Efficient method to prepare diethylphosphonacetamides

An efficient and versatile synthetic method is described to synthesize diethylphosphonacetamides in a single step.     

Zundel‐like and Eigen‐like Hydrated Protons on a Platinum Surface

The nature of hydrated protons is an important topic in the fundamental study of electrode processes in acidic environment. For example, it is not yet clear whether hydrated protons are formed in the solution or on the electrode surface in the hydrogen evolution reaction on a Pt electrode. Using mass spectrometry and infrared spectroscopy, we show that hydrogen atoms are converted into hydrated protons directly on a Pt(111) surface coadsorbed with hydrogen and water in ultrahigh vacuum. The hydrated protons are preferentially stabilized as multiply hydrated species (H₅O₂⁺ and H₇O₃⁺) rather than as hydronium (H₃O⁺) ions. These surface‐bound hydrated protons may play an important role in the interconversion between adsorbed hydrogen atoms and solvated protons in solution.     

An Efficient Labelling Approach to Harness Backbone and Side‐Chain Protons in 1H‐Detected Solid‐State NMR Spectroscopy

¹H‐detection can greatly improve spectral sensitivity in biological solid‐state NMR (ssNMR), thus allowing the study of larger and more complex proteins. However, the general requirement to perdeuterate proteins critically curtails the potential of ¹H‐detection by the loss of aliphatic side‐chain protons, which are important probes for protein structure and function. Introduced herein is a labelling scheme for ¹H‐detected ssNMR, and it gives high quality spectra for both side‐chain and backbone protons, and allows quantitative assignments and aids in probing interresidual contacts. Excellent ¹H resolution in membrane proteins is obtained, the topology and dynamics of an ion channel were studied. This labelling scheme will open new avenues for the study of challenging proteins by ssNMR.     

Synthesis of amide libraries with immobilized HOBt

Highly reactive N-acylating solid-phase reagents based on macroporous polystyrene-bound 1-hydroxybenzotriazole (P-HOBt) and silica-bound 1-hydroxybenzotriazole (Si-HOBt) were prepared and compared for reactivity by synthesis of small combinatorial libraries of acetamides and benzamides.     

Origin of the solvent effects on the barrier to amide isomerization from the combined QM/MM Monte Carlo simulations

The origin of the solvent effects on the free energy of activation for the isomerization of N,N-dimethylformamide in water, CHCl₃ and CCl₄ has been investigated through statistical mechanical simulations using the combined quantum mechanical and molecular mechanical AM1/OPLS potential. The differential solvations between the ground state and transition state in various solvents can be attributed to the differences in molecular dipole moments in solution, and to the solvent polarization effects. In polar solvents, DMF is polarized more favorably in the ground state than in the rotated conformers, leading to greater solvent contributions. The modest solvent effects in CCl₄ are a reflection of its much smaller dielectric constant.