Determining the excited‐state substituent constants of furyl and thienyl groups

Abstract

Six series of styrene derivatives XCH═CHArY (total of 65) containing the styrene parent molecular skeleton were synthesized (here, Y is OMe, Me, H, F, Cl, CF3, CN, and NO2, and X is 2‐furyl, 3‐furyl, 2′‐methyl‐2‐furyl, 2‐thienyl, 3‐thienyl, and 2′‐methyl‐2‐theniyl). Their ultraviolet absorption spectra were measured in anhydrous ethanol, and their wavelength of absorption maximum λmax was recorded. For the wavenumber νmax (cm−1, νmax = 1/λmax) of the obtained λmax, a quantitative correlation analysis was performed, and 6 excited‐state substituent constants σCC()pex of groups X were obtained by means of curve‐fitting method. Taking the νmax values of total 90 compounds of styrene derivatives as a data set (including 25 compounds from reference and 65 compounds of this work), a quantitative correlation analysis was performed, and the reliability of the obtained σCC()pex was verified. In addition, 12 samples of disubstituted Schiff bases (XCH═NArY) involving the above groups X were synthesized, and their νmax values were recorded. Using these 12 νmax together with the 14 νmax values of Schiff bases taken from reference (total of 26 compounds), it was further verified that the σCC()pex values are reliable by means of quantitative correlation method.

Effect of substituents on the UV spectra of supermolecular system: Silver nanoparticles with bi‐aryl Schiff bases containing hydroxyl

“…To quantify the effect of substituent on the UV spectra of organic compounds, author's group proposed excited‐state substituent constant . Using the constant together with Hammett electronic effect constant σ, the wavenumbers ν max of the λ max were well correlated for these conjugated compounds involving substituted stilbenes and benzenes, styrene derivatives, aryl Schiff bases, and disubstituted pyrimidines . Here, we also employed the excited‐state substituent constant and Hammett electronic effect constant σ to quantify the Δν WSL of MC‐AgNPs solutions.…”

“…Compound b The values were taken from Hansh et al [27] c The values were taken from previous studies. [28][29][30][31][32][33] d Indicator variable of 4′-OH.…”

“…To quantify the effect of substituent on the UV spectra of organic compounds, author's group [28][29][30][31][32][33] proposed excited-state substituent constant σ ex CC . Using the σ ex CC constant together with Hammett electronic effect constant σ, [27] the wavenumbers ν max of the λ max were well correlated for these conjugated compounds involving substituted stilbenes and benzenes, [25,[30][31][32][33][35][36][37][38] styrene TABLE 2 The λ′ max (nm) of MC, λ WSL (nm) of MC-AgNPs, Δν WSL (cm −1 ), and substituent effect constants of groups X and Y for XBAYs (2 and 4) No.…”

“…derivatives, [28,32] aryl Schiff bases, [39][40][41][42][43][44][45][46][47][48][49][50][51][52] and disubstituted pyrimidines. [53] Here, we also employed the excited-state substituent constant σ ex CC and Hammett electronic effect constant σ to quantify the Δν WSL of MC-AgNPs solutions.…”

Influence of substituent and push‐pull effect on the chemical shifts of the carbon in bridging bond of 1‐furyl/thienyl‐2‐arylethylene

“…The synthesis of the model compound XEBY was carried out according to the method of Seus and Wilson and Qu et al [ 21,22 ] see Figure 1, and the obtained crude product was separated and purified by column chromatography. The molecular trans‐configuration of XEBY was confirmed via infrared spectroscopy (IR) and NMR measurements, that is, in IR, the out‐of‐plane bending vibration absorption peak of the two H in the bridging bond CHCH is around 970–960 cm −1 , and in NMR, the 1 H NMR coupling constant of CHCH is about J trans = 12‐18 Hz.…”