Complex formation and intermolecular excited-state proton transfer (ESPT) between a dihydroxy-1,8-naphthalimide photoacid and organic bases are investigated in polar aprotic solvents. First, quantum chemical calculations are used to explore the acid-base and spectroscopic properties and to identify energetically favorable complexes. The two hydroxyl groups of the photoacid enable stepwise forma...

in the present study, a simple and sensitive extractive spectrophotometric method is described for determination of buspirone. the method is based on the reaction of buspirone and bromocresol green. the ion-pair complex was quantitatively extracted into chloroform at ph 2.3 followed by spectrophotometric determination at 415 nm. the complex was stable up to 2 days and obeyed beer's law over the...

a simple and sensitive extractive spectrophotometric method is described for determination of tropicamide. the method is based on the reaction of tropicamide and bromocresol green. the ion-paired colored complex was extracted with chloroform at ph 3. the extracted complex showed maximum absorbance at 423 nm. the complex was stable up to 2 days and obeyed beer's law over the concentration r...

using solvent evaporating and atomic emission spectrophotometric methods, the solubility of li2co3 in waterat 25°c was determined. comparing the value of thermodynamic solubility product constant, ksp(th),(ksp(tn) = exp(—ag.ss/rt)) of the mentioned salt to the value which is obtained from the observed solubility,shnoll-1 , and activity coefficients, f+ and f, which are estimated upon the extend...

in this study a sensitive, simple and accurate spectrophotometric method was suggested for determination of tamsulosin in bulk powder and pharmaceutical dosage form based on the formation of an ion-pair complex between the drug and bromocresol green in a buffer solution at ph 3.5. the formed yellow color complex was extracted with chloroform and measured at 415 nm. the optimum reaction conditio...

The effect of contact ion pairs and comparison the three halide ions on electrophilic C-H activation during base-free synthesis Ru(III)-NHC complexes [RuIII(PyNHCR)(Cl)3(H2O)] (1a; R = Me, 1b; iPr) have been investigated. DFT modelling two pathways for formation complexes, viz. coordination pathway ion-pair pathway, reveals generation carbene. path is preferred azolium salts with Cl− I−, wherea...

To explore how the ion-pair in a single salt molecule evolves with the addition of water, infrared (IR) spectra of complexes composed of NaCl and multiple water molecules have been recorded for the first time. The NaCl(H2O)n complexes were formed and probed in liquid helium nanodroplets, and IR spectra were recorded for n = 1 → 4. The spectra for n = 1, 2, and 3 are consistent with formation of...