<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

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Polymorphism is a central phenomenon in materials science that often results in important differences of the electronic properties of organic crystals due to slight variations in intermolecular distances and positions. Although a large number of π-conjugated organic compounds can grow as polymorphs, it is necessary to have at disposal a series of several polymorphs of the same molecule to establish clear and predictive structure-property relationships. We report here on the occurrence of two solvates and three polymorphs in single crystalline form of the organic p-type semiconductor 2,2′,6,6′-tetraphenyldipyranylidene (DIPO). When grown from chlorobenzene or toluene, the DIPO crystals spontaneously capture solvent molecules to form two pseudopolymorphic 1 : 1 binary solvates. Independently, three solvent-free DIPO polymorphs are obtained either from the vapor phase or from acetonitrile and benzene. Surprisingly, single crystal field-effect transistors (SC-FETs) reveal that the DIPO 1 : 1 binary solvate grown from chlorobenzene possesses a higher hole mobility (1.1 cm2 V-1 s-1) than the three solvent-free polymorphs (0.02-0.64 cm2 V-1 s-1). A refined crystallographic analysis combined with a theoretical transport model clearly shows that the higher mobility of the solvate results from an improved π-π overlap. Our observations demonstrate that solvation allows to tune the π-π overlap and transport properties of organic semiconductors by selecting appropriate solvents © the Owner Societies.

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Physical Chemistry Chemical Physics

Tuning the π-π Overlap and charge transport in single crystals of an organic semiconductor: Via solvation and polymorphism

A series of aroyl selenourea dibenzosuberene (1–3) derivatives were synthesized and characterized by different analytical methods and single crystal X-ray crystallography. Quantum chemical computations were made using DFT to determine the structural and molecular properties of the compounds. The in vitro antibacterial action of the compounds was evaluated against chosen gram-negative (Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli), and gram-positive (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus epidermidis) bacteria for their antifungal activity against Curvularia lunata, Penicillium notatum, and Aspergillus niger. Using molecular docking studies, the binding modes were understood along with the mechanism in opposing the target protein MurB. © 2019, © 2019 Taylor & Francis Group, LLC.

Phosphorus, Sulfur and Silicon and the Related Elements

Novel dibenzosuberene substituted aroyl selenoureas: Synthesis, crystal structure, DFT, molecular docking and biological studies

A mononuclear square planar Ni(II) complex [NiIIL] (1) with sterically encumbered phenol based tetra dentate N2O2 ligand has been synthesized. Several spectroscopic tools have been employed to characterize this complex. The crystal structure of this Ni(II) complex obtained from single crystal X-ray diffraction study reveals that the central metal ion adopts a square planar environment and crystalized in monoclinic space group C 2/c with a = 24.1784 (10), b = 9.3537 (4) and c = 8.3326 (4) with β = 97.0690 (11). The Hirshfeld surface analysis shows halogen-halogen interaction. The Ni(II) complex has been found to be an effective catalyst for the aerial oxidation of 3,5-DTBC to 3,5- DTBQ in methanol. For kinetic study, Michaelis-Menten model has been approached to determine the Kcat, KM and Vmax. The kinetic studies confirm that the turnover number (TON) of complex 1 is 1.762 × 103 h−1. © 2019 Elsevier B.V.

Journal of Molecular Structure

Synthesis, structure, Hirshfeld surface analysis and catecholase activity of Ni(II) complex with sterically constrained phenol based ligand

We have synthesized a completely new family of acyclic trimeric cyclodiphosphazane compounds comprising NH, NiPr, NtBu and NPh bridging groups. In addition, the first NH-bridged acyclic dimeric cyclophosphazane has been produced. The trimeric species display highly tuneable characteristics so that the distance between the terminal N(H)R moieties can be readily modulated by the steric bulk present in the bridging groups (ranging from ≈6 to ≈10 Å). Moreover, these species exhibit pronounced topological changes when a weak non-bonding NH⋅⋅⋅π aryl interaction is introduced. Finally, the NH-bridged chloride binding affinities have been calculated and benchmarked along with the existing experimental data available for monomeric cyclodiphosphazanes. Our results underscore these species as promising hydrogen bond donors for supramolecular host–guest applications. © 2020 Wiley-VCH GmbH

Angewandte Chemie - International Edition

N-Bridged Acyclic Trimeric Poly-Cyclodiphosphazanes: Highly Tuneable Cyclodiphosphazane Building Blocks

A Facile Modular Addition Approach to Size Control in the Synthesis of Oxo Bridged Phosphazane Macrocycles

There are many active pharmaceutical ingredients that lack N-H, O-H and S-H hydrogen-bond donor functional groups. N,N-Disubstituted O-thiocarbamates are examples of molecules that display such a feature. Despite the desirable medicinal properties displayed by some N,N-disubstituted O-thiocarbamates, the study of the solid-state properties of these compounds has been relatively unexplored. Herein, we report the synthesis and analysis of the structures and properties of a series of N,N-dimethyl-O-thiocarbamates, and use X-ray diffraction techniques to gain insight into how these molecules self-assemble in the solid-state. As part of our work, we report for the first time the crystal structure of tolnaftate, an active pharmaceutical ingredient that is indicated for the treatment of fungal infections. It was observed that the aryl-thiocarbamate C-O bonds are twisted such that the planar aryl and carbamate moieties are orthogonal. Such a non-planar molecular geometry affects the way the molecules pack and crystal structure analyses revealed four general modes in which the molecules can assemble in the solid-state, with some members of the series displaying isostructural relationships. Computational modelling of the cohesive energy densities in the crystals suggests that there is no single stacking type that is associated with greater stability. However, crystals with a combination of high packing index and π⋯π stacking interactions appear to display large cohesive energy densities. The lack of strong hydrogen bonding interactions in the crystals also leads to relatively low Young's moduli that are within a narrow range of 10-15 GPa for all 14 crystal structures reported. This journal is © The Royal Society of Chemistry.

Fulltext

CrystEngComm

Investigating the solid-state assembly of pharmaceutically-relevant: N, N -dimethyl- O -thiocarbamates in the absence of labile hydrogen bonds

A synthetic route is reported towards ruthenium-based structural mimics of the [Fe]-hydrogenase metal cofactor in which the acyl moiety is replaced by an N-heterocyclic carbene. It is observed that the pyridyl-NHC ligand has a rather different trans influence from that of a simple NHC in their ruthenium derivatives. The basis for this difference is explored crystallographically and computationally, and it accounts for their different behaviour towards thiolation. © 2020 Wiley-VCH GmbH

ChemistrySelect

Ruthenium-Based Structural Mimics of the Cofactor of [Fe]-Hydrogenase: Replacement of the Acyl Moiety with an N-Heterocyclic Carbene

The complex [Ru2(CO)4(µ-O2CCH2OSi(OEt)3)2(PPh3)2] was used as a single-source precursor to prepare silica-encapsulated ruthenium via hydrolysis followed by calcination. While the silica-encapsulated ruthenium catalyst and the molecular precursor both catalysed the [2 + 1] cycloaddition reaction between alkenes and ethyl diazoacetate to form cyclopropanes, the intermediate hydrolysis product partially directed the reaction towards [2 + 3] cycloaddition to form cyclic five-membered pyrazolines. © 2020 Elsevier B.V.

Inorganica Chimica Acta

Encapsulating ruthenium in silica using a single source precursor: Differing outcomes for a cycloaddition reaction

Zeolite encapsulated host–guest complexes [CuL(NO3)@Y], and [CuL2@Y] (where, HL is 3-[(3-dimethylamino-2,2-dimethyl-propylimino)-methyl]-naphthalen-2-ol) have been synthesized and characterized by XRD, FTIR, Raman, TEM, XPS, UV-DRS, BET, EXAFS, and EPR spectroscopy. These complexes used as heterogeneous catalysts for the oxidation of thioanisole, diphenyl sulfide, and 2-phenyl thioanisole to produce its sulfoxides analogues·H2O2 shows superior conversion efficiency and product selectivity over other common oxidants, viz tert-butyl hydroperoxide (TBHP), urea hydrogen peroxide (UHP) and di-tert-butyl hydroperoxide (DTBP). Formation of thermally stable copper hydroperoxo intermediate, which is to be believed as rate determining step in past few years, has been well proven. Besides that, for the first time, we have established that the oxidation process is not only going through by the generation of Cu(II)–OOH species but there is a considerable role of electron transfer (ET) mechanism also. Further, better TON value and recyclability make the encapsuled heterogeneous complexes more useful than that of homogeneous analogues. © 2020 Elsevier Inc.

Journal of Catalysis

Role of zeolite encapsulated Cu(II) complexes in electron transfer as well as peroxy radical intermediates formation during oxidation of thioanisole

Benzoylhydrazone Schiff base–ligated three new ONO pincer–type palladium(II) complexes, [(PdL1(PPh3)] (1), [(PdL2(PPh3)] (2), and [(PdL3(PPh3)] (3), were synthesized by the reaction of the respective ligand, N-(2-hydroxybenzylidene)benzohydrazide (HL1), N-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (HL2), or N-(5-bromo-2-hydroxybenzylidene) benzohydrazide (HL3), with Pd(OAc)2 and PPh3 in methanol and isolated as air-stable reddish-orange crystalline solids in high yields (78%–83%). All three complexes were fully characterized by elemental analysis, Fourier-transform infrared spectroscopy, UV–Visible, 1H nuclear magnetic resonance (NMR), 13C{1H} NMR, and 31P{1H} NMR spectroscopic studies. The molecular structure of all three complexes was established unambiguously by single-crystal X-ray diffraction studies which revealed a distorted square planar geometry of all three complexes. The ONO pincer–type ligands occupied three coordination sites at the palladium, while the fourth site is occupied by the monodentate triphenylphosphine ligand. The catalytic potential of all three complexes was explored in the carbonylative Suzuki coupling of aryl bromides and iodides with arylboronic acids to yield biaryl ketones, using CHCl3 as the source of carbonyl. The reported protocol is convenient and safe as it obviates the use of carbon monoxide (CO) balloons or pressured CO reactors which are otherwise needed for the carbonylation reactions. The methodology has been successfully applied to the synthesis of two antineoplastic drugs, namely, phenstatin and naphthylphenstatin, in good yields (81% and 85%, respectively). Under the optimized reaction conditions, complex 2 exhibited the best catalytic activity in the carbonylative Suzuki couplings. The reported catalysts have wide reaction scope with good functional group tolerance. All catalysts could be retrieved from the reaction after completion and recycled up to three times with insignificant loss in the catalytic activity. © 2020 John Wiley & Sons, Ltd.