Highly Stereoselective Recognition and Deracemization of Amino Acids by Supramolecular Self‐Assembly

The highly stereoselective supramolecular self‐assembly of α‐amino acids with a chiral aldehyde derived from binol and a chiral guanidine derived from diphenylethylenediamine (dpen) to form the imino acid salt is reported. This system can be used to cleanly convert D ‐amino acids into L ‐amino acids or vice versa at ambient temperature. It can also be used to synthesize α‐deuterated D ‐ or L ‐amino acids. A crystal structure of the ternary complex together with DFT computation provided detailed insight into the origin of the stereoselective recognition of amino acids.     

A New,Fast and Easy Strategy for One‐pot Synthesis of Full Substituted Cyclopropanes: Direct Transformation of Aldehydes to 3‐Aryl‐1,1,2,2‐tetracyanocyclopropanes

A new, fast and easy method for one‐pot reaction of aromatic aldehydes and dialdehydes with malononitrile and cyanogen bromide has been developed to afford full substituted 3‐arylcyclopropane‐1,1,2,2‐tetracarbonitriles in excellent yields in very short time (about 5 seconds). The structures elucidations werev characterized by IR, ¹H NMR, ¹³C NMR, mass spectrometry and X‐ray crystallography techniques. For vthese compounds the crystallographic data showed two structures in mirror image in solid case and one distinct structure in solution. The reaction mechanism was discussed.     

Complexation of Molybdenum(VI) with GLDA at Different Ionic Strengths

The interaction of the biodegradable ligand, l-glutamic acid N,N-diacetic acid tetrasodium salt (GLDA) with molybdenum(VI) was studied by determining stability constants at pH 6.00, T?=?298.15 K, and ionic strength 0.0992?<?I/mol·dm^?3?<?2.5689 of sodium chloride. The ionic strength dependence of the stability constants was fitted to both extended Debye–Hückel and specific ion interaction models. Job’s method confirmed the formation of one species, MoO₃GLDA^4?. The values of the stability constants are in agreement with the other data in the literature for the complex formation of aminopolycarboxylic acids with molybdenum(VI). Experimental data were obtained by using UV spectrophotometric method. The formation constant in pure water is 18.96?±?0.08 on the molal concentration scale.     

Exploiting the Synthetic Potential of Sesquiterpene Cyclases for Generating Unnatural Terpenoids

The substrate flexibility of eight purified sesquiterpene cyclases was evaluated using six new heteroatom‐modified farnesyl pyrophosphates, and the formation of six new heteroatom‐modified macrocyclic and tricyclic sesquiterpenoids is described. GC‐O analysis revealed that tricyclic tetrahydrofuran exhibits an ethereal, peppery, and camphor‐like olfactoric scent.     

A four-coordinate cadmium(II) polymer for efficient adsorption of Congo red,kinetic, isotherm,fluorescence and antibacterial activity

A 3-D cadmium-based coordination polymer, [CdCl₂L]_n (1) (where L = 1,1-(1,6-hexanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole-2-thione), was synthesized and structurally characterized. The capability of the polymer as an efficient sorbent for Congo red (CR) removal from aqueous solution has been evaluated. Compound 1 has a tetrahedral arrangement with a CdS₂Cl₂ core. L in 1 is bidentate to two neighboring Cd^II centers via the methimidazole sulfurs to create 1D chains propagating along the c-axis. The remaining coordination sites are occupied by two terminal chlorides. The chains are further stabilized by intermolecular C–H?Cl hydrogen bonds between the chlorides and hydrogens of the imidazole rings. Parallel chains stack in the 3-D structure. The Cd^II polymer sorbent was characterized by infrared spectroscopy, elemental analysis, UV–vis, solid fluorescence and X-ray single-crystal diffraction. Sorption kinetics were studied by three kinetic models, second order, Elovich and intraparticle diffusion. The results indicate that the mechanism of the sorption process followed Elovich kinetic model. Sorption equilibrium was also studied with Langmuir, Temkin, and Freundlich isotherm models. The sorption process followed the Temkin isotherm. MIC, MBC, and DNA cleavage activities of 1 were also studied. Furthermore, the UV–vis and solid state fluorescence spectra of 1 were measured.     

Inhomogeneous charge transfer within monolayer zinc phthalocyanine absorbed on TiO2(110)

The d-orbital contribution from the transition metal centers of phthalocyanine brings difficulties to understand the role of the organic ligands and their molecular frontier orbitals when it adsorbs on oxide surfaces. Here we use zinc phthalocyanine (ZnPc)/TiO(2)(110) as a model system where the zinc d-orbitals are located deep below the organic orbitals leaving room for a detailed study of the interaction between the organic ligand and the substrate. A charge depletion from the highest occupied molecular orbital is observed, and a consequent shift of N1s and C1s to higher binding energy in photoelectron spectroscopy (PES). A detailed comparison of peak shifts in PES and near-edge X-ray absorption fine structure spectroscopy illustrates a slightly uneven charge distribution within the molecular plane and an inhomogeneous charge transfer screening between the center and periphery of the organic ligand: faster in the periphery and slower at the center, which is different from other metal phthalocyanine, e.g., FePc/TiO(2). Our results indicate that the metal center can substantially influence the electronic properties of the organic ligand at the interface by introducing an additional charge transfer channel to the inner molecular part.     

In Vitro Effect of 445 nm Blue Laser and 660 nm Low-Level Laser on the Quantity and Quality of Human Gingival Fibroblasts

Low-level laser therapy (LLLT) has several benefits in dentistry, including anti-inflammatory effects and increased proliferation. This study aimed to investigate the effect of 445 nm blue laser and 660 nm low-power laser on the quantity and quality of human gingival fibroblasts in vitro. In this in vitro experimental study, 445 nm and 660 nm lasers were irradiated on the samples six times. After examining the cells on the 7^th and 14^th days, the data were analyzed using ANOVA PASS11 and the post hoc Tukey test. The results showed the positive effect of the 660 nm laser on fibroblast proliferation. The viability on the 7^th day was the highest in the control group, lowest in the 445 nm laser group and highest in the 660 nm laser group on the 14^th day. In the morphological examination, the cells were spherical with narrow appendages in the control group, spindle-shaped with lamellipodia appendages in the 660 nm laser group and spherical with no cytoplasmic appendages in the 445 nm laser group. Evidence of necrosis and granulation phenomenon was observed in the 445 nm laser group. The use of the 660 nm low-power laser, compared with the 445 nm laser, has a positive effect on the quantity and quality of gingival fibroblasts.