To gain insight into the attachment of =Si^＋ （SC） ion （regarded as guest） to the lowest generation, NH2-terminated poly（amidoamine） （PAMAM） dendrimers （regarded as host） in the liquid phase, density functio...To gain insight into the attachment of =Si^＋ （SC） ion （regarded as guest） to the lowest generation, NH2-terminated poly（amidoamine） （PAMAM） dendrimers （regarded as host） in the liquid phase, density functional theory is used to investigate the structures and energetics of the host-guest complex. The effect of solvent on the structures and energetics is also investigated. Various initial configurations of the ion bound to PAMAM are tested, and two stable conformers are found, i.e, types A （=Si^＋ is bound to the amine site） and C （=Si^＋ is bound to the amide site）. Types A and C are the most stable due to the chemical bond formations of Si-N° （amine nitrogen atoms） and Si-O, respectively. The IR spectra for the lowest energy conformers are thoroughly analyzed and compared with the available experimental data.展开更多
A series of shape-persistent polyphenylene dendritic C_(60)derivatives as the electron transport materials were designed and synthesized via a catalyst-free Diels-Alder[4+2]cycloaddition reaction.These increasing hype...A series of shape-persistent polyphenylene dendritic C_(60)derivatives as the electron transport materials were designed and synthesized via a catalyst-free Diels-Alder[4+2]cycloaddition reaction.These increasing hyperbranched scaffolds could effectively enhance the solubility;notably,both first and second generation dendrimers,C_(60)-G1 and C_(60)-G2,demonstrated more than 5 times higher solubilities than pristine C_(60).Furthermore,both simulated and experimental data proved their promising solution-processabilities as electron-transporting layers(ETLs)for perovskite solar cells.As a result,the planar p-i-n structural perovskite solar cell could achieve a maximum power conversion efficiency of 14.7%with C_(60)-G2.展开更多
Poly （amidoamine） dendrimers are emerging as versatile and derivatizable nano-scale drug delivery vehicles. In our study, cis-4,7,10,13,16,19-docosahexenoic acid and doxorubicin were conjugated to generation 2.5 PAM...Poly （amidoamine） dendrimers are emerging as versatile and derivatizable nano-scale drug delivery vehicles. In our study, cis-4,7,10,13,16,19-docosahexenoic acid and doxorubicin were conjugated to generation 2.5 PAMAM. The molecular architecture of the carrier was designed for optimized blood circulation and optimized drug release through the use of pH-sensitive hydrazone linkages. In vitro, DHA-PAMAM-DOX conjugates were able to release twice as much doxorubicin at pH 4.5 （lysosomal pH） as at pH 7.4, ensuring more pronounced antitumor activity. Upon intravenous administration to ICR mice, the DHA-PAMAM-DOX delivery systems resulted in more plasma exposure of doxorubicin than free doxorubicin solution. In efficacy studies performed with B6D2F1 mice bearing B16 melanoma tumors, DHA-PAMAM-DOX was significantly more efficient in inhibiting tumor growth than free doxorubicin at the dose equivalent to 5 mg/kg doxorubicin. Our research provides evidence that DHA-PAMAM-DOX conjugates have the potential to enhance the effect of cancer therapy in the course of delivering anticancer drugs to their target sites.展开更多
The Bergman cyclization has strongly impacted on a number of fields including pharmaceutics, synthetic chemistry, and material science. The diradical intermediates stemmed from enediynes can not only cause DNA cleavag...The Bergman cyclization has strongly impacted on a number of fields including pharmaceutics, synthetic chemistry, and material science. The diradical intermediates stemmed from enediynes can not only cause DNA cleavage under physiological conditions but also function as monomer or initiator participants in polymer science. The homo-polymerization of enediynes through the Bergman cyclization to fabricate conjugated polymers is a fascinating strategy due to the advantages of facial operation, high efficiency, tailored structure, and catalyst-free operation. Moreover, conjugated polymers generated through the Bergman cyclization show many remarkable properties, such as excellent thermal stability, good solubility, and processability, which enables these polymers to be further manufactured into carbon-rich materials. Recent times have seen extensive efforts devoted to the application of the Bergman cyclization in polymer science and materials chemistry. A variety of synthetic strategies have been developed to fabricate structurally unique materials via the Bergman cyclization, including the fabrication of rod-like polymers with polyester, dendrimers and chiral imide side chains, functionalization of carbon nanomaterials by surface-grafting conjugated polymers, formation of nanoparticles by intramolecular collapse of single polymer chains, and the construction of carbon nanomembranes with different morphologies. Future developments involving the Bergman cyclization in polymer science, probably by altering the reaction mechanism to precisely control the microstructure of polymeric products, are also proposed in this review article.展开更多
Dendrimers are well-defined tree-like macromolecules possessing numerous chain ends emanating from a single core, which makes them attractive candidates for mimicking light-harvesting systems and hydrogenases. Photoin...Dendrimers are well-defined tree-like macromolecules possessing numerous chain ends emanating from a single core, which makes them attractive candidates for mimicking light-harvesting systems and hydrogenases. Photoinduced electron and energy transfers are main processes involved in light-harvesting and photocatalysis. In this review, the general concepts of design strategies and recent developments of photofunctional dendrimers in biomimics of light-harvesting systems and hydrogenases are discussed. The energy transfer and electron transfer processes in light-harvesting dendrimers and the effect of dendritic structures in photochemical hydrogen production are illustrated.展开更多
Hydrophilic dendrimers, especially poly（amidoamine）（PAMAM） dendrimers are widely applied in modifying fluorescent dyes to endow them with water solubility and biocompatibility for biologic fluorescence imaging.Com...Hydrophilic dendrimers, especially poly（amidoamine）（PAMAM） dendrimers are widely applied in modifying fluorescent dyes to endow them with water solubility and biocompatibility for biologic fluorescence imaging.Common preparation strategies of fluorescent dendrimers including encapsulating dyes or attaching dyes at periphery of dendrimers might cause uncertain constituent and lower biocompatibility. Here, we have developed a series of watersoluble fluorescent dendrimers with dye as core and fanshaped PAMAM as arms. Carboxylated perylene bisimides（PBI） dye and squarylium indocyanine（SICy） dye were conjugated with PAMAM dendrons by amidation to obtain a series of fluorescent dendrimers with enhanced water-solubility. Two PBI based dendrimers（PBI-G2.5 and PBI-G1.5）were chosen as model compounds for further optical, selfassembly and biological studies. In aqueous environment,PBI-G2.5 exhibited strong fluorescence, small size（~30 nm）and slightly positive surface charge（~2.46 mV）, which are ideal for biomedical applications. In vitro assays demonstrated that PBI-G2.5 nanoparticles accumulated in the cytoplasm of He La cells with rapid cellular uptake. The strong fluorescence in He La cells remained for over 48 h. To conclude, our study provides an effective strategy for preparing water-soluble fluorescent dendrimers towards long-term live cell imaging.展开更多
Inorganic nanomaterials have a variety of fascinating properties and a wide range of promising applications.However,they often suffer from instability and poor processibility.To solve it,dendrimers,a special family of...Inorganic nanomaterials have a variety of fascinating properties and a wide range of promising applications.However,they often suffer from instability and poor processibility.To solve it,dendrimers,a special family of macromolecules having a unique three-dimensional architecture,provide one of the excellent solutions.In addition,the site-selective functionalization of the specific elements in the dendritic structure endows the nanohybrid system new functions and applications.Inspired by such ideas,a variety of dendrimer/inorganic nanomaterial composites have been designed and exploited.This review article selects a number of representative examples,and illustrates their preparation,characterization,properties,and applications.The influence and the unique features that originate from the introduced dendritic structures are particularly discussed.展开更多
A facile and green approach has been developed for the in situ synthesis of hybrid nanomaterials based on dendrite-shaped Pd nanostructures supported on graphene （RG）. The as-synthesized hybrid nanomaterials （RG-Pd...A facile and green approach has been developed for the in situ synthesis of hybrid nanomaterials based on dendrite-shaped Pd nanostructures supported on graphene （RG）. The as-synthesized hybrid nanomaterials （RG-PdnDs） have been thoroughly characterized by high resolution transmission electron microscopy, X-ray photoelectron spectroscop）~ atomic force microscop）~ Raman spectroscopy and electrochemical techniques. The mechanism of formation of such dendrite- shaped Pd nanostructures on the graphene support has been elucidated using transmission electron microscopy （TEM） measurements. The RG induces the formation of, and plays a decisive role in shaping, the dendrite morphology of Pd nanostructures on its surface. Cyclic voltammetry and chronoamperometry techniques have been employed to evaluate the electrochemical performance of RG-PdnDs towards oxidation of methanol. The electrochemical （EC） activities of RG-PdnDs are compared with graphene-supported spherical-shaped Pd nanostructures, Pd nanodendrites alone and a commercial available Pd/C counterpart. The combined effect of the graphene support and the dendrite morphology of RG-PdnDs triggers the high electrocatalytic activity and results in robust tolerance to CO poisoning.展开更多
文摘To gain insight into the attachment of =Si^＋ （SC） ion （regarded as guest） to the lowest generation, NH2-terminated poly（amidoamine） （PAMAM） dendrimers （regarded as host） in the liquid phase, density functional theory is used to investigate the structures and energetics of the host-guest complex. The effect of solvent on the structures and energetics is also investigated. Various initial configurations of the ion bound to PAMAM are tested, and two stable conformers are found, i.e, types A （=Si^＋ is bound to the amine site） and C （=Si^＋ is bound to the amide site）. Types A and C are the most stable due to the chemical bond formations of Si-N° （amine nitrogen atoms） and Si-O, respectively. The IR spectra for the lowest energy conformers are thoroughly analyzed and compared with the available experimental data.
基金Projects(2017YFE0131900,2017YFB0404500)supported by National Key Research and Development Program of ChinaProjects(91833306,91733302,62075094)supported by the National Natural Science Foundation of China+1 种基金Project(202003N4004)supported by the Ningbo Natural Science Foundation,ChinaProject(2020GXLH-Z-014)supported by the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University,China。
文摘A series of shape-persistent polyphenylene dendritic C_(60)derivatives as the electron transport materials were designed and synthesized via a catalyst-free Diels-Alder[4+2]cycloaddition reaction.These increasing hyperbranched scaffolds could effectively enhance the solubility;notably,both first and second generation dendrimers,C_(60)-G1 and C_(60)-G2,demonstrated more than 5 times higher solubilities than pristine C_(60).Furthermore,both simulated and experimental data proved their promising solution-processabilities as electron-transporting layers(ETLs)for perovskite solar cells.As a result,the planar p-i-n structural perovskite solar cell could achieve a maximum power conversion efficiency of 14.7%with C_(60)-G2.
基金China International Science and Technology Cooperation Program for Key Projects (Grant No. 2008DFA31070)
文摘Poly （amidoamine） dendrimers are emerging as versatile and derivatizable nano-scale drug delivery vehicles. In our study, cis-4,7,10,13,16,19-docosahexenoic acid and doxorubicin were conjugated to generation 2.5 PAMAM. The molecular architecture of the carrier was designed for optimized blood circulation and optimized drug release through the use of pH-sensitive hydrazone linkages. In vitro, DHA-PAMAM-DOX conjugates were able to release twice as much doxorubicin at pH 4.5 （lysosomal pH） as at pH 7.4, ensuring more pronounced antitumor activity. Upon intravenous administration to ICR mice, the DHA-PAMAM-DOX delivery systems resulted in more plasma exposure of doxorubicin than free doxorubicin solution. In efficacy studies performed with B6D2F1 mice bearing B16 melanoma tumors, DHA-PAMAM-DOX was significantly more efficient in inhibiting tumor growth than free doxorubicin at the dose equivalent to 5 mg/kg doxorubicin. Our research provides evidence that DHA-PAMAM-DOX conjugates have the potential to enhance the effect of cancer therapy in the course of delivering anticancer drugs to their target sites.
基金supported by the National Natural Science Foundation of China(21474027,91023008,20874026,20704013)Shanghai Shuguang Project(07SG33)+1 种基金New Century Excellent Talents in University,Ph D Programs Foundation of Ministry of Education of China,Shanghai Leading Academic Discipline Project(B502)the"Eastern Scholar Professorship"support from Shanghai Local Government
文摘The Bergman cyclization has strongly impacted on a number of fields including pharmaceutics, synthetic chemistry, and material science. The diradical intermediates stemmed from enediynes can not only cause DNA cleavage under physiological conditions but also function as monomer or initiator participants in polymer science. The homo-polymerization of enediynes through the Bergman cyclization to fabricate conjugated polymers is a fascinating strategy due to the advantages of facial operation, high efficiency, tailored structure, and catalyst-free operation. Moreover, conjugated polymers generated through the Bergman cyclization show many remarkable properties, such as excellent thermal stability, good solubility, and processability, which enables these polymers to be further manufactured into carbon-rich materials. Recent times have seen extensive efforts devoted to the application of the Bergman cyclization in polymer science and materials chemistry. A variety of synthetic strategies have been developed to fabricate structurally unique materials via the Bergman cyclization, including the fabrication of rod-like polymers with polyester, dendrimers and chiral imide side chains, functionalization of carbon nanomaterials by surface-grafting conjugated polymers, formation of nanoparticles by intramolecular collapse of single polymer chains, and the construction of carbon nanomembranes with different morphologies. Future developments involving the Bergman cyclization in polymer science, probably by altering the reaction mechanism to precisely control the microstructure of polymeric products, are also proposed in this review article.
基金supported by the National Basic Research Program of China(2013CB834703,2013CB834505)the National Natural Science Foundation of China(21173245,21273258,21233011,21472201,21302196)
文摘Dendrimers are well-defined tree-like macromolecules possessing numerous chain ends emanating from a single core, which makes them attractive candidates for mimicking light-harvesting systems and hydrogenases. Photoinduced electron and energy transfers are main processes involved in light-harvesting and photocatalysis. In this review, the general concepts of design strategies and recent developments of photofunctional dendrimers in biomimics of light-harvesting systems and hydrogenases are discussed. The energy transfer and electron transfer processes in light-harvesting dendrimers and the effect of dendritic structures in photochemical hydrogen production are illustrated.
基金financially supported by the National Natural Science Foundation of China (21774007, 21574009 and 51521062)the Higher Education and High-quality and World-class Universities (PY201605)
文摘Hydrophilic dendrimers, especially poly（amidoamine）（PAMAM） dendrimers are widely applied in modifying fluorescent dyes to endow them with water solubility and biocompatibility for biologic fluorescence imaging.Common preparation strategies of fluorescent dendrimers including encapsulating dyes or attaching dyes at periphery of dendrimers might cause uncertain constituent and lower biocompatibility. Here, we have developed a series of watersoluble fluorescent dendrimers with dye as core and fanshaped PAMAM as arms. Carboxylated perylene bisimides（PBI） dye and squarylium indocyanine（SICy） dye were conjugated with PAMAM dendrons by amidation to obtain a series of fluorescent dendrimers with enhanced water-solubility. Two PBI based dendrimers（PBI-G2.5 and PBI-G1.5）were chosen as model compounds for further optical, selfassembly and biological studies. In aqueous environment,PBI-G2.5 exhibited strong fluorescence, small size（~30 nm）and slightly positive surface charge（~2.46 mV）, which are ideal for biomedical applications. In vitro assays demonstrated that PBI-G2.5 nanoparticles accumulated in the cytoplasm of He La cells with rapid cellular uptake. The strong fluorescence in He La cells remained for over 48 h. To conclude, our study provides an effective strategy for preparing water-soluble fluorescent dendrimers towards long-term live cell imaging.
基金supported by the National Natural Science Foundation of China (20974119,90922019,and 21074147)Chinese Academy of Sciences,and the Science and Technology Commission of Shanghai Municipality (09PJ1411700)
文摘Inorganic nanomaterials have a variety of fascinating properties and a wide range of promising applications.However,they often suffer from instability and poor processibility.To solve it,dendrimers,a special family of macromolecules having a unique three-dimensional architecture,provide one of the excellent solutions.In addition,the site-selective functionalization of the specific elements in the dendritic structure endows the nanohybrid system new functions and applications.Inspired by such ideas,a variety of dendrimer/inorganic nanomaterial composites have been designed and exploited.This review article selects a number of representative examples,and illustrates their preparation,characterization,properties,and applications.The influence and the unique features that originate from the introduced dendritic structures are particularly discussed.
文摘A facile and green approach has been developed for the in situ synthesis of hybrid nanomaterials based on dendrite-shaped Pd nanostructures supported on graphene （RG）. The as-synthesized hybrid nanomaterials （RG-PdnDs） have been thoroughly characterized by high resolution transmission electron microscopy, X-ray photoelectron spectroscop）~ atomic force microscop）~ Raman spectroscopy and electrochemical techniques. The mechanism of formation of such dendrite- shaped Pd nanostructures on the graphene support has been elucidated using transmission electron microscopy （TEM） measurements. The RG induces the formation of, and plays a decisive role in shaping, the dendrite morphology of Pd nanostructures on its surface. Cyclic voltammetry and chronoamperometry techniques have been employed to evaluate the electrochemical performance of RG-PdnDs towards oxidation of methanol. The electrochemical （EC） activities of RG-PdnDs are compared with graphene-supported spherical-shaped Pd nanostructures, Pd nanodendrites alone and a commercial available Pd/C counterpart. The combined effect of the graphene support and the dendrite morphology of RG-PdnDs triggers the high electrocatalytic activity and results in robust tolerance to CO poisoning.
