Spectrophotometric, FTIR and Theoretical Studies of the Charge-transfer Complexes Between Nicotinamide and the Acceptors (p-Chloranil, Chloranilic Acid and DDQ) in Acetonitrile, Their Association Constants, Thermodynamic Properties and Other Related Properties

2015 ◽  
Vol 44 (12) ◽  
pp. 2357-2382 ◽  
Author(s):  
Seema Bagchi Chattaraj ◽  
Ashutosh Chakrabortty ◽  
Shiba Prasad Sharma ◽  
Sujit Chandra Lahiri
Keyword(s):  
Charge Transfer ◽  
Thermodynamic Properties ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Theoretical Studies ◽  
Chloranilic Acid

scholarly journals Analytical Study for the Charge-Transfer Complexes of Risperidone in Pure and Dosage Forms

2016 ◽  
Vol 8 (3) ◽  
pp. 1745-1753
Author(s):  
F. Ibrahim ◽  
N. El-Enany ◽  
Sh. Shalan ◽  
Rasha Mostafa Elsharawy
Keyword(s):  
Charge Transfer ◽  
Reaction Pathway ◽  
Pharmaceutical Preparations ◽  
Comparison Method ◽  
Charge Transfer Complexes ◽  
Chloranilic Acid ◽  
Spectrophotometric Methods ◽  
Ich Guidelines ◽  
Optimum Reaction ◽  
Recovery Percentage

Two simple, accurate and sensitive spectrophotometric methods were carried out to investigate through charge-transfer reactions of risperidone (RIS) as n-electron donor with various π acceptors: 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ) and p-chloranilic acid (pCA). The absorbance of reaction product was measured at 842 and 520 nm for TCNQ and pCA reagents respectively. Different experimental parameters affecting the reactions were carefully studied. The reaction pathway was postulated. The proposed spectrophotometric method was utilized for the analysis of RIS in pure form as well as in its pharmaceutical preparations. Under the optimum reaction conditions, Beer’s law is obeyed over the concentration range of 1-12 µg mL-1 and 10-180 µg mL-1 for TCNQ and pCA respectively. The limit of assays detection (LOD) is 0.114 µg mL-1 and 2.55 µg mL-1 for TCNQ and pCA respectively. The mean recovery percentage was 99.72 ± 1.06 and 100.50 ± 1.07 for TCNQ and pCA respectively. The results were compared favorably with those obtained by comparison method. The proposed method was validated statistically according to ICH guidelines.

Chemical behavior of charge-transfer complexes. VII. Solvolysis of alkyl arenesulfonate donors in the presence of aromatic acceptors

1978 ◽  
Vol 56 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Allan K. Colter ◽  
Robert E. C. Turkos
Keyword(s):  
Acetic Acid ◽  
Charge Transfer ◽  
Kinetic Data ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Chemical Behavior ◽  
Measurable Rate ◽  
Leaving Groups

Rates of solvolysis of several ethyl and 2-propyl arenesulfonates having π donor leaving groups were measured in the absence of accepter and in the presence of the π acceptors 1,3,5-trinitrobenzene (TNB) and 2,4,7-trinitrofluorenone (TNF). With four of the nine combinations investigated, added accepter produced small but measurable rate enhancements. Ester–TNF 1:1 association constants were measured spectrophotometrically at 20, 30, and 40 °C in acetic acid for 2-propyl 4-methoxy-1-naphthalenesulfonate (3b), 4,8-dimethoxy-1-naphthalenesulfonate (4), 3,7-dimethyl-1-naphthalenesulfonate (5), and 1-pyrenesulfonate (6). From the equilibrium and kinetic data, the reactivity of the 1:1 ester–TNF complex relative to that of the uncomplexed ester (kc/ku) in acetolysis at 85.73 °C was estimated to be lessthan 4.2 and 1.4 for 3b and 4, respectively, 4.4 ± 2.0 for 5, and 2.8 ± 0.4 for 6. The value of kc/ku for 6 determined from analysis of the kinetic data alone is 2.7 ± 0.8.

scholarly journals Spectrophotometric determination of quetiapine fumarate in pharmaceuticals and human urine by two charge-transfer complexation reactions

2012 ◽  
Vol 18 (2) ◽  
pp. 263-272 ◽  
Author(s):  
K.B. Vinay ◽  
H.D. Revenasiddappa
Keyword(s):  
Charge Transfer ◽  
Human Urine ◽  
Charge Transfer Complexes ◽  
Experimental Conditions ◽  
Chloranilic Acid ◽  
Quetiapine Fumarate ◽  
Complexation Reactions ◽  
Charge Transfer Complexation ◽  
Spiked Human Urine

Two simple, rapid and accurate spectrophotometric procedures are proposed for the determination of quetiapine fumarate (QTF) in pharmaceuticals and in spiked human urine. The methods are based on charge transfer complexation reactions of free base form of the drug (quetiapine, QTP), as n-electron donor (D), with either p-chloranilic acid (p-CAA) (method A) or 2,3-dichloro-5,6-dicyanoquinone (DDQ) (method B) as ?-acceptors (A). The coloured charge transfer complexes produced exhibit absorption maxima at 520 and 540 nm, in method A and method B, respectively. The experimental conditions such as reagent concentration, reaction solvent and time have been carefully optimized to achieve the maximum sensitivity. Beer?s law is obeyed over the concentration ranges of 8.0 - 160 and 4.0 - 80.0 ?g ml-1, for method A and method B, respectively. The calculated molar absorptivity values are 1.77 ? 103 and 4.59 ? 103 l mol-1cm-1, respectively, for method A and method B. The Sandell sensitivity values, limits of detection (LOD) and quantification (LOQ) have also been reported. The stoichiometry of the reaction in both cases was accomplished adopting the limiting logarithmic method and was found to be 1: 2 (D: A). The accuracy and precision of the methods were evaluated on intra-day and inter-day basis. The proposed methods were successfully applied for the determination of QTF in pharmaceutical formulations and spiked human urine.

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