3330-09-4Relevant academic research and scientific papers
Investigation of dendriplexes by ion mobility-mass spectrometry
Leriche, Emma-Dune,Hubert-Roux, Marie,Afonso, Carlos,Lange, Catherine M.,Maire, Florian,Loutelier-Bourhis, Corinne,Grossel, Martin C.
, p. 20731 - 20750 (2014)
Highly branched polyamidoamine (PAMAM) dendrimers presenting biological activities have been envisaged as non-viral gene delivery vectors. They are known to associate with nucleic acid (DNA) in non-covalent complexes via electrostatic interactions. Although their transfection efficiency has been proved, PAMAMs present a significant cytotoxicity due to their cationic surface. To overcome such a drawback, different chemical modifications of the PAMAM surface have been reported such as the attachment of hydrophobic residues. In the present work, we studied the complexation of DNA duplexes with different low-generation PAMAM; ammonia-cored G0(N) and G1(N) PAMAM, native or chemically modified with aromatic residues, i.e., phenyl-modified-PAMAM G0(N) and phenylalanine-modified-PAMAM G1(N). To investigate the interactions involved in the PAMAM/DNA complexes, also called dendriplexes, we used electrospray ionization (ESI) coupled to ion mobility spectrometry-mass-spectrometry (IM-MS). ESI is known to allow the study of non-covalent complexes in native conditions while IM-MS is a bidimensional separation technique particularly useful for the characterization of complex mixtures. IM-MS allows the separation of the expected complexes, possible additional non-specific complexes and the free ligands. Tandem mass spectrometry (MS/MS) was also used for the structural characterization. This work highlights the contribution of IM-MS and MS/MS for the study of small dendriplexes. The stoichiometries of the complexes and the equilibrium dissociation constants were determined. The [DNA/native PAMAM] and [DNA/modified-PAMAM] dendriplexes were compared.
Amido Complexes of Iridium with a PNP Pincer Ligand: Reactivity toward Alkynes and Hydroamination Catalysis
Hermosilla, Pablo,López, Pablo,García-Ordunìa, Pilar,Lahoz, Fernando J.,Polo, Víctor,Casado, Miguel A.
, p. 2618 - 2629 (2018/08/21)
The pincer ligand HN(CH2CH2PPh2)2 (1; PNHP) reacted with [{Ir(μ-X)(cod)}2] (X = Cl, OMe), affording complexes [fac-(PNHP)Ir(cod)]Cl (2) and [fac-(PNP)Ir(cod)] (3), respectively. The X-ray molecular structure of 2 showed that the PNP ligand coordinates in a facial fashion, with the N atom in an axial site and both P atoms coordinated in the equatorial plane. Compound 1 is able to protonate the hydroxo bridges in the complex [{Ir(μ-OH)(coe)2}2] forming the new amido complex [mer-(PNP)Ir(coe)] (4). Complex 4 is an extremely air sensitive compound, as confirmed by the isolation of the oxo complex [mer-(PNP)Ir(σ2-O2)] (8) from its interaction with air. Protonation of 4 with HBF4 afforded the corresponding amino complex [mer-(PNHP)Ir(coe)]BF4 (5), whose molecular structure enlightened by X-ray crystallography confirmed the PNP ligand to be coordinated in a meridional fashion. The coe ligand in 4 is tightly bonded to iridium; however, under an atmosphere of ethylene at 60 °C or with acrylonitrile at 70 °C complex 4 exchanges the olefin, affording compounds [mer-(PNP)Ir(σ2-C2H4)] (6) and [mer-(PNP)Ir(σ2-C2H3CN)] (7), respectively. Interaction of 4 with alkynes depends on the nature of the substrate; therefore, methyl phenylpropiolate reacted with 4, affording the adduct [mer-(PNP)Ir(σ2-PhCCC(O)OMe)] (9), while the parent acetylene undergoes a double C-H activation, affording the Ir(III) complex [fac-(PNHP)IrH(Ca‰?CH)2] (10). A DFT theoretical analysis of this transformation supports a metal-ligand cooperation mechanism. The reaction starts by deprotonation of an alkyne moiety by the PNP ligand followed by oxidative addition of the C-H bond to the metal of a second alkyne molecule. Additionally, we have tested complex 4 as a catalyst for the addition of gaseous ammonia to activated unsaturated substrates. A DFT theoretical analysis disclosed the operative mechanism on these organic transformations, which starts with a nucleophilic attack of ammonia to the bound alkyne, hydrogen migration to the metal, and reductive elimination steps.
A Comparison of the Selectivity of Extraction of [PtCl6]2- by Mono-, Bi-, and Tripodal Receptors That Address Its Outer Coordination Sphere
Warr, Rebecca J.,Bell, Katherine J.,Gadzhieva, Anastasia,Cabot, Rafel,Ellis, Ross J.,Chartres, Jy,Henderson, David K.,Lykourina, Eleni,Wilson, A. Matthew,Love, Jason B.,Tasker, Peter A.,Schr?der, Martin
, p. 6247 - 6260 (2016/07/06)
Extraction and binding studies of [PtCl6]2- are reported for 24 mono-, bi-, and tripodal extractants containing tris(2-Aminoethyl)amine (TREN) or tris(3-Aminopropyl)amine (TRPN) scaffolds. These reagents are designed to recognize the outer coordination sphere of [PtCl6]2- and to show selectivity over chloride anion under acidic conditions. Extraction from 0.6 M HCl involves protonation of the N-center in tertiary amines containing one, two, or three urea, amide, or sulfonamide hydrogen-bond donors to set up the following equilibrium: 2L(org) + 2H+ + [PtCl6]2- [(LH)2PtCl6](org). All reagents show higher Pt loading than trioctylamine, which was used as a positive control to represent commercial trialkylamine reagents. The loading of [PtCl6]2- depends on the number of pendant amides in the extractant and follows the order tripodal > bipodal > monopodal, with urea-containing extractants outperforming amide and sulfonamide analogues. A different series of reagents in which one, two, or three of the alkyl groups in tris-2-ethylhexylamine are replaced by 3-N′-hexylpropanamide groups all show a comparably high affinity for [PtCl6]2- and high selectivity over chloride anion in extractions from aqueous acidic solutions. 1H NMR titration of three extractants [LH·Cl] with [(Oct4N)2PtCl6] in CDCl3 provides evidence for high selectivity for [PtCl6]2- over chloride for tri-and bipodal extractants, which show higher binding constants than a monopodal analogue.
Parent-amido (NH2) palladium(II) complexes: Synthesis, reactions, and catalytic hydroamination
Kim, Youngwon,Park, Soonheum
, p. 614 - 629 (2016/06/01)
The treatment of [PdL3(NH3)](OTf)n (n = 1; L3 = (PEt3)2(Ph), (2,6-(Cy2PCH2)2C6H3), n = 2; L3 = (dppe)(NH3)) with NaNH2 in tetrahydrofuran at ambient temperature or -78 °C afforded the dimeric and monomeric parent-amido palladium(II) complexes anti-[Pd(PEt3)(Ph)(μ-NH2)]2 (1), [Pd(dppe)(μ-NH2)]2(OTf)2 (2), and Pd(2,6-(Cy2PCH2)2C6H3)(NH2) (3), respectively. The molecular structures of the amido-bridged (μ-NH2) dimeric complexes 1 and 2 were determined by single-crystal X-ray crystallography. The monomeric amido complex 3 reacted with trace amounts of water to give a hydroxo complex, Pd(2,6-(Cy2PCH2)2C6H3)(OH) (4). Exposing complex 3 to an excess of water resulted in the complete conversion of the complex into two species [Pd(2,6-(Cy2PCH2)2C6H3)(OH2)]+ and [Pd(2,6-(Cy2PCH2)2C6H3)(NH3)]+. Complex 3 reacted with diphenyliodonium triflate ([Ph2I]OTf) to give the aniline complex [Pd(2,6-(Cy2PCH2)2C6H3)(NH2Ph)]OTf. The reaction of 3 with phenylacetylene (HCCPh) yielded a palladium(II) acetylenide Pd(2,6-(Cy2PCH2)2C6H3)(CCPh) (5), quantitatively, along with the liberation of ammonia. The reaction of 3 with dialkyl acetylenedicarboxylate yielded diastereospecific palladium(II) vinyl derivatives (Z)-Pd(2,6-(Cy2PCH2)2C6H3)(CRCR(NH2)) (R = CO2Me (6a), CO2Et (6b)). The reaction of complexes 6a and 6b with p-nitrophenol produced Pd(2,6-(Cy2PCH2)2C6H3)(OC6H4-p-NO2) (7) and cis-CHRCR(NH2), exclusively. Reactions of 3 with either dialkyl maleate (cis-(CO2R)CHCH(CO2R)) (R = CH3, CH2CH3) or cis-stilbene (cis-CHPhCHPh) did not result in any addition product. Instead, isomerization of the cis-isomers to the trans-isomers occurred in the presence of catalytic amounts of 3. Complex 3 reacted with a stoichiometric amount of acrylonitrile (CH2CHCN) to generate a metastable insertion product, Pd(2,6-(Cy2PCH2)2C6H3)(CH(CN)CH2NH2). On the other hand, the reaction of 3 with an excess of acrylonitrile slowly produced polymeric species of acrylonitrile. The catalytic hydroamination of olefins with NH3 was examined in the presence of Pd(2,6-(Cy2PCH2)2C6H3)(OTf), producing a range of hydroaminated products of primary, secondary, and tertiary amines with different molar ratios of more than 99% overall yield. A mechanistic feature for the observed catalytic hydroamination is described with regard to the aminated derivatives of palladium(II).
Photocurable resin composition, dry film thereof, pattern forming method, and electrical/electronic part protective film
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, (2012/05/04)
A photocurable composition includes: (A) an epoxy group-containing polymer compound having repeating units represented by the following formula (1), where R1 to R4 are each a hydrocarbon group, m is an integer of 1 to 100, a, b, c and d are each 0 or a positive number, such that 0 (c+d)/(a+b+c+d) ≤ 1.0, and X and Y are each the formula (2) or (3), provided that at least one group of the formula (3) is present, (B) a photoacid generator represented by the formula (8) and (C) a solvent.
Resist composition and patterning process
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, (2010/02/17)
The present invention relates to: a resist composition such as a chemically amplified resist composition for providing an excellent pattern profile even at a substrate-side boundary face of resist, in addition to a higher resolution in photolithography for micro-fabrication, and particularly in photolithography adopting, as an exposure source, KrF laser, ArF laser, F2 laser, ultra-short ultraviolet light, electron beam, X-rays, or the like; and a patterning process utilizing the resist composition. The present invention provides a chemically amplified resist composition comprising one or more kinds of amine compounds or amine oxide compounds (except for those having a nitrogen atom of amine or amine oxide included in a ring structure of an aromatic ring) at least having a carboxyl group and having no hydrogen atoms covalently bonded to a nitrogen atom as a basic center.
POSITIVE RESIST COMPOSITION AND PATTERNING PROCESS
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, (2010/04/23)
A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R1 is H, methyl or trifluoromethyl, X is a single bond or methylene, m is 1 or 2, and the hydroxyl group attaches to a secondary carbon atom. The composition is improved in resolution when processed by lithography.
Photo acid generator, chemical amplification resist material and pattern formation method
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, (2008/06/13)
A high resolution resist material comprising an acid generator is provided so that high sensitivity and high resolution for high energy rays of 300 nm or less, small line-edge roughness, and excellence in heat stability and storage stability are obtained. Moreover, a pattern formation method using this resist material are provided. Specifically, a novel compound of the following general formula (1); and a positive resist material comprising this compound preferably as a photo acid generator, and a base resin; are provided. This positive resist material may contain a basic compound or a dissolution inhibitor. Further, the present invention provides a pattern formation method comprising the steps of applying this positive resist material on a substrate, then heat-treating the material, exposing the treated material to a high energy ray having a wavelength of 300 nm or less via a photo mask, optionally heat-treating the exposed material, and developing the material using a developer.
Novel tertiary (meth)acrylates having lactone structure, polymers, resist compositions and patterning process
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, (2008/06/13)
Novel tertiary (meth)acrylate compounds having a lactone structure are polymerizable into polymers having improved transparency, especially at the exposure wavelength of an excimer laser and dry etching resistance. Resist compositions comprising the polymers are sensitive to high-energy radiation, have a high resolution, and lend themselves to micropatterning with electron beams or deep-UV rays.
