荧光猝灭研究芳醚树枝形聚合物构象

本工作分别合成了外围修饰一个芘基团和核心修饰一个芘基团两个系列的芳醚树枝形聚合物Py-Gn-OH和Gn-CH₂-Py(n=1~4)。Py-Gn-OH和Gn-CH₂-Py的发光随代数增加而增强,荧光寿命增加。荧光猝灭实验结果表明,树枝形聚合物Py-Gn-OH和Gn-CH₂-Py的双分子猝灭速率常数均随代数增加而减小,表明树枝形聚合物发生了构象折叠,位于核心和外围的芘基团均被树枝形聚合物骨架包裹,随代数增加树枝形聚合物骨架增大,对芘基团包裹作用增强,导致猝灭剂接近芘基团的位阻增大。Gn-CH₂-Py体系的双分子猝灭速率常数均比相应代数Py-Gn-OH体系略小,说明树枝形聚合物骨架对连接在核心的芘基团的包裹程度比对连接在外围的芘基团略强。本工作为新型功能芳醚树枝形聚合物设计和应用提供了参考。     

Poly(diphenylacetylene)s with Electron‐Donating Alkoxy and Electron‐Withdrawing Fluoroalkyl Groups: Effect of the Substituent on Fluorescence

New poly(diphenylacetylene)s with alkoxy and fluoroalkyl groups as electron‐donating and electron‐withdrawing groups, respectively, were synthesized by using a WCl₆‐n‐Ph₄Sn catalyst. The polymer solutions emitted strong, bluish‐green lights when photo‐excited. The polymers that contained the electron‐donating alkoxy groups showed longer fluorescence‐maximum peaks when compared to the polymers that contained the electron‐withdrawing fluoroalkyl groups. However, such an effect of the substituent on the absorption property was not clearly seen. The emission bands of the solid films did not show any significant red shift, relative to that of the dilute solution.

     

Fluorescence Correlation Spectroscopy Study of Probe Diffusion in Poly(vinyl alcohol) Solutions and Gels

In this study, we demonstrate how the diffusion of probe particles in aqueous poly(vinyl alcohol) (PVA) solutions and gels is affected by: (i) the presence of cross-links, (ii) the cross-link density, (iii) the polymer concentration. We apply fluorescence correlation spectroscopy (FCS) to measure the diffusion time of a rhodamine-based fluorescent particle (TAMRA) and TAMRA-labeled dextran in PVA solutions and gels prepared at various polymer concentrations (1% to 8.6% w/v) and cross-link densities (1/400 to 1/50 cross-link monomers per PVA monomers). The measurements indicate that the probe particles are slowed down with increasing polymer concentration and with increasing cross-link density. Also, FCS can detect differences in the diffusion times measured in “fresh” and “aged” PVA solutions. We find that FCS provides a quantitative measure of network inhomogeneities.     

A Local Chain Conformation‐Based Approach to Physical Ageing Fundamentals of Poly(vinyl chloride)

Summary: Poly(vinyl chloride) (PVC) samples prepared at various temperatures have been submitted to a substitution reaction for purposes of selectively removing the GTTG–TT conformations of the mmr termini of long isotactic sequences. The physical ageing of all samples has been studied by means of differential scanning calorimetry techniques. Surprisingly, a straight relation between the loss of enthalpy and the above GTTG–TT content, which pass through a minimum, has been found. Such a novel relationship should further lead to better understanding of the reasons why polymeric materials experience nonequilibrium states which are known to cause physical ageing.

Dependence of the area of the endothermic peak (Q_t) on the degree of the substitution of PVC (sample X) in cyclohexanone solution.     

Poly(2,5‐dihydroxy‐1,4‐phenylene benzobisthiazole)/poly(1,4‐phenylene benzobisthiazole) copolymers: Chain packing and properties

Crystal‐packing, optical, and electrical properties of poly(2,5‐dihydroxy‐1,4‐phenylene benzobisthiazole) (DiOH‐PBZT) and copolymers of DiOH‐PBZT/poly(1,4‐phenylene‐benzobisthiazole) (PBZT) were examined. Intramolecular hydrogen bonds between the hydroxyl units and the neighboring nitrogen atoms, as evidenced by the IR spectra, led to the formation of a pseudoladder chain structure and changed the chain packing. The (200) and (010) planes were both affected by the copolymer composition, with the (200) plane spacing increasing from 5.895 to 6.482 Å and the (010) plane spacing decreasing from 3.539 to 3.404 Å with the transition from the unsubstituted PBZT homopolymer to the DiOH‐PBZT homopolymer. The cell dimensions of the copolymers were simple averages of those of the individual homopolymers, suggesting the isomorphic crystal structure formation of the two units. The c‐axis spacing, however, remained unchanged. The increase in the conjugation length of the copolymers as the dihydroxy content increased was confirmed by the bathochromic shift of the absorption band in the ultraviolet–visible spectra. The intrinsic conductivities of the copolymers were 3 orders of magnitude higher than that of the unsubstituted PBZT. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 559–565, 2001     

聚外消旋乳酸的IPDI溶液扩链

以异佛尔酮二异氰酸酯(IPD I)为扩链剂,以外消旋乳酸(D,L-LA)直接熔融聚合合成的低分子量聚外消旋乳酸(PDLLA)为预聚体,在四氢呋喃溶液中进行扩链得扩链产物Ⅰ。Ⅰ用粘均分子量(Mη),IR,1H NMR,DSC及X-射线衍射等表征。与2,4-甲苯二异氰酸酯(TD I)的扩链产物(Ⅱ)比较,Ⅰ成功地引入了NH和IPD I反应后的刚性片段,使M,ηTg,Tm,结晶度等相应提高。但由于IPD I反应活性不如TD I,故反应速率比用TD I时慢;Ⅰ分子中脂肪环的刚性不如苯环,TⅠg低于TⅡg。     

Synthesis and Characterization of Poly(phenylacetylene)s with Ru(II) Bis‐Terpyridine Complexes in the Side‐Chain

An alkyne‐functionalized ruthenium(II) bis‐terpyridine complex is directly copolymerized with phenylacetylene by alkyne polymerization. The polymer is characterized by size‐exclusion chromatography (SEC), ¹H NMR spectroscopy, cyclic voltammetry (CV) measurements, and thermal analysis. The photophysical properties of the polymer are studied by UV–vis absorption spectroscopy. In addition, spectro‐electrochemical measurements are carried out. Time‐resolved luminescence lifetime decay curves show an enhanced lifetime of the metal complex attached to the conjugated polymer backbone compared with the Ru(tpy)₂²⁺ model complex.

     

Chain extension of polyesters PET and PBT with N,N′-bis (glycidyl ester) pyromellitimides. I

Three N,N′-bis (glycidyl ester imide) of pyromellitic acid (diepoxides) were prepared and were used as chain extenders for poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT). The typical reaction conditions for the coupling of the polyester macromolecules were heating with the chain extender under argon atmosphere above the melting temperature (280°C for PET and 250°C for PBT) for several minutes. The Characterization of the samples, obtained at variable residence times in the reactor, was based on solution viscosity measurements and carboxyl and hydroxyl end-group determinations. Two of the diepoxides used gave satisfactory results. Starting from a PET having intrinsic viscosity [η] = 0.60 dL/g, and carboxyl content CC = 42 eq/10⁶ g, one could obtain PET with [η] = 1.15 dL/g and CC = 16 eq/10⁶ g within 30 min at 280°C. Analogous results were observed for PBT. The hydroxyl content of polyester in all cases was increased. When the quantity of the chain extender used was higher than that theoretically required for its reaction with all carboxyl end groups of the polyester, this resulted in some gel formation indicative of crosslinking. © 1995 John Wiley & Sons, Inc.     

含取代芳酰腙和单齿N-杂环分子铜(II)配合物的合成、结构及荧光性质

合成了1个含有取代芳酰腙和单齿N-杂环分子的三元铜配合物[Cu(L)(ampy)](H₂L=5-溴水杨醛苯甲酰腙，ampy=2-氨基吡啶)，并通过IR、UV、荧光光谱和循环伏安进行了性质研究。[Cu(L)(ampy)]的晶体结构分析表明，中心金属通过酰腙配体的酚基氧原子、亚胺基氮原子、去质子酰胺氧原子以及中性杂环分子的氮原子形成平面四方形的N₂O₂配位环境。配合物通过N-H…O和N-H…N氢键作用形成一维链状结构。     

Synthesis,Crystal Structure,Fluorescence Property and Antibacterial Activity of Two Unprecedented One-dimensional Chain Metal-organic Coordination Polymers: Zn(H-SSA)(Phen)(H_2O)_2and Cu(H-SSA)(Phen)(H_2O)_2

IntroductionSalicylicacid (2 oxybenzoicacid ,H2 Sal)anditsderivativeshavebeenknownforalongtimetopossessan ti inflammatoryactivity ,1whileithasbeenfoundthatthebiologicalactivityofawidevarietyoforganicdrugsisen hancedupontheirmetalcomplexation .2 ,3Forexample ,bis(salicylato)copper(II)isastrongeranalgesicandanti inflammatoryagentforanimalsthansalicylicaciditself,4andthecopper(II)complexofaspirin ,Cu2 (aspirin) 4,isamoreeffectiveanti inflammatoryandanti rheumatoida gentthanaspirinitself.5,6 I…     

镝(III)与酰腙及1,10菲啰啉多元配合物的晶体结构及荧光性质

在水乙醇混合体系中 ,首次得到 2 羰基丙酸水杨酰腙 (C10 H10 N2 O4) ,1,10 菲啉 (C12 H8N2 ,简写作phen)与Dy(NO3 ) 3 ·3H2 O的配合物 [Dy(C10 H8N2 O4) (phen) (NO3 ) (H2 O) 2 ]·H2 O .该配合物属单斜晶系 ,空间群为P2 1/c,晶胞参数a =1 5 2 4( 3 )nm ,b =1 10 18( 19)nm ,c =1 468( 3 )nm ,β =92 2 8( 2 )° ,V =2 4 63 ( 7)nm3 ,Z =4,μ =3 10 0mm-1,Dc=1 83 1g/cm3 ,F( 0 0 0 ) =13 40 ,R =0 0 3 14 ,wR =0 0 660 ,GOF =0 966.测试结果表明 ,该单晶结构为镝的 9配位配合物 ,其中一个 2 羰基丙酸水杨酰腙分子以羧基氧、酰胺基中的羰基氧和CN中的氮与Dy3 + 三齿配位 ,形成两个稳定的共边五元环 ,一个 1,10 菲啉分子以二齿方式配位、一个硝酸根和两个水分子也同时参与配位 ,在空间呈扭曲的单帽四方反棱柱 ,而在配合物周围还有一个游离的水分子 .发光性能测试表明配合物具有很好的荧光性能     

Synthesis,Characterization, and Functionalization of Hyperbranched Poly(ether ether ketone)s with Phenoxypheyl Side Group

Novel fluoride‐teminated hyperbranched poly(ether ether ketone) with 4‐phenoxyphenyl side group (HPEEK‐F) was prepared from 2‐(4‐phenoxyphenyl)‐1,4‐diphenol (A₂) and 1,3,5‐tris[4‐(4‐flourobenzoyl) phenoxy]benzene (B₃). An end‐capping approach was used to synthesize tertiary amino‐terminated fluorescent (HPEEK‐DMA) and phenyl ethynyl‐terminated self‐crosslinking poly(ether ether ketone)s (HPEEK‐PEP). These three polymers have the same backbone structure and degree of branching (DB=0.67), and different terminal groups. The nature of the terminal group was shown as the influences of the glass transition temperature (T_g) and decomposition temperature (T_d) of polymers. The T_g of HPEEK‐F and HPEEK‐DMA are 30°C lower than HPEEK‐PEP, whereas the T_d of HPEEK‐F are 90°C and 50°C higher than HPEEK‐DMA and HPEEK‐PEP, respectively. The HPEEK‐DMA fluoresce blue‐green in solid and in solution. This kind of hyperbranched polymer contains a large amount of terminal chromophore groups which can easily lead to the formation of intramolecular excimers. The fluorescence signal was decreased with increasing acidity, furthermore, the two peaks at 466 nm and 507 nm indicated a blue shift occurred. After curing, the HPEEK‐PEP displayed a T_g at 235.5°C, which is 100°C higher than original polymers. Thermally cured samples show good anti‐chemical corrodibility in DMF, THF, DMAc and NMP solvents.     

固相聚合合成聚噻吩衍生物及烷基链对固相聚合的影响

New poly(bis-3, 4-ethylenedioxythiophene methine)s derivatives with typical electro-optical moieties of thiophene, carbazole and fluorene as the side chains are obtained by facile solid state polymerization (SSP) or melt state polymerization (MSP). Detail characterizations of these polymers are carried out and some key monomers' crystals are obtained for structures analysis. It is found that existence of alkyl chains decrease monomers onset temperatures for SSP (T_onset) due to the weakening of the intermolecular interaction in crystals.     

Energy migration in poly(N‐vinyl carbazole) and its copolymers with methyl methacrylate: Fluorescence polarization,quenching, and molecular dynamics

Fluorescence polarization and quenching measurements were used to examine intramolecular energy migration for poly(N‐vinyl carbazole) and copolymers of N‐vinyl carbazole with methyl methacrylate. Quenching measurements of the carbazole fluorescence by CCl₄ were performed in dilute solution in toluene, and fluorescence anisotropy, r, was measured for the chains dispersed in a solid matrix of poly(methyl methacrylate) (PMMA). The results suggested that the chains with a high carbazole content, that is, a high content of excimer trapping sites, do not show the highest values of the singlet energy‐migration rate. Isotropies, r^?1, of the samples in vitrified PMMA corroborated such conclusions. Molecular dynamics simulations on isotactic and syndiotactic trichromophoric copolymer fragments were used to obtain parameters related to the energy‐transfer process as a function of the methyl methacrylate content. The parameters from the simulations supported the interpretation of the experiments. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1615–1626, 2003     

Structure and morphology of the aliphatic polyester poly(δ‐valerolactone) in solution‐grown,chain‐folded lamellar crystals

Poly(δ‐valerolactone) (PVL) crystals in the form of chain‐folded lamellae were prepared by isothermal crystallization from a 2‐methylbutane‐2‐ol solution. Wide‐angle and small‐angle X‐ray diffraction data, obtained from PVL lamellae sedimented to form oriented mats, were supplemented with morphological and structural data from electron microscopy, both imaging and diffraction. The diffraction signals index on an orthorhombic unit cell with the parameters a = 0.747 ± 0.002 nm, b = 0.502 ± 0.002 nm, and c (chain axis) = 0.742 ± 0.002 nm. Similar unit cell parameters were obtained from crystals grown from 1‐octanol and also from drawn melt‐pressed films. The evidence supports a model containing two antiparallel chain segments in the unit cell. The c value of 0.742 nm is appropriate for an all‐trans or onefold helical backbone conformation for the straight stems. Possible slight perturbations at the ester units from the all‐trans backbone conformation are discussed. Computerized modeling was used to optimize the adjacent‐reentry folded structure. The setting angles, with respect to the a axis, are ±58° for the corner and center chains. The lamellae are 7.26 ± 0.05 nm thick, and the chains run orthogonal to the lamellar surface. The chains fold in the diagonal (110) and (11¯0) planes in an alternating fashion. The X‐ray diffraction data suggest that a proportion of adjacent paired antiparallel entities, or hairpin units, are c‐axis‐sheared, and a relationship to the results obtained from drawn films is discussed. A brief comparison is also made with related polymer structures. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2622–2634, 2001     

Temperature‐Induced Chiroptical Changes in a Helical Poly(phenylacetylene) Bearing N,N‐Diisopropylaminomethyl Groups with Chiral Acids in Water

A stereoregular poly(phenylacetylene) bearing an N,N‐diisopropylaminomethyl group as the pendant (poly‐ 1 ) changed its structure into the prevailing one‐handed helical conformation upon complexation with optically active acids in water. The complexes exhibited induced circular dichroism (ICD) in the UV/Vis region of the polymer backbone. Poly‐ 1 is highly sensitive to the chirality of chiral acids and can detect a small enantiomeric imbalance in these acids, in particular, phenyl lactic acid in water. For example, a 0.005 % enantiomeric excess of phenyl lactic acid can be detected by CD spectroscopy. The observed ICD intensity and pattern of poly‐ 1 were dependent on the temperature and concentration of poly‐ 1 , probably due to aggregations of the polymer at high temperature as revealed by dynamic light scattering and AFM. On the basis of the temperature‐dependent ICD changes, the preferred chiral helical sense of poly‐ 1 was found to be controlled by noncovalent bonding interactions by using structurally different enantiomeric acids.     

2-(1H-1,2,4-三唑-3-基)吡啶MnⅡ配合物的合成、结构及荧光性质

采用水热合成法,通过配体[2-(1H-1,2,4-三唑-3-基)吡啶](2-HTP)与MnSO₄·H₂O中的Mn²⁺离子组装配位,得到一个结构新颖的配合物[Mn(C₇H₅N₄)·(SO₄)·2H₂O](1),对其进行元素分析、红外光谱、X射线单晶衍射、固体荧光以及热重分析等测试。 结构分析表明,配合物1属于单斜晶系P2₁/n空间群,部分晶胞参数:a=1.16373(12) nm,b=0.79324(9) nm,c=1.40241(15) nm,V=1.1996(2) nm³,Z=4。 在配合物1中,配体2-HTP与Mn²⁺离子以双齿的方式配位,Mn²⁺离子还与两个结晶水分子相连并与SO42-中O原子的桥联作用连接成为一维的链状结构。 此外,配体的芳香环之间还存在弱的π-π空间堆积效应,通过对配合物进行固体荧光测试表明其具有良好的蓝光性质,在477 nm处存在较强的荧光发射峰。