On the Molecular Structure and UV/vis Spectroscopic Properties of the Solvatochromic and Thermochromic Pyridinium-N-Phenolate Betaine Dye B30

Abstract

Quantum chemical calculations as well as vis absorption and fluorescence measurements of the pyridinium-N-phenolate betaine dye B30, dissolved in 1-chlorobutane at temperatures between 343 and 77 K, shed more light on the solvatochromism, thermosolvatochromism, and photophysical behavior of this probe dye, formerly used to establish an empirical scale of solvent polarity, called E(T)(30) or E(T)(N) scale. A new calculated gas-phase E(T)(30) value is reported. Complementary to recent work of Kharlanov and Rettig (J. Phys. Chem. A 2009, 113, 10693-10703), it is shown that fluorescence of B30 in 1-chlorobutane solution is observable already at temperatures just below the solvent's melting point and not only at 77 K. Analogous to increasing solvent polarity, decreasing solvent temperature leads to a large hypsochromic shift of the vis absorption band of B30, dissolved in 1-chlorobutane (Deltalambda = -245 nm from 797 nm at 343 K to 552 nm at 77 K). This thermosolvatochromism can be easily seen: the solution color changes from greenish yellow (343 K) to magenta-violet (77 K).

On the solvatochromism, dimerization and tautomerism of indazole

“…24 Taking into account that our SdP dipolarity scale 17 spans the range from 0 for the gas phase to 1 for such a highly polar solvent as DMSO, lowering the temperature of the ClB solution of indazole must obviously have exposed the compound to a strong dipolarity change.…”

On Saltiel's isopolarizability approach and its applicability to diphenylpolyenes

“…The polarizability SP of the solutions in 2MB and ClB below 293 K was determined by using anthracene as a probe [12,15,16]. As shown elsewhere, the first absorption band of this compound is highly structured and sensitive to the polarizability of the medium [12,15,16].…”

“…These compounds were studied in inert solvent such as 2-methylbutane (2MB), which only undergoes polarizability changes with temperature, and 1-chlorobutane (ClB), which spans the whole dipolarity scale by varying its temperature [12]. All solutions were slowly cooled at 20 • C intervals from room temperature in order to record the corresponding UV/vis absorption spectra.…”

Dilational Rheology at Air/Water Interface and Molecular Dynamics Simulation Research of Hydroxyl Sulfobetaine Surfactant

“…[20] Therefore, due to better acid, base and salt tolerance, sulfobetaines are expected to have industrial applications potential in hostile environments, for instance, enhanced oil recovery from high-salinity oil reservoirs. [21,22] The aggregation behavior of betaine-type surfactants on the interface have been researched and interpreted by the measurements of dynamic light scattering, [23] fluorescence, [24,25] and surface tension. [26,27] However, so far as we know, scientific researches on properties of sulfobetaine adsorbed film by studying interfacial dilational modulus [28] are rarely reported.…”