Publications by authors named "Mohamed Khaled Abd El-Rahman"

Radical (R) and R-hole site-based interactions are comparatively studied, for the first time, using methods. In this regard, R-bearing molecules XO (where X = Cl, Br, and I) were subjected to direct interaction with NH within dimeric and trimeric forms in the form of NH···XO/XO···NH and NH···XO···NH complexes, respectively. As confirmed by electrostatic potential analysis, the studied R-bearing molecules XO had the outstanding potentiality to interact as Lewis acid centers via two positive sites dubbed as R and R-hole sites.

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Herein, the potential of ZO and ZF aerogen-comprising molecules (where Z = Ar, Kr, and Xe) to engage in σ-, lp-, and π-hole site-based interactions was comparatively studied using various computations. For the first time, a premier in-depth elucidation of the external electric field (EEF) influence on the strength of the σ-, lp-, and π-hole site-based interactions within the ZO/ZF⋯NH and ⋯NCH complexes was addressed using oriented EEF with disparate magnitude. Upon the energetic features, σ-hole site-based interactions were noticed with the most prominent preferability in comparison to lp- and π-hole analogs.

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σ-Hole site-based interactions in the trigonal bipyramidal geometrical structure of hypervalent pnicogen, halogen, and aerogen-bearing molecules with pyridine and NCH Lewis bases (LBs) were comparatively examined. In this respect, the ZF···, XFO···, and AeFO···LB complexes (where Z = As, Sb; X = Br, I; Ae = Kr, Xe; and LB = pyridine and NCH) were investigated. The electrostatic potential (EP) analysis affirmations outlined the occurrence of σ-holes on the systems under consideration with disparate magnitudes that increased according to the following order: AeFO < XFO < ZF.

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Novel miniaturized polyvinyl chloride (PVC) membrane sensors in all-solid state graphite and platinum wire supports were developed, electrochemically evaluated and used for the assay of rivastigmine hydrogen tartrate drug (RIV). The RIV sensors are based on the formation of an ion-association complex between the drug cation and tetrakis(4-chlorophenyl)borate (TpClPB) anionic exchanger as electroactive material dispersed in a PVC matrix. Linear responses of 10(-2) - 10(-5) M and 10(-2) - 10(-4) M with cationic slopes of 56.

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