Numerous attempts for organic radical stability mostly entail steric hindrance, spin-delocalization, supramolecular interaction with the host, π-π interactions, and hydrogen bonding. To date, there is no report of single crystals containing a hydroxyl radical (•OH). In this work, we have stabilized •OH in the crystal, which has been obtained from the filtrate after separating the precipitate of the chromenopyridine radical (DCP(2)•) from the reaction mixture. DCP(2)• abstracts a hydrogen atom from dissolved water in the ethanolic filtrate to grow the single crystal containing DCPH(2) and •OH in the asymmetric unit. The crystal packing and computational studies suggest that π-•OH and •OH···N hydrogen-bonding interactions are responsible for stabilizing •OH. The presence of •OH has been further confirmed by mass analysis with the 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) adduct. Solid-state electron paramagnetic resonance (EPR), solution state nitroblue tetrazolium (NBT) assay, and spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) in the presence of super oxide dismutase suggest •OH formation in the single crystal.

The mechanism of the proton transfer in the reaction between CO2 and 3-amino-1-propanol with and without water molecules is investigated quantum-mechanically. Studies revealed that water molecules and the hydroxy group of 3-amino-1-propanol explicitly participate in the proton transfer, forming carbamic acid. It is found that water has a high impact on the energetics of CO2 absorption by reducing the barrier for proton transfer. Apart from the water molecules, the hydroxy group of alkanolamine significantly affects the energetics of the reaction. Five cases involving two, three, and four protons are discussed, and it is found that the proton transfer occurs in a concerted manner that depends on the initial configuration of the reaction complex. The present study unequivocally confirms the role of water molecules in the CO2 capturing via amine-based solvents.

Density functional theoretical studies are performed to investigate the conversion of carbon dioxide and methane to acetic acid using group 10 transition metal clusters in their free and carbon-supported states. The adsorption of CH 4 is more feasible than CO 2 for most of the clusters and the reaction is initiated with the adsorption of CH 4 over the catalysts. Energy barrier for the reaction is reduced significantly using the clusters compared to that in free state which is further reduced when coronene is used as a carbon support. Among various metal clusters, the barrier is found to be the lowest for Ni 3 .

Maintaining lipid asymmetry across membrane leaflets is critical for functions like vesicular traffic and organelle homeostasis. However, a lack of molecular-level understanding of the mechanisms underlying membrane fission and fusion processes in synthetic systems precludes their development as artificial analogs. Here, we report asymmetry induction of a bilayer membrane formed by an extended π-conjugated molecule with oxyalkylene side chains bearing terminal tertiary amine moieties (BA1) in water. Autogenous protonation of the tertiary amines in the periphery of the bilayer by water induces anisotropic curvature, resulting in membrane fission to form vesicles and can be monitored using time-dependent spectroscopy and microscopy. Interestingly, upon loss of the induced asymmetry by extensive protonation using an organic acid restored bilayer membrane. The mechanism leading to the compositional asymmetry in the leaflet and curvature induction in the membrane is validated by density functional theory (DFT) calculations. Studies extended to control molecules having changes in hydrophilic (BA2) and hydrophobic (BA3) segments provide insight into the delicate nature of molecular scale interactions in the dynamic transformation of supramolecular structures. The synergic effect of hydrophobic interaction and the hydrated state of BA1 aggregates provide dynamicity and unusual stability. Our study unveils mechanistic insight into the dynamic transformation of bilayer membranes into vesicles.

Benzotrithiophene and its derivatives obtained by fusing the aromatic rings at the peripheral sites are modelled using density functional methods for exploring their optoelectronic properties. The studies showed that absorption maximum shifted towards higher wavelengths with the extension of rings, irrespective of the functional used. The above molecules adopt anti-parallel orientations in their stacked dimer. The analysis of the stacked dimers revealed that they interact via van der Waals forces. The charge transport properties are found to vary with the orientation of the molecules. The studies showed that the designed molecules act as electron transporters in their anti-parallel orientation.

The structure and absorption properties of a series of azobenzene derivatives are investigated using the density functional theoretical methods. The study showed that π → π* transitions of azobenzene undergo red shift after mono- and di- substitutions at para positions. Considering the fact that o-fluoro and o-methoxy derivatives of azobenzene have long living cis isomers, the effect of ortho substitution on the excitation energies is examined. An investigation on the azo-protonation revealed prominent red shift for n → π* and π → π* transitions bringing both absorptions in visible region. The effect of substitution on the cis to trans thermal relaxation is also analysed.

The structural, optoelectronic and charge transport properties of porphyrin and its analogues are investigated using the density functional theoretical methods. Most of the above molecules absorb in visible region with high light harvesting efficiency. The small energy gap between the frontier molecular orbitals (FMOs) suggests that porphyrin and its derivatives can be used in organic semiconductors. Electronic properties such as ionization potential, electron affinity, reorganization energy and the charge transfer integral are calculated to obtain their charge transport properties. It is revealed that porphyrin, porphyrazine and phthalocyanine act as hole transporters, whereas corrole and corrolazine act as electron transporters.

Polymorphism in supramolecular polymers is strongly correlated with the polymerization pathways underlying their formation. To effectively control emerging polymorphs, a comprehensive understanding of nucleation pathways and mechanisms is essential. Herein, a coronene-dipeptide conjugate (Cr-o-FFOEt) is introduced and its self-assembly into two different stable 1D supramolecular polymorphs (Agg 1 and 2f) is observed in the same solvent composition (water/THF, 7:3 v/v) and same concentration at room temperature, following two competitive self-assembly pathways. The difference in the mode of solvent addition triggers the two self-assembly pathways. Furthermore, the isolated intermediate Agg 2i is found to transform into Agg 1 or Agg 2f under controlled experimental conditions. The supramolecular aggregates of Cr-o-FFOEt are thoroughly examined with the help of optical, chiroptical, and morphological techniques to understand the subtle difference in choosing the self-assembling pathways. The studies reveal that the nanotube formation of Agg 1 follows a classical nucleation-elongation supramolecular polymerization mechanism (involving monomers). In contrast, the helical fibers of Agg 2f are formed by the involvement of preorganized oligomers (nonclassical process). The observation highlights the underappreciated role of prenucleation clusters in pathway complexity and polymorphism of supramolecular 1D polymers.

Density functional theoretical studies are performed to investigate the conversion of carbon dioxide and methane to acetic acid using group 10 transition metal clusters in their free and carbon-supported states. The adsorption of CH4 is more feasible than CO2 for most of the clusters and the reaction is initiated with the adsorption of CH4 over the catalysts. Energy barrier for the reaction is reduced significantly using the clusters compared to that in free state which is further reduced when coronene is used as a carbon support. Among various metal clusters, the barrier is found to be the lowest for Ni3.

Aerial oxygen and base mediated synthesis is performed for three unprecedented neutral carbon centered radicals in solid state, whose emissions and stabilities depend on C(sp 3 )-, C(sp 2 )- or H-substitution at the radical center.

A series of thermally activated delayed fluorescent (TADF) molecules having an imidazopyridine acceptor, a benzene linker, and a 9,9-dimethyl-9,10-dihydroacridine donor are designed and examined using a quantum chemical approach. The above framework spatially separates the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), minimizing their overlap, ultimately resulting in a reduced energy gap between the excited singlet and triplet states (Delta E-ST). The impact of electron-donating substituents (-Me, -Et, -t-Bu, -OMe, and -NMe2) on the donor moiety of the parent molecule 2-(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)imidazo[1,2-a]pyridine-3,6-dicarbonitrile (Ac-CNImPy) is investigated. The calculated results revealed that for a given substituent, the para-substituted derivatives exhibit relatively less Delta E-ST, compared to that of the respective ortho- and meta derivatives. The value of Delta E-ST decreased with an increase in the electron-donating capacity of the substituent. Additionally, the Delta E-ST of the disubstituted derivatives is found to be less than that for the monosubstituted derivatives. The charge transport studies revealed that molecules with strong electron-donating substituents act as electron transporters. The effect of an external electric field (EEF) on Delta E-ST of the parent molecule Ac-CNIMPY and its derivative is also examined and revealed that the Delta E-ST can be further reduced by applying an electric field of appropriate strength in a direction perpendicular to the dipole moment of the molecule and in the plane of the acceptor moiety.

The electronic and optoelectronic properties of molecules constituted by benzene as linker, phenoxaborin as acceptor coupled with different types of donor moieties are investigated using the density functional theoretical method. The energy gap between the first excited singlet and triplet states (ΔE ST ) of the designed molecules ( 1–9 ) is found to be less than 0.5 eV suggesting them as ideal candidates for thermally activated delayed fluorescence (TADF) emitters. The analysis of frontier molecular orbitals of the molecules revealed a minimum spatial overlap between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) in favor of the small values of ΔE ST . Among the molecules studied, the one in which dihydrophenazine acts as the donor has the lowest value of ΔE ST . All designed molecules are good electron transporters. The non-linear optical properties of the molecules are also examined.

The rise in manufacturing and operating expenses in the oil and gas sector, especially in the impact of corrosive environments and wear influences, has triggered technologists to concentrate more on effectual surface modification strategies on the machines and equipment being produced in recent days. Magnesium alloys are attractive metals in the lightweight materials group due to their lower density and higher specific strength. Even though the corrosion and tribological performance of magnesium alloys are not satisfactory and surface modification techniques are adopted with various coating methods such as electroplating, thermal spray, arc spray, and plasma spray methods to overcome these limitations. Recently, post-spraying technologies have been extensively used to enhance the whole performance of coatings, particularly those developed through the electro deposition, plasma spraying technique, high-velocity oxygen fuel spraying, PVD coatings, electro plating, laser cladding, anodizing, metal cladding, and friction stir processing methods. The development of lightweight components is one of the primary concerns of the automobile, aerospace, and electronics industries. Even though most efficient design procedures contribute to lightweight component development, the usage of lightweight materials plays a significant role. The current review investigates the enhancement of various type of coatings by the various types of post treatments. The purpose of this article is to quickly address future developments, the rising use of magnesium alloys with consideration of explosive environments, and post-treatment effects. Thus, it was concluded that the magnesium-based alloys clearly demonstrate a substantial improvement in their performance in terms of mechanical and corrosion resistance, creating a potential for their use in advanced production techniques for the automotive and aerospace industries. In addition, friction stir process was suggested as a novel post treatment method for metals and alloys. This comprehensive review has been motivated by these advantages of all the post-treatments methods.

An in silico study on the properties of HF and its dimer inside C-60 using density functional theory (DFT) based approaches is presented. For this purpose, 10 different DFT functionals following Jacob's Ladder have been chosen. The geometrical parameters such as bond length and bond angle, of the molecules and their dipole moment have been computed. Two types of orientations, namely, L-shaped and anti-parallel of (HF)(2) inside C-60 are considered, the latter with an extremely short hydrogen bond. HF bond lengths are elongated upon encapsulation in comparison to its free state analogue. The calculated value of stabilization energy of HF@C-60 is found to be functional dependent, whereas, (HF)(2)@C-60 is thermodynamically unstable for all the functionals. The kinetic stability of (HF)(2)@C-60 is assessed using the atom-centered density matrix propagation (ADMP) simulation at 300 K temperature. The red shift in HF stretching frequencies is noticed in all cases. Non-covalent index (NCI) analysis revealed non-covalent interactions between HF dimer and the C-60 cage. Energy decomposition analysis (EDA) showed a high value for the repulsive & UDelta;E-pauli which makes the (HF)(2)@C-60 system unstable except for the functional BP86-D3 of GGA family. Furthermore, the quantum theory of atoms in molecules (QTAIM) analysis is performed and it confirmed the presence of (3, -1) bond critical point along the hydrogen bond region of the L-shaped (HF)(2)@C-60.

Thermally activated delayed fluorescent emitters based on carbazole donor, benzonitrile acceptor with the linkers biphenyl, bipyridine and naphthalene are investigated using the density functional theoretical method. The molecule in which bipyridine acts as the linker with the least ΔEST is further selected for the designing of a series of D-L-A framework TADF molecules. Remarkably, the ΔEST is decreased successively by attaching the additional cyano groups at the acceptor site which is further reduced when the electron donating methoxy groups are attached at the donor site. To know the effect of substituents on ΔEST, the acceptor moiety of the D-L-A framework is modified with -F, -Cl and -CF3 substituents. The studies showed a relatively less decrement in the value of ΔEST compared to the cyano substituted molecules. However, ΔEST significantly reduced further on attaching methoxy groups at the donor site.

Recent advances in synthetic methodologies have opened new strategies for synthesizing stable metal-free electron spin systems based on fullerenes. Introducing nitric oxide (NO) inside a fullerene cage is one of the methods to attain this goal. In the present study, dispersion corrected density functional theory (B3LYP-D3) has been used to evaluate the structure, stability, and electronic properties of NO encapsulated fullerene NO@C-60 and compared those with its exohedral fullerene NO.C-60 analog. The calculated stabilization energy for NO@C-60 is appreciably higher than NO.C60, and this difference is comprehended via the Quantum theory of atoms in molecules (QTAIM) and noncovalent interaction (NCI) topological analyses. The delocalization of electron density of NO and the C60 cage in NO@ C-60 is discussed using electrostatic potential analysis. In addition, an attempt has been made to understand the different locations and orientations involving the interaction of two NO radicals and the fullerene C-60. It is shown that the encapsulation of the NO dimer inside the C-60 cage is an energetically unfavorable process. On the other hand, stable structures are obtained upon the physisorption of other NO on the surface of NO@C-60 and NO.C-60. The present work provides an in-depth understanding of the interaction of NO and C-60 fullerene, its preferable position, and its orientation in both endohedral and exohedral complexes.

To improve the corrosion resistance of Mg alloy, Al alloy/alumina metal matrix composite (MMC) coatings were formed by low pressure cold spraying (LPCS) technology followed by post friction stir processing. The phase structure, microstructure, and corrosion properties of the cold-sprayed metal matrix composite coatings before and after friction stir processing were investigated. The effect of the friction stir process (FSP) on the corrosion characteristics of MMC coatings at 3.5 weight percent of NaCl solution was explored using a Tafel polarisation plot. Microstructural studies were examined to investigate the electrochemical behaviour of the cold spray (CS) and FSPed MMC coatings. The results demonstrated that an enhancement in corrosion protection of the MMC deposits occurred at the 1st and 2nd runs of FSP, with superior corrosion performance observed at the 2nd run of FSP. The enhanced surface state is the primary enhancement mechanism of the electrochemical properties of the FSPed MMC coatings. For the higher run of FSP (3rd run), the electrochemical performance of the specimens was lower owing to the amalgamate action of the enhanced surface state with the aggravated interface of interior deposits.

The structure, stability, electronic and thermochemical properties of small clusters of auro-acetylenes (C2Au2) are investigated using dispersion-corrected density functional theoretical (DFT) method. The studies showed that auro-acetylene clusters are connected mainly via C-Au center dot center dot center dot pi interactions analogous to C-H center dot center dot center dot pi interactions in acetylene clusters. In the most stable structures of trimer and tetramer, each of the constituent unit acts both as a C-Au center dot center dot center dot pi donor and as a C-Au center dot center dot center dot pi acceptor forming cyclic structures akin to acetylene clusters. The studies also revealed that the C-Au center dot center dot center dot pi interactions are stronger than the aurophilic interactions forming the clusters.

The aim of the present paper is to find the necessary and sufficient conditions for subclasses of starlike functions with respect to symmetric points, starlike functions with respect to conjugate points, starlike functions with respect to symmetric conjugate points associated with Pascal distribution series and inclusion relations for such sub-classes in the open unit disk U. Further, we consider an integral operator related to Pascal distribution series..

The host-guest complexes of cucurbituril and azobenzene are investigated using dispersion corrected density functional theoretical methods. Different orientations of the guest azobenzene inside cucurbiturils of different sizes are examined. The host-guest interaction and the alteration of the physical properties of constituent units are studied. Among different orientations of azobenzene inside cucurbituril, the horizontally oriented cis complex is found to be the most stable. The maximum absorption wavelength (lambda(max)) of trans isomer undergoes red shift due to the confinement inside the cucurbituril cage whereas that of the cis isomer exhibits a blue shift when aligned horizontally inside the cucurbituril cage. The transfer of electron density and the non-linear optical properties of these complexes are also discussed.