The Different Facets of Triclocarban: A Review

In the late 1930s and early 1940s, it was discovered that the substitution on aromatic rings of hydrogen atoms with chlorine yielded a novel chemistry of antimicrobials. However, within a few years, many of these compounds and formulations showed adverse effects, including human toxicity, ecotoxicity, and unwanted environmental persistence and bioaccumulation, quickly leading to regulatory bans and phase-outs. Among these, the triclocarban, a polychlorinated aromatic antimicrobial agent, was employed as a major ingredient of toys, clothing, food packaging materials, food industry floors, medical supplies, and especially of personal care products, such as soaps, toothpaste, and shampoo. Triclocarban has been widely used for over 50 years, but only recently some concerns were raised about its endocrine disruptive properties. In September 2016, the U.S. Food and Drug Administration banned its use in over-the-counter hand and body washes because of its toxicity. The withdrawal of triclocarban has prompted the efforts to search for new antimicrobial compounds and several analogues of triclocarban have also been studied. In this review, an examination of different facets of triclocarban and its analogues will be analyzed.     

Luminescent copper(I) halide adducts of [Au(im(CH2py)2)2]PF6 exhibiting short Au(I)···Cu(I) separations and unusual semibridging NHC ligands

The picolyl-substituted NHC complex [Au(im(CH(2)py)(2))(2)]PF(6) (1) reacts with two equivalents of copper(I) halides, affording compounds [Au(im(CH(2)py)(2))(2)(CuX)(2)]PF(6) (X = Cl, 2; Br, 3; I, 4). Each complex contains a nearly linearly coordinated [Au(NHC)(2)](+) center where the two picolyl groups on each im(CH(2)py)(2) ligand chelate a single copper atom. The Cu(I) center resides in a distorted tetrahedral environment and is coordinated to two pyridyl groups, a halide ion, and a gold metalloligand. The Au(I)-Cu(I) separations measure 2.7030(5), 2.6688(9), and 2.6786(10) ? for 2-4, respectively. Additionally, each Cu(I) center is further coordinated by a semibridging NHC ligand with short Cu-C separations of ~2.3 ?. In solution, these complexes dissociate the Cu(I) ion. In the solid state, 2-4 are photoluminescent with respective emission maxima of 512, 502, and 507 nm. The reaction of [Au(im(CH(2)py)(2))(2)]PF(6) with four equivalents of CuBr afforded the coordination polymer {[AuCu(2)Br(2)(im(CH(2)py)(2))(2)]Br·3CH(3)CN}(n) (5). This polymeric complex contains [Au(NHC)(2)](+) units interconnected by Cu(2)Br(2) dimers. In 5, the Au-Cu separations are long at 4.23 and 4.79 ?, while the Cu-Cu distance is considerably shorter at 2.9248(14) ?. In the solid state, 5 is photoluminescent with a broad band appearing at 533 nm.     

Lensless imaging for simultaneous microfluidic sperm monitoring and sorting

5.3 million American couples of reproductive age (9%) are affected by infertility, among which male factors account for up to 50% of cases, which necessitates the identification of parameters defining sperm quality, including sperm count and motility. In vitro fertilization (IVF) with or without intra cytoplasmic sperm injection (ICSI) has become the most widely used assisted reproductive technology (ART) in modern clinical practice to overcome male infertility challenges. One of the obstacles of IVF and ICSI lies in identifying and isolating the most motile and presumably healthiest sperm from semen samples that have low sperm counts (oligozoospermia) and/or low sperm motility (oligospermaesthenia). Microfluidic systems have shown potential to sort sperm with flow systems. However, the small field of view (FOV) of conventional microscopes commonly used to image sperm motion presents challenges in tracking a large number of sperm cells simultaneously. To address this challenge, we have integrated a lensless charge-coupled device (CCD) with a microfluidic chip to enable wide FOV and automatic recording as the sperm move inside a microfluidic channel. The integrated system enables the sorting and tracking of a population of sperm that have been placed in a microfluidic channel. This channel can be monitored in both horizontal and vertical configuration similar to a swim-up column method used clinically. Sperm motilities can be quantified by tracing the shadow paths for individual sperm. Moreover, as the sperm are sorted by swimming from the inlet towards the outlet of a microfluidic channel, motile sperm that reach the outlet can be extracted from the channel at the end of the process. This technology can lead to methods to evaluate each sperm individually in terms of motility response in a wide field of view, which could prove especially useful, when working with oligozoospermic or oligospermaesthenic samples, in which the most motile sperm need to be isolated from a pool of small number of sperm.     

Molecular Modeling and Experimental Evaluation of Non-Chiral Components of Bergamot Essential Oil with Inhibitory Activity against Human Monoamine Oxidases

Human monoamine oxidases (hMAOs) are well-established targets for the treatment of neurological disorders such as depression, Parkinson’s disease and Alzheimer’s disease. Despite the efforts carried out over the years, few selective and reversible MAO inhibitors are on the market. Thus, a continuous search for new compounds is needed. Herein, MAO inhibitors were searched among the non-chiral constituents of Bergamot Essential Oil (BEO) with the aid of computational tools. Accordingly, molecular modeling simulations were carried out on both hMAO-A and hMAO-B for the selected constituents. The theoretically predicted target recognition was then used to select the most promising compounds. Among the screened compounds, Bergamottin, a furocoumarin, showed selective hMAO-B inhibitory activity, fitting its active site well. Molecular dynamics simulations were used to deeply analyze the target recognition and to rationalize the selectivity preference. In agreement with the computational results, experimental studies confirmed both the hMAO inhibition properties of Bergamottin and its preference for the isoform B.     

Metal-Organic Chemical Vapor Deposition (MOCVD) Synthesis of Heteroepitaxial Pr0.7Ca0.3MnO3 Films: Effects of Processing Conditions on Structural/Morphological and Functional Properties

Calcium-doped praseodymium manganite films (Pr_0.7Ca_0.3MnO₃, PCMO) were prepared by metal-organic chemical vapor deposition (MOCVD) on SrTiO₃ (001) and SrTiO₃ (110) single-crystal substrates. Structural characterization through X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) analyses confirmed the formation of epitaxial PCMO phase films. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) characterization was used to confirm lateral and vertical composition and the purity of the deposited films. Magnetic measurements, obtained in zero-field-cooling (ZFC) and field-cooling (FC) modes, provided evidence of the presence of a ferromagnetic (FM) transition temperature, which was correlated to the transport properties of the film. The functional properties of the deposited films, combined with the structural and chemical characterization collected data, indicate that the MOCVD approach represents a suitable route for the growth of pure, good quality PCMO for the fabrication of novel spintronic devices.     

The rα structure of isoxazole,partially oriented in liquid-crystal solvents,from proton spectra and 13C satellites: solvent-induced structure deformations

The ¹H NMR spectra of isoxazole including ¹³C satellites in natural abundance have been studied in two nematic solvents: nematic phase IV and ZLI 1167. The molecular structure corrected for harmonic vibrations (r^βstructure) has been obtained in both phases and compared with a microwave “best structure”. The apparent geometric deformations observed in the phase IV solvent are discussed.     

Orientational properties of liquid-crystalline 4-n-alkyloxybenzilidene-4'-fluoroanilines

The orientational order of 4-n-hexyloxybenzilidene-4'-fluoroaniline, (FAB-OC6) and its 4-n-heptyloxy analogue, (FAB-OC7), studied by means of ²H NMR and ¹⁹F NMR is reported. The entire temperature range of the liquid-crystalline phases (S_B, S_A and N for FAB-OC6, S_B and S_A for FAB-OC7) have been investigated. The results are discussed in relation to previous X-ray diffraction measurements. The chemical shift tensor components of the fluorine bond, evaluated from the ¹⁹F NMR spectra are compared with previous results.     

Monometallic and dimetallic ruthenium(II)-terpyridine complexes employing the tetradentate ligands dipyridylpyrazolyl,dipyridyloxadiazole, and their dimethyl derivatives

The tetradentate ligands, 2,2'-(1H-pyrazole-3,5-diyl)bis(4- methylpyridine) (4,4'-Me2dppzH), 2,2'-(1H-pyrazole-3,5-diyl)bis(6-methylpyridine) (6,6'-Me2dppzH), 3,5-di(pyrid-2-yl)pyrazole (dppzH), and dipyridyloxadiazole (dpo) react with either Ru(trpy)Cl3 or trans-Ru(trpy)Cl2(NCCH3), where trpy is 2,2',2'-terpyridine, to form a variety of Ru(II) complexes. Among these are the symmetrical chloro-bridged Ru(II) dimer and the "in" and "out" geometric isomers of the monometallic Ru(II) containing species where "in" and "out" refer to the orientation of the Ru-Cl vector relative to the centroid of the ligand backbone. Thirteen complexes were prepared and painstakingly purified by careful recrystallization and/or exhaustive column chromatography. These complexes were characterized by 1H and 13C NMR, electronic absorption, and infrared spectroscopy. Additionally, [Ru2(tryp)2(6,6'-Me2dppz)mu-Cl](BF4)2 (3b(BF4)2), [Ru2(trpy)2(4,4'-Me2dppz)mu-Cl](PF6)2.0.5MeOH (3c), [Ru2(trpy)2(6,6'-Me2dppz)(CH2C(O)CH3)](PF6)2.0.5(CH3)2CO (9b), "in"-[Ru(trpy)(4,4'-Me2dppz)Cl](PF6).(CH3)2CO (1c), and "out"-[Ru(trpy)(dpo)Cl](PF6).(CH3)2CO (2d) were characterized by X-ray crystallography. Several ligand substitution reactions were attempted. For example, [Ru2(trpy)2(6,6'-Me2dppz)mu-Cl](BF4)2 (3b) was reacted with hydroxide ion to produce [Ru2(trpy)2(6,6'-Me2dppz)mu-OH](PF6)2 (6b). Complex 6b reacts with benzyl bromide to produce [Ru2(trpy)2(6,6'-Me2dppz)mu-Br](PF6)2 (7b) or with (CH3)3Sil to produce [Ru2(trpy)2(6,6'-Me2dppz)mu-I](PF6)2 (8b). of 6b with acetone forms the methyl enolate complex [Ru2(trpy)2(6,6'-Me2dppz)(CH2COCH3)](PF6)2 (9b) while, analogously to a Cannizarro reaction, the reaction with benzaldehyde forms the bridging benzoate complex [Ru2(trpy)2(6,6'-Me2dppz)(C6H4CO2)](PF6)2 (11b). The bridging azide complex [Ru2(trpy)2(6,6'-Me2dppz)mu-N3](PF6)2 (10b) is formed by reaction of 6b with (CH3)3-SiN3. Additionally, the chloride ligands of the monometallic complexes of "in"-[Ru(trpy)(dpo)Cl](PF6) (1d), "in"-[Ru(trpy)(4,4'-Me2dpo)Cl](PF6)] (1e), and "out"-[Ru(trpy)(dpo)Cl](PF6) (2d) were substituted with water to form their respective aqua complexes, 4d, 4e, and 5d. All of the complexes exhibit broad unsymmetrial absorption bands in the visible portion of the electromagnetic spectrum. The dimetallic complexes 3b and 3c exhibit two, 1e- reversible oxidation waves at +0.72 and +1.15 V, and at +0.64 and +1.13 V, respectively. These complexes were not emissive.     

Bond angle versus torsional deformation in an overcrowded alkene: 9-(2,2,2-triphenylethylidene)fluorene

Competition between bond angle and torsional strain in sterically crowded alkenes generally causes twisting in tetrasubstituted alkenes, while most structurally characterized trisubstituted alkenes are planar. To investigate structural effects of steric repulsion between a planar aromatic ring and a vicinal triphenylmethyl (trityl) group, 9-(2,2,2-triphenylethylidene)fluorene (1 a) was synthesized by reaction of 9-bromomethylenefluorene with triphenylmethyllithium. For comparison with a less strained analogue, 9-ethylidenefluorene (1 b) was prepared by reaction of fluorenone with ethylmagnesium bromide. The X-ray crystal structures show that the difference between bond angles at the 9-fluorenyl carbon atom is much larger for 1 a (12.9 degrees) than 1 b (2.6 degrees). Bond angle and torsional deformations were compared theoretically (HF/6-31+G*) with the tert-butyl analogue (1 c), 1,2,2-tri-tert-butylethene (7), and 2,4,4-trimethyl-2-pentene (8) and crystallographically with six known 1,1-diaryl-2-tert-alkylethenes (2). The trisubstituted alkenes formed three groups with 1) large angle distortion with moderate twisting (1 a, 1 b, and 7), 2) moderate bending with a large range of torsional angles (2), and 3) little bending or twisting (1 b and 8). For the entire series, there appears to be a delicate balance between angle and torsional deformation, but twisting appears to produce smaller relief from steric strain than angle bending. In the crystallographically characterized trisubstituted alkenes, the choice between the two is mainly determined by more subtle packing forces.