible and infrared spectral studies have characterized the complexes and adducts. In addition to this, the DFT i.e. Density Functional Theoretical calculations has been used for supporting experimental data. This process used B3LYP functional method. It is the method which has been introduced due to Yang, Parr and Lee. This method is comprised of 3-parameter functional because of the presence of Axel Becke. It further incorporates the basis set of Los Alamos National Laboratory 2 double-zeta (LANL2DZ). Furthermore, the calculation associated with the molecule’s vibrational frequencies was calculated with the help of optimized geometry. Tetrahedral and square planar geometry around Co2+,Ni2+ and Cu2+ have been deduced on the basis of magnetic and spectra studies..
- Research link
- key words
Dinuclear complexes, Schiff base, macrocyclicbis (dithiodimine),
density functional theory (DFT).
Theoretical Prediction of Lipophilicity for Some Drugs Compounds
- Research Summary
The theoretical calculations were evaluated for thirty four drug compounds. Many parameters have been calculated theoretically and enter as a model to predicting the best values of practical
(Log P). All these compounds were evaluated by semi-empirical (AM1) and Hartree Fock in basis set (HF/STO-3G) using Gaussian 03w. The thermodynamic descriptors like HOMO, LUMO, total energy, Gibbs Free Energy etc were computed and played an important role for predictions the practical lipophilicity values. A linearity was shown when correlated with experimental data. Multiple linear regression analysis was performed to derive quantitative structure activity relationship models which were further evaluated for the predictions.
- Research link
- key words
Lipophilicity, HOMO, LUMO, Drug Compounds.
Synthesis and DFT Study of the Complexation of Schiff Base Derived Curcumin and L-Tyrosine with Al(III), Ag(I), and Pb(II) Metal Ions
- Research Summary
The multi-dentate Schiff base ligand (H2L), where H2L=2,2'-(((1,3,5,6)-1-(3-((l1-oxidaneyl)-l5-methyl)-4-hydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)hepta-1,6-di ene-3,5-diylidene)bis(azaneylylidene))bis(3-(4-hydroxyphenyl)propanoic acid), has been prepared from curcumin and L- Tyrosine amino acid. The synthesized Schiff base ligand (H2L) and the second ligand 1,10-phenanthroline (phen) are used to prepare the new complexes [Al(L)(phen)]Cl, K[Ag(L)(phen)] and [Pb(L)(phen)]. The synthesized compounds are characterized by magnetic susceptibility measurements, micro elemental analysis (C.H.N), mass spectrometry, molar conductance, FT-infrared, UV-visible, atomic absorption (AA), 13C-NMR, and 1H-NMR spectral studies. The characterization of the synthesized complexes shows that the environment surrounding the central metal ion in the complexes adopted a distorted octahedral configuration. Moreover, the conductivity measurements show a non-electrolytic character for the [Pb(L)(phen)] complex and an electrolytic character for the [Al(L)(phen)]Cl and K[Ag(L)(phen)] complexes. The experimental infrared data are supported by density functional theory (DFT) calculations using the B3LYP level of theory and LANL2DZ basis set. The vibrational frequencies of the molecules are computed using the optimized geometry obtained from the DFT calculations. The calculated vibrational frequencies have been compared with obtained experimental values. 1H and 13C-NMR chemical shifts were computed for the H2L ligand using the DFT/GIAO method. Additionally, the molecular electronic structures of the complexes have been investigated by DFT calculations.
- Research link
- key words
curcumin; L-tyrosine; silver; aluminium; lead; Schiff base