Publications by authors named "Angshuman Roy Choudhury"

A series of six binuclear Co(II)-thiolate complexes, [Co(BPMP)(S-CH--X)] (X = OMe, ; NH, ), [Co(BPMP)(μ-S-CH--O)] (), and [Co(BPMP)(μ-Y)] (Y = bdt, ; tdt, ; mnt, ), has been synthesized from [Co(BPMP)(MeOH)(Cl)] () and [Co(BPMP)(Cl)] (), where BPMP is the anion of 2,6-bis[[bis(2-pyridylmethyl)amino]methyl]-4-methylphenol. While and could allow the two-electron redox reaction of the two coordinated thiolates with elemental sulfur (S) to generate [Co(BPMP)(μ-S)] (), the complexes, , could not undergo a similar reaction. An analogous redox reaction of with elemental selenium ([Se]) produced [{Co(BPMP)(μ-Se)}{Co(BPMP)(μ-Se)}] () and [Co(BPMP)(μ-Se)] ().

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Curcumin has antioxidant properties resulting from its radical scavenging ability and inhibition of inflammation-associated factors. However, its lack of solubility, instability, and poor bioavailability are impediments to its therapeutic use. As potential alternatives, we synthesized and performed chemical analysis of thirty diarylidene-N-methyl-4-piperidone (DANMP), diheteroarylidene-N-methyl-4-piperidone (DHANMP), and spirobibenzopyran (SBP) derivatives, one of which was also characterized by single crystal X-ray diffraction.

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Herein we report the fabrication of green emitting hybrid lead bromide perovskite single crystals (HLBPSCs), their anion exchange mediated tunable yellow luminescence and thereby their coupling ability with blue emitting inorganic complex leading to generation of a photostable white light emission, with properties close to bright day sunlight. The partial anion exchange reaction to green emitting HLBPSCs led to formation of yellow emitting anion exchanged HLBPSCs─which are termed as AE-HLBPSCs herein. Then, AE-HLBPSCs were chemically combined with blue emitting Zn-aspirin complex to produce white light with a photoluminescence quantum yield (PLQY) of 47.

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Azobenzene-based unnatural amino acid motifs were synthesized Pd(II)-catalyzed diastereoselective C(sp)-H arylation of amino acid carboxamides with iodoacetanilides and Mills azo coupling.

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A series of 22 different 3,5-diarylidenetetrahydro-2H-pyran-4(3H)-ones (DATPs) were synthesized, characterized, and screened for their in vitro antiplasmodial activities against chloroquine (CQ)-sensitive Pf3D7, CQ-resistant PfINDO, and artemisinin-resistant PfMRA-1240 strains of Plasmodium falciparum. DATP 19 (3,5-bis(4-hydroxy-3,5-dimethoxybenzylidene)tetrahydro-2H-pyran-4(3H)-one) was found to be the most potent (IC 1.07 μM) against PfMRA-1240, whereas 21 (3,5-bis(3,4,5-trimethoxybenzylidene)tetrahydro-2H-pyran-4(3H)-one) showed IC values of 1.

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The chemotherapeutic potential of ruthenium(II) complexes has recently attracted researchers' interest as antibacterial and anticancer agents. In this study, two novel half-sandwich imine-based Ru complexes ([Ru(-cymene)Cl(L-1)][PF] (Ru-1) and [Ru(-cymene)Cl(L-2)][PF] (Ru-2)) were reported for their deoxyribonucleic acid (DNA) binding and antitubercular, antibacterial, and anticancer activities. The molecular structure of Ru-2 was obtained by single-crystal X-ray crystallography.

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Negishi cross-coupling reaction of organozinc compounds as nucleophiles with aryl halides has drawn immense focus for C-C bond formation reactions. In comparison to the well-established library of Pd complexes, the C-C cross-coupling of this particular approach is largely primitive with nickel-complexes. Herein, we describe the syntheses of Ni(II) complexes, [( BICAAC) NiX ] (X=Cl (1), Br (2), and I (3)) by employing the bicyclic (alkyl)(amino)carbene ( BICAAC) ligand.

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A strategy of "Nature-to-new" with iterative scaffold-hopping was considered for investigation of privileged ring/functional motif-elaborated analogs of natural aurones. An organocatalyzed umpolung chemistry based method was established for molecular-diversity feasible synthesis of title class of chemotypes i.e.

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A palladium(II) complex [(κ-{1,2-CH(NCH-CHO)}Pd] (1) supported by a dianionic salen ligand [1,2-CH(NCH-CHO)] (L) was synthesised and used as a molecular pre-catalyst in the hydroboration of aldehydes and ketones. The molecular structure of Pd(II) complex 1 was established by single-crystal X-ray diffraction analysis. Complex 1 was tested as a competent pre-catalyst in the hydroboration of aldehydes and ketones with pinacolborane (HBpin) to produce corresponding boronate esters in excellent yields at ambient temperature under solvent-free conditions.

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The advent of d-d type complex salts for designing smart functional materials with versatile utility inspired us to develop a novel type of M(II)-Ce(IV) complex salts [M(II) = Cu and Zn ions]. In this study, we present for the first time a holistic approach to design and prepare metal complex salts of the novel hybrid d-f block type, [Cu(bpy)][Ce(NO)] (1), [Cu(phen)(NO)][Ce(NO)](HNO) (2), [Zn(bpy)(NO)][ClO] (3), and [Zn(phen)(NO)] [Ce(NO)] (4); [bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline]. The intrinsic structural and morphological properties of the compounds have been revealed by employing a suite of analytical and spectroscopic methods.

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A unique strategy for the attainment of a discotic nematic (N) mesophase is reported consisting of a central benzene core to which are attached two 4-alkylphenyl and two 4-pentylbiphenyl moieties diagonally via alkynyl linkers. The rotational nature and incompatibility of unequal phenylethynyl units led to the disruption of π-π interactions within cores that aids to the realization of N phase and favors high solid-state emission. When used in OLEDs, compounds act as an efficient solid-state pure deep-blue emitter with Commission Internationale de L'Eclairage (CIE) coordinates of (0.

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Intermolecular interactions involving the aromatic C-F group in the absence of other strong hydrogen bond acceptors is the theme of this article. Weak interactions involving fluorine are known to generate various supramolecular synthons, thereby altering the crystal structures of small organic molecules. It is demonstrated that the weak interactions involving organic fluorine play a major role in directing crystal packing of highly flexible organic molecules like diphenyl tetrahydroisoquinolines reported herein.

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Recently, an unprecedented observation of polar order, thermochromic behavior, and exotic mesophases in new chiral, bent-shaped systems with a -CH moiety placed at the transverse position of the central core was reported. Herein, a homologous series of compounds with even-numbered carbon chains from n=4 to 18 were synthesized, in which -Cl was substituted for -CH at the kink position and a drastic modification in the phase structure of the bent-shaped molecule was observed. An unusual stabilization of the cubic blue phase (BP) over a wide range of 16.

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The reactivity of a bicyclic (alkyl)(amino)carbene (BICAAC) towards different boranes has been examined in the present work. The reactions with boranes BX3·SMe2 (X = H, Cl, Br), BF3·OEt2 and BCl3 yield Lewis adducts [BICAAC·BH3] (1), [BICAAC·BHCl2] (2), [BICAAC·BH2Cl] (3), [BICAAC·BF3] (4), [BICAAC·BCl3] (5) and [BICAAC·BBr3] (6) respectively, whereas more hydridic boranes, 9-borabicyclo[3.3.

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The first examples of group 13 element containing pyridinophanes have been assembled using heteroatom N-E-N bridges (E = B, Al). The presence of B and Al as acceptor atoms in the bridges and their coordination with pyridine nitrogen has a very strong influence on the conformational rigidity of the pyridinophanes.

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The objective of pharmaceutical cocrystallization is to create crystalline analogues that have vastly different properties, such as solubility, melting point, stability, and bioavailability from that observed in the pure active pharmaceutical ingredients (APIs). Amoxapine is a benzoxazepine derivative and exhibits antidepressant properties. Amoxapine has very low solubility in water, so it was cocrystallized with natural acids in a 1:1 ratio in appropriate solvents by the solvent-drop grinding method.

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This study demonstrates the first synthesis of cyclic (alkyl)(amino)carbene (cAAC) adducts of Hg(ii), [cAACMe·HgBr(μ-Br)]2 (1a) and [cAACcy·HgBr(μ-Br)]2 (1b). Adduct 1b catalyzes intermolecular hydroamination of aromatic alkynes and amines under mild conditions to afford aromatic imines. The quest to prepare an electrophilic Hg(ii) complex resulted in the synthesis of cationic [(cAACcy)2Hg(H2O)]2+2[NO3]- (3) by reacting 1b with AgNO3.

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Strong hydrogen bonds play a significant role in crystal packing. In particular, the involvement of interactions involving fluorine in controlling the crystal packing requires appropriate attention, especially in the presence of other strong hydrogen bonds. In the present study, a detailed quantitative assessment has been performed of the nature, energetics and topological properties derived from the electron density in model compounds based on fluorinated benzamides (a total of 46 fluorine-substituted benzamides containing multiple fluorine atoms) in the solid state.

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Two equivalents of 1-benzyl-3-bromoethylbenzimidazolium bromide couple with NaSe to produce the first selenoether bridged bis-benzimidazolium salt (LH)Br. The nitrate (LH)(NO) and tetrafluoroborate (LH)(BF) salts were also synthesized from (LH)Br. The reaction of Hg(OAc) with (LH)Br gave the first pseudo pincer carbene mercury complex, [Hg(L-κC)][HgBr] (C1).

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On reaction of 2,2'-bipyridine with iridium(iii), an "aggregation induced phosphorescence (AIP)" active "rollover" complex, [Ir(PPh3)2(bipy-H)(Cl)(H)] (bipy-H = κ(2)-N,C-2,2'-bipyridine) or [Ir(bipy-H)], is obtained. The emission colour changes from bluish-green to yellowish-orange and vice versa after repeated protonation and deprotonation of [Ir(bipy-H)], respectively, which unequivocally supports its reversible nature. [Ir(bipy-H)] is sensitive to acids with different pKa values.

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Design and syntheses of 'aggregation induced emission (AIE)' active blue-emitting bis-cyclometalated iridium(III) complexes with appended diphosphine ligands [Ir(F2ppy)2(L1/L2)2(Cl)] (F2ppy = 2-(2',4'-difluoro) phenylpyridine; L1 = 1,2-bis(diphenylphosphino)ethane; L2 = bis(diphenylphosphino)propane) have been realized on a suitable route. The free phosphorous donor atom present on the appended diphosphine is shown to provide selective binding to the mercuric ion (Hg(2+)). The selective binding ability of the probe molecule towards mercuric ions results in a detectable signal due to complete quenching of their AIE properties.

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Strong solid-state greenish-blue emitting, mono-cyclometalated iridium complexes, [Ir(ppy)(PPh(3))(2)(H)(Cl)], 2a and [Ir(F(2)ppy)(PPh(3))(2)(H)(Cl)], 2b [ppyH = 2-phenylpyridine; F(2)ppyH = 2-(2',4'-difluoro)phenylpyridine], have been synthesized by a convenient route. The 'aggregation induced enhanced phosphorescence (AIEP)' activity exhibited by these complexes has been rationalized.

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[structure: see text] A novel cholaphane has been synthesized from a naturally occurring bile acid in just two steps. It has an ability to bind two fluoride ions selectively utilizing the glycolate motif in chloroform. This "inside-out" cyclodextrin analogue encapsulates fluoride through O-H.

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