Synthesis and characterization of near-infrared absorption tin octabutoxy naphthalocyanines

Synthesis and characterization of a series of tin octabutoxy naphthalocyanines are presented, which show near infrared absorptions (900–930 nm) with high extinction coefficients (ca. 1 × 10⁵ M⁻¹ cm⁻¹). The position of the Q-band is more red-shifted with the heavier halogen, which corresponds to the HOMO–LUMO gaps calculated with density functional theory (0.932, 0.911, 0.905, 0.893 eV). The interaction with SnNc(OBu)₈Br₂ and C₆₀ moves the Q-band further to the infrared region (928 nm). In ¹¹⁹Sn NMR, the upfield shift (−120 ppm) of SnNc(OBu)₈I₂ represents a relatively electron-rich environment at the tin nucleus, and the ¹¹⁹Sn-resonance (237 ppm) of SnNc(OBu)₈F₂ is different from the other halides, where ¹¹⁹Sn–¹⁹F coupling, a triplet splitting (1:2:1), was observed with 1820 Hz coupling constant. In the optimized structures obtained with BLYP, the distortion angles vary from F to I (N–Sn–N angles 178.8°, 173.1°). The tin naphthalocyanine with the heavy halide ligand becomes more concave, and the Sn–X bond is located at a longer distance out of ring. The difference of the two axial bonds varies significantly from 0.003 to 0.104 Å with the change of the axial ligands from F to I. The distorted shape is larger in the order I > Br > Cl > F with increase of the atomic size (1.33, 1.15, 0.99, 0.71 Å, respectively) and decrease of electronegativity (2.21, 2.74, 2.83, 4.10, respectively). SnNc(OMe)₈X₂ has an electric dipole moment perpendicular to the naphthalocyanine plane, and the magnitudes are, 0.81, 0.50, 0.35 and 0.01 for F, Cl, Br and I, respectively. The transition dipole moment lies in the naphthalocyanine plane along the x- or y-axis perpendicular to the permanent dipole moment in the z-axis, which indicates a π → π^∗ ligand–ligand transition. The energies of the molecular orbitals which are mainly contributed to by the naphthalocyanine ring, including the HOMO and LUMO, are slightly changed as the axial ligands change from F to I.     

Photophysics and nonlinear optical properties of tetra- and octabrominated silicon naphthalocyanines

The effect of the number of bromide substituents on the photophysical and nonlinear optical properties of the tetrabrominated naphthalocyanine Br4(tBu2PhO)4NcSi[OSi(Hex)3]2 (1) and the octabrominated naphthalocyanine Br8NcSi[OSi(Hex)3]2 (2) has been investigated through various spectroscopic techniques. Absorption and emission of 1 and 2 have been studied at room temperature and 77 K to determine the spectral properties of the ground and the excited states and the lifetimes and quantum yields of formation of the excited states. There is a moderate increase of the quantum yield of the triplet excited-state formation (PhiT = 0.10 vs 0.13) and a decrease of the triplet excited-state lifetime (tauT approximately 70 vs 50 mus) from 1 to 2. These can be attributed to the stronger heavy atom effect produced by the larger number of peripheral bromide substituents in 2 considering that an excited state with a triplet manifold is involved in the excitation dynamics of both complexes 1 and 2. The quantum yields of the singlet oxygen formation (PhiDelta) upon irradiation of 1 and 2 at 355 nm were also evaluated, and a value of PhiDelta(1) = PhiDelta(2) = 0.16 was obtained. In addition to that, octabrominated complex 2 displays a larger decrease of nonlinear optical transmission for nanosecond pulses at 532 nm with respect to the tetrabrominated complex 1. The nanosecond Z-scan experiments reveal that 1 and 2 exhibit both a reverse saturable absorption and a nonlinear refraction at 532 nm. However, both the sign and the magnitude of the nonlinear refraction change from 1 to 2. For picosecond Z-scan in the visible spectral region, these two complexes exhibit only reverse saturable absorption, and the excited-state absorption cross-section increases at longer wavelengths.     

四叔丁基萘酞菁铅化合物的非线性和光限幅特性

合成了四叔丁基萘酞菁铅[(t-Bu)₄NcPb]化合物. 利用元素分析、红外光谱、核磁共振氢谱等方法, 验证了化合物的分子结构. 应用调Q倍频ns/ps Nd:YAG脉冲激光系统, 在波长为532 nm下, 研究了化合物的非线性和光限幅特性. 测得化合物的非线性折射率n₂和三阶非线性极化率χ⁽³⁾分别为2.42×10^－11和7.91×10^－12 esu, 通过计算得到分子极化率γ'为3.4×10^－29 esu. 在透过率69%时限幅阈值为1522 mJ/cm², 箝位值为553 mJ/cm², 有效激发态与基态吸收截面比为3.16.     

Synthesis and nonlinear optical absorption of novel porphyrin-osmium-cluster complexes

Reaction of azido(tetra-p-tolylporphyrinato)indium(III) [TTPInN(3)] and [Os(3)(mu-H)(2)(CO)(10)] in toluene at 80 degrees C overnight gave two major products, complexes 1 and 2. Complex 1 had an axial bridge of "NH", while 2 had an axial bridge of "N" between the porphyrin and osmium cluster moieties. Complex 1 could be converted to 2 when refluxed in toluene. These two novel porphyrin-osmium clusters are the first axially linked porphyrin-metal cluster complexes. UV/Vis spectroscopy revealed the significant ground state electronic perturbation in the capped complex 2, demonstrating that the remarkable electronic interaction of the moieties within the molecule was achieved by this special structural arrangement. In addition, the electrochemistry of 1 and 2 were investigated and their oxidation current voltage curves are similar to those of indium(III)-porphyrins with a metal-metal sigma bond such as [TPPInRe(CO)(5)] (TPP=tetraphenylporphyrin). The two new molecules also exhibit large nonlinear optical absorption at 532 nm with a ns pulse laser and are potential optical limiting materials for sensor protection in the visible region.     

Synthesis, spectroscopic and nonlinear optical properties of multiple [60]fullerene-oligo(p-phenylene ethynylene) hybrids

A series of multiple [60]fullerene terminated oligo(p-phenylene ethynylene) (OPE) hybrid compounds has been synthesized through a newly developed in situ ethynylation method. Structural and magnetic shielding properties of the highly unsaturated carbon-rich C(60) and OPE scaffolds were characterized by 1D and 2D NMR spectroscopic analyses. Electronic interactions between the [60]fullerenes and the OPE backbones were investigated by UV/Vis spectroscopic and cyclic voltammetry (CV) experiments. Our studies clearly show that although the multiple [60]fullerene groups are connected via pi-conjugated OPE frameworks, they present diminutive electronic interactions in the ground state, and the electronic behavior of the [60]fullerene cages are only affected by the OPE backbones through modest inductive effects. Interestingly, sizable third-order nonlinear optical (NLO) responses (gamma) and enhanced two-photon absorption (TPA) cross-sections (sigma((2))) were determined for the multifullerene-OPE hybrid 31 relative to its OPE precursor from differential optical Kerr effect (DOKE) experiments. Such enhanced NLO performance is presumably due to the occurrence of periconjugation and/or charge transfer effects in the excited state. In addition, comparatively strong excited-state absorption was observed and characterized for OPE pentamer 12. Thus, the use of such fullerene-derivatized conjugated oligomers aids the quest for molecules with large third-order NLO and TPA properties.     

Alkynyl expanded donor-acceptor calixarenes: geometry and second-order nonlinear optical properties

A number of wide- and narrow-rimmed functionalized alkynylcalix[4]arenes have been synthesized by Sonogashira coupling. With respect to their optical properties, these donor-acceptor systems are treated as ensembles of covalently linked, electronically independent tolane subchromophores. Linear UV/visible and fluorescence spectroscopic investigations revealed that the charge-transfer character of the electronic transitions in calixarenes, and also the second-order nonlinear optical (NLO) properties depend on the electron-withdrawing nature of the terminal ethynylphenyl substituent (NO(2), CF(3), H). The nitro derivatives display high values of the quadratic hyperpolarizability beta. Not only do the (nonlinear) optical properties of the target compounds depend on the number and relative disposition of the subchromophores, but also on the geometry of the calixarenes. In particular, the opening angle of the calixarene cavity can be determined by the substitution pattern of the calixarene scaffold (wide- versus narrow-rim substitution) and the number of the acetylene functions introduced. Both the NLO properties and the conformational issues are conveniently assessed by using hyper-Rayleigh scattering (HRS) in solution, and supported by X-ray crystallography in the solid state.     

Synthesis,structure and nonlinear optical properties of three dimensional compounds

The combination of metal ions with H₃tbba has resulted in the formation of two three dimensional coordination compounds {[Zn(H₂tbba)₂(H₂O)] · 2(OC₃H₆)} _n (1) and {[Mn(H₂tbba)₂(H₂O)] · 2(OC₃H₆)} _n (2) (H₂tbba = 2-thiobarbituric acid anion). Compounds 1 and 2 are isostructural with metal ions bridged by four hydroxyl oxygens from four different H₂tbba ligands to form a 3D network. H₂tbba exhibits bidentate coordination with both hydroxyl oxygens participating in coordination, a new coordination mode. Nonlinear absorption and refraction of 1 and 2 in DMF are studied by using Z-scan measurement technique at 532 nm. 1 and 2 possess nonlinear optical absorption and self-focusing.     

Theoretical investigation of the second-order nonlinear optical properties of helical pyridine-pyrimidine oligomers

The structure and second-order nonlinear optical properties of a series of helical pyridine-pyrimidine oligomers recently synthesized by Barboiu and Lehn have been investigated theoretically by combining molecular mechanics and quantum chemistry approaches. In the absence of substituents, the hyper-Rayleigh scattering response (betaHRS) and the projection of the first hyperpolarizability on the dipole moment (beta||) exhibit periodic variations with chain length, but these nonlinear optical responses remain small. The first hyperpolarizabilities can, however, be enhanced by adding substituents. The greatest enhancement is obtained by substituting the pyrimidine groups by donor groups. Moreover, regular distributions of the donor groups around the helices enable the design of supramolecular structures exhibiting dipolar, octupolar or Lambda-shaped nonlinear optical characters, evident from the values of the depolarization ratios in hyper-Rayleigh scattering. Therefore this theoretical investigation demonstrates the potential of helical structures for the organization of chromophores in such a way that they exhibit large and specific second-order nonlinear optical responses.     

Synthesis of novel rod-shaped and star-shaped fluorescent phosphane oxides--nonlinear optical properties and photophysical properties

The design of a new class of fluorophores is presented. Some push-pull chromophores (D-pi-A) containing polyphenylethynyl units and a phosphane oxide moiety were efficiently prepared from common intermediates. Straightforward syntheses gave novel one-armed, rod-shaped and three-armed, star-shaped fluorophores. The optical properties of the resulting star-shaped derivatives were evaluated, showed high fluorescence quantum yields, and their excitation induces very efficient charge redistribution. Moreover, thanks to their push-pull character, the molecules exhibited significant second-order NLO properties with good transparency, up to 67x10(-30) esu at 1907 nm, with an absorption lambdamax at 369 nm. The effect of the donor group and of the number of phenylethynyl arms have been studied in this work.     

Fabrication of ultrathin films with large third-order nonlinear optical properties.

An ultrathin composite film containing anionic Ag-His complexes (His: L-Histidine) and oppositely charged BH-PPV was fabricated by means of the electrostatic layer-by-layer self-assembly technique. UV/Vis spectra showed a continuous deposition process of Ag-His complexes and BH-PPV. The film structure was characterized by using small-angle X-ray diffraction, AFM, and SEM. The nonlinear optical properties of the ultrathin film were studied by using the Z-scan technique with a laser duration of 8 ns at a wavelength of 532 nm. The film sample exhibited a strong nonlinear saturated absorption, with an alpha2 value of -3.9 x 10(-5) mW(-1) and a self-defocusing effect with an n2 value of -4.78 x 10 (-12) m2W(-1).     

Synthesis of fluorine-containing methoxy-1,3-diketones

A method is proposed for the synthesis of fluorine-containing methoxy-1,3-diketones by hydrolysis of N-phenylaminoalkenyl ketones, produced by the reaction of aniline and the respective methoxyalkynyl ketone in dioxane. With methanol an imine is also formed, and methyl trifluoroacetate is eliminated.Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1390–1392, June, 1992.     

Synthesis and characterization of interpenetrating polymer networks for nonlinear optics

Two-component simultaneous interpenetrating networks (IPN) of thepoly(4′-[[2-(methylacryloxy)ethyl]ethylamino]-4-nitroazobenzene-co-methyl meth-acrylate) (PDR1MA-co-MMA)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) system, the PDR1MA/PPO system and 4′-[[2-(acetoxy)ethyl]ethylamino]-4-nitroazo benzene (ACDR1) doped MMA/PPO system were synthesized and characterized. As studied by differential scanning calorimetry (DSC) the full IPNs of the PDR1MA-co-MMA/PPO system and the PDR1MA/PPO system showed a single T_g varying with the PPO composition. A single-phase morphology of the full IPNs was also indicated by scanning electron microscopy (SEM). Transparent films were cast onto clean microscopic glass slides and poled at 190°C for 1 h. The UV-VIS absorption spectra of the three IPN systems before and after curing and corona poling showed a shift in the maximum absorption due to the induced alignment of the nonlinear optical chromophores in the IPN systems. The absorption intensity of the full IPNs remained same after heating at 120°C for 72 h, indicating that the electric field-induced alignment is stable in the full IPN materials. Preliminary second harmonic generation (SHG) data on these IPNs are presented. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 553–561, 1998     

Oxasmaragdyrin-ferrocene and oxacorrole-ferrocene conjugates: synthesis, structure, and nonlinear optical properties

Ferrocenyl macrocyclic conjugates involving 22 pi oxasmaragdyrins and 18 pi oxacorroles have been synthesized and characterized. The direct covalent linkage of the ferrocenyl moiety to the meso position of the macrocycle is achieved by simple oxidative coupling of appropriate precursors with trifluoroacetic acid as catalyst. The electronic coupling between the ferrocenyl moiety and the macrocyclic pi system is apparent from: a) the red shifts (293-718 cm(-1)) of the Soret and Q-bands in the electronic absorption spectra of ferrocenyl conjugates; b) the shift of oxidation potentials (50-130 mV) of both the ferrocene and the corrole rings to the positive potentials; and c) considerable shortening of the C-C bond which connects the ferrocene and the meso-carbon atom of the macrocycle. The single-crystal X-ray structure of oxasmaragdyrin-ferrocene conjugate 9 reveals the planarity of the 22 pi skeleton with very small deviations of the meso-carbon atoms. The meso-ferrocenyl substituent has a small dihedral angle of 38 degrees, making way for mixing of the molecular orbitals of the ferrocene and the macrocycle. However, the other two meso substituents are almost perpendicular to the mean plane, defined by the three meso carbon atoms. Classical C-H...O and nonclassical C-H...pi interactions lead to a two-dimensional supramolecular network. Ferrocene-smaragdyrin conjugate 9 bonds to a chloride ion in the protonated form and a rhodium(i) ion in the free base form. Nonlinear optical measurements reveal a larger nonlinear refractive index (-5.83 x 10(-8)cm(2)W(-1)) and figure of merit (2.28 x 10(-8)cm(3)W(-1)) for the rhodium smaragdyrin-ferrocene conjugate 19 than for the others, suggesting its possible application in optical devices.     

Third‐order nonlinear optical properties of dendritic molecular aggregates: Effects of fractal architecture

We investigate the microscopic third‐order nonlinear optical properties, i.e., the second hyperpolarizabilities (γ), of two different sizes of molecular aggregates with a dendritic, i.e., Bethe‐lattice, structure. One possesses a nonfractal structure, while the other has a fractal structure. The aggregate is treated in a two‐exciton model composed of two‐state monomers coupled to each other by the dipole–dipole interaction. The off‐resonant γ of the aggregates are calculated by the numerical Liouville approach, including relaxation effects. The total γ value is partitioned into the contribution of virtual exciton generation, and its spatial contribution to γ is analyzed in relation to the virtual excitation processes in the perturbation theory. It is found that the intermolecular‐interaction effect enhances both one‐ and two‐exciton‐generation contributions, while the relaxation effect reduces those, although the one‐ and two‐exciton‐generation contributions have mutually opposite signs. From the comparison of spatial contributions to γ between the nonfractal and fractal aggregates, an enhancement of the contribution to γ from the periphery to the core is observed in the fractal structure, while such a feature is not observed in the nonfractal structure. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

两个新颖原子簇化合物的合成及三价非线性光学吸收性质

通过低热固相反应,我们合成了蝶型簇合物[MoOS~3Cu~2(PPh~3)~2(Py)~2](1),该簇合物与PPh~3反应,可以得到另一个新的簇合物[MoOS~3Cu~2(PPh~3)~3(Ph)](2)。使用Z-扫描方法测试这两个化合物的三阶非线性光学性质,发现它们都有较强的非线性光学吸收性质,非线性光学吸收系数分别是1.5×10^-^1^1mW^-^1和3.3×10^-^1^0mW^-^1。     

Synthesis and properties of highly thermally stable ultrathin films of fluorine-containing hyperbranched polybenzoxazoles

In this paper, we aimed to develop ultrathin films of hyperbranched polybenzoxazole with a thickness in the range between 1 and 100 nm. They are expected to have great potential for various applications as functional materials due to their high thermal stability, good chemical resistance and mechanical strength. The synthesis of various hyperbranched poly(o-hydroxyamide)s as precursors of polybenzoxazole was examined by the polycondensation of 2,2-bis(3-amino-4-hydroxyphenyl)propane (AHP) and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (AHFP) with 1,3,5-benzenetricarbonyl trichloride (BCC), yielding the corresponding hyperbranched poly(o-hydroxyamide), poly(AHFP_m-co-AHP_n-co-BCC_2.0), with M_n in the range between 12,870 and 22,210 in satisfactory yields. Poly(AHFP_3.0-co-BCC_2.0), poly(AHFP_2.25-co-AHP_0.75-co-BCC_2.0), and poly(AHFP_1.50-co-AHP_1.50-co-BCC_2.0) showed good solubility and film-forming ability, and ultrathin films 8.9–88.6 nm thick were prepared on silicon wafers. Heating of the ultrathin films of poly(AHFP_m-co-AHP_n-co-BCC_2.0) on a hot plate at 350 °C for 1 h afforded the corresponding ultrathin films of hyperbranched polybenzoxazole, poly(AHFP_m-cyclo-AHP_n-cyclo-BCC_2.0), with a thickness of 5.3–82.4 nm. Double-layer thin films consisting of resist materials on top of hyperbranched polybenzoxazole were also prepared.     

Synthesis and nonlinear optical properties of a novel indium phthalocyanine highly branched polymer

Due to the well‐known optical limiting properties of indium (III) phthalocyanines (In [III] Pcs) and aiming at extending their conjugation system, a highly branched indium phthalocyanine polymer was prepared. Flash chromatography was used for obtaining a pure polymer of polydispersity index near to the unity. The structure of the prepared polymer was determined using different spectroscopic techniques. Optical limiting and open aperture Z‐scan measurements were carried out according standard procedures. Compared with many other phthalocyanines, the prepared indium‐phthalocyanine polymer shows a high optical limiting performance that is indicated by a relatively low limiting threshold of 430 mJ cm^?2 and a large nonlinear absorption coefficient (α₂ = 3.4 × 10^?8 cmW^?1). Copyright © 2015 John Wiley & Sons, Ltd.