Comprehensive quantum mechanical studies on three bioactive anastrozole based triazole analogues and their SERS active graphene complex

SERS analysis, DFT, and solution effects regarding the structural and optical characteristics of folic acid biomolecule adsorbed on a Cu3 metal cluster

The optical characteristics of folic acid (ABP) and metal clusters of copper (Cu3) at various locations were investigated by means of density functional theory (DFT) computations. Mulliken charge analysis and molecular electrostatic potential (MEP) surface show how charge moves from Cu3 to ABP through the various groups. The peak in the UV-Vis spectra of ABP-Cu3 is caused by bonding and anti-bonding orbitals. In both vacuum and aqueous conditions, the polarizability values of ABP-Cu3 cluster are significantly higher than those of pure ABP, indicating a possible enhancement of the nonlinear optical (NLO) effect. Our research investigates the possibility of using ABP adsorbed metal clusters for NLO materials. Surface enhanced Raman scattering (SERS) in the ABP adsorbed metal clusters enhances the vibrational modes of ABP. Adsorption energies are found to be in the range -17.08 to -58.52 kcal/mol in vacuum and -53.34 to -93.44 kcal/mol in aqueous medium for the different configurations for ABP-Cu3. It indicates that metal clusters adsorbed by ABP are stable in the aqueous media. Experimental IR and UV-Vis of ABP is in agreement with theoretically predicted ones.

Computational analysis of anti-cancer drug hydroxyurea adsorption on nanocages of gold, silver and copper: SERS and DFT assessment

The use of nanostructures in targeted drug delivery is effective in decreasing anticancer drug toxicity. Here, we discuss the theoretically predicted adsorption and interaction behavior of hydroxyurea [HU] with nano metal cages (nmC). HU interact the nmC through the N4 in primary amine with energies of -29.776, -30.684 and -22.105 kcal/mol for Au, Ag and Cu cage, respectively. As a result of reactivity studies, HU complexes with nmC (Au/Ag/Cu) are becoming more electrophilic and this gives the nmC system their bioactivity. It is suggested that nanocage is going to change the FMO's energy levels by means of absorption, so that it is used in drug administration. DOS and MEP were accomplished to gain additional understandings into the reactivity of proposed complexes. Method for improving the Raman signal of biomolecules is surface enhanced Raman scattering (SERS), which uses nanosized metal substrates. Chemical enhancement is evidenced by Mulliken charge distributions of all systems for detection and chemical compositions and exerts a significant role in determining them. In HU complexes containing nmC (Au/Ag/Cu), electron density was detected via ELF and LOL calculations. Based on the results of a non-covalent interaction (NCI) analysis, Van der Waals/hydrogen bonds/repulsive steric - interactions have been found. The title compound will also be analyzed in order to determine its bioactivity and drug likeness parameters, as a result, we will able to create a molecule with a highly favorable pharmacological profile and use the docking method to determine the values of the interaction energies for drug delivery. This study suggests that adsorption of drugs on nanocage surface occurs physically and functionalizing the nanocage has increased adsorption energy.

Density Functional Theory Study on the Interaction between Aflatoxin B1/M1 and Gold Substrate

Aflatoxin M1 (AFM1) and its precursor, Aflatoxin B1 (AFB1), are highly pathogenic and mutagenic substances, making the detection and sensing of AFB1/M1 a long-standing focus of researchers. Among various detection techniques, surface-enhanced Raman spectroscopy (SERS) is considered an ideal method for AFB1/M1 detection due to its ability not only to enhance characteristic frequencies but also to detect shifts in these frequencies with high repeatability. Therefore, we employed density functional theory in conjunction with surface-enhanced Raman spectroscopy to investigate the interaction between AFB1/M1 and a Au substrate in the context of the SERS effect for the first time. To predict the potential binding sites of AFB1/M1 and Au within the SERS effect, we performed calculations on the molecular electrostatic potential of AFB1/M1. Considering the crucial role of the binding energy in molecular docking studies, we computed the binding energy between two molecules interacting with Au at different binding sites. The molecular frontier orbitals and related chemical parameters of AFB1/M1 and "molecular-Au" complexes were computed to elucidate the alterations in AFB1/M1 molecules under the SERS effect. Subsequently, the theoretical Raman spectra of AFB1/M1 and the complexes were compared and analyzed, enabling determination of the adsorption conformation of AFB1/M1 on the gold surface based on SERS surface selection rules. These findings not only provide a deeper understanding of the interaction mechanism between molecules and substrates in the SERS effect but also offer theoretical support for developing novel aflatoxin SERS sensors.

Non-covalent interaction, adsorption characteristics and solvent effect of procainamide anti-arrhythmias drug on silver and gold loaded silica surfaces: SERS spectroscopy, density functional theory and molecular docking investigations†

First-principle calculations were systematically carried out to explore the structural and electronic properties of the non-covalent interaction of procainamide (PA) anti-arrhythmias drug molecules on silver-loaded and gold-loaded silica nanostructures. Computed adsorption energies presented a higher affinity of PA towards the Ag–SiO₂ as compared with Au–SiO₂ surfaces. The non-covalent interaction analysis revealed a weak van der Waals type of forces and hydrogen bonding, associated with a noticeable repulsive steric interaction. It was conceived that silver and gold decorated silica can be used for drug administration in biological systems due to the fact that their frontier molecular orbital energy levels were considerably altered upon absorption, decreasing the pertinent energy gaps. Moreover, the electronic spectra of PA⋯Ag–SiO₂ and PA⋯Au–SiO₂ structures investigated in different solvents display a notable blue shift, suggesting that noble metal-loaded silica can be effective in the context of drug delivery systems. Therefore, silver- and gold-decorated silica of three possible drug adsorption scenarios was fully analyzed to realize the associated bioactivity and drug likeness. Theoretical findings suggest that Ag- and Au–SiO₂ nanocomposites can be considered potential drug delivery platforms for procainamide in medication protocols.

The structural and electronic properties of the non-covalent interaction of procainamide (PA) anti-arrhythmias drug molecules on silver-loaded and gold-loaded silica nanostructures were explored using first-principle calculations.

Theoretical model study of adsorbed antimalarial-graphene dimers: doping effects, photophysical parameters, intermolecular interactions, edge adsorption, and SERS

Future diagnostics and therapy applications are in part riding on the discovery and implementation of new optical techniques and strategies (which often derive from dyads) for example, prediction of features in surface-enhanced Raman spectroscopy requires the study of chromophore-chromophore interactions involve intermolecular forces, drug delivery, and photo mechanisms which are of great interest. New matches between chromophore systems (i.e. FRET), and π-delocalized surfaces are important to study. We explore low-molecular weight drug molecules and their interaction with the reporter material/surface of graphene. Bonding, charge transfer and orbital interactions for 2-amino-5-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole (megazol or AMIT) on graphene were carried out. The graphene model substrate was monotonically/monatomically substituted (doped) with one neutral heteroatom (N/O/S/B) in place of one carbon center; chemical adsorption of AMIT is due to charge transfer from doped graphene to AMIT (DFT). Our AMIT-nanocluster studies show that the nanoclusters will act as a sensor component for the detection of drugs due to SERS. Our findings identified that the greater the energy of the charge transfer, the stronger the calculated chemical adsorption. Additionally, charge transfer is highest for the N-doped systems and least for pristine graphene, resulting in a stronger adsorption energy for N-doped graphene. Mulliken charge analysis of structures confirms enhancement found in QD-AMIT systems.Communicated by Ramaswamy H. Sarma.

Graphene-Based Surface-Enhanced Raman Scattering (SERS) Sensing: Bibliometrics Based Analysis and Review

Surface-enhanced Raman scattering (SERS) has received increasing attention from researchers since it was first discovered on rough silver electrode surfaces in 1974 and has promising applications in life sciences, food safety, and environmental monitoring. The discovery of graphene has stirred considerable waves in the scientific community, attracting widespread attention in theoretical research and applications. Graphene exhibits the properties of a semi-metallic material and has also been found to have Raman enhancement effects such as in metals. At the same time, it quenches the fluorescence background and improves the ratio of a Raman signal to a fluorescence signal. However, graphene single-component substrates exhibit only limited SERS effects and are difficult to use for trace detection applications. The common SERS substrates based on noble metals such as Au and Ag can produce strong electromagnetic enhancement, which results in strong SERS signals from molecules adsorbed on the surface. However, these substrates are less stable and face the challenge of long-term use. The combination of noble metals and graphene to obtain composite structures was an effective solution to the problem of poor stability and sensitivity of SERS substrates. Therefore, graphene-based SERS has been a popular topic within the last decade. This review presents a statistically based analysis of graphene-based SERS using bibliometrics. Journal and category analysis were used to understand the historical progress of the topic. Geographical distribution was used to understand the contribution of different countries and institutions to the topic. In addition, this review describes the different directions under this topic based on keyword analysis and keyword co-occurrence. The studies on this topic do not show a significant divergence. The researchers’ attention has gradually shifted from investigating materials science and chemistry to practical sensing applications. At the end of the review, we summarize the main contents of this topic. In addition, several perspectives are presented based on bibliometric analysis.

A foundational theoreticalAl12E12(E = N, P) adsorption and quinolone docking study: cage–quinolone pairs, optics and possible therapeutic and diagnostic applications

This combined Al₁₂E₁₂ (E = N, P) surface adsorption and docking study describes the new possibility of prospective potential probing(photophysical/optical) and therapy(medicinal/biochemical) with these adsorbent conjugates. DFT investigations were undertaken herein to help generate geometrical models and better understand the possible favorable adsorption energetics. We attempt to explain their adsorption behaviors and docking involving SARS-CoV-2 viruses (PDB)to assess their possible pharmaceutical potential against the pandemic virus (COVID-19). The adsorption behavior of 8-hydroxy-2-methylquinoline (MQ) and its halogenated derivatives, 5,7-diiodo-8-hydroxy-2-methylquinoline (MQI), 5,7-dichloro-8-hydroxy-2-methylquinoline (MQCl), and 5,7-dibromo-8-hydroxy-2-methylquinoline (MQBr), with aluminum-nitrogen (AlN), and aluminum-phosphorous (AlP) fullerene-like nanocages is reported. A decrease in the hardness of the nanoclusters when adsorbed with drug molecules resulted in an incrementally improved chemical softness (see e.g., Hard-Soft Acid Base theory) indicating that reactivity of the drug molecule in the resulting complex increases upon cluster chemical adsorption. The energy gap is found to be maximized for AlN-MQ and minimized for AlP-MQI; the reduced density gradient (RDG) iso-surfaces and AIM studies also corroborated this. Therefore, these two were found, respectively, to be the least and most electrically conductive of the species under study. We selected a simple medicinal building block (chelator)in addition to selecting the cluster based on previous literature reports. Important parameters such as gap energies and global indices were determined. We assessed NLO properties. The SARS-CoV-2 virus PDB docking data for 6VW1, 6VYO, 6WKQ, 7AD1, 7AOL, 7B3C, were enlisted as ligand targets for studies of docking (PatchDock Server) using the requisite PDB geometries (For the structure of 6VW1, kindly see reference, 2020; For the structure of 6VYO kindly see reference, 2020; For the structure of 6WKQ kindly see reference, 2020; For the structure of 7AD1 kindly see reference, 2021; For the structure of 7AOL kindly see reference, 2021; For the structure of 7B3C kindly see reference, 2021). Such findings indicate that the AlN-drug conjugation have inhibitory effect against these selected receptors.Communicated by Ramaswamy H. Sarma.

Adsorption properties of dacarbazine with graphene/fullerene/metal nanocages - Reactivity, spectroscopic and SERS analysis

Drug delivery devices are an effective way to minimize anticancer drug toxicity and nanostructures are used in the targeted drug delivery. In the present work, adsorption and interaction behavior of 4-(dimethylaminodiazenyl)-1H-imidazole-5-carboxamide (DAIC) with nano complexes (graphene, fullerene and fullerene like metal cages) are reported theoretically. From the reactivity studies, the electrophilicity index of DAIC-nanoclusters are increasing and this gives the bioactivity of the nanocluster systems. Adsorption energy is highest in the case of AlP and lowest in the case of BP clusters. Mulliken charge distribution of all systems is an evidence for chemical enhancement. DAIC adsorption over nanocages causes changes in electronic properties resulting in chemical enhancement and variation in Raman spectra which suggests that nanocages could be a good candidate for DAIC detection.

Recent advances in synthesis and anticancer potential of triazole containing scaffolds

Cancer is the most lethal disease that may be found anywhere on the globe. Approximately 10% of individuals die as a result of cancer of various types, with 19.3 million new cancer cases and 10 million deaths expected in 2020. More than 100 medications are commercially available for the treatment of cancer, but only a few candidates have high specificity, resulting in several side effects. The scientific community has spent the past decades focusing on drug discovery. Natural resources are used to isolate pharmaceutically active candidates, which are then synthesized in laboratories. More than 60% of all prescribed drugs are made from natural ingredients. Unique five-membered heteroaromatic center motifs with sulfur, oxygen and nitrogen atoms are found in heterocyclic compounds such as indazole, thiazole, triazole, triazole, and oxazole, and are used as a core scaffold in many medicinally important therapies. Triazole possesses a wide range of pharmacological activities including anticancer, antibacterial, antifungal, antibiotic antiviral, analgesic, anti-inflammatory, anti-HIV, antidiabetic, and antiprotozoal activities. Novel Triazole motifs with a variety of biological characteristics have been successfully synthesized using versatile synthetic methods. We intend here to facilitate the rational design and development of innovative triazole-based anti-cancer medicines with increased selectivity for various cancer cell lines by providing insight into various ligand-receptor interactions.

Evidence of cluster formation of croconic acid with Ag, Au and Cu cages, enhancement of electronic properties and Raman activity

Investigation of the adsorption properties croconic acid (CCA) with metal clusters (mC: Ag, Au and Cu) are reported using DFT method. CCA is found to form stable cluster with transition metal clusters of copper, silver and gold. The drug-cluster complexaton energy is slightly more for the copper nanocluster-drug complex. Non-covalent interaction analysis indicated that strong interactions and weak van der Waal interaction is present between drug and metal clusters. Dipole moment of the drug-gold cluster is found to be higher than that of the other systems. SERS studies demonstrates improved Raman signals for multiple wavenumbers of all CCA-metal cluster complexes. Mulliken charge analysis show that all CCA oxygen atom's charge changes due to the interactions with the mCs. Clustering of CCA with metal cages enhances the medicinal properties and the metal nanoclusters will act as a drug carrier of CCA.

Nitrile-containing pharmaceuticals: target, mechanism of action, and their SAR studies

The nitrile group is an important functional group widely found in both pharmaceutical agents and natural products. More than 30 nitrile-containing pharmaceuticals have been approved by the FDA for the management of a broad range of clinical conditions in the last few decades. Incorporation of a nitrile group into lead compounds has gradually become a promising strategy in rational drug design as it can bring additional benefits including enhanced binding affinity to the target, improved pharmacokinetic profile of parent drugs, and reduced drug resistance. This paper reviews the existing drugs with a nitrile moiety that have been approved or in clinical trials, involving their targets, molecular mechanism of pharmacology and SAR studies, and classifies them into different categories based on their clinical usages.

Adsorption of the drug bempedoic acid over different 2D/3D nanosurfaces and enhancement of Raman activity enabling ultrasensitive detection: First principle analysis

The nanocluster-based drug delivery system is of much importance, now days. This manuscript studies the interaction of pristine/substituted/doped GQDs, fullerene, helicene and CNT with bempedoic acid, which is an effective alternative of statins in the treatment of hypercholesteremia. The adsorption energies are calculated at B3LYP-D3/6-311G+(2d,p) level in order to study the adsorption of bempedoic acid over the surfaces of the nanoclusters incorporating Grimme's dispersion correction. Surface enhanced Raman scattering (SERS), which is a sound approach to vibrational spectroscopy, is used in order to detect bempedoic acid. All the studies signify that bempedoic acid can be detected with these nanoclusters and the negative adsorption energies advocate for the possible use of these nanoclusters as effective drug delivery system in case of bempedoic acid. Adsorption energy of bempedoic acid over helicene was found to be the most negative among the mentioned nanocluster systems, while adsorption on the surface of CNT was found to be the least negative.

DFT computational study of trihalogenated aniline derivative's adsorption onto graphene/fullerene/fullerene-like nanocages, X12Y12 (X = Al, B, and Y = N, P)

Adsorption of 2,4,6-tribromoaniline (BA), 2,4,6-trifluoroaniline (FA) and 2,4,6-trichloroaniline (CA) onto the surface of coronene/fullerene/fullerene-like nanocages was investigated by theoretical calculations. Due to the adsorption of BA/FA/CA, there are significant changes in chemical descriptors and nonlinear optical properties. Energy gap values of all nanoclusters are lowered, giving an increase in conductivity of complexes except for fullerene. All complex's ultraviolet visible wavenumber is blue-shifted and especially for fullerene complex, the values are very high. The enhancement of Raman intensities shows that it is possible to design a nanocage sensor for detecting these compounds by surface-enhanced Raman scattering (SERS).Communicated by Ramaswamy H. Sarma.

Adsorption of adipic acid in Al/B-N/P nanocages: DFT investigations

Drug delivery clusters based on nanocages recently have been the most capable to study. Adipic acid (ADPA) interaction mechanism over nanocages of X(Al/B)12Y(N/P)12 was investigated. We analyzed various electronic, chemical, and spectroscopic properties with nanocages of the adsorbed ADPA molecule. Adsorption energies were calculated to study the adsorption of ADPA with nanocages. Raman enhanced surface scattering is used to track the drug as an effective approach to vibrational spectroscopy. Detection of the drug has been investigated using the SERS properties of nanocages. Title drug acts as a donor of electrons and adsorbs at the electrophilic site of nanocages. Variations in chemical descriptors to recognize the sensing property of ADPA-nanocages are also noted. Analysis of various properties explains enhancement which makes it possible to detect the drug in other products. • Interaction of adipic acid with fullerene-like metal nanocages • Enhancement of spectral properties • Changes in charge transfer values in nanocage-drug system • Docking studies identify the drug delivery property.

DFT computational study towards investigating psychotropic drugs, promazine and trifluoperazine adsorption on graphene, fullerene and carbon cyclic ring nanoclusters

Detection and qualification process related to impurities assume importance in pharmacological drug development programmes and the present article gives the structural and spectral characterisation of phenothiazine derivatives, promazine (PME) and trifluoperazine (TPE) and their self-assembly with graphene/fullerene/carbon ring (CG/CF/CR) systems theoretically. The investigation of adsorption behaviour of these compounds can provide valuable information about its reactivity, electronic and structural properties. Three-dimensional electrostatic potential diagrams were mapped. The frontier orbital energies and energy band gaps of the molecules were computed. Delocalization of charge density between the bonding or lone pair and antibonding orbitals is calculated by NBO analysis. Docking was executed to investigate binding areas of chemical compounds. Bioactivity scores show that the pharmacokinetic and pharmacological properties of the ligands are appropriate leading to be considered potential drug agents. The obtained theoretical wavenumber results of the present study were fully compatible with the experimental results.

Utilization of O/S-doped graphene nanoclusters for ultrasensitive detection of flurane derivatives-DFT investigations

Nanocluster based drug delivery systems are very useful in modern medical treatment and interaction mechanism of desflurane (DES), isoflurane ISO), sevoflurane (SEV) over carboxyl substituted graphene-doped with O and S atoms were investigated in the present study. Different electronic and chemical properties of adsorbed desflurane, isoflurane and sevoflurane with nanoclusters are analyzed. To track the drugs, SERS is used as an efficient method and drug's detection was analyzed using SERS. DES's energy over GQD-S is greater than that over GQD-O nanocluster and for ISO and SEV, adsorption energies over the O/S nanoclusters are same. The title drugs work on the reactives sites and got adsorbed. For ISO, there is an increase in fluorine atom charges and for DES and SEV, the fluorine atom charge decreases due to adsorption in both O/S nanoclusters. Changes in chemical descriptors are identified for the sensing property of drug-nanoclusters.Communicated by Ramaswamy H. Sarma.

Utilization of doped/undoped graphene quantum dots for ultrasensitive detection of duphaston, a SERS platform

Recently nanocluster based drug delivery systems have become the most skillful to study. Interaction mechanism of duphaston (DPH) over graphene (G), carboxyl substituted graphene (COG) and doped COG-X (X = O/S/N/B) were investigated. We studied different spectroscopic properties of adsorbed DPH with nanoclusters. To study effect adsorption of DPH with nanoclusters, the adsorption energies were measured. To track DPH, surface enhanced Raman scattering is used since it is an efficient approach to vibrational spectroscopy. The DPH detection was investigated using GQDs SERS property. For the adsorption of DPH with COG-B nanocluster maximum energy interaction is determined. DPH works on the electrophilic site of nanoclusters as donor of electrons and adsorbs. Charge transfer is higher for to COG-B nanocluster than for other nanoclusters. Variations in chemical descriptors are also noted to understand sensing property of DPH molecule-nanoclusters. The analysis of different properties demonstrates enhancement effect which makes it significant in detecting DPH in other products.

Two Approaches for the Synthesis of Fused Dihydropyridines via a 1,6-Electrocyclic Reaction: Fluorescent Properties and Prospects for Application

Reactions of penta-2,4-dienethioamides with acetylenedicarboxylic acid, methyl and ethyl esters, and methyl propiolate were systematically studied, and a number of new 2,3-dihydro-5H-thiazolo[3,2-a]pyridines (DTPs) and 4H,6H-pyrido[2,1-b][1,3]thiazines (PTZs) were prepared. A possible mechanism for a multistep domino transformation is suggested, and the key step is the 1,6-electrocyclic reaction. An additional alternative method for the synthesis of new heterocyclic systems was achieved. Evidence of the electrocyclic mechanism of a key step was collected from the analysis of the spatial structure of the synthesized bicyclic nonaromatic pyridines by X-ray diffraction and quantum chemical calculations, as well as from the thermodynamic quantities. DTPs exhibited yellow fluorescence in solution and yellow to red emissions in the solid state. Biological investigations demonstrated the ability of DTPs to penetrate living and fixed cells and presumably accumulate in lysosomes.

Conformational analysis and quantum descriptors of two new imidazole derivatives by experimental, DFT, AIM, molecular docking studies and adsorption activity on graphene

1-[2-(2-hydroxy-3-methoxy-5-(4-methoxyphenylazo)benzaldeneamino)ethyl]-3-methyl-3H-imidazole (HMY) and 1-[2-(2-hydroxy-3-methoxy-5-(4-methylphenylazo)benzaldene amino)ethyl]-3-methyl-3H-imidazole (HMM) were synthesized and characterized using spectral analysis. Conformational analysis has been achieved using potential energy scan for different rotable bonds for obtaining the lowest energy conformer. Conformer with minimum energy is obtained along the dihedral angle N30-C31-C34-N37. QTAIM analysis gives nature and strength of hydrogen bonding interactions. UV-Vis, electrostatic potential and chemical descriptors are analyzed. Interaction of HMY and HMM with graphene is analyzed in terms of SERS activity. Chemical reactivity descriptors were investigated for graphene-drug systems. NLO activity of parent drugs and its graphene complexes show good activity. The wavenumber downshift of different modes is noted. Title molecules exhibit inhibitory activity against cytochrome C peroxidase. Interactions with graphene sheets are theoretically predicted for the title compounds.

Spectroscopic characterization, DFT studies, molecular docking and cytotoxic evaluation of 4-nitro-indole-3-carboxaldehyde: A potent lung cancer agent

The 4-nitro-1H-indole-carboxaldehyde (NICA) molecule was characterized experimentally using FT-IR, FT-Raman and UV-Vis spectra, and it was studied theoretically using DFT calculations. The optimized structure of the NICA molecule was determined by DFT calculations using B3LYP functional with cc-pVTZ basis set. The electron localization function (ELF) and local orbital localizer (LOL) studies were performed to visualize the electron delocalization in the molecule. The experimental and theoretical wavenumbers of the title molecule were assigned using VEDA 4.0 program. The charge delocalization and stability of the title molecule were investigated using natural bond orbital (NBO) analysis. Frontier molecular orbitals (FMOs) and related molecular properties were calculated. UV-Vis spectrum was calculated theoretically and validated experimentally. The reactive sites of the molecule were studied from the MEP surface and Fukui function analysis. The molecular docking analysis reveals that the NICA ligand shows better inhibitory activity against RAS, which causes lung cancer. The in vitro cytotoxic activity of the molecule against human lung cancer cell lines (A549) was determined by MTT assay. Thus, the NICA molecule can be used as a potential candidate for the development of the drug against lung cancer.