Uv vis spectrometer uv 1700

The solvatochromic probe 4-nitroanisol was used to estimate the Kamlet–Taft parameter π* (polarizability index). A stock solution of the dye in DCM was prepared to a concentration of 4 mM. The dye stock solution was added to the solvents understudy to a final concentration of 0.1 mM, which enables to obtain the absorbance values within the required measurable range, and DCM was removed by evaporation at room temperature. The absorption spectra of the solvatochromic probe were recorded from 250 nm to 500 nm in a quartz cell with a 10 mm path length, using a Shimadzu UV/VIS spectrometer UV-1700 at 1 nm stepwise. The wavelength at maximum absorption ν_max was determined for the probe in each solvent. The solvatochromic π* parameter was determined using the equation [32 (link)].
${\mathsf{\pi }}^{*}= \frac{\left(34.12 - {\mathsf{\nu }}_{\max }\right)}{2.343}$
The constant values were obtained from multiple correlation equations where the best fit for Δν_max was normalized to provide π* values for 28 solvents on a scale of 0 to 1, which was consistent with a π* of zero for cyclohexane, due to its low polarity, and unity for dimethyl sulfoxide, which is a highly polar organic liquid [33 (link)].