Tuning of Hyperpolarizability, One- and Two-Photon Absorption of D-A and D-A-A Type Intramolecular Charge Transfer Based Sensors

Photon Absorption ◽

First Hyperpolarizability ◽

Two Photon Absorption ◽

Two Photon ◽

Nlo Response ◽

Solvents play an important role in shaping the intramolecular charge transfer (ICT) properties of π-conjugated molecules, which in turn can affect their one-photon absorption (OPA) and two-photon absorption (TPA) as well as the static (hyper)polarizabilities. Here, we study the effect of solvent and donor-acceptor arrangement on linear and nonlinear optical (NLO) response properties of two novel ICT-based fluorescent sensors, one consisting of hemicyanine and dimethylaniline as electron withdrawing and donating groups (molecule 1), respectively and its boron-dipyrromethene (BODIPY, molecule 2)-fused counterpart (molecule 3). Density functional theoretical (DFT) calculations using long-range corrected CAM-B3LYP and M06-2X functionals, suitable for studying properties of ICT molecules, are employed to calculate the desired properties. The dipole moment (µ) as well as the total first hyperpolarizability (βtotal) of the studied molecules in the gas phase is dominantly dictated by the component in the direction of charge transfer. The ratios of vector component of first hyperpolarizability (βvec) to βtotal also reveal unidirectional charge transfer process. The properties of the medium significantly affect the OPA, hyperpolarizability and TPA properties of the studied molecules. Time dependent DFT (TDDFT) calculations suggest interchanging between two lowest excited states of molecule 3 from the gas phase to salvation. The direction of charge polarization and dominant transitions among molecular orbitals involved in the OPA and TPA processes are studied. The results presented are expected to be useful in tuning the NLO response of many ICT-based chromophores, especially those with BODIPY acceptors.

Tuning of hyperpolarizability, and one- and two-photon absorption of donor–acceptor and donor–acceptor–acceptor-type intramolecular charge transfer-based sensors

Physical Chemistry Chemical Physics ◽

10.1039/c9cp03772a ◽

2019 ◽

Vol 21 (31) ◽

pp. 17343-17355 ◽

Cited By ~ 4

Author(s):

Pralok K. Samanta ◽

Md. Mehboob Alam ◽

Ramprasad Misra ◽

Swapan K. Pati

Keyword(s):

Charge Transfer ◽

Fluorescent Sensors ◽

Photon Absorption ◽

Response Properties ◽

Two Photon Absorption ◽

Two Photon ◽

Effect Of Solvent ◽

Nlo Response ◽

Effect of solvent as well as arrangement of donor–acceptor groups on the linear and non-linear optical (NLO) response properties of two intramolecular charge-transfer (ICT)-based fluorescent sensors are studied.

Preparation and Photophysical Properties of All-trans Acceptor–π-Donor (Acceptor) Compounds Possessing Obvious Solvatochromic Effects

Australian Journal of Chemistry ◽

10.1071/ch17021 ◽

2017 ◽

Vol 70 (9) ◽

pp. 1048

Author(s):

Yu-Lu Pan ◽

Zhi-Bin Cai ◽

Li Bai ◽

Sheng-Li Li ◽

Yu-Peng Tian

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Photophysical Properties ◽

Emission Spectra ◽

Photon Absorption ◽

Linear Absorption ◽

Functional Theory ◽

Two Photon Absorption ◽

Two Photon ◽

A series of all-trans acceptor–π-donor (acceptor) compounds (BAQ, SFQ, BLQ, and XJQ) were conveniently synthesised and characterised by infrared, nuclear magnetic resonance, mass spectrometry, and elemental analysis. Their photophysical properties, including linear absorption, one-photon excited fluorescence, two-photon absorption, and two-photon excited fluorescence, were systematically investigated. All the compounds show obvious solvatochromic effects, such as significant bathochromic shifts of the emission spectra and larger Stokes shifts in more polar solvents. Under excitation from a femtosecond Ti : sapphire laser with a pulse width of 140 fs, they all exhibit strong two-photon excited fluorescence, and the two-photon absorption cross-sections in THF are 851 (BAQ), 216 (SFQ), 561 (BLQ), and 447 (XJQ) GM respectively. A combination of density functional theory (DFT) and time-dependent density functional theory (TDDFT) approaches was used to investigate the relationships between the structures and the photophysical properties of these compounds. The results show that they may have a potential application as polarity-sensitive two-photon fluorescent probes.

STUDY OF THE S1 AND S2 EXCITED STATES OF GAS-PHASE PROTONATED SCHIFF BASE RETINAL CHROMOPHORES IN ONE AND TWO PHOTON ABSORPTION

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633611006372 ◽

2011 ◽

Vol 10 (02) ◽

pp. 121-132 ◽

Cited By ~ 2

Author(s):

YUANZUO LI ◽

PENG SONG ◽

YING SHI ◽

YONG DING ◽

FENGJIE ZHOU ◽

...

Keyword(s):

Schiff Base ◽

Excited State ◽

Charge Transfer ◽

Gas Phase ◽

Excited States ◽

Density Functional ◽

Three Dimensional ◽

Photon Absorption ◽

Two Photon ◽

The One

The S1 and S2 excited states of gas-phase protonated Schiff base retinal chromophores in the one- and two-photon absorptions (TPAs) are investigated with time-dependent density functional theory. In one-photon absorption, the two-dimensional (2D) site and three-dimensional (3D) cube representations reveal that S1 and S2 excited states of gas-phase protonated Schiff base retinal chromophores are all charge transfer excited states. To better study the weak S2 excited states of gas-phase protonated Schiff base retinal chromophores, we investigated theoretically excited state properties of them in TPA. For 11-cis dimethyl retinal, it is found that the cross section of S2 excited state is 51.04 GM in PTA, which is only slightly smaller than that of S1 (77.04 GM) in TPA. Therefore, the S2 excited state of 11-cis dimethyl retinal can be clearly observed in TPA experiment. The 2D site and 3D cube representations reveal that electronic transition from S1 to S2 excited state of gas-phase protonated Schiff base retinal chromophores in TPA are also of charge transfer character.

Two-photon absorption of styryl-quinolinium, -pyridinium, and -barbituric acid derivatives, and intramolecular charge transfer

Canadian Journal of Chemistry ◽

10.1139/v00-188 ◽

2001 ◽

Vol 79 (2) ◽

pp. 174-182 ◽

Cited By ~ 26

Author(s):

XiaoMei Wang ◽

Chun Wang ◽

WenTao Yu ◽

YuFang Zhou ◽

Xian Zhao ◽

...

Keyword(s):

Dipole Moment ◽

Charge Transfer ◽

Barbituric Acid ◽

Theoretical Calculations ◽

Photon Absorption ◽

Amino Groups ◽

Element Analysis ◽

Two Photon Absorption ◽

Two Photon

A series of new chromophores, styryl-parent end-capped with various donors, and with barbituric acid, methyl-pyridinium, and methyl-quinolinium as the acceptors, have been synthesized and characterized by element analysis or X-ray diffraction. Using the Z-scan system, their two-photon absorption (TPA) cross-section values (δ) have been determined under excitation with 10 Hz, and 1064 nm, 35 ps mode-locked Nd:YAG laser pulse in DMF with do= 0.05 M. The effective δ value is as high as 10.9 × 1048 cm4 s per photon for trans-4-(4'-N,N-diphenyl amino) styryl-N-methyl quinolinium iodide (DPASQI). The δ value increases from barbituric acid- to pyridinium- to quinolinium-derivatives apparently due to the increase in both the conjugated degree and planarity; however, when the acceptor is fixed, the δ value increases from dialkyl amino groups to diphenyl amino groups even though the latter is a weaker donor than the dialkyl amino groups. Theoretical calculations confirm that the increased distortion from planarity for the barbituric acid derivative makes its δ value decrease. The relatively large δ value for quinolinium- or pyridinium-derivatives originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment (Δµge) between the S0 and S1, and the transition dipole moment (Mee') between S1 and S2.Key words: two-photon absorption, intramolecular charge transfer, styryl-quinolinium, styryl-pyridinium, styryl-barbituric acid.

Predicting Excitation Energies of Twisted Intramolecular Charge-Transfer States with Time-Dependent Density Functional Theory: Comparison with Experimental Measurements in the Gas-Phase and Solvents Ranging from Hexanes to Acetonitrile

10.26434/chemrxiv.12522233.v1 ◽

2020 ◽

Author(s):

James Shee ◽

Martin Head-Gordon

Keyword(s):

Charge Transfer ◽

Gas Phase ◽

Excited States ◽

Linear Response ◽

Density Functional ◽

Experimental Measurements ◽

Excitation Energies ◽

Donor And Acceptor ◽

Electronically-excited states characterized by intramolecular charge-transfer play an essential role in many biological processes and optical devices. The ability to make quantitative ab initio predictions of the relative energetics involved is a challenging yet desirable goal, especially for large molecules in solution. In this work we present a data set of 61 experimental measurements of absorption and emission processes, both in the gas phase and solvents representing a broad range of polarities, which involve intramolecular charge-transfer mediated by a non-zero, “twisted” dihedral angle between one or more donor and acceptor subunits. Among a variety of density functionals investigated within the framework of linear-response theory, the “optimally tuned” LRC-ωPBE functional, which utilizes a system-specific yet non-empirical procedure to specify the range-separation parameter, emerges as the preferred choice. For the entire set of excitation energies, involving changes in dipole moment ranging from 4 to >20 Debye, the mean signed and absolute errors are 0.02 and 0.18 eV, respectively (compared, e.g., to -0.30 and 0.30 for PBE0, 0.44 and 0.47 for LRC-ωPBEh, 0.83 and 0.83 for ωB97X-V). The performance of polarizable continuum solvation models for these charge-transfer excited states is closely examined, and clear trends emerge when measurements corresponding to the four small DMABN-like molecules and a charged species are excluded. We make the case that the large errors found only for small molecules in the gas phase and weak solvents cannot be expected to improve via the optimal tuning procedure, which enforces a condition that is exact only in the wellseparated donor-acceptor limit, and present empirical evidence implicating the outsized importance for small donor-acceptor systems of relaxation effects that cannot be accounted for by linear-response TDDFT within the adiabatic approximation. Finally, we demonstrate the utility of the optimally tuned density functional approach by targeting the charge-transfer states of a large biomimetic model system for light-harvesting structures in Photosystem II.