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101.
Paolo Ravarino Dr. Santanu Panja Simona Bianco Dr. Todor Koev Dr. Matthew Wallace Prof. Dave J. Adams 《Angewandte Chemie (International ed. in English)》2023,62(4):e202215813
We use a pH-driven annealing process to convert between co-assembled and self-sorted networks in multicomponent gels. The initially formed gels at low pH are co-assembled, with the two components coexisting within the same self-assembled structures. We use an enzymatic approach to increase the pH, resulting in a gel-to-sol transition, followed by a hydrolysis to lower the pH once again. As the pH decreases, a self-sorted network is formed by a two-stage gelation process determined by the pKa of each component. This approach can be expanded to layered systems to generate many varied systems by changing composition and rates of pH change, adapting their microstructure and so allowing access to a far greater range of morphologies and complexity than can be achieved in single component systems. 相似文献
102.
Paolo Antonioli Angela Bachi Elisa Fasoli Pier Giorgio Righetti 《Journal of chromatography. A》2009,1216(17):3606-3612
Several methods have been described in the literature for removal of DNA from protein samples prior to proteome analysis. They in general involve protein precipitation techniques. In other protocols, DNAse treatment is suggested prior to precipitation of proteins in excess acetone. All these methods have been evaluated and found to perform poorly in DNA removal, as illustrated by two-dimensional (2D) maps where horizontal and vertical sample streaking are still substantial. Such removal is in general necessary in tissue lysates and especially when analysing sub-cellular organelles, such as nuclei, where the high DNA levels strongly interfere with proteome analysis. Another method is proposed here for efficient DNA removal: two-phase extraction of DNA in chloroform/phenol/isoamyl alcohol, a procedure commonly used to rid DNA samples of protein contaminants, but rarely applied to protein preparation. This extraction is not very efficient if performed at slightly acidic to neutral pH values, but it performs extremely well at pH values of 9.5 or higher. The 2D maps thus obtained of Escherichia coli lysates as well as extracts from purified nuclei of eukaryotic cells are not only devoid of any vertical or horizontal streaking, but exhibit many more spots, especially in the alkaline region of the 2D gels, suggesting that these basic proteins were in general lost to proteome analysis due to co-precipitation in tenacious protein–DNA complexes. It is hypothesized that the alkaline pH values adopted in the two-phase extraction help to fully disrupt any residual DNA–protein complexes, due to strong Coulombic repulsion. 相似文献
103.
104.
The template effects exerted by guests 14 and 15 in the ring closure reaction of 3 have been quantitatively evaluated. The rate largely increases in the presence of the two templates. The results are compared with those relative to the ring closure reaction of 1 yielding cyclobis(paraquat-p-phenylene), 2. The comparison indicates that the formation of tetracationic aromatic cycles templated by aromatic donors benefits from the use of extended pi surfaces both in the acceptor and in the donor components. 相似文献
105.
Luminescent Di‐ and Trinuclear Boron Complexes Based on Aromatic Iminopyrrolyl Spacer Ligands: Synthesis,Characterization, and Application in OLEDs 下载免费PDF全文
Dr. D. Suresh Dr. Clara S. B. Gomes Patrícia S. Lopes Dr. Cláudia A. Figueira Bruno Ferreira Prof. Pedro T. Gomes Dr. Roberto E. Di Paolo Prof. António L. Maçanita Prof. M. Teresa Duarte Dr. Ana Charas Prof. Jorge Morgado Diogo Vila‐Viçosa Prof. Maria José Calhorda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9133-9149
New bis‐ and tris(iminopyrrole)‐functionalized linear (1,2‐(HNC4H3‐C(H)?N)2‐C6H4 ( 2 ), 1,3‐(HNC4H3‐C(H)?N)2‐C6H4 ( 3 ), 1,4‐(HNC4H3‐C(H)?N)2‐C6H4 ( 4 ), 4,4′‐(HNC4H3‐C(H)?N)2‐(C6H4‐C6H4) ( 5 ), 1,5‐(HNC4H3C‐(H)?N)2‐C10H6 ( 6 ), 2,6‐(HNC4H3C‐(H)?N)2‐C10H6 ( 7 ), 2,6‐(HNC4H3C‐(H)?N)2‐C14H8 ( 8 )) and star‐shaped (1,3,5‐(HNC4H3‐C(H)?N‐1,4‐C6H4)3‐C6H3 ( 9 )) π‐conjugated molecules were synthesized by the condensation reactions of 2‐formylpyrrole ( 1 ) with several aromatic di‐ and triamines. The corresponding linear diboron chelate complexes (Ph2B[1,3‐bis(iminopyrrolyl)‐phenyl]BPh2 ( 10 ), Ph2B[1,4‐bis(iminopyrrolyl)‐phenyl]BPh2 ( 11 ), Ph2B[4,4′‐bis(iminopyrrolyl)‐biphenyl]BPh2 ( 12 ), Ph2B[1,5‐bis(iminopyrrolyl)‐naphthyl]BPh2 ( 13 ), Ph2B[2,6‐bis(iminopyrrolyl)‐naphthyl]BPh2 ( 14 ), Ph2B[2,6‐bis(iminopyrrolyl)‐anthracenyl]BPh2 ( 15 )) and the star‐shaped triboron complex ([4′,4′′,4′′′‐tris(iminopyrrolyl)‐1,3,5‐triphenylbenzene](BPh2)3 ( 16 )) were obtained in moderate to good yields, by the treatment of 3 – 9 with B(C6H5)3. The ligand precursors are non‐emissive, whereas most of their boron complexes are highly fluorescent; their emission color depends on the π‐conjugation length. The photophysical properties of the luminescent polyboron compounds were measured, showing good solution fluorescence quantum yields ranging from 0.15 to 0.69. DFT and time‐dependent DFT calculations confirmed that molecules 10 and 16 are blue emitters, because only one of the iminopyrrolyl groups becomes planar in the singlet excited state, whereas the second (and third) keeps the same geometry. Compound 13 , in which planarity is not achieved in any of the groups, is poorly emissive. In the other examples ( 11 , 12 , 14 , and 15 ), the LUMO is stabilized, narrowing the gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO–LUMO), and the two iminopyrrolyl groups become planar, extending the size of the π‐system, to afford green to yellow emissions. Organic light‐emitting diodes (OLEDs) were fabricated by using the new polyboron complexes and their luminance was found to be in the order of 2400 cd m?2, for single layer devices, increasing to 4400 cd m?2 when a hole‐transporting layer is used. 相似文献
106.
Dr. Stefano Fedeli Dr. Paolo Paoli Prof. Alberto Brandi Dr. Lorenzo Venturini Dr. Giuliano Giambastiani Dr. Giulia Tuci Prof. Stefano Cicchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15349-15353
A series of azido‐dyes were synthesized through Knoevenagel reactions of an azido‐BODIPY with aromatic aldehydes. The nature of the substituents allowed the fine tuning of their spectroscopic properties. The dyes were used to decorate oxidized multiwalled carbon nanotubes (ox‐MWCNTs), bearing terminal triple bond groups, by CuAAC reactions, affording fluorescent materials. This decoration allowed the efficient determination of the internalization of the ox‐MWCNT derivatives by different model cancer cells, such as MCF7. 相似文献
107.
Levy JN Latham CM Roisin L Kandziora N Di Fruscia P White AJ Woodward S Fuchter MJ 《Organic & biomolecular chemistry》2012,10(3):512-515
A synthetic route towards a number of novel IBiox N-heterocyclic carbene (NHC) ligands has been developed. The resulting ligands have restricted flexibility and high steric demand. Preliminary studies have shown these ligands to give high levels of asymmetric induction in the copper-free allylic alkylation of cinnamyl bromide. 相似文献
108.
Top-down patterning of zeolitic imidazolate framework composite thin films by deep X-ray lithography
Dimitrakakis C Marmiroli B Amenitsch H Malfatti L Innocenzi P Grenci G Vaccari L Hill AJ Ladewig BP Hill MR Falcaro P 《Chemical communications (Cambridge, England)》2012,48(60):7483-7485
For the first time a top-down process was used to control the spatial location of Metal-Organic Frameworks on a surface. Deep X-ray lithography was utilised to micropattern a Zeolitic Imidazolate Framework layer on a sol-gel surface, with exposure hardening the sol-gel by inducing crosslinking while leaving the frameworks intact. 相似文献
109.
Barbero M Cadamuro S Cauda F Dughera S Gervasio G Venturello P 《The Journal of organic chemistry》2012,77(9):4278-4287
An initial study has been accomplished into the synthetic feasibility of the preparation of diarylcarbenium salt via the direct coupling of aryl (or heteroaryl) aldehydes and arenes (or heteroaryl analogues) in the presence of a strong organic Br?nsted acid. A number of stabilized aryl or heteroaryl(3-indolyl)carbenium ions, never previously prepared in the solid state, have been isolated in excellent yields as highly stable o-benzenedisulfonimide salts and have been fully characterized. Their purity has been proven by spectroscopic methods and chemical reduction with NaBH(4). An X-ray crystal structure analysis has been performed on one of the products: an azafulvenium species was shown to be the exclusive structure in the solid state. 相似文献
110.
Blanco S Melandri S Ottaviani P Caminati W 《Journal of the American Chemical Society》2007,129(9):2700-2703
The trimer of difluoromethane, (CH2F2)3, has been characterized by supersonic jet Fourier transform microwave spectroscopy. The rotational spectrum displays all types (mu(a), mu(b), and mu(c)) of transitions, showing that the adduct does not possess any element of molecular symmetry. The investigation of the three 13C species in natural abundance indicates that the three carbon atoms form a triangle where the C-C distances are 3.648(2), 3.825(8), and 3.942(6) A, respectively. The three subunits are held together by nine CH...F weak hydrogen bonds. 相似文献