Potential facile separation strategy for mixtures of 3- and 4-methylpyridine by employing N,N′-bis(9-phenyl-9-xanthenyl)ethylenediamine as an alternative host compound

In the present work, a plausible host candidate is provided for the separation of 3-methylpyridine (3MP) from 4-methylpyridine (4MP), isomers that are extremely difficult to separate by conventional means. Host compound N,N′-bis(9-phenyl-9-xanthenyl)ethylenediamine (H2), when recrystallized from an equimolar mixture of 3MP and 4MP, contained 91.6% 3MP, a significantly improved outcome compared with the alternate host compound N,N′-bis(9-phenyl-9-thioxanthenyl)ethylenediamine (H1) which only enclathrated 70% of this isomer in the same experimental conditions. Single crystal diffraction and thermoanalytical experiments were conducted in order to investigate this preference for 3MP by considering both host?guest interactions and relative complex stabilities. Many of the guest components in 3(H2)·5(3MP)·0.268(O) experienced at least one other short contact measuring less than the sum of the van der Waals radii of the involved atoms, an observation that may explain the selectivity of H2 for this guest since this was not the case in complexes containing PYR and 4MP. Results from the thermal analyses were less informative.

     

Syntheses and reactions of 2,2′-bisbenzimidazole systems

Nucleophilic reactions of two 2,2′-bisbenzimidazole systems, namely the bis(2H-benzimidazole-2-ylidene) 2 and the dispiro[2H-benzimidazole-2,1′-cyclohexane-4′,2″-2″H-benzimidazole] 3, as well as the syntheses of new 2,2′-bisbenzimidazoles are reported and their conversion into other heterocycles is described.     

Compounds N,N′-bis(9-cyclohexyl-9-xanthenyl)ethylenediamine and its thio derivative,N,N′-bis(9-cyclohexyl-9-thioxanthenyl)ethylenediamine,as potential hosts in the presence of xylenes and ethylbenzene: Conformational analyses and molecular modelling considerations

Two novel crystalline compounds, N,N′-bis(9-cyclohexyl-9-xanthenyl)ethylenediamine (OED) and its thio derivative, N,N′-bis(9-cyclohexyl-9-thioxanthenyl)ethylenediamine (SED), were designed and synthesized in our laboratories, and assessed for their potential as host compounds for the four C8 aromatic compounds, namely o-, m- and p-xylene (o-Xy, m-Xy, p-Xy), and ethylbenzene (EB). Despite the only difference between the two compounds being the heteroatoms in their B rings, immense behaviour differences were noted: only OED displayed host behaviour in these conditions, clathrating all but m-Xy, while SED failed to form complexes with any of the four organic solvents. These observations prompted an investigation into the conformations of OED and SED through single crystal diffraction (SCXRD) analyses as well as computational studies with surprising results. SCXRD was also employed to analyse the three complexes that successfully formed with OED, and thermal analyses (TA) assisted in understanding the selectivity behaviour of OED when presented with mixed guests.     

Behaviour of host compounds 1,2-DAX and 1,2-DAT in the presence of mixed xylene and ethylbenzene guest solvents,and comparisons with their 1,4 host derivatives

Journal of Inclusion Phenomena and Macrocyclic Chemistry - trans-N,N′-Bis(9-phenyl-9-xanthenyl)cyclohexane-1,2-diamine (1,2-DAX) and...     

trans-α,α,α′,α′-Tetraphenyl-9,10-dihydro-9,10-ethanoanthracene-11,12-dimethanol and its tetra(p-chlorophenyl) derivative: roof-shaped host compounds for the purification of aromatic C8H10 isomeric guest mixtures

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Roof-shaped host compounds trans-α,α,α′,α′-tetraphenyl-9,10-dihydro-9,10-ethanoanthracene-11,12-dimethanol...     

Microencapsulation of dichromate and paracetamol with Eudragit Retard polymers using phase separation by nonsolvent addition

A coacervation technique for microencapsulation using Eudragit Retard polymers [poly(methyl methacrylates) substituted by quaternary ammonium groups] as wall material is described, based upon phase separation using a cold chloroform-cyclohexane mixture together with polyisobutylene as a stabilizer. The effect of various parameters on the nature and properties of the microcapsules of potassium dichromate and paracetamol has been studied, in particular the alteration in wall content and structure and release rate of contents. The microcapsules are discrete, their properties are reproducible, and various degrees of sustained release are obtained.     

Influence of 40 Hz and 100 Hz Vibration on SH-SY5Y Cells Growth and Differentiation—A Preliminary Study

(1) Background: A novel bioreactor platform of neuronal cell cultures using low-magnitude, low-frequency (LMLF) vibrational stimulation was designed to discover vibration influence and mimic the dynamic environment of the in vivo state. To better understand the impact of 40 Hz and 100 Hz vibration on cell differentiation, we join biotechnology and advanced medical technology to design the nano-vibration system. The influence of vibration on the development of nervous tissue on the selected cell line SH-SY5Y (experimental research model in Alzheimer’s and Parkinson’s) was investigated. (2) Methods: The vibration stimulation of cell differentiation and elongation of their neuritis were monitored. We measured how vibrations affect the morphology and differentiation of nerve cells in vitro. (3) Results: The highest average length of neurites was observed in response to the 40 Hz vibration on the collagen surface in the differentiating medium, but cells response did not increase with vibration frequency. Also, vibrations at a frequency of 40 Hz or 100 Hz did not affect the average density of neurites. 100 Hz vibration increased the neurites density significantly with time for cultures on collagen and non-collagen surfaces. The exposure of neuronal cells to 40 Hz and 100 Hz vibration enhanced cell differentiation. The 40 Hz vibration has the best impact on neuronal-like cell growth and differentiation. (4) Conclusions: The data demonstrated that exposure to neuronal cells to 40 Hz and 100 Hz vibration enhanced cell differentiation and proliferation. This positive impact of vibration can be used in tissue engineering and regenerative medicine. It is planned to optimize the processes and study its molecular mechanisms concerning carrying out the research.     

Comparative investigation of the inclusion preferences of optically pure versus racemic TADDOL hosts for pyridine and isomeric methylpyridine guests

Here we consider the effect of the optical purity of TADDOL (α,α,α′,α’-tetraphenyl-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol) on its discriminatory behaviour. We synthesized optically pure and racemic TADDOL, which form complexes with pyridine and the methylpyridines, and recrystallized them from various equimolar mixtures of these guests, and showed that both TADDOLs, surprisingly, discriminate similarly between them. The selectivity of optically active TADDOL was in the order 3-methylpyridine > 4-methylpyridine > pyridine > 2-methylpyridine, while this order was 3-methylpyridine > 4-methylpyridine > 2-methylpyridine > pyridine for the racemate. For many of the experiments, the extent of selectivity displayed by the two hosts was comparable. Single crystal X-ray diffraction experiments showed that preferred guests experienced stronger π-π and, even more so, H-bonding interactions with the host. Thermal analyses confirmed reports that suggested that guests that reside in channels in the host structure form less thermally stable complexes than those where the guests are accommodated in discrete cavities.