1‐(Arylalkenyl)pyrenes – Synthetic, Structural, Photophysical, Theoretical, and Electrochemical Investigations

Abstract

As a new approach for tuning the electronic properties of pyrene derivatives, we converted 1‐bromopyrene into different substituted styrenes using the Mizoroki–Heck reaction. Several 1‐(arylalkenyl)pyrenes have been characterized and their electronic properties studied by absorption and emission spectroscopy. The effect of the electronic ambience on the emission spectra of these compounds is discussed. Amongst the intramolecular influences, such as electron donating or withdrawing groups, other influences in the form of solvatochromatism are considered. Electrochemical oxidation potentials determined by DPV (differential pulse voltammetry) are discussed with regard to substituent effects. The fine structure of the absorbance spectra obtained from photophysical measurements is compared with theoretical calculations performed by time dependent B3LYP DFT (TD‐DFT) methods using the 6‐31G* basis set. In this context, we discuss the calculated potential energy surfaces and geometric structures with regard to the substitution pattern of the pyrenes.

3-Pyrenylacrylates: Synthetic, Photophysical, Theoretical and Electrochemical Investigations

“…Planar molecules like trans-stilbene and pyrene show such vibronic bands in their electronic absorption spectra as well, while the spectrum of the less planar cis-stilbene does not show such bands [3,26]. The vibronic bands in the spectrum of 3d are more distinct than in the spectra of 1-(arylalkenyl)pyrenes [24]. Hence, it is likely that 3d has a more planar structure in liquid phase than 1-(arylalkenyl)pyrenes.…”

“…1) [25,26]. In earlier studies it was pointed out that the shape of electronic absorption spectra of these classes of compounds depends strongly on the pyrene-type backbone [2,24]. While the bands in the spectrum of parent pyrene occur at 1 B a : 241 nm, 1 B b : 273 nm, and 1 L a : 335 nm [26], the 1 L a band in the spectra of pyrenylacrylate appear at higher wavelengths.…”

“…Selected alkenylpyrenes, containing electron donor or electron acceptor substituents, were studied regarding their absorption, emission, and electrochemical properties. The fine structure of the absorption spectra was compared with the electronic states derived from theoretical calculations [24]. As an extension of our previous work [24] we herein report the synthesis of a set of 3-pyrenylacrylates and their photophysical and solvatochromic properties (Scheme 1) [25].…”

“…The fine structure of the absorption spectra was compared with the electronic states derived from theoretical calculations [24]. As an extension of our previous work [24] we herein report the synthesis of a set of 3-pyrenylacrylates and their photophysical and solvatochromic properties (Scheme 1) [25]. In addition, DPV measurements were carried out to determine the potential values.…”

“…We studied in detail the physical properties of one derivative, e. g. (E)-iso-butyl 3-(pyren-3-yl)acrylate. Since no dramatic changes within the series of different esters in their general properties were observed, we compared the data of this example with those of a series of 1-(arylalkenyl)pyrenes which were recently prepared by us [24].…”