The selective reactivity of carbamate and thiocarbamate toward alkylation and amidation is reported under stable, high-valent, cost-effective cobalt(III) catalysis. This method reveals the wide possibility of designing a different branch of synthetically challenging yet highly promising asymmetric catalysts based on BINOL and SPINOL scaffolds. Late-stage C-H functionalization of l-tyrosine and estrone was also achieved through this approach. The mechanistic study shows that a base-assisted internal electrophilic substitution mechanism is operative here.Amides were prepared using rhodium-catalyzed coupling of organozinc iodides and carbon-11 (11C, t1/2 = 20.4 min) isocyanates. Nonradioactive isocyanates and sp3 or sp2 organozinc iodides generated amides in yields of 13%-87%. Incorporation of cyclotron-produced [11C]CO2 into 11C-amide products proceeded in yields of 5%-99%. The synthetic utility of the methodology was demonstrated through the isolation of [11C]N-(4-fluorophenyl)-4-methoxybenzamide ([11C]6g) with a molar activity of 267 GBq μmol-1 and 12% radiochemical yield in 21 min from the beginning of synthesis.We report a study of the structure and bonding of a transition-metal-doped boron cluster, MnB6-, using high-resolution photoelectron imaging and quantum chemical calculations. Vibrationally resolved photoelectron spectra indicate a significant geometry change between the anionic and neutral ground states of MnB6. The electron affinity of MnB6 is measured to be 2.4591(5) eV, and vibrational frequencies for five of its vibrational modes were determined. The experimental data are combined with theoretical calculations to determine the structure and bonding of MnB6-, which is found to be planar with a B-centered hexagonal structure (C2v symmetry) and a quintet spin state (5A2). Nuclear-independent chemical shift calculations indicate that MnB6- is aromatic. Molecular orbital analyses reveal that MnB6- contains three π orbitals, one of which is singly occupied. Hence, MnB6- can be considered as an open-shell metallaboron analog of 3d metallabenzenes.While many practically important electrolytes contain lithium ions, interactions of these ions are particularly difficult to probe experimentally because of their small X-ray and neutron scattering cross sections and large neutron absorption cross sections. Molecular dynamics (MD) is a powerful tool for understanding the properties of nonaqueous electrolyte solutions from the atomic level, but the accuracy of this computational method crucially depends on the physics built into the classical force field. Here, we demonstrate that several force fields for lithium bistriflimide (LiTFSI) in acetonitrile yield a solution structure that is consistent with the neutron scattering experiments, yet these models produce dramatically different ion dynamics in solution. Such glaring discrepancies indicate that inadequate representation of long-range interactions leads to excessive ionic association and ion-pair clustering. We show that reasonable agreement with the experimental observations can be achieved by renormalization of the ion charges using a "titration" method suggested herewith. This simple modification produces realistic concentration dependencies for ionic diffusion and conductivity in less then 2 M solutions, without loss in quality for simulation of the structure.Molecular dynamics simulations are used to provide insights into the molecular mechanisms accounting for binding of amyloid fibrils to lipid bilayers and to study the effect of cholesterol in this process. We show that electrostatic interactions play an important role in fibril-bilayer binding and cholesterol modulates this interaction. In particular, the interaction between positive residues and lipid head groups becomes more favorable in the presence of cholesterol. Consistent with experiments, we find that cholesterol enhances fibril-membrane binding.Bis-triazinyl pyridines (BTPs) exhibit solution selectivity for trivalent americium over lanthanides (Ln), the origins of which remain uncertain. Here, electrospray ionization was used to generate gas-phase complexes [ML3]3+, where M = La, Lu, or Am and L is EtBTP 2,6-bis(5,6-diethyl-1,2,4-triazin-3-yl)-pyridine. Collision-induced dissociation (CID) of [ML3]3+ in the presence of H2O yielded a protonated ligand [L(H)]+ and hydroxide [ML2(OH)]2+ or hydrate [ML(L-H)(H2O)]2+, where (L-H)- is a deprotonated ligand. Although solution affinities indicate stronger binding of BTPs toward Am3+ versus Ln3+, the observed CID process is contrastingly more facile for M = Am versus Ln. To understand the disparity, density functional theory was employed to compute potential energy surfaces for two possible CID processes, for M = La and Am. In accordance with the CID results, both the rate determining transition state barrier and the net energy are lower for [AmL3]3+ versus [LaL3]3+ and for both product isomers, [ML2(OH)]2+ and [ML(L-H)(H2O)]2+. More facile removal of a ligand from [AmL3]3+ by CID does not necessarily contradict stronger Am3+-L binding, as inferred from solution behavior.  https://www.selleckchem.com/products/idf-11774.html  In particular, the formation of new bonds in the products can distort kinetics and thermodynamics expected for simple bond cleavage reactions. In addition to correctly predicting the seemingly anomalous CID behavior, the computational results indicate greater participation of Am 5f versus La 4f orbitals in metal-ligand bonding.The dimetallic boron hydride cluster, (PMe2Ph)4Pt2B10H10 (1-Pt2), is known to reversibly sequester small molecules (e.g., O2, CO, and SO2) across its Pt-Pt cluster vector. Here, we report the very different effect of the addition of nitric oxide (NO) to solutions of (1-Pt2) that prompts the elimination of some of its phosphine ligands and the autofusion of the resultant (PMe2Ph)xPt2B10H10 units to afford the metallaborane conglomerates (PMe2Ph)8Pt8B40H40 (2-Pt8, 38%) and (PMe2Ph)5Pt4B20H20 (3-Pt4, 34%). Single-crystal X-ray studies of these multicluster assemblies reveal the links between the clusters to be a combination of both Pt-Pt bonds and Pt-μH-B 2-electron, 3-center bonds in (2-Pt8) and Pt-μH-B 2-electron, 3-center bonds in (3-Pt4). For compound (2-Pt8), the cluster assemblage can be effectively reversed by the addition of ethyl isonitrile (EtNC) to afford (EtNC)3(PMe2Ph)2Pt2B10H10 4 in quantitative yield. The compounds were characterized by mass spectrometry, multielement NMR spectroscopy, and single-crystal X-ray diffraction studies.