Pseudopeptide‐Based Hydrogels Trapping Methylene Blue and Eosin Y

We present herein the preparation of four different hydrogels based on the pseudopeptide gelator Fmoc‐l ‐Phe‐d ‐Oxd‐OH (Fmoc=fluorenylmethyloxycarbonyl), either by changing the gelator concentration or adding graphene oxide (GO) to the water solution. The hydrogels have been analysed by rheological studies that demonstrated that pure hydrogels are slightly stronger compared to GO‐loaded hydrogels. Then the hydrogels efficiency to trap the cationic methylene blue (MB) and anionic eosin Y (EY) dyes has been analyzed. MB is efficiently trapped by both the pure hydrogel and the GO‐loaded hydrogel through π–π interactions and electrostatic interactions. In contrast, the removal of the anionic EY is achieved in less satisfactory yields, due to the unfavourable electrostatic interactions between the dye, the gelator and GO.     

Chemoenzymatic synthesis of both enantiomers of 3-hydroxy- and 3-amino-3-phenylpropanoic acid

Ethyl (S)-3-hydroxy-3-phenylpropionate (S)-2 was obtained by the asymmetric reduction of ethyl 3-phenyl-3-oxopropionate 1 with the yeast Saccharomyces cerevisiae (ATCC 9080). The kinetic resolution of racemic ethyl 2-acetoxy-3-phenyl-propionate rac-3 with the same microorganism, gave after hydrolysis ethyl (R)- and (S)-3-hydroxy-3-phenylpropionates (R)-2 and (S)-2 which were converted by a straightforward series of reactions to the enantiomers of 3-amino-3-phenyl-propionic acids (S)-6 and (R)-6. The asymmetric reduction and hydrolytic kinetic resolution were also tested with several other whole cell systems under a variety of conditions.     

A Journey from Thermally Tunable Synthesis to Spectroscopy of Phenylmethanimine in Gas Phase and Solution

Phenylmethanimine is an aromatic imine with a twofold relevance in chemistry: organic synthesis and astrochemistry. To tackle both aspects, a multidisciplinary strategy has been exploited and a new, easily accessible synthetic approach to generate stable imine-intermediates in the gas phase and in solution has been introduced. The combination of this formation pathway, based on the thermal decomposition of hydrobenzamide, with a state-of-the-art computational characterization of phenylmethanimine laid the foundation for its first laboratory observation by means of rotational electric resonance spectroscopy. Both E and Z isomers have been accurately characterized, thus providing a reliable basis to guide future astronomical observations. A further characterization has been carried out by nuclear magnetic resonance spectroscopy, showing the feasibility of this synthetic approach in solution. The temperature dependence as well as possible mechanisms of the thermolysis process have been examined.     

Relaxation Dynamics and Magnetic Anisotropy in a Low‐Symmetry DyIII Complex

The magnetic behaviour of a Dy(LH)₃ complex (LH^? is the anion of 2‐hydroxy‐N′‐[(E)‐(2‐hydroxy‐3‐methoxyphenyl)methylidene]benzhydrazide) was analysed in depth from both theoretical and experimental points of view. Cantilever torque magnetometry indicated that the complex has Ising‐type anisotropy, and provided two possible directions for the easy axis of anisotropy due to the presence of two magnetically non‐equivalent molecules in the crystal. Ab initio calculations confirmed the strong Ising‐type anisotropy and disentangled the two possible orientations. The computed results obtained by using ab initio calculations were then used to rationalise the composite dynamic behaviour observed for both pure Dy^III phase and Y^III diluted phase, which showed two different relaxation channels in zero and non‐zero static magnetic fields. In particular, we showed that the relaxation behaviour at the higher temperature range can be correctly reproduced by using a master matrix approach, which suggests that Orbach relaxation is occurring through a second excited doublet.     

Controlling the propagation of broadband light pulses by Electromagnetically Induced Transparency

We present an experimental and theoretical investigation, performed on hot sodium atoms in a ladder scheme, showing the control of the absorption and of the propagation velocity of a probe light pulse with a spectral bandwidth as large as 1.8 GHz. The predictions of the theoretical model compare favorably with the experimental results.     

Tautomerism in liquid 1,2,3-triazole: a combined energy-dispersive X-ray diffraction, molecular dynamics, and FTIR study

In this work, we report a multitechnique (energy-dispersive X-ray diffraction, computational methods, and FTIR spectroscopy) study of the tautomeric equilibrium of 1,2,3-triazole, one of the few small nitrogen-containing eterocycles liquid at room temperature. The T-2H form (C _2v symmetry) is found to be strongly favored in gas and solid phases, whereas the neat liquid gives diffraction patterns that can be interpreted satisfactorily with the structure functions calculated from some molecular dynamics results for both T-2H and T-1H tautomers, although the T-2H form gives a slightly better agreement.     

Additive-Free Chemoselective Acylation of Amines

Aliphatic and aromatic amines are efficiently acylated by acetic, pivalic, benzoic, phthalic, or maleic anhydrides in ethyl acetate at room temperature. Under the same experimental conditions, amino alcohols are chemoselectively acylated at the amino group.