With the rapidly developing wireless communication technology, electromagnetic pollution problems have become more prominent. Electromagnetic pollution has caused great harm to wireless equipment, precision instruments, military safety, etc., which urgently requires the development of lightweight, high-efficiency, broadband electromagnetic waves (EMW) absorbing materials. MXene is an emerging two-dimensional (2D) material with the advantages of lamellar structure, excellent conductivity, and abundant surface groups. At the same time, conducting polymers (CPs) have excellent performance in terms of conductivity, surface activity, quality, and electromagnetic loss, making them have excellent potential in EMW absorbing direction. This article examines the preparation, structure, and performance of MXene and CPs-based radar absorbing materials (RAM). A comprehensive summary and objective analysis of the nowaday study progress on the EMW absorbing performances of MXene and CPs, and a comprehension of the absorbing mechanism are reviewed. Finally, the research direction of absorbing materials has been prospected.

Antimicrobial resistance is an ever-increasing problem throughout the world and has already reached severe proportions. Bacteria can develop ways to render traditional antibiotics ineffective, raising a crucial need to find new antimicrobials with novel mode of action. We demonstrate here a novel class of pyrazine functionalized Ag(I) and Au(I)-NHC complexes as antibacterial agents against human pathogens that are resistant to several antibiotics. Complete synthetic and structural studies of Au(I) and Ag(I) complexes of 2-(1-methylimidazolium) pyrimidinechloride (L-1), 2,6-bis(1-methylimidazol)pyrazinechloride (L-2) and 2,6-bis(1-methyl imidazol) pyrazinehexa-fluorophosphate (L-3) are reported herein. Chloro[2,6-bis(1-methyl imidazol)pyrazine]gold(I), 2b and chloro [2,6-bis(1-methyl imidazol)pyrazine]silver(I), 2a complexes are found to have more potent antimicrobial activity than other synthesized compounds and several conventionally used antibiotics. Complexes 2b and 2a also inhibit the biofilm formation by Gram-positive bacteria, Streptococcus mutans and Gram-negative bacteria, Escherichia coli, causing drastic damage to the bacterial cell wall and increasing membrane permeability. Complexes 2b and 2a strongly binds to both Lys and Dap-Type peptidoglycan layers, which may be the reason for damage to the bacterial cell wall. Theoretical studies of all the complexes reveal that 2b and 2a are more reactive than other complexes, and this may be the cause of differences in antibacterial activity. These findings will pave the way towards developing a new class of antibiotics against different groups of conventional antibiotic-resistant bacteria.

Keratitis treatment has become more complicated due to the emergence of bacterial or fungal pathogens with enhanced antibiotic resistance. The pharmaceutical applications of N-heterocyclic carbene complexes have received remarkable attention due to their antimicrobial properties. In this paper, the new precursor, 3,3′-(p-phenylenedimethylene) bis{1-(2- methyl-allyl)imidazolium} bromide (1a) and its analogous PF6 salt (1b) were synthesized. Furthermore, silver(I) and gold(I) -N-heterocyclic carbene (NHC) complexes [Ag2LBr2/Au2LBr2; 2a/3a], [(Ag2L2)(PF6)2/(Au2L2)(PF6)2; 2b/3b] were developed from their corresponding ligands. All compounds were screened for their antimicrobial activities against multiple keratitis-associated human eye pathogens, including bacteria and fungi. Complexes 2a and 3a showed highest activity, and the effectiveness of 3a was also studied, focusing eradication of pathogen biofilm. Furthermore, the structures of 1a, 2a and 3b were determined using single crystal X-ray analysis, 2b and 3a were optimized theoretically. The mechanism of action of 3a was evaluated by scanning electron microscopy and docking experiments, suggesting that its target is the cell membrane. In summary, 3a may be helpful in developing antimicrobial therapies in patients suffering from keratitis-associated eye infections caused by multidrug-resistant pathogens.

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Superalkalis are complexes that have a lower ionization energy than that of the corresponding alkali and alkaline earth metals. Based on First Principles calculations, the plausible existence of a superalkali complex consisting of an all-metal aromatic trigonal Au3 core coupled with pyridine (Py) and imidazole (IMD) ligands is suggested. The calculated ionization energy (IE) values of the subsequent organometallic complexes, Au3(Py)3 and Au3(IMD)3, are low, thereby mimicking the usual behavior of a superalkali. First order hyperpolarizability calculations show the existence of non-linear optical properties in some of the complexes, which is also on par with the properties of a superalkali.