- Manganese porphyrin-incorporated conjugated polymer nanoparticles for T1-enhanced magnetic resonance and fluorescent imaging
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Conjugated polymer nanoparticles (CPNs) possess many useful and fascinating properties, including high brightness, excellent photostability, good water-dispersibility, low cytotoxicity, and easy functionalization, showing promising application in bioimaging. In this work, one kind of optical/magnetic conjugated polyelectrolyte has been designed and synthesized by introducing Mn(III) porphyrin (T1-weighted relaxivity) into a fluorescent fluorene based polymer backbone. Fluorescent/magnetic conjugated polymer nanoparticles (FM-CPNs) were prepared by self-assembly in the phosphate buffer solution caused by their amphiphilic structures with hydrophobic backbones and hydrophilic side chains. Their photophysical properties have been investigated in details via UV–vis absorption and fluorescent emission spectra. Investigation of its magnetic properties has shown that the FM-CPNs exhibit high T1-weighted relaxivity value, making them promising candidates for T1-enhanced magnetic resonance imaging agent. Further cell imaging has been realized successfully using FM-CPNs as staining label, and cytotoxicity was evaluated by the methyl thiazolyl tetrazolium (MTT) assay.
- Yang, Tianshe,Feng, Wenguo,Hu, Changyong,Lv, Zhuang,Wei, Huanjie,Jiang, Jiayang,Liu, Shujuan,Zhao, Qiang
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- A delocalizable cationic headgroup together with an oligo-oxyethylene spacer in gemini cationic lipids improves their biological activity as vectors of plasmid DNA
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Lipoplex nano-aggregates constituted of plasmid DNA (pDNA) pEGFP-C3 and mixed cationic liposomes, consisting of several percentages of a gemini cationic lipid (GCL) of the 1,2-bis(hexadecyl imidazolium) oxyethylene series, referred to as (C16Im)2(C2O)n, with oxyethylene spacers (n = 1, 2 or 3) between the imidazolium cationic groups and the DOPE zwitterionic helper lipid, have been characterized by various biophysical and biological approaches carried out at several GCL compositions (α), and either the mass or the effective charge ratio of the lipoplex. The electrochemical study by ζ-potential confirms that the three GCLs yield a 10% lower effective charge than the nominal one, while compacted pDNA yields only a 25% effective negative charge. The SAXS study reveals, irrespective of the spacer length (n) and effective charge ratio (ρeff), the presence of two lamellar structures, i.e., one (Lα,main) in the whole GCL composition and another (Lα,DOPE,rich) with higher periodicity values that coexists with the previous one at low GCL composition (α = 0.2). The cryo-TEM analysis shows two types of multilamellar structures consisting of cationic lipidic bilayers with pDNA sandwiched between them: a cluster-type (C-type) at low α = 0.2 and a fingerprint-type (FP-type) at α ≥ 0.5, both with similar interlamellar spacing (d) in agreement with the Lα,main structure determined by SAXS. Transfection efficacies (TEs) of each lipid mixture were determined in four different cell lines (HEK293T, HeLa, Caco-2 and A549) at several α and ρeff values in the absence and presence of serum (FBS). The optimized formulations (α = 0.2 and ρeff = 2.0) substantially transfect cells much better than a commercial transfection reagent, Lipofectamine 2000 and previously studied efficient lipoplexes containing other cationic head groups or spacers both in the absence and presence of serum. The activity of optimized formulations may be attributed to the combination of several factors, such as: (a) the fusogenic character of DOPE which results in higher fluidity of the lipoplexes at α = 0.2, (b) the coexistence of two lamellar structures at α = 0.2 that synergizes the TE of these lipid vectors, and mainly (c) the higher biocompatibility of the GCLs reported in this work due to the presence of two imidazolium cationic groups together with an oligo-oxyethylene spacer. The length of the spacer in the GCL seems to have less impact, although (C16Im)2(C2O)n/DOPE-pDNA lipoplexes with n = 1 and 3 show higher gene transfection than n = 2. All the optimum formulations reported herein are all highly efficient with negligible levels of toxicity, and thus, may be considered as very promising gene vectors for in vivo applications. This journal is
- Kumar, Krishan,Barrn-Berdn, Ana L.,Datta, Sougata,Muoz-beda, Mnica,Aicart-Ramos, Clara,Kondaiah, Paturu,Junquera, Elena,Bhattacharya, Santanu,Aicart, Emilio
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- Transmission of Unidirectional Molecular Motor Rotation to a Remote Biaryl Axis
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Molecular motors undergo repetitive directional motions upon external energy input. A profound challenge is the defined transfer of directional motor motions to remote entities at the molecular scale. Herein, we present a molecular setup that allows for the transfer of the directional rotation of a light-powered motor unit onto a remote biaryl axis via an ethylene glycol chain link. Based on a combination of X-ray crystallographic analysis, ECD, and NMR experiments as well as a comprehensive theoretical assessment, we provide evidence for the coupled stepwise directional motions of both molecular units. With the presented setup, facile integration of molecular motor units into larger functional frameworks and complex molecular machines can be explored consciously in the future.
- Uhl, Edgar,Thumser, Stefan,Mayer, Peter,Dube, Henry
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- A platinum(II)-acetylide-based conjugated polyelectrolyte for hypoxia imaging via ratiometric and time-resolved luminescence microscopy
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A platinum(II)-acetylide-based conjugated polyelectrolyte has been designed and synthesized by using polyfluorenes as an O2-insensitive fluorophore and Pt(II) complex as an O2-sensitive phosphor, which can generate conjugated polyelectrolyte nanoparticle (CPE-nanoparticle) in the aqueous solution owing to their amphiphilic structures. The CPE-nanoparticle displays good sensitivity to O2 concentration and can detect oxygen levels reversibly. The intracellular ratiometric O2 sensing performance of the CPE-nanoparticle has been demonstrated by the remarkable variation in the Igreen/Iblue ratio values (0.18–0.85) in HeLa cells under different O2 levels. Furthermore, O2 level detection was carried out through time-resolved luminescence imaging (TRLI) to demonstrate the accuracy of the probe based on the CPE-nanoparticle. The CPE-nanoparticle shows a high phosphorescence quantum yield (19.98%) and oxygen quenching efficiency (0.975), which are superior to the existing O2 probe. The CPE-nanoparticle has been successfully applied in photoluminescence lifetime imaging and time-gated luminescence imaging for monitoring intracellular O2 levels.
- Li, Guo,Huang, Tianci,Xie, Mingjuan,Zhang, Xiangxiang,Yu, Qi,Liu, Shujuan,Yang, Tianshe,Zhao, Qiang
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- Dynamic Assemblies of Molecular Motor Amphiphiles Control Macroscopic Foam Properties
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Stimuli-responsive supramolecular assemblies controlling macroscopic transformations with high structural fluidity, i.e., foam properties, have attractive prospects for applications in soft materials ranging from biomedical systems to industrial processes, e.g., textile coloring. However, identifying the key processes for the amplification of molecular motion to a macroscopic level response is of fundamental importance for exerting the full potential of macroscopic structural transformations by external stimuli. Herein, we demonstrate the control of dynamic supramolecular assemblies in aqueous media and as a consequence their macroscopic foam properties, e.g., foamability and foam stability, by large geometrical transformations of dual light/heat stimuli-responsive molecular motor amphiphiles. Detailed insight into the reversible photoisomerization and thermal helix inversion at the molecular level, supramolecular assembly transformations at the microscopic level, and the stimuli-responsive foam properties at the macroscopic level, as determined by UV-vis absorption and NMR spectroscopies, electron microscopy, and foamability and in situ surface tension measurements, is presented. By selective use of external stimuli, e.g., light or heat, multiple states and properties of macroscopic foams can be controlled with very dilute aqueous solutions of the motor amphiphiles (0.2 weight%), demonstrating the potential of multiple stimuli-responsive supramolecular systems based on an identical molecular amphiphile and providing opportunities for future soft materials.
- Chen, Shaoyu,Feringa, Ben L.,Leung, Franco King-Chi,Stuart, Marc C. A.,Wang, Chaoxia
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- A versatile and robust vesicle based on a photocleavable surfactant for two-photon-tuned release
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A small amphiphile that contains a coumarin unit and alkynyl groups, as a two-cleavable segment and polymerizable groups, respectively, was designed and synthesized. The amphiphile showed a critical aggregation concentration of about 4.6×10-5M and formed a vesicle-type assembly. The formed vesicles were stabilized by insitu "click" polymerization without altering their morphology. Hydrophobic and hydrophilic guests can be encapsulated within the vesicle membrane and inside the aqueous core of the vesicle, respectively. The loaded guests can be released from the vesicle by using UV or near-IR stimuli, through splitting up the amphiphilic structure of the amphiphile. Distinguished dose-controlled photorelease of the polymeric vesicle is achieved with the maintenance of vesicular integrity, which makes the guest release dependent on the amount of cleavage of the amphiphilic structure during irradiation. This study provides a potential strategy for the development of versatile and stable drug-delivery systems that offer sustained and photo-triggered release. Copyright
- Li, Yi,Dong, Jianming,Xun, Zhiqing,Zeng, Yi,Yu, Tianjun,Han, Yongbin,Chen, Jinping,Li, Ying-Ying,Yang, Guoqiang
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- Metal-organic frameworks constructed from crown ether-based 1,4-benzenedicarboxylic acid derivatives
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A series of unprecedented crown ether- and thiacrown ether-derivatized benzene dicarboxylic acid (H2bdc) ligands has been synthesized and incorporated into the prototypical isoreticular metal-organic framework (IRMOF) and UiO-66 materials. In the case of UiO-66, only MOFs comprised from a mixed-ligand composition, requiring both unsubstituted bdc and crown ether containing ligands, could be prepared. These are among the few ligand derivatives, and resulting MOFs, that incorporate a macrocyclic group directly on the bdc ligand, providing a new, modular platform for exploring new supramolecular and coordination chemistry within MOFs.
- Chen, Teng-Hao,Schneemann, Andreas,Fischer, Roland A.,Cohen, Seth M.
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- Cationic amphitropic gemini surfactants with hydrophilic oligo(oxyethylene) spacer chains
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New gemini diammonium surfactants have been synthesized in which the spacer chain consists of oligo(oxyethylene) units and which exhibit thermotropic liquid crystalline lamellar α and β as well as lyotropic mesophases.
- Dreja, Michael,Gramberg, Susanne,Tieke, Bernd
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- Novel gemini micelles from dimeric surfactants with oxyethylene spacer chain. Small angle neutron scattering and fluorescence studies
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Three new gemini surfactants containing mono-, di-, and trioxyethylene spacer chains have been synthesized. Small angle neutron scattering (SANS) cross sections from the micellar aggregates of these dimeric amphiphiles Br-, n-C16H33NMe2+-CH2(CH 2OCH2)pCH2-N+Me 2-n-C16H33, Br-, (where p = 1, 2, and 3) in aqueous media (D2O) have been measured. The data have been analyzed using the Hayter and Penfold model for macro-ion solution to compute the interparticle structure factor S(Q) taking into account the screened Coulomb interactions between the dimeric micelles. The SANS analysis showed that the micellar morphology depends on both the nature and the length of the spacer unit. Detailed analysis of the data further indicates that the introduction of oxyethylene spacer is not sufficient enough to prevent looping of the spacer chain. Thus the average separation between the dimethylammonium ion headgroups is considerably lower than is expected from a fully extended conformation of the spacer chain. The micelles from these surfactants have also been characterized in terms of their critical micelle concentrations (cmc), microviscosities, and micropolarities on the basis of the information provided by micelle-solubilized fluorescent probes. These results indicate little difference in their micellar properties such as cmc, microviscosity, and micropolarity.
- De, Soma,Aswal, Vinod K.,Goyal, Prem S.,Bhattacharya, Santanu
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- Photochromic controlled permeable small molecule cross-linked vesicle as well as preparation method and application thereof
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The invention discloses a photochromic controlled-permeation small-molecule crosslinked vesicle CSMVs as well as a preparation method and application thereof. Belong to micromolecule self-assembly technical field. The invention firstly synthesizes an azobenzene amphiphilic compound, and then further cross-linking to prepare the photochromic controllable permeable small-molecule cross-linked vesicle. The controlled release system is simple to prepare, high in stability, intelligent in control, and capable of exhibiting real-time controllable permeability in time and space, CSMVs at the molecular level due to the molecular structure of the vesicle wall, and instantaneous controlled release is exhibited. In cancer. The method has wide application prospects in the accurate treatment of diseases such as diabetes and bacterial infection.
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Paragraph 0045-0047
(2021/09/01)
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- COMPOUND, DECORATIVE MATERIAL, DECORATED ARTICLE, AND INK COMPOSITION
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To provide a compound exhibiting golden glossiness and providing a film having flexibility.SOLUTION: There is provided a compound represented by the formula (1). Rand Rare each independently a substituted or unsubstituted C1 to 12 alkyl group, -(CH)-COO-R, -(CH)-O-R, -(CH)-CONH-R, -(CH)-CONH-(CH)-OH or the like; Rto Rare each independently a C1 to 6 alkyl group; nis an integer of 2 to 10; and mto mare integer of 1 to 6.SELECTED DRAWING: None
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Paragraph 0105; 0114-0116; 0122-0124
(2020/03/27)
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- MODULATORS OF PROTEOLYSIS AND ASSOCIATED METHODS OF USE
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The present disclosure relates to bifunctional compounds, which find utility as modulators of Kirsten rat sarcoma protein (target protein). In particular, the present disclosure is directed to bifunctional compounds, which contain on one end a Von Hippel-Lindau, cereblon, Inhibitors of Apotosis Proteins or mouse double-minute homolog 2 ligand which binds to the respective E3 ubiquitin ligase and on the other end a moiety which binds the target protein, such that the target protein is placed in proximity to the ubiquitin ligase to effect degradation (and inhibition) of target protein. The present disclosure exhibits a broad range of pharmacological activities associated with degradation/inhibition of target protein. Diseases or disorders that result from aggregation, accumulation, and/or overactivation of the target protein are treated or prevented with compounds and compositions of the present disclosure.
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Paragraph 001432-001433
(2019/10/29)
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- A Novel Conjugate of Bis[((4-bromophenyl)amino)quinazoline], a EGFR-TK Ligand, with a Fluorescent Ru(II)-Bipyridine Complex Exhibits Specific Subcellular Localization in Mitochondria
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The epidermal growth factor receptor (EGFR) is a key target in anticancer research, whose aberrant function in malignancies has been linked to severe irregularities in critical cellular processes, including cell cycle progression, proliferation, differentiation, and survival. EGFR mutant variants, either transmembrane or translocated to the mitochondria and/or the nucleus, often exhibit resistance to EGFR inhibitors. The ability to noninvasively image and quantify EGFR provides novel approaches in the detection, monitoring, and treatment of EGFR-related malignancies. The current study aimed to deliver a new theranostic agent that combines fluorescence imaging properties with EGFR inhibition. This was achieved via conjugation of an in-house-developed ((4-bromophenyl)amino)quinazoline inhibitor of mutant EGFR-TK, selected from a focused aminoquinazoline library, with a [Ru(bipyridine)3]2+ fluorophore. A triethyleneglycol-derived diamino linker featuring (+)-ionizable sites was employed to link the two functional moieties, affording two unprecedented Ru conjugates with 1:1 and 2:1 stoichiometry of aminoquinazoline to the Ru complex (mono-quinazoline-Ru-conjugate and bis-quinazoline-Ru-conjugate, respectively). The bis-quinazoline-Ru-conjugate, which retains an essential inhibitory activity, was found by fluorescence imaging to be effectively uptaken by Uppsala 87 malignant glioma (grade IV malignant glioma) cells. The fluorescence imaging study and a time-resolved fluorescence resonance energy transfer study indicated a specific subcellular distribution of the conjugate that coincides with that of a mitochondria-targeted dye, suggesting mitochondrial localization of the conjugate and potential association with mitochondria-translocated forms of EGFR. Mitochondrial localization was further documented by the specific concentration of the bis-quinazoline-Ru-conjugate in a mitochondrial isolation assay.
- Ilmi, Rashid,Tseriotou, Eleni,Stylianou, Panayiota,Christou, Yiota A.,Ttofi, Iakovia,Dietis, Nikolas,Pitris, Costas,Odysseos, Andreani D.,Georgiades, Savvas N.
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p. 4260 - 4273
(2019/10/16)
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- Synthesis and cytotoxicity of novel bisellipticines and bisisoellipticines
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A series of bis-ellipticines 7-9 and bis-isoellipticines 10-12 tethered through the indole nitrogen was synthesized and screened for antitumor cytotoxicity in the L-1210 murine leukemia assay. Activity was only displayed by 1,10-bis(6-ellipticinyl)-?-decane (8).
- Obaza-Nutaitis, Judy A.,Gribble, Gordon W.
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p. 171 - 187
(2019/07/31)
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- Mitochondria-targeted betulinic and ursolic acid derivatives: Synthesis and anticancer activity
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A series of new betulinic and ursolic acid conjugates with a lipophilic triphenylphosphonium cation, meant to enhance the bioavailability and mitochondriotropic action of natural triterpenes, have been synthesized. The in vitro experiments on three human cancer cell lines (MCF-7, HCT-116 and TET21N) revealed that all the obtained triphenylphosphonium triterpene acid derivatives not only showed higher cytotoxicity as compared to betulinic acid but were also markedly superior in triggering mitochondria-dependent apoptosis, as assessed using a range of apoptosis markers such as cytochrome c release, stimulation of caspase-3 activity, and cleavage of poly(ADP-ribose) polymerase, which is one of the targets of caspase 3. The IC50 was much lower for all triphenylphosphonium derivatives when compared to betulinic acid. Out of the tested group of conjugates, the most potent toxicity was exhibited by the betulinic acid conjugate 9 (for 9, the IC50 values against MCF-7 and TET21N cells were 0.70 μM and 0.74 μM; for betulinic acid (BA), IC50 > 25 μM against MCF-7 cells).
- Nedopekina, Darya A.,Gubaidullin, Rinat R.,Odinokov, Victor N.,Maximchik, Polina V.,Zhivotovsky, Boris,Bel'Skii, Yuriy P.,Khazanov, Veniamin A.,Manuylova, Arina V.,Gogvadze, Vladimir,Spivak, Anna Yu.
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p. 1934 - 1945
(2017/10/27)
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- LOW MOLECULAR WEIGHT POLYETHYLENE GLYCOL DRUG CONJUGATES HAVING IMPROVED DRUG BIOLOGICAL ACTIVITY
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Provided are polyethylene glycol drug conjugates of general formula (I), (II) or (III) and pharmaceutical compositions and a use thereof. The conjugates are formed by combining low molecular weight polyethylene glycol with 2-4 drug molecules. The conjugates can interact with receptor dimers or polymers, thereby improving the in vivo distribution of the drug, changing the oil and water distribution coefficient, enhancing the pharmacological activity, reducing the blood-brain barrier permeability of the drug, and improving the bioavailability of the drug.
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- BODIPY/Nile-Red-Based Efficient FRET Pair: Selective Assay of Endoplasmic Reticulum Membrane Fluidity
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We synthesized a boron-dipyrromethene (BODIPY)/Nile Red hybrid probe capable of selectively recognizing fluidity changes in the endoplasmic reticulum (ER) membrane due to its preferential localization to the ER and strong energy transfer from BODIPY to the Nile Red moiety, emitting only in nonaqueous environments. ER membrane fluidity in HepG2 cells was markedly reduced by a cell model of metabolic syndrome.
- Yang, Zhigang,Wi, Youngjin,Yoon, Young-Min,Verwilst, Peter,Jang, Joo Hee,Kim, Tae Woo,Kang, Chulhun,Kim, Jong Seung
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supporting information
p. 527 - 531
(2016/03/12)
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- Cationic gemini lipids containing polyoxyethylene spacers as improved transfecting agents of plasmid DNA in cancer cells
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Lipoplex nano-aggregates have been analyzed through biophysical characterization (electrostatics, structure, size and morphology), and biological studies (transfection efficiency and cell viability) in five cancer cell lines. Lipoplexes were prepared from pEGFP-C3 plasmid DNA (pDNA) and mixed liposomes, constituted by a zwitterionic lipid (DOPE) and a gemini cationic lipid (GCL) synthesized in this work, [bis(hexadecyl dimethyl ammonium) oxyethylene], referred to as (C16Am)2(C2O) n, (where n is the oxyethylene spacer length, n = 1, 2 or 3, between the ammonium heads). Cryo-TEM micrographs show nano-aggregates with two multilamellar structures, a cluster-type (at low-to-medium GCL composition) and a fingerprint-type that coexists with the cluster-type at medium GCL composition and appears alone at high GCL composition. SAXS diffractograms show that these lipoplexes present three lamellar structures, two of them coexisting at low and high GCL composition. The optimized transfection efficiency (TE) of pDNA was higher for lipoplexes containing GCLs with a longer (n = 3) or shorter (n = 1) polyoxyethylene spacer, at high GCL composition (α = 0.7) with low charge ratio (ρeff = 2). In the all cancer cell lines studied, the TE of the optimized formulations was much better than those of both lipofectamine 2000 and lipoplexes with GCLs of the bis(hexadecyl dimethyl ammonium) alkane series recently reported. Probably, (a) the coexistence of two lamellar structures at high GCL composition synergizes the TE of these lipid vectors, (b) the orientation of the polyoxyethylene region in (C16Am) 2(C2O)3/DOPE may occur in such a way that the spacing between two cationic heads becomes smaller than that in (C 16Am)2(C2O)2/DOPE which is poor in terms of TE, and (c) the synergistic interactions between serum proteins and (C16Am)2(C2O)n/DOPE-pDNA lipoplexes containing a polyoxyethylene spacer improve TE, especially at high GCL content. Lipoplexes studied here show very low levels of toxicity, which confirm them as improved vectors of pDNA in gene therapy.
- Barran-Berdon, Ana L.,Misra, Santosh K.,Datta, Sougata,Munoz-Ubeda, Monica,Kondaiah, Paturu,Junquera, Elena,Bhattacharya, Santanu,Aicart, Emilio
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supporting information
p. 4640 - 4652
(2014/07/21)
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- The bivalent ligand approach as a tool for improving the in vitro anti-alzheimer multitarget profile of dimebon
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Inspired by the concept of bivalent ligands, we prepared a small set of analogues of the drug candidate dimebon. They were shown to inhibit AChE, Aβ42 aggregation, and NMDA receptor activation to a greater extent than dimebon. Some of these compounds also enhanced the survival of chicken neurons under apoptosis-inducing conditions. Copyright
- Rosini, Michela,Simoni, Elena,Bartolini, Manuela,Soriano, Elena,Marco-Contelles, Jose,Andrisano, Vincenza,Monti, Barbara,Windisch, Manfred,Hutter-Paier, Birgit,Mcclymont, David W.,Mellor, Ian R.,Bolognesi, Maria Laura
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supporting information
p. 1276 - 1281
(2013/08/23)
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- Design of task-specific ionic liquids for catalytic conversion of CO 2 with aziridines under mild conditions
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A series of polyethylene glycol (PEG)-functionalized ionic liquids (ILs) were developed as recyclable and efficient catalysts for selective synthesis of 5-aryl-2-oxazolidinones from aziridines and CO2 without addition of any organic solvents or additives. In particular, high yields, chemo- and regio-selectivities of oxazolidinones were attained when BrDBNPEG 150DBNBr (DBN: 1,5-diazabicyclo[4.3.0]non-5-ene) was used as the catalyst, presumably due to activation of CO2 by the ether linkage in the PEG backbone, and stabilization of the ring-opened species of aziridine by the delocalized cation BrDBNPEG150DBN+. Furthermore, the catalyst could be reused for over four consecutive cycles without appreciable loss of catalytic activity and selectivity. The effects of catalyst structure and various reaction parameters on the catalytic performance were also investigated in detail. It was demonstrated that the catalyst worked well for a variety of aziridines producing the corresponding oxazolidinones in good yields and excellent regio-selectivities. Therefore, this solvent-free process could thus represent an environmentally friendly approach for ILs-catalyzed conversion of CO2 into value-added chemicals.
- Zhao, Ya-Nan,Yang, Zhen-Zhen,Luo, Si-Hang,He, Liang-Nian
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- Lead(ii) tetrafluoroborate and hexafluorophosphate complexes with crown ethers, mixed O/S- and O/Se-donor macrocycles and unusual [BF4] - and [PF6]- coordination
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The reaction of Pb[BF4]2 in H2O/MeCN solution with the macrocycle 18-crown-6 gave the dinuclear complex [{Pb(18-crown-6)(H2O)(μ2-BF4)} 2][BF4]2, containing two nine-coordinate lead centres, each bound to all six oxygens of a crown ligand, one water molecule and bridged by two μ2-BF4 groups. In contrast, the oxa-thia crown [18]aneO4S2 gave the mononuclear [Pb([18]aneO4S2)(H2O)2(BF 4)][BF4] in which the lead is coordinated O 4S2 within the puckered ring of the macrocycle, and with two water molecules on one side of the plane and a chelating (κ2) BF4- on the other. The [Pb([18]aneO4Se2)(BF4)2] has the two BF4- groups arranged mutually cis and with the macrocycle folded; within each BF4- group the Pb-F distances differ by ~0.5 A, producing a very unsymmetrical chelate. The 15-membered ring macrocycles 15-crown-5 and [15]aneO3S2 produce sandwich complexes [Pb(macrocycle)2][BF4]2 which contain 10-coordinate lead centres. Pb[PF6]2 in H2O/MeCN solution formed [Pb(18-crown-6)(H2O) 2(PF6)][PF6] and [Pb([18]aneO4S 2)(H2O)2(PF6)][PF6] which contain weak κ2-coordination of the PF6- group on the opposite side of the macrocyclic ring to two coordinated water molecules, giving 10-coordinate lead. In contrast, [Pb([18]aneO 4Se2)(PF6)2] has two κ2-coordinated PF6- groups disposed cis, with a very folded macrocycle conformation. In [Pb(18-crown-6)(NO 3)(PF6)] a chelating nitrate group occupies the coordination sites at Pb(ii) instead of the two water molecules, and the weakly coordinating PF6- group is tridentate. The crystal structures of the lead nitrate complexes, [Pb(15-crown-5)(NO3) 2] and [Pb([18]aneO4Se2)(NO3) 2], containing nine- and 10-coordinate lead respectively, are also reported. In solution the complexes are labile, and both conductivity and 19F NMR spectroscopic studies show the BF4- and PF6- groups are dissociated, whereas in the nitrate complexes the anion coordination is retained in solution. The identification of the coordination modes of the NO3- and BF4 - groups in the solid complexes by IR spectroscopy is discussed. The Royal Society of Chemistry 2013.
- Farina, Paolo,Latter, Thomas,Levason, William,Reid, Gillian
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p. 4714 - 4724
(2013/05/09)
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- Highly efficient conversion of carbon dioxide catalyzed by polyethylene glycol-functionalized basic ionic liquids
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A series of polyethylene glycol (PEG)-functionalized basic ionic liquids (ILs) were developed for efficient CO2 conversion into organic carbonates under mild conditions. In particular, BrTBDPEG150TBDBr was proven to be a highly efficient and recyclable catalyst for the synthesis of cyclic carbonates without utilization of any organic solvents or additives. This is presumably due to the activation of epoxide assisted by hydrogen bonding and activation of CO2 by the ether linkage in the PEG backbone or through the formation of carbamate species with the secondary amino group in the IL cation on the basis of in situ FT-IR study under CO2 pressure. In addition, the subsequent transesterification of cyclic carbonate e.g. ethylene carbonate (EC) with methanol to dimethyl carbonate (DMC) can also be effectively catalyzed by BrTBDPEG150TBDBr, thanks to the activation of methanol by the secondary and tertiary nitrogen in the IL to easily form CH 3O-, realizing a so-called "one-pot two-stage" access to DMC from CO2 without separation of cyclic carbonate by using one kind of single component catalyst. Therefore, this protocol represents a highly efficient and environmentally friendly example for catalytic conversion of CO2 into value-added chemicals such as DMC by employing PEG-functionalized basic ILs as catalysts.
- Yang, Zhen-Zhen,Zhao, Ya-Nan,He, Liang-Nian,Gao, Jian,Yin, Zhong-Shu
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experimental part
p. 519 - 527
(2012/03/27)
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- SYNTHESIS OF DIFUNCTIONAL OXYETHYLENE-BASED COMPOUNDS
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A method of reacting a toluenesulfonyl-terminated polyoxyethylene compound having the formula CH3—C6H4—SO2—(O—CH2—CH2)n—O—R1 with an ammonium salt having the formula NR24X to form a compound having the formula X—CH2—CH2—(O—CH2—CH2)n-1—R3. The value n is a positive integer. X is a halogen, cyanide, cyanate, thiocyanate, or azide. R1 is a terminating group. Each R2 is hydrogen or an alkyl group. —R3 is —O—R1 or —X.
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Page/Page column 2-3
(2009/07/25)
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- Mono- and dicationic short PEG and methylene dioxyalkylglycerols for use in synthetic gene delivery systems
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A range of monocationic and dicationic dioxyalkylglycerol cytofectins have been synthesised possessing methylene and short n-ethylene glycol spacers. The monocationic compounds were found to be effective in transfections when formulated as lipopolyplexes with peptide and DNA components, in particular with shorter PEG head groups which may have less effect on peptide targeting in the ternary complex. The Royal Society of Chemistry 2008.
- Hurley, Christopher A.,Wong, John B.,Ho, Jimmy,Writer, Michele,Irvine, Scott A.,Lawrence, M. Jayne,Hart, Stephen L.,Tabor, Alethea B.,Hailes, Helen C.
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supporting information; experimental part
p. 2554 - 2559
(2009/02/02)
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- Practical use of NH4X salts for difunctional oxyethylene-based intermediates
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A series of tosyl functionalized oxyethylene-based organic compounds were selected to analyze the scope and efficiency of a general substitution method for conversion to difunctional, soluble oxyethylene based intermediates using readily available ammonium salts, glycols and commercially modified ethoxy-ethanols. Straightforward preparation, product purification and low cost reagents are particularly advantageous for compounds incorporating halides, thiocyanates and methoxy groups.
- Holmes, Brian T.,Snow, Arthur W.
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p. 4813 - 4815
(2008/02/05)
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- Synthesis of unique 17β-estradiol homo-dimers, estrogen receptors binding affinity evaluation and cytocidal activity on breast, intestinal and skin cancer cell lines
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A rapid and efficient synthesis of a series of C2-symmetric 17β-estradiol homo-dimers is described. The new molecules are linked at position 17α of the steroid nucleus with either an alkyl chain or a polyethylene glycol chain. They are made from estrone in only five chemical steps with an overall yield exceeding 30%. The biological activity of these compounds was evaluated in vitro on estrogen dependent and independent (ER+ and ER-) human breast tumor cell lines: MCF-7 and MDA-MB-231. Some of the dimers present selective cytotoxic activity against the ER+ cell line. However, they are not very cytotoxic when compared to the antiestrogen tamoxifen. Unfortunately, they show only weak affinity for the estrogen receptor alpha (ERα) and no affinity for the estrogen receptor beta (ERβ). The new compounds were also tested on human intestinal (HT-29) cancer and on murine skin cancer (B16-F10) cell lines for further biological assessment. Interestingly, the dimers were found to be cytotoxic to the murine skin cancer cell line but were inactive towards the intestinal cancer cell line.
- Bérubé, Gervais,Rabouin, Daniel,Perron, Valérie,N'Zemba, Blaise,Gaudreault, René-C.,Parent, Sophie,Asselin, éric
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p. 911 - 921
(2007/10/03)
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- Label-free detection of protein-protein interactions on biochips
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(Figure Presented) Eliminating the middle-man: The combination of MALDI-TOF mass spectrometry and self-assembled monolayers on gold (SAMDI) offers a new detection method for protein-ligand (shown) and protein-protein interactions. Proteins and protein complexes are selectively bound to biochips and then directly analyzed by MALDI-TOF MS without the need for labels.
- Yeo, Woon-Seok,Min, Dal-Hee,Hsieh, Robert W.,Greene, Geoffrey L.,Mrksich, Milan
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p. 5480 - 5483
(2007/10/03)
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- Estrogen-linked platinum (II) complexes as anticancer agents
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wherein n may be 1, 2, 3, 4 or 5 when X is O, wherein n may be 2/3, 1, 4/3, 5/3, 2, 7/3, 8/3, 3, or 10/3 when X is C, wherein o may be 1, 2 or 3, wherein Y may be O or 17β-OH, wherein R1 may be selected from the group consisting of H, a straight alkyl group of 1 to 5 carbon atoms, a branched alkyl group of 3 to 5 carbon atoms, wherein R2 may be selected for the group consisting of H, a straight alkyl group of 1 to 4 carbon atoms, a branched alkyl group of 3 or 4 carbon atoms, F, Cl, Br, I, —CF3, —NO2, —OR1, —COR1 and —CH2OH. These compounds possess anticancer activity against hormono-dependent breast, uterus as well as ovarian cancer.
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Page/Page column 7
(2008/06/13)
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- A facile synthesis of C2-symmetric 17β-estradiol dimers
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A rapid and efficient synthesis of a series of C2-symmetric 17β-estradiol dimers is described. The new molecules are linked at position 17α of the steroid nucleus with either an alkyl chain or a polyethylene glycol chain. They are made from estrone in five chemical steps with an overall yield exceeding 30%. The biological activity of these compounds was evaluated in vitro on estrogen dependent and independent (ER+ and ER-) human breast tumor cell lines: MCF-7 and MDA-MB-231. Some of the dimers present selective cytotoxic activity against the ER+ cell line.
- Rabouin, Daniel,Perron, Valerie,N'Zemba, Blaise,C.-Gaudreault, Rene,Berube, Gervais
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p. 557 - 560
(2007/10/03)
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- Synthesis of dicycloheptano- and dicyclooctanothiacrown ethers their properties as extractants
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12- and 15-Membered thia- and oxathiacrown ethers and podands containing cycloheptane and cyclooctane fragments have been synthesized. The properties of the synthesized compounds as extractants for Ra2+ and Pd2+ ions have been studied.
- Nasyrov,Bobyleva,Abramov,Anfilogova,Vasil'Kov,Anisimov
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p. 456 - 465
(2007/10/03)
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- An optically-active [2]catenane made to order
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The self-assembly of an optically-active [2]catenane, incorporating a chiral hydrobenzoin unit in one of its component rings, has been achieved.
- Ashton, Peter R.,Iriepa, Isobel,Reddington, Mark V.,Spencer, Neil,Slawin, Alexandra M. Z.,Fraser Stoddart,Williams, David J.
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p. 4835 - 4838
(2007/10/02)
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- Di-, Tri-, Tetra-, and Pentacationic Alkylammonium Salts. Ligands Designed To Prevent the Nonspecific Electrostatic Precipitation of Polyanionic, Functionalized Cyclopentadienyltitanium-Substituted Heteropolytungstate Electron Microscopy Labels with Cationic Biomolecules.
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This work relates to the use of organic functionalized heteropolytungstates (HPTs) as protein-specific electron microscopy labels.The objective is the development of a polycationic ligand that prevents the nonspecific precipitation reaction observed between certain polycationic biomolecules and polianionic heteropolytungstates.Simple tetra- and pentaammonium salts between Keggin HPT 1b or Dawson HPT 2b and amines 3-6 or quaternary ammonium compounds 8 and 9 were all of low aqueous solubility as were salts derived from the oxygenated partners 7, 11, 12, and 15-18.However, tetrakis quaternary salt 23a, which is made up of several highly oxygenated alkyl groups, effectively prevents precipitation between Dawson HPT 2b and the exemplary basic proteins lysozyme and poly-L-lysine as well as the lectin concanavalin A.
- Keana, John F. W.,Wu, Yexin,Wu, Guanli
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p. 2571 - 2576
(2007/10/02)
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- Metal-assisted Reactions. Part 17. Ring-opening and Dimerization of Cyclic Ethers by Titanium Halides
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Reaction of TiCl4 or TiBr4 with a variety of cyclic ethers gives, predominantly, products resulting from simple ring-opening or from ring-opening with simultaneous condensation to dimeric species.The variations in yields of these two kinds of products might be correlated qualitatively with an initial formation of the complex TiX4*2E (X = Cl or Br; E = cyclic ether) in which the ethers were held in a cis or trans relationship.Although such a correlation might suggest that TiCl4 but not TiBr4 exerts a template effect on the condensation, stereochemical considerations of the reaction products indicate otherwise.TiCl3 and VCl3 do not give similar results and TiF4 gives no reaction.
- Delaney, Paul A.,Johnstone, Robert A. W.,Entwistle, Ian D.
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p. 1855 - 1860
(2007/10/02)
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- Synthesis, N.m.r. Spectra, and Structure of Macrocyclic Compounds containing the Ferrocene Unit
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The condensation of 1,1'-bis(chlorocarbonyl)ferrocene with diaza-18-crown-6 gives 1,1'-(1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane-7,16-diyldicarbonyl)ferrocene (5) together with its dimer 1,1'':1',1'''-bis-(1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane-7,16-diyldicarbonyl)bisferrocene (6) and the separation and isolation of these compounds are described.High resolution 1H and 13C n.m.r. spectra using homo- and hetero-nuclear decoupling techniques allow a complete assignment of the spectral data for (5) and (6) and lead to a proposal of a structure for (5) involving a trans-disposition of the amide carbonyl groups.Variable-temperature n.m.r. data on (6) reveal two distinct dynamic processes within the molecule involving rotation about the ferrocene-carbonyl bond (ΔG=50 kJ mol-1, Tc=-10 deg C) and rotation about the N-CO bond (ΔG=67 kJ mol-1, Tc=+60 deg C).The preparation, 1H and 13C n.m.r. data of monocyclic compounds containing the ferrocene unit (13a-c), (14) and (15) are also described and the details of the synthesis of an 15N-labelled analogue of (13c), the macrocycle (16), are reported.
- Hammond, Philip J.,Bell, Alan P.,Hall, C. Dennis
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p. 707 - 715
(2007/10/02)
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- Ring-Closure Reactions. 19. Kinetics of Formation of Benzo-Crown Ethers by Intramolecular Nucleophilic Substitution. A Comparison between Poly(oxyethylene) and Polymethylene Chains
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Kinetic data have been obtained for the formation of 9-, 12-, 15-, 21-, 30-, and 48-membered benzo-crown ethers by intramolecular Williamson synthesis in Me2SO-water (99:1, v/v).Comparison with earlier data for the formation of catechol polymethylene ethers provides an insight into the influence on the ease of ring closure of the replacement of methylene groups by oxygen atoms.Little or no effect occurs at ring size 9.In the next higher homologues the ease of cyclization of the poly(oxyethylene) chains is some 3 times as great as that of the polymethylene chains of similar length, but in the limit of the very long chains the two series behave much in the same way.Interestingly, literature data related to the fast, encounter-controlled reactions between end groups linked by poly(oxyethylene) and polymethylene chains reveal much the same features of the slow, activation-controlled reactions.The general picture fits in with well-established conformational arguments based on the expected strain relief due to replacement of trasannular CH...HC interactions with CH...O or O...O interactions.The oxygen atom effect turns out to be a sensitive tool for the detection of even weak strain energies in ring compounds.
- Illuminati, Gabriello,Mandolini, Luigi,Masci, Bernardo
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p. 4142 - 4145
(2007/10/02)
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- Macroheterocycles. III. Synthesis, properties, and tautomeric transformations of macrocyclic thioureas
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Macrocyclic thioureas of the and types, where R=CH2(CH2OCH2)nCH2 and (CH2)m (n=1, 2, 3, m=8), were obtained for the first time by the reaction of diamines with carbon bisulfide.The UV, IR, and PMR spectra of the compounds were studied.It was shown that they exist in the thione form in the crystalline state and in protic solvents.Thione - thiol isomerization is observed in nonpolar solvents.
- Bogatskii, A.V.,Luk'yanenko, N. G.,Kirichenko, T. I.
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p. 1124 - 1129
(2007/10/02)
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- Complexes of macrocyclic compounds
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Novel macrocyclic (monocyclic and bicyclic) compounds having nitrogen bridgehead atoms and having in the hydrocarbon bridging chains at least two additional hetero atoms selected from the group consisting of sulfur, oxygen, and nitrogen, when admixed with a compatible cation-donor compound form stable cation-containing macrocyclic complexes which, in turn, can be conveniently dissociated by addition of acid or a quaternizing agent. The novel macrocyclics are valuable for use in the same way and for the same purposes as chelating agents.
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- Ditertiary diamine compounds
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The preparation of ditertiary aliphatic diamines 3 designed as drugs protecting CNS acetylcholinesterase against organophosphate inhibition, is described. Owing to the radicals at the basic nitrogen atoms, these compounds should exist in appreciable amounts both as base and as diammonium ion at biological pH's.
- Schnekenburger
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p. 1853 - 1858
(2007/10/05)
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