398-24-3Relevant articles and documents
Conformational Heterogeneity of Arylamine-Modified DNA: 19F NMR evidence
Zhou, Li,Rajabzadeh, Masoumeh,Traficante, Daniel D.,Cho, Bongsup P.
, p. 5384 - 5389 (1997)
One- and two-dimensional 19F NMR spectroscopy was used to investigate the conformational heterogeneity of two arylamine-modified DNA duplexes, d[CTTCTTG*ACCTC]·d[GAGGTCAAGAAG], in which G* is either N-(deoxyguanosin- 8-yl)-4'-fluoro-4-aminobiphenyl (dG-C8-FABP) (I) or N-(deoxyguanosin-8-yl)- 7-fluoro-2-aminofluorene (dG-C8-FAF) (II). The 19F NMR spectrum of I showed a single peak, while that of II revealed two prominent signals with a 55:45 ratio, in good agreement with previous 1H NMR results (Cho et al. Biochemistry 1992, 31, 9587-9602; 1994, 33, 1373-1384). Slow interconversion between the two conformations of II was established by temperature-dependent two-dimensional 19F NMR chemical exchange spectra. On the basis of magnetic anisotropy effects and isotopic solvent-induced shifts, the 19F signals at -117.31 and -118.09 ppm in the 19F NMR spectrum of 11 were assigned to a relatively undisturbed 'B-type' conformer and a highly perturbed 'stacked' conformer, respectively. Analysis of the temperature dependent (5-40°C) line shapes by computer simulation yielded an interconversion barrier (ΔG((+))) of 14.0 kcal/mol with a chemical exchange time of 2 ms at 30°C. This new 19F approach should be very useful in investigating the sequence-dependent conformational heterogeneity of arylamine-modified DNA.
Supramolecular Nanopatterns of Molecular Spoked Wheels with Orthogonal Pillars: The Observation of a Fullerene Haze
Grimme, Stefan,H?ger, Sigurd,Jester, Stefan-S.,Jochemich, Anna,Keller, Tristan J.,Kr?nert, Anna,Müller, Ute,Poluektov, Georgiy,Spicher, Sebastian
supporting information, p. 27264 - 27270 (2021/11/30)
Molecular spoked wheels with intraannular functionalizable pillars are synthesized in a modular approach. The functionalities at their ends are variable, and a propargyl alcohol, a [6,6]-phenyl-C61-butyrate, and a perylene monoimide are investigated. All compounds form two-dimensional crystals on highly oriented pyrolytic graphite at the solid–liquid interface. As determined by submolecularly resolved scanning tunneling microscopy, the pillars adopt equilibrium distances of 6.0 nm. The fullerene has a residual mobility, limited by the length of the flexible connector unit. The experimental results are supported and rationalized by molecular dynamics simulations. These also show that, in contrast, the more rigidly attached perylene monoimide units remain oriented along the surface normal and maintain a smallest distance of 2 nm above the graphite substrate. The robust packing concept also holds for cocrystals with molecular hexagons that expand the pillar–pillar distances by 15 % and block unspecific intercalation.
Palladium nanoparticle supported on nitrogen-doped porous carbon: Investigation of structural properties and catalytic activity on Suzuki–Miyaura reactions
Bu?day, Nesrin,Alt?n, Serdar,Ya?ar, Sedat
, (2021/08/25)
Novel palladium-doped nanoporous carbon composite material obtained via thermolysis of amorphous zeolitic imidazolate framework (aZIF) was synthesized and used as an efficient catalyst on Suzuki–Miyaura cross-coupling reactions of aryl bromides. With this developed catalytic system, the Suzuki–Miyaura cross-coupling reaction was accomplished in aqueous solutions, and biaryls were obtained in good to excellent yields in a short reaction time. The APC-750@Pd catalyst was characterized by Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Eicroscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Thermal Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Brunauer–Emmett–Teller (BET) analysis tecniques. N-doped porous carbon material (NPC-1000) was synthesized by thermolysis from aZIF. Activated porous carbon material (APC-750) was fabricated via fused at 750°C with KOH from NPC-1000. The APC-750@Pd was obtained as a result of the interaction of APC-750 and PdCl2 in deionized water. The cross-coupling reaction of different aryl bromides with phenylboronic acid was investigated to show the potential of the APC-750@Pd in the Suzuki–Miyaura cross-coupling reactions. The APC-750@Pd catalyst could be recycled at least five times with a 15% loss of catalytic efficiency in this catalytic system.