The ultraviolet spectra of N-substituted phenylglycines (RPhG, R= p-OCH_3, p-CH_3 m-CH_3,-H, m-OCH_3, p-Cl, m-Cl, m-NO_2, p-NO_2) have been studied in n-hexane, n-heptane, dioxane, carbon tetrachloride, benzene, mehtylbenzene, diethyl ether, chlorobenzene,ethyl acetate, ethanol,acetonitrile, 30% ethanol-water, in different ratios of ethanol-n-heptane mixtures by means of Beckman DU-8 Spectrophotometer. The experiment results showed that
1. To compare with the characterized absorption bands of benzene, the bath-ochromic shift of ultraviolet absorption spectra of RPhG in varous solvents was observed. The energy difference between ground state and first excited state of RPhG followed the order
In 30% ethanol-water the order appeared to be p-NO_2
2. Linear relationships were found between v of PRhG in various solvents and their base strengths pK_2 and between the transference energy ΔE as well.
3. In non-polar solvents, the frequency v of PRhG varies linearly with the solvent charcterization function f(n~2). In polar solvents, linear relationships did exist between [v-AL_0+B)·f(n~2)] and the solvent characterization function φ(ε)-φ(n~2) and between v of PRhG and f(ε) of solvent as well.
4. In different solvents, linear relationships did exist between the v_R of the same substitutent group of RPhG and the v_H of unsubstituted PhG.