Synthesis,structure and nonlinear optical properties of two novel two-photon absorption chromophores

Two triphenylamine-based derivatives that can be used as two-photon absorption chromophore,tris{4-[4-(3-trifluoromethyl-3-oxopanoyl)]phenyl}amine (1) and tris{4-[4-(3-phenyl-3-oxopanoyl)] phenyl} amine (2) were successfully synthesized and fully characterized by elemental analysis,IR,1H NMR and MS. The single crystal X-ray diffraction analysis showed that the molecules possess D-(π-A)3 structures. One-and two-photon absorption and fluorescence in various solvents were experimentally investigated. A data rec...     

Synthesis and nonlinear optical properties of new symmetrically substituted stilbenes

Three new chromophores and trans-4-(N-(ethyl 4″-nitrobenzoate)-N-ethyl amino)-4′-(dimethyl amino) stilbene (DMANHAS) have been synthesized and whose chemical structures have been characterized by ¹H NMR, IR, and elemental analyses. Linear absorption, single-photon-induced fluorescence and two-photon-induced fluorescence are experimentally studied. Trans-4-(N-2-hydroxyethyl-N-ethyl amino)-4′-(dimethyl amino)stilbene (DMAHAS) and trans-4-(N-2-hydroxyethyl-N-ethyl amino)-4′-(diethyl amino)stilbene (DEAHAS) have effective two-photon absorption cross-sections of σ₂=0.91×10⁻⁴⁶ cm⁴ s/photon and σ₂=1.19×10⁻⁴⁶ cm⁴ s/photon at 532 nm by using an open aperture Z-scan technique, respectively. When pumped with 800 nm laser irradiation, DMAHAS and DEAHAS indicate strong two-photon-induced blue fluorescence of 436 and 440 nm, respectively, while trans-4-(N-(ethyl 4″-nitrobenzoate)-N-ethyl amino)-4′-(diethyl amino) stilbene (DEANHAS) and DMANHAS exhibit no fluorescence.     

Synthesis and photophysical properties of novel pyrimidine-based two-photon absorption chromophores

Three new two-photon absorption chromophores based on a pyrimidine core were synthesized by Aldol condensation in the absence of any organic solvents. Their single-photon spectroscopic characterization as well as their two-photon absorption properties is reported. In addition, strong modulation of single-photon and two-photon fluorescent spectra of these molecules by (de)protonation is also discussed.     

Synthesis and nonlinear optical absorption properties of two new conjugated ferrocene-bridge-pyridinium compounds

Two electron donor-π-acceptor (D-π-A) chromospheres, with ferrocene as the electron donor and pyridinium as the electron acceptor, were synthesized. The nonlinear optical absorption (NOA) properties in the solution state were investigated by the Z-scan technique. Both compounds exhibited reverse saturable absorption (RSA) and optical limiting effect under nanosecond pulse irradiation.     

Relationship between structure and nonlinear optical properties of new bisazo chromophores. Theoretical and experimental study

Two new bisazo chromophores—derivatives of bis-2,2-(4-hydroxyphenyl)propane (bisphenol A), heterocyclic amines (2-aminobenzothiazole, and 2-amino-6-nitrobenzothiazole) and aniline—were synthesized. Nonlinear optical properties of these chromophores were studied by solvatochromic method (obtained compounds have β_CT value ∼10⁻²⁹ esu). Dependence among the structure of molecules, their dipole moments, and first hyperpolarizabilities was considered on the basis of semi-empirical calculations. A correlation between the measured and calculated β values was studied. The NLO chromophores were used as special monomers to synthesize copolyarylates. The basic characterization of obtained polymers was carried out.     

Synthesis and characterization of naphthalene diimide (NDI)-based near infrared chromophores with two-photon absorbing properties

A new series of 2,7-bis-(2-ethylhexyl)-benzo[lmn][3,8]-phenanthroline-1,3,6,8-tetraone (NDI) based pseudo-quadrupolar molecules (1-6) is presented and their two-photon absorption (2PA) cross-sections measured with the Z-scan method. The spectral properties of these compounds can be fine-tuned via modification of the donor segments. The corresponding 2PA cross-section (σ₂) values at the most readily available 800 nm excitation range from 229±15 to 1092±59 GM owing to differences in conjugation length and/or position of substitution.     

Synthesis and two-photon absorption of triphenylbenzene-cored dendritic chromophores

The synthesis and the characterization of triphenylbenzene-cored dendrimers of first- and second-generation are described. Their absorption, photoluminescence as well as their two-photon absorption properties have been investigated and compared to a quadrupolar counterpart. These molecules combine wide transparency in the visible range and high two-photon absorption cross-sections that increase with the generation, making these dendrimers promising systems for optical power limiting applications.     

Multi-carbazole derivatives for two-photon absorption data storage:Synthesis,optical properties and theoretical calculation

Two novel quadrupolar organic compounds, 3-(4-((E)-2-(9-butyl-9H-carbazol-6-yl) vinyl)styryl)-9-propyl-9H-carbazole (BCSPC) and 3-(3-(3-((1E)-2-(4-((E)-2-(3-(3,5-bis(9-butyl-9H-carbazol-6-yl)phenyl)-9-butyl-9H-carbazol-6-yl)vinyl)phenyl) vinyl)-9-butyl-9H-carbazol-6-yl)-5-(9-butyl-9H-carbazol-6-yl)phenyl)-9-butyl-9H-carbazole (BCPBC), with different conjugated arms, have been designed and synthesized. Their one-and two-photon absorption (TPA) and excited fluorescence properties have been experimentally inve...     

新型双光子吸收化合物的合成、光物理及其在固态分散体系中的性质

通过多步反应制备了三个新型的双光子吸收化合物,测试了它们的光物理性质,发现该系列化合物具有较大的双光子吸收截面,并且随温度降低其双光子吸收截面增大.尤其是化合物TMVDB,其量子效率为0.83,常温时的双光子吸收截面达到1164GM,其双光子吸收截面除以分子量为2.08,表现出了优良的双光子吸收发光性能.进一步将TMVDB掺杂到固体材料中,得到强双光子诱导发光的固体材料.     

Synthesis, structure and two-photon absorption properties of a new multi-branched compound, 1,2,4,5-tetrakis(4-pyridylvinyl)benzene

A conjugated and symmetric multi-branched compound, 1,2,4,5-tetrakis(4-pyridylvinyl)benzene (TKPVB), has been synthesized and the crystal structures of TKPVB and its intermediate, 1,2,4,5-tetrakis(dimethoxyphosphorylmethyl)benzene, were determined by diffraction method. TKPVB with four units of 4-vinylpyridine moieties attached to the central benzene core presents an A-π-A general framework, where A is a π-deficient pyridine ring. The single-photon and two-photon absorption and fluorescence properties in different solvents of varying polarity have been investigated. It is also found that the one- and two-photon-induced fluorescence spectra are quite similar, which indicate that the one- and two-photon allowed-excited states are the same.     

Theoretical investigation of two-photon absorption properties for a series of bifluorene molecules

The two-photon absorption (TPA) cross-sections of a series of bifluorene molecules with different substituents (constructing three types of structures D–π–D, A–π–A and D–π–A) were calculated using ZINDO/SOS program. The results showed that the A–π–A structure with strong substituent-nitro had the largest TPA cross-section for these molecules. To verify the results, we analyzed the charge quantity of the ground and the main excited states as well as the frontier orbitals of the investigated molecules. The equilibrium geometries were obtained with AM1 method, and using ZINDO-SOS to calculate the third-order nonlinearities of the molecules, then gained the TPA cross-sections. We found that for the compounds with bifluorene as π center, the donor and acceptor strength are the important factor for the enhancement of the TPA properties, and compared with molecules with fluorene as π center, the large TPA cross-sections of bifluorene are caused by coupling effects between the two monomers.     

Synthesis and characterization of new thienylpyrrolyl-benzothiazoles as efficient and thermally stable nonlinear optical chromophores

The synthesis and full characterization of new chromophores with second-order nonlinearities containing thienylpyrrolyl and benzothiazolyl moieties are reported. The solvatochromic behavior of the compounds was investigated. The hyperpolarizabilities β of derivatives 4-6 were measured using hyper-Rayleigh scattering and thermogravimetric analysis (TGA) was used to evaluate their thermal stability. The experimental results indicate that strong nonlinearity is balanced by good thermal stability especially for chromophores 6b and 6c, making them good candidates for NLO applications.     

Synthesis and two-photon absorption property of novel salen complexes incorporated with two pendant azo dyes

New salen compounds have been developed to possess two pendant azo dye chromophores. The two-photon absorption properties have been observed which result from the chromophores. The additive property has been found to exist as a result of no detrimental dipole-dipole interaction between chromophores.     

Synthesis and second-order nonlinear optical properties of new chromophores containing benzimidazole, thiophene, and pyrrole heterocycles

A new series of thermally stable benzimidazole-based nonlinear optical (NLO) chromophores 4 and 5 have been developed. These chromophores possess a thienylpyrrolyl π-conjugated system attached to functionalized benzimidazole heterocycles. This feature leads to robust chromophores with excellent solvatochromic properties, high thermal stabilities and good molecular optical nonlinearities.     

Illuminating the origins of two-photon absorption properties in fluorescent protein chromophores

We provide here a structural impact on two-photon absorption cross-section (σ^TPA) for 22 distinct fluorescent protein (FP) chromophores. By employing time-dependent density functional theory, we gain insight into two-photon absorption (TPA) process by investigating relationship between σ^TPA and one-photon electronic transition dipole moment and permanent dipole moment change (Δμ) upon transition. Our results reveal that for the S₁ excited state, σ^TPA is proportional to (Δμ)² in agreement with two-state model of TPA process. On the contrary, the TPA spectroscopy of higher excited states (S _n, n > 1) is much more complex. We do not find a main driving force of large σ^TPA that would be common for investigated chromophores. Instead, it seems that channel interference between one-photon transition dipole moment vectors is responsible for enhancement or diminishment of σ^TPA. Our in vacuo results may serve as a benchmark to investigate a role of chromophore-protein interaction in shaping TPA spectra of FPs.     

Synthesis and two-photon properties of a multipolar chromophore containing indenofluorenyl units

A new multipolar fluorophore derived from triphenylamine as the core with diphenylaminoindenofluorenyl moieties incorporated at the peripheral positions has been synthesized and experimentally shown to possess strong two-photon absorptivities in near-IR region and intense upconverted visible emission under the irradiation of femtosecond laser pulses.     

Theoretical investigation on the two-photon absorption of C60

We present a theoretical study on the two-photon absorption (TPA) properties of C₆₀. On the basis of the equilibrium geometry optimized by B3LYP/6-31G method, we employ the ZINDO method combined SOS formula to investigate the second hyperpolarizability and TPA cross section of C₆₀. The calculated result of the real part of the second hyperpolarizability of C₆₀ is in good agreement with the previous calculation and the experimental observation. In the 400–1000 nm range of TPA wavelength, we calculated TPA cross sections corresponding to all two photon allowed states. As a result, we find that there is only a TPA cross section maximum—995.7×10⁻⁵⁰ cm⁴ s/photon at 518 nm. Another interesting phenomenon is that C₆₀ possesses the distinct TPA process in contrast to other conjugated molecules in terms of three-state approximation. This paper provides a theoretical basis of further studying TPA properties of C₆₀.     

新型双重电荷转移分子的二阶非线性光学性质的 理论研究

以INDO/SCI方法为基础,按完全态求和(SOS)公式编制了计算分子二阶非线性光学系数β~i~j~k和β~μ的程序。研究了1,2-二氨基-4,5-二硝基苯1和其异构体1,3-二氨基-4,6-二硝基苯2的电子光谱和二阶非线性光学性质。计算表明分子1具有与分子2几乎相等的二阶非线性极化率。但由于分子1的偶极矩明显大于分子2的,故分子1的μβ值比分子2的μβ值大的多。在此基础上,研究了2,3-二(β-苯乙烯基)-5,6-二氰基吡嗪和2,3-二(β-噻吩乙烯基)-5,6-二氰基吡嗪和2,3-二(β-噻吩乙烯基)-5,6二氰基吡嗪衍生物的电子光谱和二阶非线性光学性质。结果表明,这些化合物均具有两个相距很近的强吸收峰,它们对β值的呈加和模式。由于这类化合物特征吸收峰均位于413nm以下且具有大的μβ值,所以,它们是一类很有前途的二阶非线性光学候选材料。