The photophysics and two-photon absorption of a series of quadrupolar and tribranched molecules: The role of the edge substituent

Fakis, Mihalis; Fitilis, Ioannis; Stefanatos, S.; Vellis, Panagiotis D.; Mikroyannidis, John A.; Giannetas, V.; Persephonis, P.

doi:10.1016/j.dyepig.2008.08.014

Cited by 20 publications

(10 citation statements)

References 33 publications

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“…193,219,302,303 Recently, Mikroyannidis and co-workers reported the synthesis of bisterpyridines 49-51 applying the Heck reaction with Pd(OAc) 2 as catalyst. 28,317 The key building block, 4 0 -(4vinylphenyl)-2,2 0 :6 0 ,2 00 -terpyridine (1d), was obtained from 1a in a Stille cross-coupling reaction. The terminal vinyl-group was subsequently used for the Pd II -catalyzed Heck crosscoupling reaction with 1a (to yield 49) or the respective p-conjugated spacer units (to yield 50b and 51a).…”

Section: C-c Single Bond Formation By Cross-coupling Methodsmentioning

confidence: 99%

Advances in the field of π-conjugated 2,2′:6′,2″-terpyridines

et al. 2011

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This critical review summarizes the research progress made in the field of π-conjugated terpyridines within the last decade. Supramolecular materials based on metal ion complexes of 2,2':6',2"-terpyridine derivatives have found manifold potential applications-from opto-electronic devices to life science. In this contribution, synthetic strategies towards π-conjugated terpyridines and their incorporation into advanced supramolecular architectures are evaluated. Applications as photoactive species in, e.g., photovoltaic devices, polymer light-emitting diodes (PLEDSs) and nanotechnology are discussed comprehensively (523 references).

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Section: C-c Single Bond Formation By Cross-coupling Methodsmentioning

confidence: 99%

Advances in the field of π-conjugated 2,2′:6′,2″-terpyridines

et al. 2011

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“…It has been shown that intramolecular charge-transfer (ICT) processes can significantly enhance 2PA. [8][9][10][11][12][13] Thus, both the permanent ground-state and excited-state dipole moments and the transition dipole moment are considered key parameters in the 2PA process. 14 This necessitates design of molecules with electron-donating (D) and/or electron-accepting (A) groups or increasing the pi-conjugation length.…”

Section: Introductionmentioning

confidence: 99%

Symmetry- and Solvent-Dependent Photophysics of Fluorenes Containing Donor and Acceptor Groups

et al. 2014

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Three two-photon absorption (2PA) dyes (donor-π-donor (DPA2F), donor-π-acceptor (AF240), and acceptor-π-acceptor (BT2F); specifically, D is Ph2N-, A is 2-benzothiazoyl, and the π-linker is 9,9-diethylfluorene) are examined in a variety of aprotic solvents. Because the 2PA cross section is sensitive to the polarity of the local environment, this report examines the solvent-dependent linear photophysics of the dyes, which are important to understand before probing more complex solid-state systems. The symmetrical dyes show little solvent dependence; however, AF240 has significant solvatochromism observed in the fluorescence spectra and lifetimes and also the transient absorption spectra. A 114 nm bathochromic shift is observed in the fluorescence maximum when going from n-hexane to acetonitrile, whereas the lifetimes increase from 1.25 to 3.12 ns. The excited-state dipole moment for AF240 is found to be 20.1 D using the Lippert equation, with smaller values observed for the symmetrical dyes. Additionally, the femtosecond transient absorption (TA) spectra at time zero show little solvent dependence for DPA2F or BT2F, but AF240 shows a 52 nm hypsochromic shift from n-hexane to acetonitrile. Coupled with the solvatochromism in the fluorescence and large excited-state dipole moment, this is attributed to formation of an intramolecular charge-transfer (ICT) state in polar solvents. By 10 ps in AF240, the maximum TA in acetonitrile has shifted 30 nm, providing direct evidence of a solvent-stabilized ICT state, whose formation occurs in 0.85-2.71 ps, depending on solvent. However, AF240 in nonpolar solvents and the symmetrical dyes in all solvents show essentially no shifts due to a predominantly locally excited (LE) state. Preliminary temperature-dependent fluorescence using frozen glass media supports significant solvent reorganization around the AF240 excited state in polar solvents, and may also support a twisted intramolecular charge-transfer (TICT)-state contribution to the stabilization. Finally, time-dependent density functional theory calculations support ICT in AF240 in polar media and also allow prediction of the 2PA cross sections in the 0-0 band, which are much larger for AF240 than the symmetrical dyes.

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“…On the other hand, when the peripheral EWGs in the (A-π-) 3 D analogues were alkylsulfonyl or perfluoroalkylsulfonyl substituents featuring strong inductive effects, δ 2PA also approached values ranging from 1000–1450 GM. , In comparison, D2 showed higher δ max than both the CN-substituted and trifyl-substituted analogues. , Extending the π-conjugation of the aforementioned sulfonylated analogues, i.e., by inserting additional arylenevinylene linkers, enabled higher δ 2PA of 2070–2080 GM to be obtained (Table S2). ,,,− With D2 , the 2PA cross-section of 2205 GM was achieved without the introduction of π-extensions, thus allowing high δ 2PA / N π values to be maintained. Aside from having higher δ 2PA than prior analogues, D2 also performed well against many other related but nonanalogous (A-π-) 3 D octupolar tripods, which typically present lower δ 2PA than the inverse (D-π-) 3 A systems. − For instance, D2 showed δ 2PA that was an order of magnitude higher than tripodal (A-π-) 3 D systems where vinylene linkers were absent, and the terminal acceptors were various combinations of CHO, CN, CHC(CN) 2 , CF 3 , and NO 2 …”

Section: Resultsmentioning

confidence: 99%

Using the Negative Hyperconjugation Effect of Pentafluorosulfanyl Acceptors to Enhance Two-Photon Absorption in Push–Pull Chromophores

et al. 2018

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A series of first-generation pentafluorosulfanylsubstituted chromophores with high two-photon crosssections is described. The pentafluorosulfanyl functional group is a very intriguing moiety that possesses not only a strong inductive effect due to its high electronegativity but also a sizable resonance acceptor constant due to negative hyperconjugation involving the sulfur(VI) center. This negative hyperconjugation effect imparts cationic character to the sulfurs, a feature that we exploit in the design of potent two-photon-absorbing systems where the pentafluorosulfanyl groups serve as strong terminal acceptors. Herein, we report five multibranched triarylamine-based dyes with two-photon absorption cross-sections ranging from 1100−2200 GM. This demonstrates for the first time that when coupled to a suitable donor, pentafluorosulfanyl acceptors are a viable molecular handle for designing large cross-sections in relatively small metal-free π-conjugated systems.

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The photophysics and two-photon absorption of a series of quadrupolar and tribranched molecules: The role of the edge substituent

Cited by 20 publications

References 33 publications

Advances in the field of π-conjugated 2,2′:6′,2″-terpyridines

Advances in the field of π-conjugated 2,2′:6′,2″-terpyridines

Symmetry- and Solvent-Dependent Photophysics of Fluorenes Containing Donor and Acceptor Groups

Using the Negative Hyperconjugation Effect of Pentafluorosulfanyl Acceptors to Enhance Two-Photon Absorption in Push–Pull Chromophores

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