Azetidines-Containing Fluorescent Purine Analogs: Synthesis and Photophysical Properties

Analogues of N,N-dimethyladenine exploiting both thieno-and isothiazolo-pyrimidine cores were modified with 3-subsituted azetidines to yield visibly emissive and responsive fluorophores. The emission quantum yields, among the highest seen for purine analogues (0.64 and 0.77 in water and dioxane respectively), correlated with the Hammett inductive constants of the substituents on the azetidine ring. Ribosylation of the difluoroazetidino-modified nucleobase yielded an emissive nucleoside that displayed a substantially lower emission quantum yield in water, compared to the precursor nucleobase. Importantly, high emission quantum yield was restored in deuterium oxide, which highlights the potential impact of the sugar moiety on the photophysical features of fluorescent nucleosides, a functionality usually considered non-chromophoric and photophysically benign.     

Synthesis and Electrochemical and Photophysical Properties of Azaterrylene Derivatives

A series of terrylene derivatives, such as monoazaterrylene (MATerry), 1,6‐diazaterrylene (DiATerry) and pristine terrylene (Terry), were synthesized by changing the number of nitrogen atoms at the bay region (1 and 6 positions of the Terry core). The electrochemical measurements suggested that the first one‐electron reduction and oxidation potentials became positively shifted with increasing numbers of nitrogen atoms. This agreed with the energies of the corresponding highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) states estimated by DFT methods. In contrast, the HOMO–LUMO gaps approximately remained constant. This trend is quite similar to the spectroscopic behaviors observed by absorption and fluorescence spectra. The solvent polarity‐dependent spectroscopic trends of DiATerry suggested the intramolecular charge‐transfer (ICT) characters. The evaluation of the excited‐state dynamics in various solvents indicated the electronic configurational changes of the excited states relative to the ground state via the ICT. This was supported by the Lippert–Mataga plots. Finally, the reversible protonation and deprotonation processes were also observed.     

Highly Emissive 9-Borafluorene Derivatives: Synthesis,Photophysical Properties and Device Fabrication

A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 % for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m⁻². These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability.     

Synthesis and Photophysical Properties of Alkoxysilyl Derivatives of Dibenzoylmethanatoboron Difluoride

Alkoxysilyl derivatives of dibenzoylmethanatoboron difluoride (DBMBF₂) are synthesized by the hydrosilylation reaction of the corresponding O‐allyl derivatives of DBMBF₂ with triethoxysilane. The photophysical properties of the synthesized O‐allyl and alkoxysilyl derivatives are investigated. It is found that the absorption and fluorescence spectra of the DBMBF₂ derivatives essentially depend on the position of the O‐allyl or O‐propyl alkoxysilyl substituent. The highest fluorescence quantum yield is obtained for the para‐position, whereas the substitution at the meta‐position gives the largest bathochromic shift in the fluorescence spectrum. Density functional theory calculations of the structures and time‐dependent density functional theory calculations of the gas‐phase excitation and emission energies of alkoxysilyl derivatives are performed at the PBE0/SVP level of theory. Some spectral features of para‐, ortho‐, and meta‐substituted derivatives can be adequately explained by the overlapping of two absorption bands.     

Synthesis and Novel Properties of Alkyl Thiophosphoramidate Derivatives of Nucleosides

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Synthesis and Novel Properties of Alkyl Thiphosporamidate Derivatives of Nucleosides

Novel alkyl thiophosphoramidate derivatives of nucleosde analogues(5) have been prepared by phosphochloridothioate chemistry.O-Isopropyl 2‘,3‘-O-isopropylidene uridine-5‘-yl N-thiophosphoryl threonine and serine methyl esters(5a and 5b )underwent the intramolecular catalyzed hydrolysis reaction.     

Synthesis and Photophysical Properties of Some PEG Substitued Titanyl Phthalocyanine Derivatives

Summary: Polyethylene glycol substituted titanyl phthalocyanine was prepared in two steps starting from phthalonitrile and characterized by FT-IR, UV-vis spectrophotometry, and fluorescence spectrophotometry. The titanyl phthocyanine derivatives (TiOPcs) showed high solubility in common organic solvents, such as, CH₃Cl and DMF. These compounds decreased in absorbance intensity with increase of molecular weight of polyethylene glycol at maxima wavelength of visible range. The fluorescence spectra showed a fluorescence emission near 690 nm with a quantum yield of 0.05–0.32 (λ_ex = 625 nm).     

新型含双酚衍生物三枝氟硼二吡咯染料的合成及其光物理性能

以三聚氯氰为原料合成含醛基的二酚氧基取代中间体（1）; 1分别与酚衍生物（2a~2e）经取代反应制得三酚氧基中间体（3a~3e）; 3a~3e经缩合、氧化和配位等反应合成了5个新型的含双酚衍生物三枝氟硼二吡咯（BODIPY）荧光染料（4a~4e）,其结构经¹H NMR, ¹³C NMR和HR-MS(ESI)表征。4a~4e的最大吸收波长和发射波长分别位于499 nm和508 nm,荧光量子产率为0.41~0.55,显示出BODIPY荧光核典型的光物理性能。     

Novel Fluorene-Thiophene Copolymers: Synthesis,Photophysical and Electrochemical Properties

Summary: Novel alternating fluorene - thiophene copolymers, F3HT, FIPT , and FPyT , consisting of 9,9-dihexylfluorene and 3-substituted (with hexyl, 3-methylbutyl and 2-(pyren-1-yl)vinyl, respectively) thiophene units were synthesized. Photoluminescence (PL) and electrochemical behavior of these polymers were studied. PL behavior of FPyT polymer differed from that of the other copolymers. Thin films of F3HT and FIPT showed an intense green PL emission whereas the PL emission of FPyT thin films was orange. The PL emission spectra in thin films differ from those measured in THF solutions. Aggregate formation played an important role in the solid state. The aggregation was more pronounced with FPyT than with F3HT and FIPT thin films. In all polymers reversible oxidation and reduction were observed. Similar values of ionization potentials and electron affinities were estimated for F3HT and FIPT , but a higher value of electron affinity for FPyT .     

1,8-萘啶衍生物的结构、光物理性质及其应用

1,8-萘啶衍生物的刚性平面氮杂环结构使其具有丰富的光物理性质,因而在金属离子识别、配位化学等方面有着广泛的应用. 许多1,8-萘啶衍生物还具有独特的生理活性,并应用于临床治疗,这为该类化合物在生物医学领域中的研究和应用奠定了基础. 本文简要介绍了1,8-萘啶衍生物的结构特点及近期的研究进展.     

Synthesis,Photophysical, and Two‐Photon Absorption Properties of Elongated Phosphane Oxide and Sulfide Derivatives

A series of rod‐shaped and related three‐branched push–pull derivatives containing phosphane oxide or phosphane sulfide (PO or PS)—as an electron‐withdrawing group conjugated to electron‐donating groups, such as amino or ether groups, with a conjugated rod consisting of arylene–vinylene or arylene–ethynylene building blocks—were prepared. These compounds were efficiently synthesized by a Grignard reaction followed by Sonogashira coupling. Their photophysical properties including absorption, emission, time‐resolved fluorescence, and two‐photon absorption (TPA) were investigated with special attention to structure–property relationships. These fluorophores show high fluorescence quantum yields and solvent‐dependent experiments reveal that efficient intramolecular charge transfer occurs upon excitation, thereby leading to highly polar excited states, the polarity of which can be significantly enhanced by playing on the end groups and conjugated linker. Rod‐shaped and related three‐branched systems show similar fluorescence properties in agreement with excitation localization on one of the push–pull branches. By using stronger electron donors or replacing the arylene–ethynylene linkers with an arylene–vinylene one induces significant redshifts of both the low‐energy one‐photon absorption and TPA bands. Interestingly, a major enhancement in TPA responses is observed, whereas OPA intensities are only weakly affected. Similarly, phosphane oxide derivatives show similar OPA responses than the corresponding sulfides but their TPA responses are significantly larger. Finally, the electronic coupling between dipolar branches promoted by common PO or PS acceptor moieties induces either slight enhancement of the TPA responses or broadening of the TPA band in the near infrared (NIR) region. Such behavior markedly contrasts with triphenylamine‐core‐mediated coupling, which gives evidence for the different types of interactions between branches.     

苯并咪唑衍生配体锌-铕(或铽)异金属双核配合物的合成、结构与光学性质

合成了四个锌-铕(或铽)异金属双核配合物[ZnLnL¹(NO₃)₃Py] (Ln=Eu (1), Tb (2); HL¹=1-H-2-(2-羟基-3-甲氧基苯基)苯并咪唑; Py=吡啶)和[ZnLnL²(NO₃)₃Py] (Ln=Eu (3), Tb (4); HL²=1-H-2-(2-羟基-3-甲氧基-5-溴苯基)苯并咪唑; Py=吡啶), 其中1、2、3是单晶态, 化合物4则为多晶样品; 通过单晶X射线衍射、元素分析、傅里叶变换红外光谱和电喷雾质谱对化合物进行了表征. 化合物的紫外-可见吸收光谱、荧光激发和发射光谱表明配体的激发态能量有效传递到配合物中的镧系金属离子中, 含有铽(III)离子的配合物发射出其特征发射光谱, 而含有铕(III)离子的配合物由于其它去活方式, 没有辐射出铕(III)离子的特征发射光谱.     

Pyridazine Derivatives and Related Compounds,Part 28. 1 Pyridazinesulfonamides: Synthesis and Antimicrobial Activity

The reaction of 3-chloropyridazine 1 with N –(un)Substituted 4-aminosulfonamides 3 gave the 3-substituted aminopyridazines 4 . Also In addition, pyridazine-3-sulfonamides 7 were prepared from the reaction of pyridazine-3-sulfonylchloride 6 with different amines. All of these derivatives have been characterized by analytical and spectroscopic studies, and also were tested for their in vitro antibacterial and antifungal activity against a variety of microorganisms.     

氮硫杂冠醚及其衍生物的合成

以噻吩、水杨醛、二胺、溴乙酸、烯丙基氯和丙烯腈为原料合成了 4,5 :14 ,15 二苯 3 ,16 二氧 2 1 硫 7,12 二氮双环[16.2 .1]二十一环 1( 2 0 ) ,18 二烯 (简称氮硫杂冠醚 )及其 5种衍生物 ,经元素分析 ,IR ,1 HNMR和MS谱表征了这些化合物的结构 .     

叶绿素-a降解产物的酰基化反应及其二氢卟吩衍生物的合成

以脱镁叶绿酸-a甲酯(MPa)为起始原料,经化学结构修饰和中心氮原子金属化后,与三氯氧磷/3-N,N-二甲基氨基丙烯醛(3-DMA)或者N,N-二甲基甲酰胺进行Vilsmerier反应,在二氢卟吩周环上区域选择性地引进甲酰基或者甲酰乙烯基;用硝酸铊对MPa衍生物实施氧化,将3-位乙烯基顺利地转化为甲酰甲基;利用3-位乙烯基和E-环酮基的化学反应活性,在大环上引进羟烷氧基或者羟烷氨基结构,然后选用高钌酸四丙基铵(TPAP)和N-甲基吗啉-N-氧化物混合氧化剂,分别将其羟基氧化成甲酰基.新合成的连有酰基结构的二氢卟吩衍生物的化学结构均经UV,IR,1H NMR及元素分析得以证实.     

Synthesis, Structure and Photophysical Properties of Silole-Oxadiazole Copolymers

A new conjugated copolymer (PTST‐DyOXD) derived from 1,1‐dimethyl‐3,4‐diphenyl‐2,5‐bis(5‐bromo‐2‐thienyl)‐silole (TST) and 2,5‐bis(4‐ethynylphenyl)‐1,3,4‐oxadiazole (DyOXD) was synthesized by Pd(0)‐catalyzed Sonogashira coupling reaction. For comparison, another copolymer without acetenyl group (PTST‐OXD) was also synthesized by Pd(0)‐catalyzed Suzuki coupling reaction. Chemical structures and optoelectronic properties of the copolymers were characterized by ¹H NMR, ¹³C NMR, IR, UV‐vis absorption, photoluminescence and cyclic voltammetry. The number‐average molecular weight (M_n) is 4010 Da for PTST‐DyOXD and 3890 Da for PTST‐OXD, respectively. The thermogravimetric analysis (TGA) measurements show that they have good thermal stability with decomposition temperature at 312 and 318°C, respectively. The optical band gap is 2.21 eV for PTST‐DyOXD and 2.10 eV for PTST‐OXD based on the absorption onset. CV analysis revealed the LUMO level of PTST‐DyOXD is ?3.04 eV, lower than that of PTST‐OXD (about ?2.89 eV), which is attributed to the introduction of acetylene group in PTST‐DyOXD, increasing the system of the conjugate chain length.     

Circularly Polarized Fluorescent Helicene-Boranils: Synthesis,Photophysical and Chiroptical Properties

Mono- and di-boranil-substituted helicenes were prepared by BF₂-borylation of the corresponding anils, readily synthesized by condensation of 2-amino- and 2,15-diamino-helicenes with 4-(diethylamino)salicylaldehyde. After enantiomeric resolution using HPLC, their chiroptical properties including circularly polarized fluorescence in solution and in PMMA films were investigated and rationalized with the help of NMR, X-ray and quantum-chemical calculations.