Photophysical Properties of 4-(Dicyanomethylene)-2-Methyl-6-(4-Dimethylaminostyryl)-4H-Pyran (DCM) and Optical Sensing Applications

Abstract

4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) is, commonly known as red dye, an electron donor-acceptor molecule that exhibits very interesting photophysical properties such as high molar absorption coefficients, tunable electronic absorption and fluorescence emission energies, and high fluorescence quantum yields. Several DCM analogous have been synthesized and explored for various practical applications that include solid-state lasers, organic light-emitting diode (OLED), fluorescent sensors, logic gates, photovoltaics, nonlinear optics (NLO), and bioimaging of cells. In recent years, a significant amount of research work has been devoted for developing optical sensors based on DCM dye for detection of various guest analytes. The first part of this book chapter describes comprehensive photophysical properties of the DCM dye which include the results of steady-state and time-resolved absorption and fluorescence studies. The second part of the book chapter summarizes the recent developments of DCMbased optical sensors that exhibit colorimetric, ratiometric, and fluorosensing towards selective detection of metal cations, anions, and neutral species.

Push-Pull Effect of Terpyridine Substituted by Triphenylamine Motive—Impact of Viscosity, Polarity and Protonation on Molecular Optical Properties

“…The plot of the Stokes shift of tBuTPAterpy against the orientation polarizability ( Figure 3 , top inset) shows a very good linearity, spanning from 2887 cm −1 in n -hexane to 8609 cm −1 in acetonitrile, as expected for a push-pull compound. The large Stokes shift values in polar environments can be ascribed to a remarkable change in the dipole moment of tBuTPAterpy between the GS and the emitting excited state [ 74 ], with an estimated Δ µ value of 23.49 D, assuming the Onsager cavity radius of 6.79 Å determined by quantum chemical calculations.…”

A novel strategy for the functionalization and design of 4-methylene-4H-pyran merocyaninesviaenamination and 1,8-conjugate addition

“…These results are associated with the stabilization of the polar excited state, which is typical for 4-dicyanomethylene-4 H -pyrans. 3,4 It is known 2 d that the fluorescence quantum yield should increase with the emission energy. However, for compound 5a , the lowering of the emission energy due to the solvatochromic shift is accompanied by an increase in the fluorescence quantum yield.…”

“…1). 3 These compounds exhibit tunable strong red emission, including NIR, excellent light stability, and a weak overlap between the absorption and emission spectra (significant Stokes shift). 4 DCM derivatives have been explored for various practical applications in laser dyes, 5 dopants or hosts for organic light-emitting diodes (OLEDs), 6 memory devices, 7 fluorescent chemosensors, 8 solar cells, 9 nonlinear optic materials (NLOs), 10 photodynamic therapy of cancer, 11 and bioimaging.…”

“…2). 3 The preparation of distyryl derivatives usually does not cause difficulties, while the synthesis of monosubstituted derivatives requires the use of highly selective methods or hard-to-reach unsymmetrical pyrans. 14,15 In the case of readily accessible 2,6-dimethyl-4 H -pyrans, low selectivity, which is the main scope limit, causes the formation of a poorly separable mixture of products, even when equimolar amounts of reactants are used.…”

Generation of red light with intense photoluminescence assisted by Forster resonance energy transfer from Znq2 and DCM thin films

“…In polar environments, the DCM undergoes an intramolecular charge transfer (Kumar Kanaparthi et al 2021 ) but in the following study we work on thin films, and due to the rigid environment hindering the movement of the molecules it is impossible that this phenomenon will occur, and therefore it is very likely that there is a Forster resonance energy transfer phenomena which results in nonradiative energy transfer from the donor fluorophore in the excited state to an acceptor molecule via a Coulomb interaction (Sasaki et al 2016); this hypothesis can be reinforced by the spectral overlap of the emission spectra of the donor and the absorption spectra of the acceptor. The presence of the two decay times in pure DCM can be explained by two different physical processes illustrated in the transitions that occur from the ground state to the excited state of the donor and the transition from the ground state to the excited state of the acceptor, while for pure Znq 2 samples, a study suggests that the presence of the two decomposition rates is made up of two distinct physical processes that take place during the transfer of energy from the ground state to a higher state or a central metal atom to a quinoline ligand (Painuly et al 2020).…”