Synthesis, Characterization, Biological Evaluation, and In Silico Studies of Imidazolium-, Pyridinium-, and Ammonium-Based Ionic Liquids Containing n-Butyl Side Chains.

Ionic liquids (ILs) have emerged as active pharmaceutical ingredients because of their excellent antibacterial and biological activities. Herein, we used the green-chemistry-synthesis procedure, also known as the metathesis method, to develop three series of ionic liquids using 1-methyl-3-butyl imidazolium, butyl pyridinium, and diethyldibutylammonium as cations, and bromide (Br-), methanesulfonate (CH3SO3-), bis(trifluoromethanesulfonyl)imide (NTf2-), dichloroacetate (CHCl2CO2-), tetrafluoroborate (BF4-), and hydrogen sulfate (HSO4-) as anions. Spectroscopic methods were used to validate the structures of the lab-synthesized ILs. We performed an agar well diffusion assay by using pathogenic bacteria that cause various infections (Escherichia coli; Enterobacter aerogenes; Klebsiella pneumoniae; Proteus vulgaris; Pseudomonas aeruginosa; Streptococcus pneumoniae; Streptococcus pyogenes) to scrutinize the in vitro antibacterial activity of the ILs. It was established that the nature and unique combination of the cations and anions were responsible for the antibacterial activity of the ILs. Among the tested ionic liquids, the imidazolium cation and NTf2- and HSO4- anions exhibited the highest antibacterial activity. The antibacterial potential was further investigated by in silico studies, and it was observed that bis(trifluoromethanesulfonyl)imide (NTf2-) containing imidazolium and pyridinium ionic liquids showed the maximum inhibition against the targeted bacterial strains and could be utilized in antibiotics. These antibacterial activities float the ILs as a promising alternative to the existing antibiotics and antiseptics.

Magnetic, Electronic, and Optical Studies of Gd-Doped WO3: A First Principle Study.

Tungsten trioxide (WO3) is mainly studied as an electrochromic material and received attention due to N-type oxide-based semiconductors. The magnetic, structural, and optical behavior of pristine WO3 and gadolinium (Gd)-doped WO3 are being investigated using density functional theory. For exchange-correlation potential energy, generalized gradient approximation (GGA+U) is used in our calculations, where U is the Hubbard potential. The estimated bandgap of pure WO3 is 2.5 eV. After the doping of Gd, some states cross the Fermi level, and WO3 acts as a degenerate semiconductor with a 2 eV bandgap. Spin-polarized calculations show that the system is antiferromagnetic in its ground state. The WO3 material is a semiconductor, as there is a bandgap of 2.5 eV between the valence and conduction bands. The Gd-doped WO3's band structure shows few states across the Fermi level, which means that the material is metal or semimetal. After the doping of Gd, WO3 becomes the degenerate semiconductor with a bandgap of 2 eV. The energy difference between ferromagnetic (FM) and antiferromagnetic (AFM) configurations is negative, so the Gd-doped WO3 system is AFM. The pure WO3 is nonmagnetic, where the magnetic moment in the system after doping Gd is 9.5599575 µB.