Electron Push–Pull Effects on Intramolecular Charge Transfer in Perylene-Based Donor–Acceptor Compounds

Abstract

A series of asymmetric donor−acceptor (D−A) perylene-based compounds, 3-(N,N-bis(4′-(R)-phenyl)amino)perylene (Peri−DPA(R)), were successfully prepared to explore their intramolecular charge transfer (ICT) properties. To induce ICT between the donor and acceptor, diphenylamine (DPA) derivatives (electron donor units) with the same functional groups (R = CN, F, H, Me, or OMe) at both para positions were linked to the C-3 position of perylene to produce five Peri−DPA derivatives. A steady-state spectroscopy study on Peri−DPA(R)s exhibited a progressively regulated ICT trend consistent with the substituent effect as it progressed from the electron-withdrawing group to the electrondonating group. In particular, a comparative study using a D−A−D (donor−acceptor− donor) system demonstrated that not only the electron push−pull substituent effect but also subunit combinations influence photophysical and electrochemical properties. The different ICT characters observed in Lippert−Mataga plots of D−A(CN) and D−A−D(CN) (CNsubstituted D−A and D−A−D) led to the investigation on whether ICT emission of two systems with differences in subunit combinations is of the same type or of a different type. The femtosecond transient absorption (fs-TA) spectroscopic results provided direct evidence of ICT origin and confirmed that D− A(CN) and D−A−D(CN) exhibited the same transition mix of ICT (from donor to acceptor) and reverse ICT (rICT, from arylamine to CN unit). Density functional theory (DFT)/TD-DFT calculations support the presence of ICT for all five compounds, and the experimental observations of rICT presented only for CN-substituted compounds.

Donor moieties with D–π–a framing modulated electronic and nonlinear optical properties for non-fullerene-based chromophores

“…For instance, the β total and 〈 γ 〉 endorsed the estimation of the NLO response of the chromophores, which is then related with the ICT from the D moiety toward an A unit via π-linkers. 53 Such kind of interactions for our compounds are displayed in Fig. 2 .…”

“… 52 NBO is also used to predict the charge transfer between donor and acceptor moieties in D–π–A type organic compounds by calculating the natural charges. 53 Therefore, NBO calculations were performed at the M06/6-311G (d, p) level using the optimized structures of FH and FHD1–FHD6 and their results in terms of natural charges for the donor, π-spacer, and acceptor segments are tabulated in Table 4 .…”

Facile intra- and intermolecular charge transfer control for efficient mechanofluorochromic material

“…To clarify the solvation effects, this study analyzed the dipole moments between the ground and excited states using a Lippert-Mataga plot (Figure S27, S28 and Table S7). 61,62 As shown in Figure S27b, the plot of F-OMe did not obey the linear relationship predicted by the Lippert-Mataga equation well and showed two sets of linearity indicative of two different excited states: one for high polarity solvents and the other for low polarity solvents. As the solvent polarity increases, the ICT state begins to stabilize, leading to a significantly lower energy barrier between the LE and ICT states.…”

A new insight into the push‐pull effect of substituents via the stilbene‐like model compounds

“…Push‐pull effect of substituents is an important concept, which is often employed to improve the properties of organic compounds [1–24], such as UV absorption [4, 15], fluorescence emission [6, 16], intramolecular charge transfer [1, 3, 14], nonlinear optical properties [5, 13], photovoltaic performance [10], organic light‐emitting diode [19], and so on. If we input the word “push‐pull effect” into the Web of Science, we will obtain more than 100,000 items, which implies that the push‐pull effect of substituents is widely used in physics and chemistry.…”