Optical Operation by Chromophores Featuring 4,5-Dicyanoimidazole Embedded within Poly(methyl methacrylate) Matrices

Abstract

We have studied photoinduced absorption, birefringence, and optical second-harmonic generation in poly(methyl methacrylate) (PMMA) films doped by organic chromophores featuring 4,5-dicyanoimidazole in the weight content equal to 5%. The chromophores indicated as IM1-IM6 were synthesized from 2-bromo-1-methylimidazole-4,5-dicarbonitrile by either nucleophilic substitution or Suzuki-Miyaura cross-coupling reaction. The samples were obtained as films of several micrometers thickness by the spin-coating method on a quartz substrate. Measurements of the optically induced birefringence were done by the Senarmont method at wavelength 1150 nm, and photoinduced absorption was studied in the spectral range 250-700 nm under optical treatment by 300 mW cw 532 nm laser. Photoinduced optical effects were studied by bicolor 1064 and 532 nm coherent laser pulses. The maximal changes were observed for the ratio between fundamental and writing beam intensities equal to about 7:1. To interpret the observed experimental measurements, theoretical simulations of photoinduced optical properties were performed by quantum chemical computational methods.

Theoretical investigation of the static (hyper)polarizabilities and reorganization energy of 4,5-dicyanoimidazole chromophore and derivatives containing benzene rings and a saturated bridge

“…1). The results of l for molecules with the AN(CH 3 ) 2 donor group were in agreement with others studies, at a HF and DFT levels [22]. Since the intramolecular charge transfer ICT is an essential point in the analysis of the values a, b, c and k as function of the molecular structure, i.e., D/A groups, we have analyzed the tendencies for negative natural charge in the N atom on ACN groups in the 4,5-dicyanoimidazole electron acceptor core using NBO analysis at MP2/6-31+G(d,p) level.…”

“…As observed in Table 2, the LUMO energies are predicted in the order AH < AOCH 3 < AN(CH 3 ) 2 . Is important to note that the results showed in Table 2 were in accord with a similar analysis at PM6 [24] and Ab initio/DFT levels [22]. The calculations of the longest wavelength of maximal absorption k max , at TD(CAM-B3LYP)/6-31+(d) for 4,5-dicyanoimidazole derivatives are shown in Table 2.…”

Synthesis and properties of push-pull imidazole derivatives with application as photoredox catalysts

“…29 In this work, we focus on synthesis of Yshaped push-pull analogues 2 and 3 based on five-membered acceptor unit -imidazole-4,5-dicarbonitrile (dicyanoimidazole, DCI) and further evaluation of their optoelectronic properties and photoredox catalytic activities. The DCI unit proved to be readily available heterocyclic acceptor for push-pull molecules, [30][31][32][33][34][35][36] however, none of them has been investigated as potential photoredox catalyst. In principal, the structural tuning of the original DCP derivative 1 can be achieved by replacing the acceptor unit (DCPDCI) and also by variation of the peripheral R-substituent (H or OMe).…”

“…Bromo precursor 4 is well-known to undergo Suzuki-Miyaura cross-coupling, whereas Sonogashira reaction is complicated by a subsequent polymerization. [30][31][32][33][34][35][36] Hence, we introduced the (5-methoxy)thienyl donors via the reaction with commercially available thiophen-2-ylboronic acid 5 and 5-methoxythiophen-2-ylboronic acid pinacol ester 6. The latter was prepared from 2-methoxythiophene and its lithiation and reaction with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (iPrOBpin) with 89% yield.…”

Effects of the Nature and Length of the π‐Conjugated Bridge on the Second‐Order Nonlinear Optical Responses of Push–Pull Molecules Including 4,5‐Dicyanoimidazole and Their Protonated Forms

“…For instance, 4,5-dicyanoimidazole is an efficient organic electronics component, [14] and recently, photoinduced absorption and birefringence of 4,5-dicyanoimidazole-derived chromophores embedded into poly(methylmethacrylate) films were studied. [15] In addition, 2-bromo-1-methylimidazole-4,5-dicarbonitrile precursors can easily be substituted by donors with systematically extended p-conjugated systems, [16] which are key elements to increase the first hyperpolarizability.…”