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排序方式: 共有513条查询结果,搜索用时 15 毫秒
1.
Edward G. Sheetz Zhao Zhang Alyssa Marogil Minwei Che Dr. Maren Pink Dr. Veronica Carta Prof. Dr. Krishnan Raghavachari Prof. Dr. Amar H. Flood 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201584
The recognition of boron compounds is well developed as boronic acids but untapped as organotrifluoroborate anions (R−BF3−). We are exploring the development of these and other designer anions as anion-recognition motifs by considering them as substituted versions of the parent inorganic ion. To this end, we demonstrate strong and reliable binding of organic trifluoroborates, R−BF3−, by cyanostar macrocycles that are size-complementary to the inorganic BF4− progenitors. We find that recognition is modulated by the substituent's sterics and that the affinities are retained using the common K+ salts of R−BF3− anions. 相似文献
2.
Metal Oxide Assisted Preparation of Core–Shell Beads with Dense Metal–Organic Framework Coatings for the Enhanced Extraction of Organic Pollutants 下载免费PDF全文
Mateo del Rio Dr. Carlos Palomino Cabello Veronica Gonzalez Dr. Fernando Maya Dr. Jose B. Parra Dr. Victor Cerdà Dr. Gemma Turnes Palomino 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11770-11777
Dense and homogeneous metal–organic framework (MOF) coatings on functional bead surfaces are easily prepared by using intermediate sacrificial metal oxide coatings containing the metal precursor of the MOF. Polystyrene (PS) beads are coated with a ZnO layer to give ZnO@PS core–shell beads. The ZnO@PS beads are reactive in the presence of 2‐methylimidazole to transform part of the ZnO coating into a porous zeolitic imidazolate framework‐8 (ZIF‐8) external shell positioned above the internal ZnO precursor shell. The obtained ZIF‐8@ZnO@PS beads can be easily packed in column format for flow‐through applications, such as the solid‐phase extraction of trace priority‐listed environmental pollutants. The prepared material shows an excellent permeance to flow when packed as a column to give high enrichment factors, facile regeneration, and excellent reusability for the extraction of the pollutant bisphenol A. It also shows an outstanding performance for the simultaneous enrichment of mixtures of endocrine disrupting chemicals (bisphenol A, 4‐tert‐octylphenol and 4‐n‐nonylphenol), facilitating their analysis when present at very low levels (<1 μg L?1) in drinking waters. For the extraction of the pollutant bisphenol A, the prepared ZIF‐8@ZnO@PS beads also show a superior extraction and preconcentration capacity to that of the PS beads used as precursors and the composite materials obtained by the direct growth of ZIF‐8 on the surface of the PS beads in the absence of metal oxide intermediate coatings. 相似文献
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4.
Dr. Mariane Le Fur Nicholas J. Rotile Carlos Correcher Dr. Veronica Clavijo Jordan Alana W. Ross Prof. Ciprian Catana Prof. Peter Caravan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1490-1494
Gadolinium-based contrast agents (GBCAs) are used to provide diagnostic information in clinical magnetic resonance (MR) examinations. Gadolinium (Gd) has been detected in the brain, bone and skin of patients, months and years following GBCA administration, raising concerns about long term toxicity. Despite increased scrutiny, the concentration, chemical form and fate of the retained gadolinium species remain unknown. Importantly, the whole body biodistribution and organ clearance of GBCAs is poorly understood in humans. Gadolinium lacks suitable isotopes for nuclear imaging. We demonstrate that the yttrium-86 isotope can be used as a gadolinium surrogate. We show that Gd and their analogous Y complexes have similar properties both in solution and in vivo, and that yttrium-86 PET can be used to track the biodistribution of GBCAs over a two-day period. 相似文献
5.
Dr. Francesco Della Monica Dr. Veronica Paradiso Prof. Dr. Alfonso Grassi Dr. Stefano Milione Prof. Dr. Luigi Cavallo Prof. Dr. Carmine Capacchione 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(24):5347-5353
A new chromium(III) complex, bearing a bis-thioether-diphenolate [OSSO]-type ligand, was found to be an efficient catalyst in the copolymerization of CO2 and epoxides to achieve poly(propylene carbonate), poly(cyclohexene carbonate), poly(hexene carbonate) and poly(styrene carbonate), as well as poly(propylene carbonate)(cyclohexene carbonate) and poly(propylene carbonate)(hexene carbonate) terpolymers. 相似文献
6.
Robert D. Bradley Brennan D. McManus Jessalyn G. Yam Dr. Veronica Carta Dr. Ana Bahamonde 《Angewandte Chemie (International ed. in English)》2023,62(43):e202310753
This work demonstrates the dominance of a Ni(0/II/III) cycle for Ni-photoredox amide arylation, which contrasts with other Ni-photoredox C-heteroatom couplings that operate via Ni(I/III) self-sustained cycles. The kinetic data gathered when using different Ni precatalysts supports an initial Ni(0)-mediated oxidative addition into the aryl bromide. Using NiCl2 as the precatalyst resulted in an observable induction period, which was found to arise from a photochemical activation event to generate Ni(0) and to be prolonged by unproductive comproportionation between the Ni(II) precatalyst and the in situ generated Ni(0) active species. Ligand exchange after oxidative addition yields a Ni(II) aryl amido complex, which was identified as the catalyst resting state for the reaction. Stoichiometric experiments showed that oxidation of this Ni(II) aryl amido intermediate was required to yield functionalized amide products. The kinetic data presented supports a rate-limiting photochemically-mediated Ni(II/III) oxidation to enable C−N reductive elimination. An alternative Ni(I/III) self-sustained manifold was discarded based on EPR and kinetic measurements. The mechanistic insights uncovered herein will inform the community on how subtle changes in Ni-photoredox reaction conditions may impact the reaction pathway, and have enabled us to include aryl chlorides as coupling partners and to reduce the Ni loading by 20-fold without any reactivity loss. 相似文献
7.
Dr. Yafei Gao Prof. Wei-Tsung Lee Dr. Veronica Carta Dr. Chun-Hsing Chen Prof. Joshua Telser Prof. Jeremy M. Smith 《欧洲无机化学杂志》2023,26(8):e202200675
Reduction of the cobalt(II) chloride complex, Ph2B(tBuIm)2Co(THF)Cl ( 1 ) in the presence of tBuN≡C affords the diamagnetic, square planar cobalt(I) complex Ph2B(tBuIm)2Co(C≡NtBu)2 ( 2 ). This is a rare example of a 16-electron cobalt(I) complex that is structurally related to square planar noble metal complexes. Accordingly, the electronic structure of 2 , as calculated by DFT, reveals that the HOMO is largely dz2 in character. Complex 2 is readily oxidized to its cobalt(II) congener [Ph2B(tBuIm)2Co(C=NtBu)2]BPh4 ( 3 -BPh4), whose EPR spectral parameters are characteristic of low-spin d7 with an unpaired electron in an orbital of dz2 parentage. This is also consistent with the results of DFT calculations. Despite its 16-electron configuration and the dz2 parentage of the HOMO, the only tractable reactions of 2 involve one electron oxidation to afford 3 . 相似文献
8.
9.
Adesola A. Adeleke Sizwe J. Zamisa Md. Shahidul Islam Kolawole Olofinsan Veronica F. Salau Chunderika Mocktar Bernard Omondi 《Molecules (Basel, Switzerland)》2021,26(5)
A series of fifteen silver (I) quinoline complexes Q1–Q15 have been synthesized and studied for their biological activities. Q1–Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1–L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1–Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3 Q1, [Ag(L1)2]ClO4 Q6, [Ag(L2)2]ClO4 Q7, [Ag(L2)2]CF3SO3 Q12 and [Ag(L4)2]CF3SO3 Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes′ moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4 Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4 Q9 with a methyl substituent had excellent cytotoxicity against HELA cells. 相似文献
10.
Valentina Marturano Francesco Abate Veronica Ambrogi Valeria Califano Pierfrancesco Cerruti Giovanni Piero Pepe Luciano R. M. Vicari Giovanni Ausanio 《Molecules (Basel, Switzerland)》2021,26(9)
Herein, smart coatings based on photo-responsive polymer nanocapsules (NC) and deposited by laser evaporation are presented. These systems combine remotely controllable release and high encapsulation efficiency of nanoparticles with the easy handling and safety of macroscopic substrates. In particular, azobenzene-based NC loaded with active molecules (thyme oil and coumarin 6) were deposited through Matrix-Assisted Pulsed Laser Evaporation (MAPLE) on flat inorganic (KBr) and organic (polyethylene, PE) and 3D (acrylate-based micro-needle array) substrates. SEM analyses highlighted the versatility and performance of MAPLE in the fabrication of the designed smart coatings. DLS analyses, performed on both MAPLE- and drop casting-deposited NC, demonstrated the remarkable adhesion achieved with MAPLE. Finally, thyme oil and coumarin 6 release experiments further demonstrated that MAPLE is a promising technique for the realization of photo-responsive coatings on various substrates. 相似文献