Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• multiblock copolymers with the possibility to introduce stimuli-responsive functionalities were obtained using a bimetallic ruthenium initiator [74]. The initiator allowed for the single-step fabrication of symmetrically end-functionalized telechelic polymers using ROMP and functional chain terminators

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• topologically complex TTF catenanes and cage compounds [52][74][102][103][104]. 6.1. Stimuli-responsive circumrotation The TTF-based catenane 26 allows implementing a stimuli-responsive circumrotation motion (Figure 24) [105]. Similar to the corresponding donor–acceptor rotaxanes, the macrocycle preferentially

• organosulfur compound TTF developed from a molecular switch with multiple electronic and material applications to one of the most widely used building blocks for the construction of stimuli-responsive MIMs and functional molecular devices. The development of straightforward organic reactions to implement TTFs

A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• and thiol functional groups. The reversible shuttling movement of the macrocycle between two different recognition sites on the molecular thread can be driven by external acid and base. This kind of rotaxane bearing functional groups provides a powerful platform for preparing stimuli-responsive

• ][5][6][7]. During the past years, a large number of different MIMs has been constructed, such as handcuff catenane [8], molecular elevators [9][10], molecular muscles [11][12], trefoil necklace [13][14][15], molecular walkers [16][17][18] and molecular pumps [19][20]. Combining the stimuli-responsive

• , which act as important precursors for constructing stimuli-responsive supramolecular materials [21][22]. Rotaxanes [23][24][25][26][27][28][29][30][31], as one of the most important MIMs, have been deeply investigated because of their excellent properties and convenient synthesis. By introducing various

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• gels are typically made of low-molecular-weight (LMW) compounds self-assembled in different solvents via non-covalent interactions. In most cases, this feature enables reversible stimuli-responsive gel-to-sol transitions [31]. Usually, the entanglement of 1D nanofibers of gelator molecules generates a

A conformationally adaptive macrocycle: conformational complexity and host–guest chemistry of zorb[4]arene

• Liu-Pan Yang,
• Song-Bo Lu,
• Arto Valkonen,
• Fangfang Pan,
• Kari Rissanen and
• Wei Jiang

Beilstein J. Org. Chem. 2018, 14, 1570–1577, doi:10.3762/bjoc.14.134

• binding behavior of ZB4 and lays the basis for the construction of stimuli-responsive materials with ZB4 as a major component. Keywords: conformations; host–guest chemistry; macrocycles; supramolecular chemistry; zorb[4]arene; Introduction Macrocyclic receptors are the principal workhorses used in

• understand the importance of conformational adaptivity in biomolecular recognition and even design stimuli-responsive materials by harnessing this large amplitude of conformational changes. X-ray single crystal structure of ZB4 and the host–guest complexes. a) ZB4, b) 2+@ZB4-IV, c) 3+@ZB4-IV, d) 10+@ZB4-I

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

• different enzymes and/or the tumor microenvironment might trigger the improper release of the drug from the PDC, i.e., to end up with the drug-carrying part of the linker. Another class of linkers is the stimuli-responsive/degradable linkers, designed to achieve an efficient release of the drug from the

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

• Françoise Debart,
• Christelle Dupouy and
• Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

• under different stimuli. The interest in stimuli-responsive ONs for gene silencing functions has been notable in recent years. The ON prodrug strategies usually help to overcome limitations of natural ONs due to their low metabolic stability and poor delivery. Nevertheless, compared to permanent ON

• the modification in the nucleotide: the internucleosidic phosphate, the nucleobase, the sugar or the extremities of ONs. Moreover, the review provides a current and detailed account of stimuli-responsive ONs with the main goal of gene silencing. However, for some stimuli-responsive ONs reported in

• group; oligonucleotide prodrugs; reduction-responsive; stimuli-responsive nucleic acids; thermolytic prodrugs; Introduction For past decades, oligonucleotide-based therapies have been widely developed using short synthetic oligonucleotides (ONs) and their chemically modified mimics as powerful tools to

A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation

• Wangkhem P. Singh and
• Rajkumar S. Singh

Beilstein J. Org. Chem. 2017, 13, 138–149, doi:10.3762/bjoc.13.17

• such as acids or bases [17], metal ions [18], oxidation and reduction [19], reactive species enzymes, etc. Such responsive gel systems are highly desirable in stimuli-responsive sensor materials, drug delivery, catalysis, nano- and mesoscopic assemblies, light harvesting systems, and many others [20

Stimuli-responsive HBPS-g-PDMAEMA and its application as nanocarrier in loading hydrophobic molecules

• Yongsheng Chen,
• Li Wang,
• Haojie Yu,
• Zain-Ul-Abdin,
• Ruoli Sun,
• Guanghui Jing,
• Rongbai Tong and
• Zheng Deng

Beilstein J. Org. Chem. 2016, 12, 939–949, doi:10.3762/bjoc.12.92

• Yongsheng Chen Li Wang Haojie Yu Zain-Ul-Abdin Ruoli Sun Guanghui Jing Rongbai Tong Zheng Deng State Key Laboratory of Chemical Engineering College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China 10.3762/bjoc.12.92 Abstract The topic of stimuli-responsive

• -responsive nanocarriers; Introduction Stimuli-responsive polymers have attracted much attention due to their broad applications including drug controlled release [1][2][3][4][5], sensing [6][7] and 4D printing [8][9]. Nanocarriers prepared from amphiphilic stimuli-responsive polymers are promising

• candidates for transporting hydrophobic guest molecules such as anticancer or antitumor drugs. In the cases of polymeric nanocarriers with responsive shell and stable core, the external hydrophilic shell makes these nanocarriers soluble in water and affords stimuli-responsive properties. The interior

Superstructures with cyclodextrins: chemistry and applications III

• Gerhard Wenz and
• Eric Monflier

Beilstein J. Org. Chem. 2016, 12, 937–938, doi:10.3762/bjoc.12.91

• styrene from ethylbenzene [3][4]. Highly porous networks were synthesized by crosslinking β-CD with tetrafluoroterephthalonitrile. These networks were able to almost completely remove pollutants (e.g., bisphenol A) within a short time from wastewater [5]. Stimuli-responsive nanoparticles were assembled by

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• stimuli-responsive materials collectively called “smart materials”. These include “self-healing materials” which after being disrupted can recover their former state through host–guest interactions. Some examples of these materials are now discussed. 5.1 Photo-responsive materials Among the better known

• properties may be tailored to give smart-materials possessing stimuli responsive characteristics exemplified by photo-, pH-, thermo-, and redox-responsivity and self-healing. Inevitably, many more novel polymer network systems incorporating cyclodextrins will appear; some of which will find exciting

Preparation of Pickering emulsions through interfacial adsorption by soft cyclodextrin nanogels

• Shintaro Kawano,
• Toshiyuki Kida,
• Mitsuru Akashi,
• Hirofumi Sato,
• Motohiro Shizuma and
• Daisuke Ono

Beilstein J. Org. Chem. 2015, 11, 2355–2364, doi:10.3762/bjoc.11.257

• property of CD nanogels on the droplet surface has great potential to become new microcapsule building blocks with porous surfaces. These microcapsules may act as stimuli-responsive nanocarriers and nanocontainers. Keywords: crosslinked cyclodextrin polymer; interfacial adsorption; nanogel; Pickering

• crosslinked polymers, have recently been demonstrated as Pickering emulsifiers with pH or thermo-responsive properties [7][8][9]. Such emulsions have potential in pharmaceutical, food, and cosmetic products. Moreover, emulsions stabilized by stimuli-responsive soft microgels should be applicable as templates

• new building blocks for microcapsules with porous surfaces and stimuli-responsive nanocarriers in storage and/or release systems. Experimental Materials Heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) was purchased from Nacalai Tesque, Inc. (Japan). DM-β-CD was vacuum dried at 80 °C overnight prior

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study

• Yulia I. Denisova,
• Maria L. Gringolts,
• Alexander S. Peregudov,
• Liya B. Krentsel,
• Ekaterina A. Litmanovich,
• Arkadiy D. Litmanovich,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2015, 11, 1796–1808, doi:10.3762/bjoc.11.195

• easily cleavable moieties in their backbone [4][5]. It aims at stimuli-responsive, intelligent polymeric materials, the structure and properties of which can be precisely controlled by adjusting temperature, pH or by introducing low molecular additives. Much less is known about the possibility of monomer

Synthesis and characterization of pH responsive D-glucosamine based molecular gelators

• Navneet Goyal,
• Hari P. R. Mangunuru,
• Bargav Parikh,
• Sonu Shrestha and
• Guijun Wang

Beilstein J. Org. Chem. 2014, 10, 3111–3121, doi:10.3762/bjoc.10.328

• the controlled release of certain biological agents [17][18][19][20][21][22][23][24][25][26][27]. Molecular gelators containing photo or pH responsive functional groups are able to form multi-stimuli responsive gels. These resulting gels may find applications as advanced soft functional materials [28

Cyclodextrin–polysaccharide-based, in situ-gelled system for ocular antifungal delivery

• Anxo Fernández-Ferreiro,
• Noelia Fernández Bargiela,
• María Santiago Varela,
• Maria Gil Martínez,
• Maria Pardo,
• Antonio Piñeiro Ces,
• José Blanco Méndez,
• Miguel González Barcia,
• Maria Jesus Lamas and
• Francisco.J. Otero-Espinar

Beilstein J. Org. Chem. 2014, 10, 2903–2911, doi:10.3762/bjoc.10.308

• patient compliance and comfort [10]. Specifically, stimuli-responsive polymer hydrogels have recently attracted special attention as drug delivery systems due to their capacity to respond to changing environmental conditions such as ion composition, pH, temperature, presence of chemicals, or changes on

Linear-g-hyperbranched and cyclodextrin-based amphiphilic block copolymer as a multifunctional nanocarrier

• Yamei Zhao,
• Wei Tian,
• Guang Yang and
• Xiaodong Fan

Beilstein J. Org. Chem. 2014, 10, 2696–2703, doi:10.3762/bjoc.10.284

• ) (PDMAEMA) block (Scheme 1A, P1), allows for the self-assembly and controlled release by taking advantage of the amphiphilic structure and the stimuli-responsive property of PDMAEMA block, respectively. When the hyperbranched polycarbonsilane (HBPCSi) is grafted onto the side chain of PHEMA blocks (Scheme

• release was obtained by taking advantage of the stimuli-responsive property of the PDMAEMA segments. Furthermore, the cumulative amounts of LND released from DLMP1, DLMP2 and DLMP3 were only 18.4, 15.5, and 9.2%, respectively, within the release time of 48 h, indicating the clear sustained release

Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

• Ji-Hun Seo,
• Shino Nakagawa,
• Koichiro Hirata and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2014, 10, 2623–2629, doi:10.3762/bjoc.10.274

• disassembling of PRX by a cytoplasmic reductant such as glutathione. The characteristic property of cleavable PRXs may also be harnessed to develop a stimuli-responsive crosslinker to modulate the hardness of acrylic resins. Acrylic resins are irreversible photosetting polymers adopted to increase the

• , the introduction of a stimuli-responsive and degradable crosslinkable resin monomer into the composite resin, the hardness of the polymerized resin composite could be modulated under specific conditions. Because the degradable PRX structure is a suitable molecular platform for an efficient degradation

Host–guest-driven color change in water: influence of cyclodextrin on the structure of a copper complex of poly((4-hydroxy-3-(pyridin-3-yldiazenyl)phenethyl)methacrylamide-co-dimethylacrylamide)

• Nils Retzmann,
• Gero Maatz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2480–2483, doi:10.3762/bjoc.10.259

• experiments. Keywords: cyclodextrin; copolymer; copper(II) sulfate; supramolecular; water complex; Introduction In recent years, the interest in stimuli-responsive polymers increased exponentially [1]. Many polymers have been described, showing sensitivity towards e.g. light, pH and heat [2][3][4

• -copper complexes in aqueous media. In result we could show that supramolecular structures and metal complexes open up a wide field for the development of novel stimuli-responsive polymer materials. We thus described that the simple addition of copper and γ-CD to a poly((4-hydroxy-3-(pyridin-3-yldiazenyl

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• titration (pH), nephelometry, rheology and dynamic light-scattering. Moreover, preliminary studies about stimuli-responsive interpolyelectrolyte complexes are presented. Results and Discussion Synthesis The synthesis of a novel polyzwitterion based on cellulose was performed by activation of the polymer

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

• Sebastian Reinelt,
• Daniel Steinke and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 680–691, doi:10.3762/bjoc.10.61

• interactions in living systems [3][4]. Since then, the field of self-assembly through molecular recognition has attracted much attention also in the design of smart materials. In this context, cyclodextrins (CD) are of interest as ring shaped host molecules, e.g., for the design of stimuli-responsive hydrogels

• [5] or of optical sensors [6]. Certain stimuli-responsive materials are characterized by the presence of thioethers in the main chain. Tirelli et al. investigated the oxidation-responsive behavior of thioethers for biomedical applications [7][8][9][10]. The stimulus of these mostly poly(propylene

• ]. Some publications make use of free-radical chain transfer polymerization and subsequent polymer post-modification [25][27][35][36]. The scope of our investigation was the preparation of multiple-stimuli-responsive PDEAAm polymers possessing hydrophobic end-groups suitable for host–guest interactions

Polymeric redox-responsive delivery systems bearing ammonium salts cross-linked via disulfides

• Christian Dollendorf,
• Martin Hetzer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 1652–1662, doi:10.3762/bjoc.9.189

• (DEAAm); Introduction Hydrogels with stimuli-responsive properties, in combination with targeted release of embedded drugs, have emerged as a fascinating class of biomedical materials and attracted great interest in medical science, polymeric biotherapeutics and drug delivery in general [1][2][3][4]. In

Substituent effect on the energy barrier for σ-bond formation from π-single-bonded species, singlet 2,2-dialkoxycyclopentane-1,3-diyls

• Jianhuai Ye,
• Yoshihisa Fujiwara and
• Manabu Abe

Beilstein J. Org. Chem. 2013, 9, 925–933, doi:10.3762/bjoc.9.106

• compounds 1–5, AZc–g, and CPc–g. Acknowledgements NMR and MS measurements were performed at N-BARD, Hiroshima University. This work was supported by a Grant-in-Aid for Science Research on Innovative Areas “Stimuli-responsive Chemical Species” (No. 24109008), “pi-Space” (No. 21108516), and No. 19350021 from

Interaction of cyclodextrins with pyrene-modified polyacrylamide in a mixed solvent of water and dimethyl sulfoxide as studied by steady-state fluorescence

• Akihito Hashidzume,
• Yongtai Zheng and
• Akira Harada

Beilstein J. Org. Chem. 2012, 8, 1312–1317, doi:10.3762/bjoc.8.150

• systems are applicable to stimuli-responsive systems [13][14][15][16][17][18]. We have been working on the interaction of CDs with water-soluble polymers bearing various guest residues, including linear, branched, and cyclic aliphatics, as well as aromatics [19][20][21], and realized stimuli-responsive

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

• Gareth L. Nealon,
• Romain Greget,
• Cristina Dominguez,
• Zsuzsanna T. Nagy,
• Daniel Guillon,
• Jean-Louis Gallani and
• Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

• factors, such as applied magnetic and electric fields and surface effects, all of which lend these materials towards their use in stimuli-responsive advanced materials [24]. What follows is a brief introduction to some of the salient points in LC science, but a thorough introduction to the theory and

The interplay of configuration and conformation in helical perylenequinones: Insights from chirality induction in liquid crystals and calculations

• Elisa Frezza,
• Silvia Pieraccini,
• Stefania Mazzini,
• Alberta Ferrarini and
• Gian Piero Spada

Beilstein J. Org. Chem. 2012, 8, 155–163, doi:10.3762/bjoc.8.16

• Programme (PRIN 2009, grant 2009N5JH4F_002 “Stimuli responsive liquid crystalline phases and supramolecular systems”). Computational resources and assistance were provided by the “Laboratorio Interdipartimentale di Chimica Computazionale” (LICC) at the Dipartimento di Scienze Chimiche of the University of