Organic luminophores with orange-red and red luminescence

New organic luminophores that have orange-red and red luminescence and contain conjugated 1,3,5-triaryl-2-pyrazoline and 7H-imidazo[1,2-b]benz[de]isoquinoline-7-one groupings in the same molecule were synthesized. The introduction of a 2-naphthyl residue in the 1 position of the pyrazoline ring and annelation of 1,2-naphthylene or 4,5-naphthylene systems to the imidazole ring in place of the phenylene system lead to bathochromic and bathofluoric effects. The luminescence maxima of the synthesized compounds are found at 575 to 645 nm, and the quantum yields range from 0.7 to 0.9.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 262–264, February, 1983.     

Effect of Particle Size and Capping on Photoluminescence Quantum Efficiency of 1,3,5-Triphenyl-2-pyrazoline Nanocrystals

Organic nanocrystals of 1,3,5-triphenyl-2-pyrazoline(TPP) with a series of sizes were synthesized by reprecipitation method.The luminescence quantum efficiency of TPP nanocrystals increases from 24.2% for the nanocrystals with an average size of 300nm to 34.6% for those with an average size of 20nm.Surface capping by polyvinyl pyrrolidone(PVP) will improve the quantum efficiency of TPP nanocrystals.The size-dependence and capping-induced variation of the luminescence quantum efficiency was elucidated in viewpoint of aggregation quenching and the equilibrium between the TPP monomers and the aggregates in TPP nanocrystals.     

Energy-variable collision-induced dissociation study of 1,3,5-trisubstituted 2-pyrazolines by electrospray mass spectrometry

The pathways of the ([M+H](+)) ions generated from electrosprayed solutions of nine 1,3,5-trisubstituted 2-pyrazoline derivatives were studied using energy-variable collision-induced dissociation (CID) and pseudo-MS(3) (in-source CID combined with MS/MS) methods. It was shown that under CID conditions several structurally important product ions such as the 2,4-substituted azete and 1,2-substituted aziridine ions were formed. The compositions of the product ions were unambiguously supported by accurate mass measurement (mass accuracy was within +/- 8 ppm). The fragmentation pathways of 1,3,5-trisubstituted 2-pyrazolines were established by means of pseudo-MS(3). It was found that a substituent at the N-1 position greatly affects the fragmentation pathways of the 2-pyrazoline derivatives. The 1-acetyl- and 1-propionyl-2-pyrazoline derivatives dissociate mainly through formation of a pyrazolium cation, while in the case of 1-phenyl-2-pyrazoline derivatives product ions arising from the consecutive fragmentation of 2,4-substituted azete and 1,2-substituted aziridine ions dominate. Another interesting finding is the formation of a radical cation from the 2,4-substituted azete by loss of a methyl radical. The fragmentation yield as a function of the collision energy for each of the 1,3,5-trisubstituted 2-pyrazolines was determined. Based on the fragmentation yield versus collision energy curves the relative fragmentation stabilities for the 1,3,5-trisubstituted 2-pyrazoline derivatives were also evaluated.     

1-苯基-3-(4-硝基苯基)-5-(9-蒽基)-2-吡唑啉分子内高位共轭

通过对1 苯基 3 (4 硝基苯基) 5 (9 蒽基) 2 吡唑啉及其相关化合物的吸收光谱进行比较研究,发现该分子的吸收不同于分子内"Ar—N—N=C—Ar"发色团与蒽发色团的叠加.其中"Ar—N—N=C—Ar"发色团的吸收系数增强了12倍,存在极大的增色效应,蒽的精细吸收峰也均红移了20nm左右.说明两者存在基态下的相互作用.优势构象理论分析表明这是由于基态π电子轨道重叠的高位共轭效应引起的.该发现将有助于解释该类分子激发态下发色团间的非共轭电荷转移以及能量转移,并为寻找更大吸收系数的该类化合物提供了较好的方法.     

New 1,3,5-triphenyl-2-pyrazoline-containing 3-hydroxychromones as highly solvatofluorochromic ratiometric polarity probes

Two novel 1,3,5-triphenyl-2-pyrazoline moiety containing derivatives of 3-hydroxychromone were synthesized and studied by ¹H NMR, absorption and fluorescence spectroscopy. The prospects of practical application of these compounds exhibiting high solvatofluorochromism into analytical chemistry and biophysics as effective ratiometric polarity probes were discussed proceeding from the data on their fluorescent properties.     

α-三唑基查尔酮与苯肼的加成-关环反应研究

(Z)或(E)-1,3-二芳基-2-(1H-1,2,4-三唑-1-基)-2-丙烯-1-酮与苯肼在醋酸中反应均生成顺式和反式吡唑啉异构体混合物,但是在三乙胺催化下却只生成反式的异构体。制备了三对顺、反式的1-苯基-3,5-二芳基-4-(1H-1,2,4-三唑-1-基)-2-吡唑啉衍生物,其结构为^1HNMR和元素分析证实,初步论证了经α-氮原子的加成-环化反应机理。     

2-吡唑啉类化合物光物理行为的研究──分子内两种电荷转移机制的竞争

近年来,1,3,5-三芳基-2-吡唑啉类化合物的光物理及光化学问题研究引起了广泛兴趣^[1,2],这是由于2-吡唑啉化合物不仅是一种良好的荧光增白剂,在纺织工业中得到普遍应用,而且还是一种可在静电复印中应用的良好光导材料^[3,4].     

Photoinduced electron transfer in coaggregates of dicyanonaphthalene and pyrazoline

The photophysical properties of mixed coaggregates containing 1,4-dicyanonaphthalene (DCN) and 1,3,5-triphenyl-2-pyrazoline (TPP) have been studied. The absorption spectra of mixed coaggregates indicate that a charge-transfer complex is not formed in the ground state between DCN and TPP. The fluorescence of TPP in the mixed coaggregates is quenched by DCN, accompanied with a broad and structureless emission at about 560 nm from an exciplex between DCN and TPP. The color of the emission from mixed coaggregates is tunable by changing the DCN content. The excited-state properties of the TPP-DCN molecule pair are investigated theoretically with a quantum chemistry method. The theoretical results have also confirmed that the broad emission at about 560 nm in the mixed coaggregates originates from the exciplex rather than from the charge-transfer complex.     

On the low-lying excited states of sym-triazine-based herbicides.

We report a joint computational and luminescence study on the low-lying excited states of sym-triazines, namely, 1,3,5-triazine (1) and the ubiquitous herbicides atrazine [6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (2)] and ametryn [6-methylthio-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (3)]. Geometrical structures, energetics, and transition and state properties of I and 2 were computed at the TD-DFT, CASSCF, and CASPT2 levels of theory. The fluorescence and phosphorescence emission spectra, lifetimes, and fluorescence quantum yields were measured for the three compounds, and from these, the energies of the lowest excited states and their corresponding radiative rates were determined. The predictions from CASPT2 calculations are in good agreement with the experimental results obtained from the luminescence studies and allow the interpretation of different absorption and emission features.     

1,3,5-Triaryl-Δ2-pyrazoline

2-Iodo-3-chloro-1,3-diphenyl-1-propanones react with phenylhydrazine to yield the 1,3,5-Triaryl-Δ²-pyrazoline. The reaction proceeds with elimination of ICl to the chalcones and their reaction with an excess of phenylhydrazine.     

Terpyridine platinum(ii) complexes containing triazine di- or tri-thiolate bridges: structures, luminescence, electrochemistry, and aggregation

Dinuclear complexes [{Pt(trpy)}(2)(L)](PF(6))(2) (trpy = 2,2':6',2'-terpyridine, L = 2-octylthio-1,3,5-triazine-4,6-dithiolate ion (1), L = 2-octadecylthio-1,3,5-triazine-4,6-dithiolate ion (2), L = 2-di-n-butylamino-1,3,5-triazine-4,6-dithiolate ion (3)) and a trinuclear complex [{Pt(trpy)}(3)(L)](PF(6))(3) (L = 1,3,5-triazine-2,4,6-trithiolate ion (4)) have been synthesized and characterized. The single crystal X-ray analysis revealed that the two {Pt(trpy)}(2+) fragments in 1 and 3 adopt a syn-configuration. The PtPt distances are around 4.3 ?, suggesting no intramolecular PtPt interactions. Complexes 1-4 in acetonitrile show broad absorption bands at around 470 nm, assigned to mainly the ligand-to-ligand charge transfer ((1)LLCT) from triazine thiolates to trpy based on the comparison to the related complexes and the density functional theory (DFT) calculations. The red luminescence of 1-4 in acetonitrile is attributable to emission predominantly from (3)LLCT. Cyclic voltammograms of 1-3 exhibit four redox couples from -2.0 V to 0 V vs. Ag/AgCl. The two consecutive processes at around -0.70 V are assigned to the sequential reduction of two trpy ligands. This assignment was further supported by the observation of the anion radical of trpy in spectroelectrochemical experiments. The splitting of the redox potentials of two trpy ligands evidences the moderate electronic coupling interactions mediated by the triazine dithiolate bridges. Complex 2 formed a transparent red gel in CH(3)CN, whereas 4 produced a gel-like solid in the mixtures of CH(3)CN and other solvents. The interactions dominating the aggregative behaviours have been discussed based on the results of electronic absorption and emission spectroscopy.     

Synthesis and spectral-luminescence properties of 1-(4′-formylphenyl)-3,5-diaryl-2-pyrazolines

It was demonstrated by means of the IR and PMR spectra that 1-phenyl-3,5-diaryl-2-pyrazolines that contain a grouping with a strong electron-acceptor effect, viz. a 4-nitrophenyl or 4-naphthalanhydride group or a 1,8-naphthoylene-1,2-benzimidazole fragment, in the 3 position undergo Vilsmeier formylation, like unsubstituted 1,3,5-triphenyl-2-pyrazoline, in the para position of the 1-phenyl ring. An investigation of the spectral-luminescence properties of the synthesized 1-(4-formylphenyl)-3,5-diaryl-2-pyrazolines showed that the introduction in the 1-phenyl ring of an electron-acceptor aldehyde group, which is inferior with respect to its acceptor effect to the groupings in the 3 position of the heteroring, does not change the nature of the long-wave absorption band. Substantial hypsochromic and hypsofluoric effects as compared with the corresponding 1-phenyl-unsubstituted compounds are noted in the electronic spectra of these compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 807–811, June, 1982.The authors thank I. D. Kalikhman for recording the PMR spectra.     

含六苯基苯结构单元桨型分子的合成及光致发光特性

以1,3,5-三苯基苯为中心核, 4-乙烯基联苯为桥联结构, 通过Heck偶联反应合成了含六苯基苯结构单元的桨型分子, 对其结构进行了表征; 对桨型分子及其结构单元[包括4-乙烯基联苯、含六苯基苯结构的“臂”及其母体结构1,3,5-三(4-苯乙烯基苯基)苯]在溶液中的光致发光特性的研究结果表明, 桨型分子具有2个发光中心, 最大发射波长在蓝色光范围内分别为397和445 nm.     

Luminescence properties of 5-oxazolone derivatives containing a pyrazoline ring

New difluorophors have been synthesized containing both 2-phenyl-4-benzyliden-5-oxazolone and 1,3,5-tri-aryl-2-pyrazoline fragments. A study was carried out on the effect of the structure of these compounds on their spectroluminescence properties in solvents of different polarity. Positive solvatofl uorochromy was detected. The use of these compounds as luminescent dyes for polymers was proposed taking account of their solvatofuorochromic effects.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 407–410, March, 1994.     

Pyrylium salts in the synthesis of 2-pyrazoline derivatives and earlier unknown substituted 3,3a,4,7-tetrahydropyrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyridin-7-ones

New 1,3,5-substituted 2-pyrazoline derivatives were synthesized from 2,6-diphenylpyrylium perchlorate and acylhydrazines. Method for the synthesis of earlier unknown 3,3a,4,7-tetrahydropyrazolo[1,5-a]pyridin-7-one derivatives from pyrylium salts and cyanoacetic acid hydrazide was proposed.     

Synthesis,Photophysical Properties of Tribranched Chromophores Based on 1,3,5‐Triazine Core and Different Electro‐donating End‐groups

Three two‐photon absorption (TPA) tribranched chromophores were successfully prepared, in which 1,3,5‐triazine is been as electron deficient core, 1,4‐phenylenedivinylene as conjugated bridge, 3,4‐ethylenedioxythiophene (EDOT) ( T1 ), N‐methylpyrrole ( T2 ) or triphenylamine ( T3 ) as electron‐donating end‐groups. Their photophysical properties were studied by absorption, one‐ and two‐photon fluorescence and TPA cross‐section determination. The nonlinear transmission (NLT) measurement in femtoseconds (fs) regime at 800 nm indicates that TPA cross‐section (₂ values of T1 , T2 and T3 with extended Π‐conjugated bridge are much larger than the corresponding chromophore T4 with a short length bridge, and TPA cross‐section of T1 with end‐groups EDOT exhibits a remarkable enhancement compared with T2 and T3 having the same length Π‐system. The chromophores T1 , T2 and T3 show also remarkable up‐converted luminescence and optical limiting activity.     

Kinetic study of the 1,3,5-triphenyl-Δ2-pyrazoline/technetium(VII) system: Determination of Technetium

The interaction of technetium with 1,3,5-triphenyl-Δ²-pyrazoline (TPP) is examined and kinetic methods for the determination of technetium (0.01–1.2 mg l^?1) are developed; absorbances are measured at 678 nm. The optimal hydrochloric acid concentration for the reaction is 8.3 M, with a TPP concentration of 6.6 × 10^?5 M in 15 % (v/v) ethanol. Interferences by Cu(II), V(V) and Fe(III) are discussed. The method is applied to two synthetic nuclear fuels and to vegetation spiked with technetium.     

Tuning the photoinduced electron-transfer thermodynamics in 1,3,5-triaryl-2-pyrazoline fluorophores: X-ray structures,photophysical characterization,computational analysis,and in vivo evaluation

A series of donor-substituted 1,3,5-triaryl-2-pyrazoline fluorophores were structurally characterized by X-ray analysis, and their photophysical properties studied by steady-state absorption and emission spectroscopy. The photoinduced electron-transfer thermodynamics of the derivatives was estimated on the basis of the spectroscopic data and redox potentials of the fluorophores. The aryl substituents in the 1- and 3-position of the pyrazoline ring influence the photophysical properties of the fluorophores in distinctly different ways. The excited-state equilibrium energy DeltaE(00) is primarily influenced by changes of the substituent in the 1-position, whereas the reduction potential of the fluorophore is essentially determined by the 3-aryl group. Density functional calculations were used to probe the electronic structure and energy ordering of the emissive and the electron-transfer state. The results from the computational analysis agree qualitatively well with the experimental data. In addition, we have evaluated a water soluble pyrazoline derivative in vivo as a potential intracellular pH probe. Membrane permeability, low toxicity, and high quantum yield render the fluorophore attractive for biological applications.     

Synthesis and photophysical properties of hyperbranched polyfluorenes containing 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine as the core

A series of new hyperbranched polymers containing a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core unit and polyfluorene chain arms have been synthesized via Suzuki coupling, and characterized by NMR, IR and GPC. All the polymers exhibit good thermal stability with a high decomposition temperature. By changing the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio the UV-vis absorption and emission spectra can be partially tuned. It has been found that the polymers containing a low ratio of 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine units (P1-P3) have an absorption maximum around 385 nm, localized in the polyfluorene chain, and a shoulder around 425 nm ascribable to a charge transfer state involving the fluorene and the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core. Increasing the molar ratio of the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit enhances the charge transfer band which becomes dominant for P4. The LUMO level of these polymers is relatively low due to the electron affinity of the triazine group. The polymers show dual emission, with a structured band in the blue (410-440 nm), attributed to the polyfluorene, and a broad band in the red (470-500 nm) associated with the charge transfer state. All the polymers exhibit two-photon absorption activity in the range of 660 to 900 nm with the maximum two-photon absorption (TPA) cross-section red-shifted from the corresponding linear absorption. The values of the TPA cross-sections vary from 1000 to 5000 GM, following the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio.     

高有机可溶性聚酰胺负载磷钨酸(PW_(12)/PA):合成1,3,5-三芳基-2-吡唑啉衍生物的高效催化剂(英文)

A novel compound constructed from polyoxometalate (H3PW12O40,PW12) and poly(amidoamine) (PA) was prepared at room temperature in an aqueous solution by an impregnation method.A series of novel 1,3,5-triaryl-2-pyrazoline derivatives was synthesized by the reaction between chalcone and phenylhydrazine in the presence of the title compound,PW12/PA,in high yields.The structures of the compounds obtained were determined by IR and 1H NMR spectra.