Solvatochromic studies of novel azo merocyanine dyes. The .pi.*azo scale of solvent polarity

Buncel, Erwin; Rajagopal, Srinivasan

doi:10.1021/jo00265a017

Cited by 69 publications

(26 citation statements)

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“…Hence correlations between different scales based on different indicator molecules have been established. 11,13,19,20 Liquid interfaces, which are the subject of the present study, is a field of intense activity because of the scientific, environmental, and technological importance of interfaces. [21][22][23][24] The asymmetry of the forces at the interface, exemplified by the observation that molecules at liquid surfaces are aligned in a preferential direction rather than randomly oriented as they are in the bulk, 25 is the origin of many of the unique chemical and physical properties of this region.…”

Section: Introductionmentioning

confidence: 99%

Polarity of Liquid Interfaces by Second Harmonic Generation Spectroscopy

1997

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A spectroscopic method, based on the interface selectivity of second-harmonic generation, is used to obtain the polarity of liquid interfaces. In this paper the second-harmonic measurement of the spectrum of the polarity indicator molecule N, N′-diethyl-p-nitroaniline (DEPNA) at the air/water interface demonstrates the method. Two different approaches are used to measure the intramolecular charge transfer (CT) absorption band position of DEPNA at the air/water interface. The DEPNA CT band blue-shifts from 429 nm in bulk water (polar solvent) to 359 nm in bulk hexane (nonpolar solvent) and 329 nm in the gas phase (no solvent). At the air/water interface, the charge transfer peak band maximum occurs at 373 nm, which indicates that the polarity of the air/water interface is similar to those of the bulk solvents carbon tetrachloride and butyl ether. The DEPNA results together with the results from another solvatochromic polarity indicator molecule, ET-(30), which will be reported elsewhere, show that the polarity results of the air/water interface are general.

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Section: Introductionmentioning

confidence: 99%

Polarity of Liquid Interfaces by Second Harmonic Generation Spectroscopy

1997

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“…The effort was thus made to find correlations between the position of maxima of long wavelength bands (ν max ) and values of selected parameters characterizing the used solvents (π*), where π* is a measure of solvent dipolarity/ polarizability, 52 dielectric constant (εr), Dimorth and Reichard solvent polarity parameter, ET (30). [53][54][55] Plots of νmax versus the above mentioned parameters showed no regular relations between the two variables.…”

Section: Resultsmentioning

confidence: 99%

Experimental and Theoretical Investigations of Spectral, Tautomerism and Acid-Base Properties of Schiff Bases Derived from Some Amino Acids

Ebead¹,

Salman²,

Abdellah³

2010

Bulletin of the Korean Chemical Society

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The electronic absorption spectra of five Schiff bases derived from 2-hydroxy-1-naphthaldehyde with glycine, alanine, leucine, valine and phenylalanine have been measured in various solvents. The observed bands were assigned to the proper electronic transitions and compared with the predicted transitions at the semiempirical level of theory. The calculated equilibrium constants are in agreement with the experimental results, predicting the existence of all studied compounds predominantly or completely in keto-imine tautomerism. On the other hand, a correlation between ν (cm -1 ) (main frequency of each compound) and the well known solvent parameters ET (30), εr, π* has been made. Furthermore, the acid dissociation constants, pKa, were determined by using three different spectrophotometric methods.

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“…In most cases pair domains include less than 6 atoms. However, the azo-dye 51 given in Table II also has a very delocalized system with pair domains up to 11 atoms and shows much smaller errors. Systems like these are stringent tests for the AO domain selection and certainly show the limits of our proposed criterion.…”

Section: Effects Of Thresholdsmentioning

confidence: 99%