Non-covalent Interaction Analysis Research Articles

Intermolecular Interactions in Mixed Choline Acetate and Maleic Acid Systems

Mixed systems based on ionic liquids are promising innovative solvents due to their properties, which are strictly connected to the interactions that arise among the components. The present work investigates the intermolecular interactions of a mixed choline acetate and maleic acid system and their modifications with increasing acid content. MM/DFT calculations provided indications about the possible geometric configurations of the systems while Non-Covalent Interaction analysis was useful to describe and distinguish secondary interactions. The number of available configurations decreases at high acid concentration. Moreover, intramolecular hydrogen bonding was observed in all configurations except that in the most stable one of the lowest acid content mixture. Concomitantly, far-infrared spectroscopy was used to investigate intermolecular interactions and provided support to the computational results.

Effect of a single water molecule on the conformational preferences of a capped Pro–Gly dipeptide in the gas phase

Herein, we have investigated the effect of microhydration on the secondary structure of a capped dipeptide Boc-DPro-Gly-NHBn-OMe (Boc = tert-butyloxycarbonyl, Bn = Benzyl), i.e., Pro–Gly (PG) with a single H2O molecule using gas-phase laser spectroscopy combined with quantum chemistry calculations. Observation of a single conformer of the monohydrated peptide has been confirmed from IR-UV hole-burning spectroscopy. Both gas-phase experimental and theoretical IR spectroscopy results confirm that the H2O molecule is inserted selectively into the relatively weak C7 hydrogen bond (γ-turn) between the Pro C=O and NHBn N–H groups of the peptide, while the other C7 hydrogen bond (γ-turn) between the Gly N–H and Boc C=O groups remains unaffected. Hence, the single H2O molecule in the PG⋯(H2O)1 complex significantly distorts the peptide backbone without appreciable modification of the overall secondary structural motif (γ–γ) of the isolated PG monomer. The nature and strength of the intra- and inter-molecular hydrogen bonds present in the assigned conformer of the PG⋯(H2O)1 complex has also been examined by natural bond orbital and non-covalent interaction analyses. The present investigation on the monohydrated peptide demonstrates that several H2O molecules may be required for switching the secondary structure of PG from the double γ-turn to a β-turn that is favorable in the condensed phase.

An AIE-based fluorescent dye for selective staining of polyamide microplastics without pretreatment: Applications to environmental samples and zebrafish

A novel staining dye, BEM ((1E,1'E)-1,1'-([2,2'-bithiophene]-5,5'-diyl)bis(N-(9-ethyl-9H-carbazol-3-yl)methanimine)) was synthesized for selective identification of polyamide (PA) micrplastics. BEM showed unique photophysical properties such as solvatochromism, intramolecular charge transfer (ICT), and aggregation induced emission (AIE) which were demonstrated through spectroscopic analysis and density functional theory (DFT) calculations. The optimal staining conditions for selective staining of PA by BEM were established by evaluating the staining efficiency according to the variation of the solvent compositions, concentrations of BEM, and staining durations. BEM demonstrated outstanding selective staining of PA among 11 types of microplastics (MPs) and 5 types of non-plastics through the emission of green fluorescence. BEM successfully identified PA without any noticeable influence on the size change of PA, aging of PA, and pH alteration of the solvent. In addition, BEM was practically applied to environmental samples like river water, seawater, and soil for selective identification of PA without pretreatment. In particular, the cost-effective technique of BEM-labeled PA allowed to monitor the location and accumulation of PA in living zebrafish. The interaction between PA and BEM was investigated through scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), which suggested that BEM might be adsorbed onto the surface of PA. Moreover, non-covalent interaction (NCI) analysis demonstrated that the intermolecular hydrogen bonds and van der Waals interactions would play a significant role in the adsorption process between PA and BEM.

Drug molecules beyond chemical biology: fluorescence- and DFT-based investigations for fluoride ion sensing and the trace detection of chloroform.

Excessive unmonitored use of fluoride has remained a threatening issue for a long time now as its long-term use is linked to several health issues. Similarly, chloroform is a highly carcinogenic solvent that requires proper monitoring. The increasing demand for a convenient, selective and sensitive fluoride and chloroform sensor intrigued us to utilize etoricoxib (ECX) as a sensor as it is highly safe and easily available. The photophysical properties of ECX, which were previously unexplored, were now studied with increasing water fractions and a significant aggregation-induced emission enhancement (AIEE) was seen through fluorescence spectroscopy. ECX was also successfully used for the trace level detection of chloroform through a significant emission enhancement. Similarly, the ECX-based sensor successfully detected fluoride ions by showing enhancement in emission intensity with maximum emission wavelength at 373 nm. Through fluorescence titration experiments, the effects of different conditions and interfering species on the sensing efficiency of ECX were studied, and the results showed that the sensor was highly selective and sensitive towards fluoride, with a limit of detection of 20 nM. Other than fluorescence spectroscopy, the type of interaction between the sensor and analyte was also studied through UV-Vis spectroscopy, revealing a non-covalent type of interaction, which was further validated through DFT studies. Frontier molecular orbital (FMO) analysis was performed along with density of state (DOS) studies to investigate the energy levels of the orbitals. Non-covalent interaction (NCI) and natural bond orbital (NBO) analysis provided information about the types of interaction and charge transfer. ECX has the potential to be used for real-time sensing applications and could be used for sensing moisture and fluoride in real samples.

Computational Library Enables Pattern Recognition of Noncovalent Interactions and Application as a Modern Linear Free Energy Relationship.

A quantitative and predictive understanding of how attractive noncovalent interactions (NCIs) influence functional outcomes is a long-standing goal in mechanistic chemistry. In that context, better comprehension of how substituent effects influence NCI strengths, and the origin of those effects, is still needed. We sought to build a resource capable of elucidating fundamental origins of substituent effects in NCIs and diagnosing NCIs in chemical systems. To accomplish this, a library of 893 NCI energies was calculated encompassing cation-π, anion-π, CH-π, and π-π interactions across 60 different arenes and heteroarenes. The interaction energies (IEs) were calculated using symmetry-adapted perturbation theory (SAPT), which identifies electrostatic, inductive, exchange-repulsive, and dispersive contributions to total IE. This descriptor library provides a comprehensive platform for evaluating substituent effect trends beyond traditional molecular descriptors such as Hammett values, frontier molecular orbital energies, and electrostatic potential, thereby expanding the tools available to analyze modern chemical processes that involve NCIs. To demonstrate the application of this library, three case studies in asymmetric catalysis and supramolecular chemistry are presented. These case studies informed the development of an automated NCI analysis tool, which employs statistical analyses to diagnose a particular NCI in a chemical system of interest.

POCOP-Ni(II) pincer compounds derived from phloroglucinol. Cytotoxic and antioxidant evaluation.

POCOP-Ni(II) pincer compounds have primarily been explored as catalysts, but their potential biological activity has been scarcely studied. To address this gap, we evaluated the anticancer and antioxidant potential of four POCOP-Ni(II) complexes derived from phloroglucinol. A comprehensive supramolecular analysis, based on single-crystal X-ray diffraction (DRX) structures, was conducted using Hirshfeld surfaces and non-covalent interaction analysis. The cytotoxicity of all complexes was systematically assessed against various cancerous cell lines, as well as a non-cancerous cell line (COS-7). The results revealed that complexes 1b and 1c exhibited remarkable antiproliferative activity, with IC50 values ranging from 2.43 to 7.85μM against cancerous cell lines U251, K562, HCT-15, MCF-7, and SK-LU-1. To further elucidate their mechanism of action, a competitive fluorescence displacement assay with ethidium bromide (EB) suggested that these complexes possess the ability to intercalate with DNA. This multifaceted investigation not only enhances our understanding of the biological potential of POCOP-Ni complexes but also provides valuable insights into their structural features and interactions, paving the way for future exploration in both catalytic and therapeutic domains.

End Group Effects on Anion Binding in Tetraglycine Peptide: A Computational Study.

The importance of anions in various processes has led to a search for molecules that can effectively recognize and interact with these anions. This study explores how the tetraglycine [(Gly)4] peptide in its zwitterionic, neutral, and terminally capped forms acts as a receptor for H2PO4 - and HSO4 - anions within the framework of supramolecular host-guest chemistry. Using molecular dynamics (MD) simulations, we obtained the conformations of the receptor-anion complexes. Density functional theory (DFT), quantifies the complexes' interaction energies in both gas and solvent phases. Proton transfer within the zwitterionic complex with H2PO4 - anion alters peptide charge distribution, affecting its conformation and binding site arrangement, as analysed by quantum mechanics/molecular mechanics (QM/MM) methods. Symmetry-adapted perturbation theory (SAPT) and noncovalent interactions analysis highlight the role of electrostatic interactions in these receptor-anion complexes. It emphasizes the key interactions such as N-H⋅⋅⋅⋅O and O-H⋅⋅⋅O=C between the peptide backbone and anions and elucidates the molecular recognition mechanism driven by crucial noncovalent interactions. The termination of the peptide's end groups modulates anion binding sites from the backbone to the charged N-terminal, resulting in distinct binding sites. Our findings provide insights for designing peptides tailored to function as anion receptors in diverse supramolecular chemistry applications.

Unraveling the noncovalent interactions in a organic crystal using Quantum theory of atoms in molecules

X-ray diffraction analysis, combined with the Quantum Theory of Atoms in Molecules (QTAIM), serves as a powerful tool for describing chemical bonding in real space for solids. By integrating theoretical and experimental data, a more accurate representation of atomic interactions including Van der Waals forces, hydrogen bonds, covalent, ionic, and metallic bonds is achieved. The analysis of noncovalent interactions through electronic density enables the identification of Lewis acid and base sites, while also revealing the directional ‘key-lock’ interactions that correspond to molecular recognition. The examination of critical points in the electron density and its derivatives allows for the characterization of the types of interactions present in crystal packing. This study focuses on the experimental and theoretical investigation of noncovalent interactions within a molecular crystal of a newly synthesized carbohydrazide derivative. The crystal structure was determined using X-ray single-crystal diffraction, and the crystallographic asymmetric unit was optimized via DFT, with the results compared to experimental data. Noncovalent interactions in real space such as Van der Waals forces, hydrogen bonds, and inter- and intramolecular steric repulsions were analyzed in terms of electron density and its derivatives. The QTAIM framework was applied to quantify the strength of these interactions, employing Voronoi deformation density and electron localization and delocalization indices for solids. The results presented in this work, using crystal engineering, reveal that derivatives of diurea compounds crystallize following a characteristic pattern that forms a synthon configuration. The strength of this interaction, quantified through QTAIM analysis of the electronic density, provides a deeper understanding of the chemistry of these compounds, both in terms of biological activity and coordination chemistry.

Quenching Rate Constants of Lewis Base-Boryl Radical by Substrates: a Laser Flash Photolysis Study.

The advanced strategy using Lewis base-boryl radicals (LBRs) has recently been proposed for the addition of alkyl substituents to the full-carbon quaternary center of an organic molecule. However, as the rate-determining step in the whole route, reaction rate constants of LBRs with substrates are extremely lacking. In this paper, 4-dimethylaminopyridine (DMAP)-BH2• was selected as a representative of LBRs, and its reactions with six monochloro-substituted substrates, including three methyl chlorobenzoates and three chlorinated acetanilides were studied in experiments and theoretical calculations. The bimolecular reaction rate constants, kq, were determined using laser flash photolysis approach. By comparing activation energies along the two addition pathways, we have clarified the rate-determining step as the attacking to carbonyl oxygen instead of chlorine atom. Furthermore, noncovalent interaction (NCI) analyses on these substrates indicate that weak interactions, such as hydrogen-bonding and van der Waals interactions, have significant influence on the reactivity of these substrates. Our study provides concrete clues to extend this synthetic strategy.

Engaging Two Anions with Single Cation in Energetic Salts: Approach for Optimization of Oxygen Balance in Energetic Materials.

The field of high energy density materials faces a long-standing challenge to achieve an optimum balance between energy and stability. While energetic salt formation via a combination of oxygen- and nitrogen-rich anions (providing energy) with nitrogen-containing cations (providing stability) has been a proven approach for improving physical stability, constraints such as lowering density and energetic performance remain unresolved. This can be addressed by utilizing oxygen-containing cations for salt formation. However, this approach is rarely explored because its synthesis is challenging. In this work, we have designed an oxygen-rich cationic precursor 2 by incorporating 4-amino-3,5-dinitropyrazole with 3,4-diaminotriazole via an N-methylene-C bridge. Further combination with energetic acids resulted in the formation of high-performing, physically stable energetic salts 3-10. The salts were found to be generally more energetic than the salts of respective energetic acids with previously reported cations and showed prominent improvement in physical stability with respect to their anionic precursors. All the compounds were thoroughly characterized through IR, NMR spectroscopy, HRMS, and elemental analysis. Salt 9 was confirmed through 15N NMR analysis, and salts 2 and 8 were confirmed through single-crystal X-ray diffraction. Additional analyses such as Hirshfeld surface analysis, noncovalent interaction (NCI) analysis, and electrostatic potential studies were also carried out to correlate the structure-property relationship.

Impact of UV-B Photoaging on Chlorpyrifos Adsorption by PET Microplastics: Insights from Experimental and DFT Analysis.

Microplastics (MPs) in the environment pose a persistent concern, as these plastic particles can adversely impact both aquatic ecosystems and human health. MPs are subject to natural weathering and aging processes, such as photodegradation, which significantly alter their surface morphology and physicochemical properties, thereby influencing their fate, transport, and sorption behavior. To better understand how aging affects these properties and to elucidate the mechanisms behind the interactions with the chlorpyrifos pesticide, poly(ethylene terephthalate) (PET) microplastics (<100 μm) were subjected to accelerated photoaging in a UV-B chamber for varying exposure times. Several characterization techniques were employed, including scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), infrared spectroscopy (IR), point of zero charge (pHPZC), and thermogravimetric analysis (TGA). Additionally, the percentage of crystallinity and carbonyl index (CI) were calculated. The results demonstrated a decrease in pHPZC following photodegradation, likely due to an increase in δ- (-C=O) groups, consistent with the CI findings. SEM revealed surface deterioration caused by aging, while TGA indicated an early thermal degradation stage associated with water volatilization, suggesting enhanced hydrophilicity. Density functional theory (DFT) calculations showed that the PET monomer absorbs slightly in the UV-B region, leading to excitation and subsequent radical reactions that form Norrish type I products. The adsorption capacity of aged PET increased compared to the pristine material, likely due to the molecular geometry becoming more planar, facilitating interactions between the aged MPs and chlorpyrifos, as confirmed by noncovalent interaction (NCI) analysis. These findings highlight the significant potential of aged microplastics to adsorb micropollutants and act as vectors in aquatic environments.

Solvents and their influence on electronic properties in IEFPCM solvation model, anticancer activity, and docking studies on (E)-2-((4-chlorobenzylidene) amino)phenol

The Schiff base (E)-2-((4-chlorobenzylidene)amino)phenol (4CL2AM) has been synthesized from 4-chlorobenzaldehyde and 2-aminophenol. Spectroscopic techniques like FTIR, Raman, UV, fluorescence, and NMR were used to characterize the synthesized compound. The experimental data well matched with the DFT method (B3LYP/cc-pVDZ basis set). The frontier molecular orbital (FMO), molecular electrostatic potential (MEP), and electronic spectra (UV–visible) analysis were conducted on three different solvents such as gas, DMSO, and water. The frontier molecular orbital (FMO) analysis calculated the HOMO-LUMO energy gap as 4.0109 eV, 4.0406 eV, and 4.0411 eV for the gas phase, DMSO, and water respectively. Molecular electrostatic potential (MEP), localized orbital locator (LOL), and electron localize function (ELF) analysis revealed positions of localized and delocalized orbitals as well as electrophilic and nucleophilic attack sites. The natural bond orbital analysis (NBO) predicted highest stabilization energy was 33.37 kcal/mol. The locations of the covalent and non-covalent interactions were investigated by density overlaps region indicator (DORI), interaction region indicator (IRI), and noncovalent interaction (NCI) analysis. Drug likeness and ADME analysis were investigated. In vitro, anticancer activity studies revealed against MCF-7 breast cancer cell lines. In the molecular docking study, the predicted lowest binding energy is −5.77 kcal/mol for the 6NLV-4CL2AM system.

Behaviour of 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimdazolium thiocyanate and 1-butyl-1-methypyrrolidium chloride in dimethyl sulfoxide: Experimental, NCI and QTAIM analysis

The aim of this study is to examine the cation and anion influence on intermolecular interactions of mixtures comprising ionic liquids (ILs): 1-butyl-3-methylimidazolium chloride [Bmim][Cl], 1-butyl-3-methylimdazolium thiocyanate [Bmim][SCN] and 1-butyl-1-methylpyrrolidium chloride [Bmpym][Cl] with dimethyl sulfoxide (DMSO) at various temperatures. To understand the influence of cation and anion as well as temperature on interactions between the mixtures, thermodynamics parameters: apparent molar properties were calculated from the measured density (ρ) and sound velocity (u) data and fitted to the Redlich-Mayer type equation in order to obtained limiting apparent molar properties of the studied mixtures. A detailed non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analysis was done using density functional theory calculations. These calculations provided information on the electrostatic interactions between the anion, cation, and solvent. The experimental and computational results show that there is hydrogen bonding and strong ionic interactions in the studied systems.

Exploring the Impact of Protein Chain Selection in Binding Energy Calculations with DFT.

Calculation of binding free energies between a protein and a ligand are highly desired for computer-aided drug design. Here we approximate the binding energies of ABL1, an enzyme which is the target for drugs used in the treatment of chronic myeloid leukaemia, with minimal models and density functional theory (DFT). Starting from the crystal structures of protein-drug complexes, we estimated the binding free energies having used all available individual molecules (protein chains) within each structure, not only a single one as commonly used, in order to see if the choice of the protein chain is important in such calculations. Differences were observed between chains in the same file. Energy decomposition analysis (EDA) revealed that the most important factors for binding were exchange, repulsion and electrostatics. The desolvation term varied dramatically between the inhibitors (between 4.2 and 92.3 kcal/mol). All functionals showed similar patterns in the EDA and in discriminating between the ligands. Non-covalent interactions (NCI) analysis was used to further explain the differences between protein chains and functionals. Overall, it is shown that small minimal models of a drug binding site can be useful to infer on the suitability of an initial crystal structure for further analysis such as EDA.

Vibrational Spectra and Computational Study of Amyl Acetate: MEP, AIM, RDG, NCI, ELF and LOL Analysis

This work is focused on biologically active neat amyl acetate and its solutions in ethanol/heptane. According to the experimental results, when the concentration of amyl acetate in the amyl acetate-ethanol solution decreases, the additional band appears on the low-frequency side. The primary reason for the formation of such additional band is the intermolecular hydrogen bonding between amyl acetate and ethanol. In the amyl acetate-heptane solution, as the concentration of amyl acetate in the solution decreases, the band corresponding to the C=O stretching vibrations shifted to a higher frequency. This is explained by the fact that heptane breaks intermolecular interactions in solution, resulting in a simpler spectral band corresponding to the C=O stretching vibrations. Calculations are also used to study interactions in amyl acetateethanol complexes and their spectral manifestations. When the complex formation energies are calculated, this energy increases with the number of molecules, but the average hydrogen bond energy per one bond remains unchanged. The density functional theory (DFT) method is used to analyze molecular structural parameters: Mulliken atomic charge distribution; thermodynamic parameters; molecular electrostatic potential (MEP) surface; atoms in molecules (AIM) analysis; quantum chemical parameters such as reduced density gradient (RDG) and noncovalent interaction (NCI) analysis; electron localization functions (ELF) analysis; and localized orbital locator (LOL) analysis.

Mechanistic studies on phosphine-catalyzed [4 + 3] annulation of β′-acetoxy allenoate with 1C,3N-dinucleophile

The mechanism and role of catalyst on the PPh3-catalyzed [4 + 3] annulation reaction have been systematically investigated using density functional theory (DFT) method. Based on the calculations, the possible mechanism contains six steps: nucleophilic addition of PPh3 to allenoate to give Z-configured intermediate, cleavage of CO bond for forming phosphonium diene, nucleophilic addition of phosphonium diene with anionic 1C,3N-dinucleophile, intramolecular [1,5]-proton shift, ring-closure, and dissociation of catalyst. Non-covalent interaction (NCI) analysis shows that the O⋯P interaction would be the key for leading to the Z-configured pathway more favorable and electron localization function (ELF) analysis indicates that the implication of PPh3 can significantly lower the energy barrier involved in CO cleavage process, which mainly because the addition of PPh3 reduces the electron density of CO bond and thus facilities the cleavage of CO bond. This theoretical study would provide some clues for understanding the role of catalyst in a catalytic reaction.

Conformations of α-cyclodextrin and its role on the stability of inclusion complexes in aqueous solution

α-Cyclodextrin (αCD), a cyclic carbohydrate polymer, presents a wealth of opportunities for drug delivery and various industrial applications. Its high affinity and selectivity in encapsulating target molecules have been well-documented. However, the influence of αCD's conformational variations on its encapsulation capacity remains a promising area for further exploration. This study explores the conformational dynamics of αCD and its relationship with the formation of inclusion complexes (ICs) in aqueous solutions, focusing on understanding the forces driving these dynamics and the formation of stable ICs. Classical molecular dynamics (CMD) demonstrate that αCD solvated in water can adopt two conformations: a truncated cone shape with a suitable cavity for encapsulation and a distorted cone shape with a collapsed cavity. The predominant conformation observed in the CMD trajectory of pristine αCD is the distorted cone. However, under complexation conditions with aliphatic molecules, the guest molecule's size dictates the ICs' stability, forcing αCD to maintain the truncated cone conformation. Quantum chemistry methods and electron density analyses (Quantum Theory of Atoms in Molecules and Non-Covalent Interactions index) support CMD observations by characterizing and quantifying non-covalent interactions. Findings indicate that the shift from the truncated to the distorted cone conformation in αCD is primarily driven by intramolecular non-covalent interactions and the reconfiguration of water molecules surrounding αCD. The ICs' analysis displays a significant correlation between the size of the aliphatic chain and the intensity of intermolecular interactions. The strength of these interactions can effectively disrupt the αCD intramolecular non-covalent interactions that lead to a conformational change and, consequently, the loss of the inclusion complex. In conclusion, although αCD's conformational change can affect encapsulation, guest molecules can manipulate the conformational preference. The systematic analysis of non-covalent interactions offers a way to characterize and quantify these forces, enhancing our ability to understand and predict the stability of inclusion complexes.

Empirical, computational studies and non-covalent interactions analysis of a novel salt with cadmium transition metal precursor

In this research paper, (C3H5N2)6[CdCl4][CdCl6] was successfully synthesized using a slow evaporation process. The structure was confirmed through single-crystal X-ray crystallography, FT-IR, and thermal analysis. The material was found to crystallize in the tetragonal system (space group I41/a) and the following parameters a = b = 12.0872 (8) Å; c = 24.6985 (16) Å, the crystal packing shows parallel layers of cations and stacks of discrete anions positioned at y = 1/4 and 3/4. The junction between the monoprotonated imidazolium cations and the anions, along with the crystal structure stability, relies on Cl···H−N, and Cl···H−C hydrogen bonds. Computational investigations, conducted using the B3LYP method with 6–311++G(d,p) and LANL2DZ mixed basis set, demonstrated close alignment between the computed and the experimental data, providing insights into the material's geometrical and vibrational properties. The non-covalent interactions were studied through Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analysis and quantitatively using the Hirshfeld surfaces associated with 2D fingerprint plots. Furthermore, thermal stability was assessed through Thermogravimetric and Differential Scanning Calorimetry (TG–DSC) analysis.

Structure and noncovalent interaction analysis of half-sandwich chiral-at-metal organoruthenium complexes with planar and η6-arene-metal axial chirality

The preparation of organometallic compounds has provided new molecular complexity in molecular science. The stereochemistry of organometallics has long been a great challenge due to the large atom radius and more valency. Herein, eight ruthenium piano-stool shaped Ru complexes 2a-d and 3a-d with η6-planar chirality and Ru-center chirality were successfully synthesized and resolved, and the absolute configurations were determined by X-ray diffraction analysis. Racemization experiment revealed the stability differences of the Ru complexes in various solvents. Furthermore, in asymmetric unit of complex 3b, there are two conformers bearing opposite η6-arene-Ru axial chirality. In the supramolecular organization, all of the Ru complexes are stabilized by hydrogen bonding, C-H···π and Cl/I···π interactions. π···π interaction was only observed in complex 3b. The Hirshfeld surface analysis and 2D fingerprint plot show that the eight complexes have a similar contribution composed of different noncovalent interactions to the stabilization of crystal packing. Interestingly, only complex 3b has 3.5 % C···C interaction. The pairwise interaction energies were calculated using CE-B3LYP energy model and further visualized by 3D-energy framework, which show that the dominant interaction for all complexes is dispersion. Theoretical energies of each conformer of complex 2a-d and 3a-d with η6-arene rotated at different angles were calculated by DFT method, and the energy barrier between the two conformations was around 2–3 kcal/mol. Halide ligand exchange experiments on complex (SRu)-1a were performed and the plausible mechanism was proposed. These results have provided new evidence for the design of molecules with specific fine stereochemical information for potential applications in medicinal and material chemistry.

Supradecoration induced novel Properties: A comparative study of Ferrocene and Ferrocenyl α-aminophosphonate

Decorating chemical motifs with appropriate functional groups capable of supramolecular interactions hold key in modulating these novel systems for targeted applications. This work by means of a comparative study of Ferrocene and Ferrocenyl α- aminophosphonate highlight supradecoration induced multi paradigm properties across materials to medicine. The observed results indicate an increase in crystal framework energy with induction of mechanochromism and aggregation-induced emission in case of Ferrocenyl-α-amino phosphonate as novel supra decorated Ferrocene motif. Comparative BSA and BLC studies indicated improved biocompatibility with enhancement of catalase enzyme activity in case of Ferrocenyl-α- aminophosphonate compared to pristine Ferrocene. The relative quantification of intermolecular non covalent interactions of Ferrocene and Ferrocenyl-α- aminophosphonate evaluated using Quantum crystallographic methods and non-covalent interaction analysis were used to corroborate the supramodulation effects. The observed influence of Ferrocenyl α-aminophosphonate on the enzymatic activity of catalase was also examined using a comparative molecular docking analysis. The docking results corroborated influence of supradecoration on binding affinity and binding site, which are vital for designing ligands of enhanced catalase activity and also helpful in prediction of newer regulatory sites on enzyme. Taken together this work signifies how supra decoration of Ferrocene motif with functionalities capable of diverse intermolecular non-covalent interactions modulate molecular properties for newer applications.