“Dark” Excited States of Diphenylacetylene Studied by Nonresonant Two-Photon Excitation Optical-Probing Photoacoustic Spectroscopy

Suzuki, Tadashi; Nakamura, Masaaki; Isozaki, Tasuku; Ikoma, Tadaaki

doi:10.1007/s10765-012-1296-8

Cited by 14 publications

(18 citation statements)

References 37 publications

(56 reference statements)

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“…In this article, we investigated the two-photon excitation wavelength and the two-photon absorption cross-section σ (2) of taDTGuo by optical-probing photoacoustic spectroscopy (OPPAS), − a PAS technique for detecting transient angular deflection of the probe beam. We also simulated two-photon absorption spectra of thioguanine derivatives using the quantum chemical calculation to better understand the nature of higher two-photon absorption cross-sections for thioguanosines.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Two-Photon Absorption of the Thioguanosine Analogue 2′,3′,5′-Tri-O-acetyl-6,8-dithioguanosine with Its Potential Application to Photodynamic Therapy

Ando

Isozaki

et al. 2020

J. Phys. Chem. A

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Milton Keynes MK7 6AA, United Kingdom ABSRACT 2',3',5'-Tri-O-acetyl-6,8-dithioguanosine (taDTGuo) is an analog of nucleoside and currently under investigation as a potential agent for photodynamic therapy (PDT). Excitation by simultaneous two-photon absorption of visible or near-infrared light would provide an efficient PDT for deep-seated tumors. The two-photon absorption spectrum of taDTGuo was obtained by optical-probing photoacoustic spectroscopy (OPPAS). A two-photon absorption band corresponding to the S 5 ←S 0 transition was observed at 556 nm, and the two-photon absorption cross section (2) was determined to be 26±3 GM, which was much larger than those of other nucleobases and nucleosides. Quantum chemical calculations suggested that the large (2) value of taDTGuo was responsible for large transition dipole moments and small detuning energy resulting from the thiocarbonyl group at 6-and 8-positions. This is the first 1

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Section: Introductionmentioning

confidence: 99%

“…(OPPAS), [16][17][18] a PAS technique detecting a transient angular deflection of the probe beam. We also simulated two-photon absorption spectra of thioguanine derivatives by using the quantum chemical calculation to better understand the nature of higher two-photon absorption cross sections for thioguanosines.…”

mentioning

confidence: 99%

Simultaneous Two-Photon Absorption of the Thioguanosine Analogue 2′,3′,5′-Tri-O-acetyl-6,8-dithioguanosine with Its Potential Application to Photodynamic Therapy

Ando

Isozaki

et al. 2020

J. Phys. Chem. A

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“…Consequently, we shall make reference to the orbitals provided in Ref [17], though it should be noted that we find the HOMO-4 in-plane acetylene π bond to be of B 2g and not B 2u symmetry. The CAS (12,12) includes the next HOMO-5/LUMO+5 and the CAS (16,16) includes all the ππ * orbitals. Calculations were made with Molpro 09 [28].…”

Section: Electronic Structure and Geometry Optimisationsmentioning

confidence: 99%

“…These dendrimers show much promise in applications such as photoactive arrays in polymeric systems [2] and single-molecular light emitting diodes (LEDs) [3]. Tolane has been studied more than any other dendrimer segment [4,5,6,7,8,9,10,11,12,13], and an overall mechanism of its photo-relaxation is emerging, but not yet complete.…”

Section: Introductionmentioning

confidence: 99%

Modelling the non-radiative singlet excited state isomerization of diphenyl-acetylene: A vibronic coupling model

Robertson

Worth

2018

Chemical Physics

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Tolane (diphenyl-acetylene) is the smallest component of macromolecular arrays known as dendrimers that have interesting energy transport properties after photo-excitation. In this paper, a vibronic coupling Hamiltonian is set up to describe the initial internal conversion of this molecule. The calculated absorption spectrum is in good agreement with experiment, with the ordering of states and energies from MRCI-DFT calculation. The focus of the study is the pathway for photo-excited isomerisation from the linear geometry at the Frank-Condon point to a trans-structure. The model shows that the origin of the excited-state minimum for the trans-isomer is due to stabilisation of a high lying state. Quantum dynamics calculations using the MCTDH algorithm show the model agrees with experiment that isomerisation only occurs at high temperature. It also suggests that internal conversion to the S 1 global minima happens via second order coupling terms, which can explain the observed picosecond timescales.

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“…Tolanes, which consist of two benzene rings connected with alkyne moiety, have drawn enormous interest as promising small-sized functional molecules owing to their broad applications, such as two-photon absorbers [ 1 , 2 , 3 ], liquid crystals [ 4 , 5 , 6 ], light-activated DNA cleavers [ 7 , 8 ], and organic semiconductors [ 9 ]. Small-sized solid-state luminescent materials are also needed for practical applications in light-emitting diodes or lighting devices, whereas it is known that tolanes do not emit photoluminescence (PL) because they undergo excitation via the “dark” trans -bent πσ* excited states [ 10 , 11 , 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Systematic Studies on the Effect of Fluorine Atoms in Fluorinated Tolanes on Their Photophysical Properties

2021

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In this study, we synthesized a series of fluorinated and non-fluorinated tolanes, in which one or more fluorine atoms were systematically introduced into one aromatic ring of a tolane scaffold, and systematically evaluated their photophysical properties. All the tolanes with or without fluorine substituents were found to have poor photoluminescence (PL) in tetrahydrofuran (THF) solutions. On the other hand, in the crystalline state, non-fluorinated and fluorinated tolanes with one or four fluorine atoms were less emissive, whereas fluorinated tolanes with three or five fluorine atoms exhibited high PL efficiencies (ФPL) up to 0.51. X-ray crystallographic analyses of the emissive fluorinated tolanes revealed that the position of the fluorine substituent played a key role in achieving a high ФPL. Fluorine substituents at the ortho (2/6) and para (4) positions led to tight and rigid packing due to plural π–π stacking and/or hydrogen bonding interactions, resulting in enhanced ФPL caused by the suppression of non-radiative deactivation. Additionally, fluorinated tolanes with three fluorine atoms exhibited notable aggregation-induced PL emission enhancement in THF/water mixed solvents. This demonstrates that the PL characteristics of small PL materials can be tuned depending on the usage requirements.

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“Dark” Excited States of Diphenylacetylene Studied by Nonresonant Two-Photon Excitation Optical-Probing Photoacoustic Spectroscopy

Cited by 14 publications

References 37 publications

Simultaneous Two-Photon Absorption of the Thioguanosine Analogue 2′,3′,5′-Tri-O-acetyl-6,8-dithioguanosine with Its Potential Application to Photodynamic Therapy

Simultaneous Two-Photon Absorption of the Thioguanosine Analogue 2′,3′,5′-Tri-O-acetyl-6,8-dithioguanosine with Its Potential Application to Photodynamic Therapy

Modelling the non-radiative singlet excited state isomerization of diphenyl-acetylene: A vibronic coupling model

Systematic Studies on the Effect of Fluorine Atoms in Fluorinated Tolanes on Their Photophysical Properties

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