- Mechanochemical Release of Non-Covalently Bound Guests from a Polymer-Decorated Supramolecular Cage
-
Supramolecular coordination cages show a wide range of useful properties including, but not limited to, complex molecular machine-like operations, confined space catalysis, and rich host–guest chemistries. Here we report the uptake and release of non-covalently encapsulated, pharmaceutically-active cargo from an octahedral Pd cage bearing polymer chains on each vertex. Six poly(ethylene glycol)-decorated bipyridine ligands are used to assemble an octahedral PdII6(TPT)4 cage. The supramolecular container encapsulates progesterone and ibuprofen within its hydrophobic nanocavity and is activated by shear force produced by ultrasonication in aqueous solution entailing complete cargo release upon rupture, as shown by NMR and GPC analyses.
- G?stl, Robert,Küng, Robin,Pausch, Tobias,Rasch, Dustin,Schmidt, Bernd M.
-
-
Read Online
- N,P-Doped carbon with encapsulated Co nanoparticles as efficient electrocatalysts for oxygen reduction reactions
-
Exploring efficient non-noble ORR catalysts as alternatives to Pt-based catalysts are highly demanded for their possible application in fuel cells and rechargeable metal-air batteries. Herein, we demonstrate a rational design and synthesis of a N, P-doped carbon with encapsulated Co nanoparticles as efficient electrocatalysts for ORR. The catalyst is derived from a mixture of Co-MOF and triphenylphosphine with a mass ratio of 3?:?1 by pyrolysis in N2 atmosphere at 700 °C. The catalyst exhibited a superior ORR catalytic performance among its counterparts in 0.1 M KOH with onset and half-wave potentials of 0.88 V and 0.80 V, a much larger limiting current density of ?5.93 mA cm?2 that surpassed commercial 20% Pt/C, in addition to its durability and resistance to methanol. This enhanced ORR activity of the catalyst can be attributed to the synergistic effect between Co NPs and N, P atoms, the relatively large contact surface, more exposed active sites and good electrical conductivity. This study would provide some new ideas for the design and construction of promising carbon-based non-precious metal electrocatalysts for future practical fuel cell applications.
- Fan, Lili,Du, Xinxin,Zhang, Yuming,Li, Mengfei,Wen, Meilian,Ge, Xiyang,Kang, Zixi,Sun, Daofeng
-
-
Read Online
- Supramolecular networks derived from hexacyanoferrates and nitrogen heterocyclic cations
-
Eight novel supramolecular frameworks (bpyH2)2[Fe(CN)6]·2H2O (1), (bpyH2)(H3O)[Fe(CN)6] (2), (bpeH2)(H3O)[Fe(CN)5(CNH)]·H2O (3), (bpeH2)(H5O2)[Fe(CN)6]·2H2O (4), (dabcoH2)(H3O)[Fe(CN)6]·2H2O (5), (ampyH2)2[Fe(CN)6]·2H2O (6), (tptzH3)2[Fe(CN)4(CNH)2]3·10H2O (7), and (tptzH3)[Fe(CN)6]·3H2O (8) (where bpy = 4,4′-bipyridine, bpe = 1,2-bis(4-pyridyl)ethylene, dabco = 1,4-diazabicyclo[2.2.2]octane, ampy = 4-aminomethylpyridine, tptz = tris(4-pyridyl)triazine) have been synthesized by the reaction of the nitrogen heterocycle with ferrocyanide or ferricyanide salts, under mild conditions. The supramolecular structures are constructed mainly by cooperative hydrogen bonding between the inorganic anions, the organic cations and oxoniums or lattice water molecules. There are some characteristic features that can separate the compounds in groups. Those are (a) increase of H-bonding ability by formation of supramolecular complexes, (b) formation of hydro- and dihydro-hexacyanoferrates and (c) the participation of the cationic heterocycle as constituent of the structure or as a guest. The structures are additionally discussed in terms of topology.
- Xydias, Pantelis,Lymperopoulou, Smaragda,Dokorou, Vasiliki,Manos, Manolis,Plakatouras, John C.
-
-
Read Online
- N-TYPE SEMICONDUCTOR, AND ORGANIC PHOTOELECTRIC DEVICE, IMAGE SENSOR, AND ELECTRONIC DEVICE INCLUDING THE SAME
-
Disclosed are an n-type semiconductor including compound represented by Chemical Formula 1 or Chemical Formula 2, an image sensor, and an electronic device. In Chemical Formula 1 and Chemical Formula 2, each substituent is as defined in the detailed description.
- -
-
Paragraph 0243-0245
(2021/05/14)
-
- Mixed-matrix materials using metal-organic polyhedra with enhanced compatibility for membrane gas separation
-
Discrete metal-organic polyhedra (MOPs) containing copper(ii), palladium(ii), and iron(ii) nodes were synthesized as fillers for mixed-matrix materials (MMMs) with a polyvinylidine fluoride (PVDF) polymer phase and contrasted against an MMM containing a metal-organic framework, MOF-5. When a given MOP was soluble in the precursor solutions, the resulting MMMs were thin, flexible, and homogeneous based on microscopy and SEM imaging. Analogous MMM formation using either insoluble MOPs or the inherent insoluble MOF-5 showed a higher degree of phase separation and inhomogeneity. Even when a MOP was not fully soluble, a significant particle size decrease was observed in contrast to the MOF-5 materials wherein the crystallites remained largely intact. This is a consequence of solubilizing the MOP fillers into the polymer solvent. The crystallinity and thermal stabilities of the MMMs were compared to pure PVDF using powder X-ray diffraction, and differential scanning calorimetry, indicating that the incorporation of MOPs both decreased overall crystallinity as well as increased thermal stability. In addition, MMMs containing PdMOP and FeMOP showed improved gas permeabilities relative to pure PVDF for H2, N2, CH4, and CO2, with the 10 wt% FeMOP membrane more selective for CO2 over N2 and H2.
- Fulong, Cressa Ria P.,Liu, Junyi,Pastore, Vincent J.,Lin, Haiqing,Cook, Timothy R.
-
supporting information
p. 7905 - 7915
(2018/06/29)
-
- Selective Co-Encapsulation Inside an M6L4Cage
-
There is broad interest in molecular encapsulation as such systems can be utilized to stabilize guests, facilitate reactions inside a cavity, or give rise to energy-transfer processes in a confined space. Detailed understanding of encapsulation events is required to facilitate functional molecular encapsulation. In this contribution, it is demonstrated that Ir and Rh-Cp-type metal complexes can be encapsulated inside a self-assembled M6L4metallocage only in the presence of an aromatic compound as a second guest. The individual guests are not encapsulated, suggesting that only the pair of guests can fill the void of the cage. Hence, selective co-encapsulation is observed. This principle is demonstrated by co-encapsulation of a variety of combinations of metal complexes and aromatic guests, leading to several ternary complexes. These experiments demonstrate that the efficiency of formation of the ternary complexes depends on the individual components. Moreover, selective exchange of the components is possible, leading to formation of the most favorable complex. Besides the obvious size effect, a charge-transfer interaction may also contribute to this effect. Charge-transfer bands are clearly observed by UV/Vis spectrophotometry. A change in the oxidation potential of the encapsulated electron donor also leads to a shift in the charge-transfer energy bands. As expected, metal complexes with a higher oxidation potential give rise to a higher charge-transfer energy and a larger hypsochromic shift in the UV/Vis spectrum. These subtle energy differences may potentially be used to control the binding and reactivity of the complexes bound in a confined space.
- Leenders, Stefan H. A. M.,Becker, René,Kumpulainen, Tatu,de Bruin, Bas,Sawada, Tomohisa,Kato, Taito,Fujita, Makoto,Reek, Joost N. H.
-
supporting information
p. 15468 - 15474
(2016/10/13)
-
- ELECTROCHROMIC COMPOUND, ELECTROCHROMIC COMPOSITION, DISPLAY ELEMENT, AND DIMMING ELEMENT
-
An electrochromic compound, represented by the following general formula (I): where X1 to X4 are each a substituent represented by the following general formula (II), an alkyl group that may contain a functional group, an aromatic hydrocarbon group that may contain a functional group, or a hydrogen atom, and at least two selected from X1 to X4 are the substituents represented by the general formula (II): where R1 to R8 are each independently a hydrogen atom, or a monovalent group that may contain a substituent; B is a substituted or unsubstituted monovalent group that may contain a functional group; A- is a monovalent anion; and m is any of 0 to 3, and R1 to R8, B, and m may each independently be different when a plurality of the substituents represented by the general formula (II) are present.
- -
-
Page/Page column 139-140
(2015/01/16)
-
- Template-directed synthesis of flexible porphyrin nanocage and nanorings via one-step olefin metathesis
-
We describe the fabrication of a suite of flexible porphyrin cages and nanorings from a simple tetraalkene-derived zinc porphyrin monomer via a highly efficient template-directed strategy. The zinc porphyrin monomers were preorganized together by coordination with N atoms of multidentate ligands. Subsequent one-step olefin metathesis furnished a bisporphyrin cage, a triporphyrin nanoring, and a hexaporphyrin nanoring. In the case of the hexaporphyrin nanoring, 24 terminal olefins from six porphyrin monomers reacted with each other to form 12 new double bonds, delivering the final product. The triporphyrin and hexaporphyrin nanorings were further employed as hosts to encapsulate C60 and C70.
- Zhu, Bin,Chen, Huanxin,Lin, Wei,Ye, Yang,Wu, Jing,Li, Shijun
-
supporting information
p. 15126 - 15129
(2015/01/09)
-
- Addition of amines to nitriles catalyzed by ytterbium amides: An efficient one-step synthesis of monosubstituted N-arylamidines
-
A one-step synthesis of monosubstituted N-arylamidinates via addition of amines to nitriles catalyzed by ytterbium amides is reported. The reactions with various substrates give the products in good to excellent yields with 5 mol % ytterbium at 100 °C under solvent-free conditions.
- Wang, Junfeng,Xu, Fan,Cai, Tao,Shen, Qi
-
p. 445 - 448
(2008/09/19)
-
- Sonic spray ionization mass spectrometry: A powerful tool used to characterize fragile metal-assembled cages
-
Sonic spray ionization mass spectrometry (SSI MS) is shown to be effective in characterizing metal-assembled cage structures that are not observed using conventional electrospray ionization mass spectrometry (ESI MS) techniques. A palladium-assembled resorcinarene-based cage containing nitrile ligands and a palladium(ii) triazine cage were characterized and their +1 molecular ion peaks were observed using this method. An N,N-bis(pyridylmethyl)amine resorcinarene cavitand-metal ion complex was observed to yield peaks corresponding to open tetranuclear complexes and closed cage complexes depending on the metal ion. Molecular ion peaks for these complexes were not detected when ESI MS was used. The soft ionization inherent in SSI MS coupled with its relatively simple design provides a powerful tool to characterize such supramolecular assemblies, which are of current interest. the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006.
- Gardner, Joseph S.,Harrison, Roger G.,Lamb, John D.,Dearden, David V.
-
p. 1276 - 1282
(2007/10/03)
-
- Catalytic trimerization of 2- and 4-cyanopyridine isomers to the triazine derivatives in presence of magnesium phthalocyanine
-
The crystals of 2,4,6-tris(2-pyridyl)-1,3,5-triazine and 2,4,6-tris(4-pyridyl)-1,3,5-triazine isomers have been obtained by a catalytic trimerization of 2- and 4-cyanopyridine in presence of magnesium phthalocyanine. For the 2,4,6-tris(2-pyridyl)-1,3,5-triazine isomer there are two possible conformations that differ in the positions of the N atoms in pyridine rings in relation to the triazine ring. These conformations differ by ~11.30 kJ mol-1 as shown by the molecular orbital calculations. The 2,4,6-tris(2-pyridyl)-1,3,5-triazine crystallises in the centrosymmetric space group of the triclinic system, while the 2,4,6-tris(4-pyridyl)-1,3,5-triazine isomer crystallises in the C2/c space group of monoclinic system. The 2,4,6-tris(2-pyridyl)-1,3,5-triazine molecule is non-planar in the crystal, due to the steric effect of lone-pair electron at the N atom in both pyridine and triazine rings is non-planar. The repulsive interaction between the lone-pair electron is the reason for the rotation of the pyridine rings along the C-C bonds. The pyridine rings in the 2,4,6-tris(4-pyridyl)-1,3,5-triazine molecule are not coplanar with the central triazine ring. The arrangement of molecules in both crystals is mainly determined by the π-π intermolecular interactions. The X-ray geometry of both molecules in the solid-state is compared with the gas-phase geometry obtained by the ab initio molecular orbital calculations.
- Janczak, Jan,?led?, Ma?gorzata,Kubiak, Ryszard
-
-
- Samarium diiodide promoted synthesis of N,N′-disubstituted amidines
-
An efficient one-step preparation of an N,N′-disubstituted amidine by the direct nucleophilic addition of an amine to the parent nitrile using catalytic amounts of SmI2 under relatively mild conditions is developed. Alkyl, benzyl and aryl amidi
- Xu, Fan,Sun, Jianhua,Shen, Qi
-
p. 1867 - 1869
(2007/10/03)
-
- Ligand binding by butadiyne-linked porphyrin dimers, trimers and tetramers
-
The binding of oligopyridyl ligands to butadiyne-linked zinc porphyrin dimers, trimers and tetramers has been investigated in detail using NMR and electronic spectroscopy.Pyridine binds to zinc porphyrin monomers in CH2Cl2 solution at 300 K with binding constants of ca. 103 mol-1 dm3, while 4,4'-bipyridyl binds to the cyclic zinc porphyrin dimer with a binding constant of 1 x 109 mol-1 dm3, giving an effective molarity, or chelation factor, of 76 mol dm-3.The analogous linear dimer binds to this ligand 100 times less strongly, but adopts a similar conformation when bound. s-Tri(4-pyridyl)triazine has an affinity of ca. 1010 mol-1 dm3 for the cyclic zinc trimer, reflecting reasonably good host-guest complementarity.The affinity of 4,4'-bipyridyl for the trimer is ca. 105 mol-1 dm3, implying two-point binding accompanied by host distortion and strain which reduce the binding constant; the trimer is therefore an elastic host, able to respond to the geometrical demands of rigid guests.The cyclic tetramer is a relatively flexible molecule, but its complexes with both bidentate and tetradentate ligands have more highly defined geometries.The cyclic dimer and trimer have open pre-organised cavities, with no conformational barrier to ligand binding inside the cavity, whereas the cyclic tetramer can adopt many conformations in free solution.
- Anderson, Harry L.,Anderson, Sally,Sanders, Jeremy K. M.
-
p. 2231 - 2246
(2007/10/02)
-
- Lanthanide(III) Ion Catalyzed Reaction of Ammonia and Nitriles: Synthesis of 2,4,6-Trisubstituted-s-triazines
-
Lanthanum and yttrium trifluoromethanesulfonates at 1 mole percent concentration, have been found to catalyze a reaction between ammonia and aromatic nitriles to yield symmetrically substituted 2,4,6-triaryl-s-triazines.The generally high yields and relatively mild reaction conditions of this procedure suggest it as an alternative to other aromatic nitrile cyclotrimerization reactions.Of the aliphatic nitriles studied, acetonitrile and cyclopropanecarbonitrile gave good yields of triazine, propionitrile and butyronitrile gave significantly reduced yields of triazines 3b and3c respectively.Rearrangement of 3a and 3b to alkylated-4-aminopyrimidines was observed.
- Forsberg, John H.,Spaziano, Vincent T.,Klump, Stephen P.,Sanders, Kathleen M.
-
p. 767 - 770
(2007/10/02)
-