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Shiv Nadar University

(SoNS) School of Natural Sciences

Organic room-temperature phosphorescence (RTP) materials with persistent RTP (PRTP) have attracted huge interest in inks, bioimaging, and photodynamic therapy. However, the design principle to increase the lifetime of organic molecules is underdeveloped. Herein, we show donor(D4)–acceptor(A) molecules (TOEPh, TOCPh, TOMPh, TOF and TOPh) with similar orientation of donor rings in aggregates that cause a large number of noncovalent interactions. We observed that TOEPh, TOCPh, TOMPh and TOF showed PRTP, whereas TOPh showed only phosphorescence emission (ΦP = ∼11%) with no PRTP property at ambient conditions. The spectroscopic and single-crystal X-ray analyses confirm the molecular assembly via J-aggregation with a face-to-face orientation of the donor rings. The crystal structure analysis (TOEPh, TOCPh, TOMPh, TOF) reveals that moderate π···π interactions (3.706 to 4.065 Å) between the donor rings cause the enhancement of the phosphorescence lifetime (26 to 245 ms), whereas the short phosphorescence lifetime (12 ms) of TOPh was observed because of the absence of π···π interactions. We found that TOEPh shows a long lifetime (245 ms) as compared to other derivatives because of the presence of ethoxy (−OEt) groups that enables spin–orbit coupling caused by strong lone pair (O)···π interactions present in the molecule. Utilizing the PRTP feature of TOEPh and the fluorescence emission of TOPh, we have shown data security applications in poly(methyl methacrylate).

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Chemistry

Fulltext

ACS Omega

Effect of π···π Interactions of Donor Rings on Persistent Room-Temperature Phosphorescence in D4−A Conjugates and Data Security Application

Physics

Bulletin of the American Physical Society

First-Principles Investigation of Selective Gas Sensing Property of Two-Dimensional 1T-HfTe 2

A real square matrix is a Z-matrix if it’s off diagonal elements are nonpositive. A Z-matrix with nonnegative principal minors is called an M-matrix. The problem of testing whether a given matrix is an M-matrix or not is an important research problem in matrix theory as M-matrices arise naturally in a wide range of applications including finite difference methods for partial differential equations, input-output models in economics, linear complementarity problems in operations research, and Markov processes in probability and statistics. In this paper, we present a polynomial-time algorithm for testing whether a Z-matrix is an M-matrix based on modified simplex method. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Mathematics

Annals of Operations Research

On testing nonnegativity of principal minors of Z -matrices using simplex method

Herein, we have reported a blue LED mediated manganese pentacarbonyl bromide catalysed incorporation of carbene moieties from aryl diazoesters onto 1H-pyrroles via their selective C2−H activation. A manganese metal-carbene has been identified as the active catalyst to facilitate the reaction. Eighteen mono substituted pyrrole derivatives were isolated in good to excellent yields (67→82%) and the disubstituted products were also formed in minor quantities (5 to 8%). HPLC based kinetics study enabled optimization of the reaction. Control experiments, FT-IR, NMR and GC-MS based characterization elucidated the putative reaction mechanism. (Figure presented.). © 2021 Wiley-VCH GmbH

Advanced Synthesis and Catalysis

Blue LED Induced Manganese (I) Catalysed Direct C2−H Activation of Pyrroles with Aryl Diazoesters

The origin of nitrogen-incorporated boron-doped nanocrystalline diamond (NB-NCD) nanowires as a function of substrate temperature (Ts) in H2/CH4/B2H6/N2 reactant gases is systematically addressed. Because of Ts, there is a drastic modification in the dimensional structure and microstructure and hence in the several properties of the NB-NCD films. The NB-NCD films grown at low Ts (400 °C) contain faceted diamond grains. The morphology changes to nanosized diamond grains for NB-NCD films grown at 550 °C (or 700 °C). Interestingly, the NB-NCD films grown at 850 °C possess one-dimensional nanowire-like morphological grains. These nanowire-like NB-NCD films possess the co-existence of the sp3-diamond phase and the sp2-graphitic phase, where diamond nanowires are surrounded by sp2-graphitic phases at grain boundaries. The optical emission spectroscopy studies stated that the CN, BH, and C2 species in the plasma are the main factors for the origin of nanowire-like conducting diamond grains and the materialization of graphitic phases at the grain boundaries. Moreover, conductive atomic force microscopy studies reveal that the NB-NCD films grown at 850 °C show a large number of emission sites from the grains and the grain boundaries. While boron doping improved the electrical conductivity of the NCD grains, the nitrogen incorporation eased the generation of graphitic phases at the grain boundaries that afford conducting channels for the electrons, thus achieving a high electrical conductivity for the NB-NCD films grown at 850 °C. The microplasma devices using these nanowire-like NB-NCD films as cathodes display superior plasma illumination properties with a threshold field of 3300 V/μm and plasma current density of 1.04 mA/cm2 with a supplied voltage of 520 V and a lifetime stability of 520 min. The outstanding plasma illumination characteristics of these conducting nanowire-like NB-NCD films make them appropriate as cathodes and pave the way for the utilization of these materials in various microplasma device applications. © 2021 American Chemical Society.

ACS Applied Materials and Interfaces

Nitrogen-Incorporated Boron-Doped Nanocrystalline Diamond Nanowires for Microplasma Illumination

Introduction: Assessment of myelodysplasia (MDS) by flow cytometry (FCM) includes elaborate panels, and interpretation is observer-dependent. This study evaluates single tube 10-color FCM in a test cohort of clinically suspected MDS patients. Methods: We analyzed fifty-six bone marrow (BM) samples from clinically suspected MDS patients in a morphology-blinded manner along with controls using a 10-color single tube flow cytometry. We analyzed the reproducibility of Ogata score and modified FCM scores, additionally incorporating the proportion of CD15, CD11b, CD56, and CD38MFI on CD34+CD19-cluster for each patient. Patients were grouped as proven-MDS, suspected-MDS, and non-MDS groups based on morphology and cytogenetics. Optimized multi-axial radar-plots were also used to analyze maturation patterns in the granulocytic, monocytic, and blast progenitor compartments of proven-MDS cases and controls. Results: Flow cytometric abnormalities ≥3 were present in proven-MDS (n = 23) with a sensitivity and specificity of 78 % and 94 %, respectively, as per Ogata score. The addition of CD38 MFI to the score yielded sensitivity and specificity of 82 % and 88 %, respectively. Additional analysis of aberrant expression of CD15, CD11b, and CD56 increased the diagnostic power of the FCM score. A qualitative analysis of data also showed differences in maturation patterns in proven-MDS compared to the control group. Conclusion: Single tube 10-color FCM scoring, including Ogata score, modified-FCM scores, and radar plots pattern analysis, showed significant abnormalities in proven-MDS cases in this pilot study. Large databases, including FCM-scoring and pattern-based analysis for normal BM maturation, could be further validated and standardized for screening MDS. © 2021 Elsevier Ltd

Leukemia Research

The utility of a single tube 10-color flow cytometry for quantitative and qualitative analysis in myelodysplastic syndrome- a pilot study

The coexistence of ferroelectricity and negative thermal expansion (NTE) in a material is rare and has yet to be observed in a purely organic single-component system. Here, we report the bifunctional characteristics of 2-(4-(trifluoromethyl)phenyl)-1H-phenanthro [9,10-d] imidazole, a single-component system, exhibiting uniaxial ferroelectricity and anisotropic NTE properties in its various crystal forms. This purely organic material exists in trimorphic and hydrated forms. While one of the two polar forms retains its ferroelectric phase up to ∼497 K, the other exhibits a reversible large NTE below room temperature (RT), and a third centric form divests these properties. Further, the noncentric hydrated form also experiences NTE below RT. The mechanisms of ferroelectricity and NTE in this material are elucidated based on the analyses of their single-crystal X-ray structures. The interconversion of the trimorphs is demonstrated via thermal analyses. The experimental value of the in-crystal spontaneous polarization (4.6 μC/cm2) agrees well with that estimated from the periodic theoretical calculations. Given its promising figures of merit for ferroelectricity including a low coercive field (5.8 kV/cm), unusual thermal behavior, switching from NTE to positive thermal expansion, and a minimal volumetric change, this lightweight material is expected to find potential applications in nonexpansive organic electronics. © 2021 American Chemical Society.

ACS Applied Electronic Materials

Ferroelectricity and Uniaxial Negative Thermal Expansion in a Purely Organic Multifunctional Material

We investigate the most general form of the one-dimensional Dirac Hamiltonian HD in the presence of scalar and pseudoscalar potentials. To seek embedding of supersymmetry (SUSY) in it, as an alternative procedure to directly employing the intertwining relations, we construct a quasi-Hamiltonian K, defined as the square of HD, to explore the consequences. We show that the diagonal elements of K under a suitable approximation reflect the presence of a superpotential, thus proving a useful guide in unveiling the role of SUSY. For illustrative purposes, we apply our scheme to the transformed one-dimensional version of the planar electron Hamiltonian under the influence of a magnetic field. We generate spectral solutions for a class of isochronous potentials. © 2021 Author(s).

Journal of Mathematical Physics

Dirac Hamiltonian in a supersymmetric framework

Dual-peak electrocaloric effect (ECE) exists over a broad range significantly below Curie temperature in co-mixed SrBi1.98La0.02Nb2–xTaxO9 (SBLNT) compositions exhibiting diffused phase transition. The indirect measurement method is used to study the influence of defect-modified potential barrier distributions on the ECE of lead-free SBLNT ceramics. Variation in isothermal entropy change and adiabatic temperature change with varying tantalum (Ta) content signify effects of morphology and impact of altered potential barriers in the parent lattice without involving structural phase transition. A unique appearance of twin-peak positive–negative ECE in equally doped SrBi1.98La0.02Nb-TaO9 matrix is attributed to doping-induced formation of polar nanoregions and distinct dipole switching mechanisms controlled by evenly distributed Nb–Ta potential barriers in SBLNT lattice. Higher doping concentration reduces porosity and promotes electric polarization, thereby the relative cooling power gradually increases with increasing Ta at Nb sites. © 2021 Wiley-VCH GmbH

Physica Status Solidi (B) Basic Research

Twin-Peak Electrocaloric Effect in Ferroelectric Phase of Diffusive SrBi1.98La0.02Nb2−xTaxO9 Materials

A unique and highly water-soluble ICT-based fluorescent probe is developed for efficient detection and discrimination of reactive monocarbonyl formaldehyde (FA) from dicarbonyl methylglyoxal (MGO)/glyoxal (GO) by modulating the ICT process, which was confirmed by photophysical and TD-DFT analysis. The probe is applied in cellular imaging and quantifying FA in preserved food and MGO in manuka honey. © The Royal Society of Chemistry 2021.