含磺酸根侧链的聚苯乙炔-吡啶类共轭聚合物的荧光传感性能

利用Sonogashira偶合反应合成了两种新的含磺酸根侧链的聚苯乙炔-吡啶类共轭聚合物P1, P2. 通过紫外-可见吸收光谱和荧光光谱对其光学性质及Cu^2＋传感检测进行了研究. 结果表明, 按一定比例嵌段引入吡啶环的聚合物P1能有效地改善共轭主链的刚性, 提高检测的灵敏度, 使共轭聚合物具有更优异的荧光化学传感性能. 在甲醇溶剂中, P1 的荧光能被Cu^2＋有效地猝灭, 相对单体模型分子PESO₃, 其响应信号扩大222倍.     

一种侧基横挂偶极单元的聚苯撑乙炔的光学性质

以对苯二乙炔和2,5-二溴苯衍生物为单体,无水N,N-二甲基甲酰胺（DMF）为溶剂,通过Sonogashira偶联反应,采用2种Pd催化剂（Pd(PPh₃)₄和PdCl₂(PPh₃)₂）合成了一种侧基带有偶极基团的聚苯撑乙炔。 单体的化学结构通过IR、NMR和元素分析等测试技术得到确证。 聚合物外观为黄色粉状固体,室温下溶于CHCl₃和THF等有机溶剂。 2种Pd催化剂对合成聚合物的分子量以及光学性质影响不大,但对聚合物的发光效率影响较大,由Pd(PPh₃)₄催化得到的聚合物分子链具有较高的立构规整性,因此,具有较高的发光效率。 不同溶剂环境以及聚合物固体膜的紫外以及荧光光谱研究结果表明,侧基偶极基团的相互静电排斥力,可以有效阻止大分子链之间的聚集,从而有效地抑制了聚苯撑乙炔聚集体的形成。     

一类芳香酰胺螺旋折叠聚合物的设计与合成

利用3,5-二氨基苯甲酸和4,6-二羟基间苯二酸的衍生物设计并合成了一类新芳香酰胺聚合物.其溶解度、浓度核磁、紫外可见吸收光谱(UV)和圆二色谱(CD)实验表明,聚合物可以发生折叠形成螺旋结构,折叠聚合物的侧链酰胺间的分子内氢键作用可以稳定螺旋构像.     

液晶性9-苯亚甲基取代芴-苯共聚物的设计合成及催化剂对聚合物链立构规整性、液晶性和光学性质的影响

为了制备适于制造有机发光场效应管的高分子材料, 通过Suzuki偶联反应, 采用不同Pd催化剂, 合成了一种侧基横挂偶极基团的液晶9-苯亚甲基取代芴-苯共聚物. 考察了不同催化剂对合成的聚合物的分子量、聚合物链中单体单元的结构排列及液晶性质和光学性质的影响. 结果表明, 2种不同的Pd催化剂对合成的聚合物的分子量影响不大, 但对聚合物链的立构规整性以及聚合物的液晶态温度范围有较大的影响. Pd(PPh3)4作催化剂合成的聚合物(PA)中单体单元的结构排列较单一, 立构规整性好, 有较宽的液晶态温度范围. Pd(OAc)2为催化剂合成的聚合物(PB)链中单体单元的结构排列相对复杂, 液晶态温度范围较窄. 聚合物链的立构规整性对其光学性质影响很大. PA具有较高的溶液及固体膜的紫外最大吸收峰值和溶液荧光效率, 其退火膜的激发和发射光谱的半峰宽均比PB的窄, 并且光学性质不随加热条件的变化而变化.     

含苯并三氮唑单元的聚对苯撑乙炔类聚合物的合成及性能

利用Pd（Ⅱ）配合物为催化剂,使用4,7-二溴-2-十二烷基-1,2,3-苯并三氮唑和1,4-二乙炔基-2,5-二（烷氧基）苯通过Sonogashira反应合成了3个带有不同长度烷氧基侧链,主链中含有1,2,3-苯并三氮唑单元的聚苯乙炔类聚合物。采用FT-IR、1H-NMR对其化学结构进行了表征。结果表明：这类聚合物的数均分子量在0.93×104～1.13×104,苯并三氮唑单元上长链烷基和苯环上长链烷氧基的存在使此类聚合物在CHCl3、THF等溶液中的溶解度较大,其固态薄膜也较容易制备,聚合物在固态薄膜状态下的紫外-可见最大吸收波长比在CHCl3溶液中红移了约45 nm,在固态薄膜状态下的荧光发射峰比在CHCl3溶液中也发生了较大的红移。     

聚（N,N—二甲基苯胺）中稳定自由基的性质研究

介绍了聚（Ｎ，Ｎ－二甲基苯胺）阳离子自由基的结构特点，利用顺磁共振波谱和紫外－可见吸收光谱，研究了温度及溶液粘度对聚合物自由基的影响，发现聚（Ｎ，Ｎ－二甲基苯胺）的主，侧链结构构象变化与其自由基的稳定性很大的关系。     

侧基横挂偶极单元的液晶聚苯撑乙炔的合成与表征

为了制备电致偏振光发光材料, 以对苯二乙炔和2,5-二溴苯衍生物为单体,通过Sonogashira偶联反应, 采用不同Pd催化剂, 合成了一种侧基横挂偶极基团的液晶聚苯撑乙炔. 单体的化学结构通过IR, NMR和元素分析等方法得到确证. 聚合物外观为黄色粉状固体, 室温下溶于CHCl3和THF等有机溶剂. 将聚合物加热到各自的玻璃化转变温度以上都能形成液晶态并显示双向液晶性. 考察了不同催化剂对合成的聚合物的分子量、聚合物链中单体单元的结构排列以及液晶性质的影响. 结果表明, 两种不同的Pd催化剂对合成的聚合物的分子量以及液晶态温度范围影响不大, 但对聚合物的立构规整性以及聚合物的液晶态织构有较大的影响. Pd(PPh3)4作催化剂合成的聚合物中单体单元的结构排列较单一, 可以观察到清晰的液晶态织构. 以PdCl2(PPh3)2为催化剂合成的聚合物链中单体单元的结构排列相对复杂, 液晶态织构不明显. 变温X 射线衍射研究证实聚合物均为向列相液晶.     

聚{N-[2-(4′-硫代乙酸苄酯基)丙酰基]-对氨基苯乙炔}的合成和热稳定性及有序纳米结构的形成

采用两性离子型的催化剂Rh+[η-C6H5(nbd)B-(C6H5)3]实现了含手征性中心和硫代乙酸酯基的苯乙炔单体的聚合,用红外光谱、核磁共振氢谱和紫外-可见吸收光谱表征了聚合物的结构,证实得到了预期产物.聚合物的重均分子量达到了73200,在氯仿、四氢呋喃、二氯甲烷等有机溶剂中有良好的溶解性能.聚合物热稳定性高,在氮气氛围下热分解温度为336℃,在900℃的高温下有31%的重量残留.用扫描电子显微镜观察发现,在浓度为5.0mg/mL的聚合物氯仿溶液形成的薄膜中有微米长度的棒状有序结构;由浓度为0.5mg/mL的聚合物氯仿稀溶液形成的薄膜表面有晶体析出.用透射电子显微镜观察聚合物在氯仿溶液中缓慢形成的微结构,发现当浓度高于1.0mg/mL时,聚合物在碳膜上形成铺展的薄膜,薄膜由纳米尺寸的丝带状结构取向排列而成;当浓度低于0.5mg/mL时,聚合物形成具有规则几何形态的微晶体.在聚合物热稳定性的显著提高和有序微结构的形成过程中,聚苯乙炔侧链中的手征性中心发挥了关键的作用.     

侧链带有L-氨基酸乙酯的螺旋聚苯乙炔衍生物的手性识别能力研究

采用Rh(nbd)BPh4催化剂合成了3种侧链带有L-氨基酸乙酯的螺旋聚苯乙炔衍生物PPA-S-Phe、PPA-S-Leu和PPA-A-Leu,并将其涂覆在氨丙基硅胶上制备高效液相色谱(HPLC)手性固定相(CSP),研究其对7种对映体的手性识别能力.由于侧链手性基团或主链与手性基团之间的链接基团不同,PPA-S-Phe、PPA-S-Leu和PPA-A-Leu形成了不同的螺旋构象,并表现出对对映体不同的手性识别能力.PPA-S-Phe和PPA-S-Leu的主链与手性基团之间的链接基团均为磺酰胺基,侧链手性基团为L-亮氨酸乙酯的PPA-S-Leu的手性识别能力优于侧链手性基团为L-苯丙氨酸乙酯的PPA-S-Phe.PPA-S-Leu和PPA-A-Leu的侧链手性基团均为L-亮氨酸乙酯,以酰胺基为链接基团的PPA-A-Leu的手性识别能力明显优于以磺酰胺基为链接基团的PPA-S-Leu.螺旋聚苯乙炔主链与侧链手性基团之间的链接基团、侧链手性基团在手性识别中均发挥十分着重要作用.     

含空间位阻侧链取代炔烃的合成及其催化聚合

设计并合成了具有较大空间位阻侧链的取代炔烃2-炔丙氧基-1,4-对苯二甲酸二甲酯单体,分别采用WCl6,WCl6-SnPh4和[Rh(nbd)Cl]2催化体系使其聚合,考察了不同催化剂对聚合的影响.采用红外光谱和核磁共振等技术对单体及聚合物结构进行了表征,并用紫外光谱和荧光光谱研究了所得聚合物的光学性能.结果表明,使用[Rh(nbd)Cl]2催化剂时得到的聚合物是高反式结构,荧光光谱中除了侧基的350 nm发射峰外,还在429 nm处存在较弱的共轭主链发射.使用WCl6-SnPh4催化体系得到的聚合物由于较高的顺式含量,主要是侧基的发射,而较大侧基位阻使主链共轭降低.尽管存在较短的间隔基,引入较大空间位阻侧基仍然迫使聚合物主链扭曲,顺式结构中侧基空间位阻的影响更大.     

Facile iterative synthesis, spectral characterization, electron microscopic study and thermogravimetric analysis of phosphorus dendron with bisphenol A at the focal point

A facile iterative synthesis of a phosphorus dendron with bisphenol A at the focal point by following the divergent procedure is described. The phosphorus dendron peripherally functionalized with phenolic OH group has been accomplished in a very versatile simple fashion, using the Schiff condensation and nucleophilic substitution reactions using P(S)Cl₃, P(O)Cl₃, 3-hydroxybenzaldehyde and 3-aminopheno. The structures of intermediate dendrons were confirmed by IR, NMR (¹H, ¹³C and ³¹P), LC-Mass and C, H, N analysis. The structure of the final dendron (5) was confirmed by IR, NMR (¹H, ¹³C and ³¹P), MALDI-TOF-MS, and C, H, N analysis. The thermal stability of the resulting functionalized dendron has been checked by TGA/DTA analysis. The surface topography observed by scanning electronic microscopic study (SEM) gives the reminiscent of the dendritic structure.     

Synthesis,Characterization, and Thermogravimetric Studies of a Phosphorus-Containing Dendron Built from 1,5-Diaminonaphthalene at the Core

A facile divergent synthesis of a phosphorus-containing dendron containing 1,5-diaminonaphthalene is described. The phosphorus-containing dendron, functionalized with a 1,5-diaminonaphthalene unit at the core and phenolic OH groups grafted at the periphery, has been accomplished in a versatile, simple fashion, using Schiff's condensation and nucleophilic substitution reactions with POCl₃, 3-hydroxy-benzaldehyde, 4-hydroxy-benzaldehyde, and 3-amino-phenol iteratively. The structures of intermediate dendrons were characterized by infrared, NMR (¹H, ¹³C, and ³¹P), liquid chromatography–mass spectrometry, and C, H, N analysis. The structure of the final dendron (6) was confirmed by infrared, NMR (¹H, ¹³C, and ³¹P), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and C, H, N analysis. The thermal stability and degradation of the resulting final dendron was checked by thermal gravitometric analysis/differential thermal analysis.     

Supramolecular polymer chemistry: self-assembling dendrimers using the DDA.AAD (GC-like) hydrogen bonding motif

Heterocyclic unit 2 containing complementary donor-donor-acceptor (DDA) and acceptor-acceptor-donor (AAD) hydrogen bonding arrays at an angle of about 60 degrees was designed to self-assemble into a hexamer. To investigate whether this unit could self-assemble dendrimers, the 2,8-diamino-2-N-ethylpyrimido-(4,5-b)(1,8)naphthyridine-3H-4-one subunit was synthesized with a first (2a), second (2b), and third generation (2c) Fréchet-type dendron attached to the 8-amino group. The synthesis of 2a-c was accomplished in 11 steps beginning with 2,6-diaminopyridine and the corresponding dendron bromide. Studies using (1)H NMR, size exclusion chromatography (SEC), and dynamic light scattering (DLS) support the cooperative formation of cyclic hexamers in apolar solvents. The stability of the self-assembled dendrimers is dependent on the size of the attached dendron, and mixing studies with 2a-c indicate their usefulness in constructing dynamic combinatorial libraries.     

Self-assembling behavior of amphiphilic dendron coils in the bulk crystalline and liquid crystalline states

We prepared a series of amphiphilic dendron coils (1-3) containing aliphatic polyether dendrons with octadecyl peripheries and a poly(ethylene oxide) (PEO) coil (DP = 44). The molecular design in this study is focused on the variation of dendron generation (from first to third) with a fixed linear coil, upon which the thermal and self-assembling behavior of the dendron coils was investigated in the bulk. All the dendron coils exhibit two crystalline phases designated as k1 (both crystalline octadecyl chains and PEO) and k2 states (crystalline octadecyl chains and molten PEO). Crystallinities for both octadecyl peripheries and the PEO decrease as generation increases. In particular, the dendron coil (3) containing third generation shows a drastic reduction of the PEO crystallinity, which is attributed to the considerable chain folding and plasticization effects by the largest hydrophilic dendritic core segment. All the crystalline phases are bilayered lamellar morphologies. On going from k1 to k2, the periodic lamellar thickness decreases in the dendron coil (1) with first generation, but interestingly increases in 3. After melting of octadecyl peripheries, 1 shows no mesophase (i.e., liquid crystalline phase). Additionally, dendron coil 2 (3) displays a network cubic mesophase with Ia3d symmetry (micellar cubic with Pm3n) which is transformed into a lamellar (hexagonal columnar) mesophase upon heating. Remarkably, the temperature-dependent mesomorphic behavior in 2 and 3 is a completely reverse pattern in comparison with conventional linear-linear block copolymers. The unusual bulk morphological phenomena in the crystalline and liquid crystalline phases can be elucidated by the dendron coil architecture and the associated coil conformational energy.     

Molecular batteries: ferrocenylsilylation of dendrons, dendritic cores, and dendrimers: new convergent and divergent routes to ferrocenyl dendrimers with stable redox activity

The ferrocenylsilylation of the phenol triallyl dendron 2, of the phenol nonaallyl dendron 4, and of the 9-, 27-, 81-, and 243-allyl dendrimers 7-10 (monitored by the disappearance of the signals of the olefinic protons in 1H NMR spectra) has been achieved using ferrocenyldimethylsilane 1 and Karstedt's catalyst in diethyl ether at 40 degrees C, yielding the corresponding ferrocenyl dendrons and dendrimers. An alternative convergent synthesis of the nonaferrocenyl dendron 5 was carried out by reaction of the triferrocenyl dendron 2 with a protected triododendron followed by deprotection. Reaction of the nonaferrocenyl dendron 5 with hexakis(bromomethyl)benzene gave the 54-ferrocenyl dendron 6. All the ferrocenyl dendron and dendrimers produce a chemically and electrochemically reversible ferrocenyl oxidation wave at seemingly the same potential. Stable platinum electrodes modified with the high ferrocenyl dendrimers were fabricated. The soluble orange-red ferrocenyl dendrimers can also be oxidized in CH2Cl2 by [NO][PF6] to the insoluble deep blue polyferrocenium dendrimers. For instance, the 243-ferrocenium dendrimer has been characterized by its Mossbauer spectrum, which is of the same type as that of ferrocenium itself. The ferrocenium dendrimers can be reduced without any decomposition back to the ferrocenyl dendrimer, indicating that these multielectronic redoxstable dendrimers behave as molecular batteries.     

两亲嵌段树枝状分子Gx-PBE-b-Gx-PMPA(OH)x2的合成及多重氢键作用

合成了1~3代的嵌段树枝状分子聚苄醚-聚脂肪酯(Gx-PBE-b-Gx-PMPA, x=1,2,3)和两亲嵌段树枝状分子聚苄醚-周边含羟基的聚脂肪酯[Gx-PBE-b-Gx-PMPA(OH)x2, x=1,2,3]. PMPA(OH)x2-树枝片(Dendron)段周边的羟基数目分别是2, 4和8. 通过1H NMR, 13C NMR, FTIR和基质辅助激光解吸附电离飞行时间质谱(MALDI-TOF)(或场解析电离质谱)技术表征了Gx-PBE-b-Gx-PMPA和Gx-PBE-b-Gx-PMPA(OH)x2的结构. 同时, 采用变温FTIR光谱研究了在两亲嵌段树枝状分子中形成的氢键模式. 结果表明, 随着树枝片代数的增加, 两亲嵌段树枝状分子内趋向于形成作用较弱的分子内氢键, 说明形成3代两亲嵌段树枝状分子的三维结构削弱了羟基形成分子间氢键的能力.     

以磁纳米粒为核的pH敏感型聚谷氨酸树状分子药物载体

报道了一种新的肽类树枝状分子改性磁性纳米药物载体.以天然氨基酸L-谷氨酸为原料,通过收敛法合成了聚(L-谷氨酸)树状分子,将多巴胺配体键合到聚(L-谷氨酸)树状分子上,用核磁(1H-NMR)、质谱(MS)对合成出的树状分子配体进行了表征,然后通过配体交换对四氧化三铁磁纳米粒表面进行多功能化.以阿霉素为模型药物通过pH敏...     

Janus-type dendrimer-like poly(ethylene oxide)s

A straightforward and original methodology allowing the synthesis of Janus-type dendrimer-like poly(ethylene oxide)s (PEOs) carrying orthogonal functional groups on their surface is described. The use of 3-allyloxy-1,2-propanediol (1) as a latent AB2-type heterofunctional initiator of anionic ring-opening polymerization (AROP) of ethylene oxide (EO) and of selective branching agents of PEO chain ends served to construct the two dendrons of these dendrimer-like PEOs, following a divergent pathway. Thus, the first PEO generation of the first dendron was grown by AROP from 1 followed by the reaction of the corresponding alpha-allyl,omega,omega'-bishydroxy- heterofunctional PEO derivative with 2-(3'-chloromethybenzyloxymethyl)-2-methyl-5,5-dimethyl-1,3-dioxane (2) used as a branching agent. This afforded the dendron A with four latent peripheral hydroxyls protected in the form of two ketal rings. The remaining alpha-allylic double bond of the PEO thus prepared was transformed into two hydroxyl groups using OsO4 in order to create the first PEO generation of the dendron B by AROP of EO. Allyl chloride (3) was then used as another (latent) branching agent to react with the terminal hydroxyl of the corresponding PEO chains. Deprotection under acidic conditions of the ketal groups of dendron A, followed by AROP of EO, afforded the second PEO generation on this face. This alternate and divergent procedure, combining AROP of EO and selective branching of PEO branches, could be readily iterated, one dendron after the other up to the generation six, leading to a Janus-type dendrimer-like PEO exhibiting a total mass of around 300 kg/mol and possessing 64 peripheral groups on each face. The possibility of orthogonal functionalization of the surfaces of such Janus-type dendritic PEOs was exploited. Indeed, a dendron of generation 4 was functionalized with hydroxyl functions at its periphery, whereas the other was end-capped with either tertiary amino or disulfide groups. In a variant of this strategy, azido groups and acetylene could also be orthogonally introduced at the periphery of the fourth generation Janus-type dendrimer-like PEO and subjected to polycondensation by a 1,3-dipolar cycloaddition reaction. This afforded a necklace-like covalent assembly of dendrimer-like PEOs through the formation of stable [1,2,3]-triazole linkages.     

Preparation, characterization, and electrochemical properties of a new series of hybrid dendrimers containing a viologen core and Frechet and Newkome dendrons

Five new 4,4'-bipyridinium (viologen) core dendrimers containing a Frechet (Fn, n = 1-3, first to third generation) and a Newkome (Nn, n = 1-3) dendron linked to each of the termini of the viologen residue were prepared and characterized. These macromolecules (FnNn) were prepared according to synthetic methodology already developed by our group. The electrochemical behavior of these dendrimers is characterized by the stepwise reduction of the viologen nucleus (V(2+)/V(+) and V(+)/V). The recorded half-wave potentials are affected by dendron growth in the three surveyed solvent media (dichloromethane, tetrahydrofuran, and acetonitrile). The size of the Newkome dendron has a more pronounced effect on the half-wave potentials than the size of the Frechet dendron. However, increasing the size of the Frechet dendron diminishes the magnitude of the cathodic potential shifts resulting from Newkome dendron growth. The largest dendrimers investigated (F1N3 and F2N3) exhibit quasi-reversible voltammetric behavior. The diffusion coefficients of these molecules were also determined using pulse gradient stimulated echo NMR techniques.     

Synthesis of nanoparticle-cored dendrimers by convergent dendritic functionalization of monolayer-protected nanoparticles

This article presents a synthesis method for nanoparticle-cored dendrimers (NCDs), which have dendritic architectures around a monolayer-protected gold nanoparticle. The synthesis method is based on a strategy in which the synthesis of monolayer-protected nanoparticles is followed by adding dendrons on functionalized nanoparticles by a single coupling reaction. NMR spectroscopy, IR spectroscopy, and thermogravimetric analysis (TGA) characterizations confirmed the successful coupling reaction between dendrons with different generations ([G1], [G2], and [G3]) and COOH-functionalized nanoparticles ( approximately Au201L71). The dendrimer wedge density also could be controlled by reacting nanoparticles having different loading of COOH groups ( approximately 60 and approximately 10% COOH of the 71 ligands per gold nanoparticle) with functionalized dendrons. Transmission electron microscope results showed that this synthesis strategy maintains the average size of the nanoparticle core during dendron coupling reactions. This control over the composition and core size makes the systematic study of NCDs with different generations possible. The chemical stability of NCDs was found to be affected by dendron generation around the nanoparticle core. The current-potential response of NCD films on microelectrode arrays exhibited better electrical conductivity for NCDs with lower dendron generation.