@article {46399, title = {Additive induced capture of elusive polymorphs of conformationally flexible Sulfonamides/Sulfoesters}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C776}, type = {Meeting Abstract}, keywords = {additive induced polymorphism, intermolecular interactions, phase transition}, issn = {2053-2733}, author = {Shaikh, Samir Rashid and Gawade, Rupesh L. and Chakravarty, Debamitra K. and Puranik, Vedavati G. and Gonnade, Rajesh} } @article {46397, title = {Cocrystals/salts of Furosemide : Interesting case of colour cocrystal polymorphism}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C724}, type = {Meeting Abstract}, keywords = {Color cocrystal polymorphism, Sandwich assembly, Stacking interactions}, issn = {2053-2733}, author = {Sangtani, Ekta and Jha, Kunal and Munshi, Parthapratim and Gonnade, Rajesh} } @article {43608, title = {Ultrahydrophobic fluorous metal-organic framework derived recyclable composite as apromising platform to tackle marine oil spills}, journal = {Chemistry-A European Journal}, volume = {22}, year = {2016}, month = {JUL}, pages = {10937-10943}, abstract = {Derived from a strategically chosen hexafluorinated dicarboxylate linker aimed at the designed synthesis of a superhydrophobic metal-organic framework (MOF), the fluorine-rich nanospace of a water-stable MOF (UHMOF-100) exhibits excellent water-repellent features. It registered the highest water contact angle (approximate to 176 degrees) in the MOF domain, marking the first example of an ultrahydrophobic MOF. Various experimental and theoretical studies reinforce its distinc-tive water-repellent characteristics, and the conjugation of superoleophilicity and unparalleled hydrophobicity of a MOF material has been coherently exploited to achieve real-time oil/water separation in recyclable membrane form, with significant absorption capacity performance. This is also the first report of an oil/water separating fluorinated ultrahydrophobic MOF-based membrane material, with potential promise for tackling marine oil spillages.}, doi = {10.1002/chem.201601724}, author = {Mukherjee, Soumya and Kansara, Ankit M. and Saha, Debasis and Gonnade, Rajesh and Mullangi, Dinesh and Manna, Biplab and Desai, Aamod V. and Thorat, Shridhar H. and Singh, Puyam S. and Mukherjee, Arnab and Ghosh, Sujit K.} } @article {43904, title = {Binding selectivity of vitamin K3 based chemosensors towards nickel(II) and copper(II) metal ions}, journal = {Journal of molecular Structure}, volume = {1143}, year = {2017}, month = {SEP}, chapter = {495-514}, abstract = {

The vitamin K3 derivatives 2-methyl-3-[(pyridin-2-ylmethyl)-amino]-1,4-naphthoquinone (M-1), 2-methyl-3-[(pyridin-2-ylethyl)-amino]-1,4-naphthoquinone (M-2), 2-methyl-3-((2-(thiophen-2-yl) methyl)amino)naphthalene-1,4-dione (M-3) and 2-methyl-3-((2-(thiophen-2-yl)ethyl)amino)naphthalene-1,4-dione (M-4) have been synthesized, characterized and studied for their chemosensor abilities towards transition metal ions. Crystal structures of M-1 to M-4 revealed a variety of N-H center dot center dot O, C-H center dot center dot center dot O, C-H center dot center dot center dot pi and pi center dot center dot center dot pi interactions. Minor variations in such interactions by chemical stimuli such as metal ions, results in change in color that can be visualized by naked eyes. It has been shown that electronic structure and H-1 NMR, vibrational as well as electronic spectra from the density functional theory agree well with the experiments. The metal ion binding in ethanol, ethanol-water and in mild base triethylamine brings forth recognizing ability of M-1 toward Ni2+ whereas M-2 exhibits large sensing ability for Cu2+ ion. Interestingly M-1 display varying metal ion binding specificity in different solvents with the association constant in ethanol being 11,786 M-1 for Ni2+ compared to 9462 M-1 for the Cu2+. A reversal in preferential binding of M-2 with the respective association constants being 4190 M-1 and 6370 M-1 is discernible. (C) 2017 Elsevier B.V. All rights reserved.

}, keywords = {Aminonaphthoquinone Molecular-structures, Anthraquinone, Aqueous-solution, Chemosensor, Crystal-structures, Cu(II), Derivatives, DFT, Fluorometric Chemosensors, hydrogen bonding, Naphthoquinone, pi-pi stacking, Recognition, sensors}, issn = {0022-2860}, doi = {10.1016/j.molstruc.2017.04.094}, author = {Patil, Amit and Lande, Dipali N. and Nalkar, Archana and (Gejji, Shridhar P. and Chakrovorty, Debamitra and Gonnade, Rajesh and Moniz, Tania and Rangel, Maria and Pereira, Eulalia and Salunke-Gawali, Sunita} } @article {45769, title = {N-Heterocyclic carbene-catalyzed aldol-lactonization of ketoacids via dynamic kinetic resolution}, journal = {ACS Catalysis}, volume = {7}, year = {2017}, month = {JUN}, pages = {3995-3999}, type = {Article}, abstract = {

N-Heteroryclic carbene (NHC)-catalyzed enantioselective aldol lactonization of acyclic ketoacids, proceeding via dynamic kinetic resolution, is presented. The carbene generated from the chiral anninoinclanol-derived triazolium salt in the presence of LiCl was the key for the success of this transformation. The reaction allowed the diastereoselective and enantioselective synthesis of cyclopentane-fused beta-lactones having three contiguous stereocenters. The reaction products are shown to undergo substrate-controlled beta-lactone opening in the presence of amines to afford succinimide derivatives with four contiguous stereocenters.

}, keywords = {aldol lactonization, beta-lactones, DKR strategies, ketoacids, N-heterocyclic carbenes, organocatalysis}, issn = {2155-5435}, doi = {10.1021/acscatal.7b00681}, author = {Mondal, Santigopal and Mukherjee, Subrata and Das, Tamal Kanti and Gonnade, Rajesh and Biju, Akkattu T.} } @article {44520, title = {Mechano-responsive room temperature luminescence variations of boron conjugated pyrene in air}, journal = {Chemical Communications}, volume = {54}, year = {2018}, month = {JUN}, pages = {6028-6031}, abstract = {

Stimuli responsive tunable luminescence is a promising field of research. Even though mechanofluorescence is widely studied, mechanophosphorescence remains unexplored. Here we report the mechano-driven fluorescence and phosphorescence variations of a pyrene tetraboronic ester derivative. The fluorochromic and room temperature phosphorescence features are supported by theoretical studies and single crystal analysis. The mechanically ground fluorescence active but phosphorescence inactive pyrene tetraboronic ester exhibits room temperature phosphorescence in air withmechanical force. The efficient intermolecular electronic coupling in the dimer formed upon scratching enables a good communication between singlet and triplet states, hence resulting in room temperature mechanophosphorescence.

}, issn = {1359-7345}, doi = {10.1039/c8cc03494j}, author = {Wakchaure, Vivek C. and Ranjeesh, Kayaramkodath C. and Goudappagouda and Das, Tamal and Vanka, Kumar and Gonnade, Rajesh and Babu, Sukumaran S.} } @article {46318, title = {Dimedone-based rigid organic scaffold for organizing symmetrical helical peptide chains.}, journal = {ChemistrySelect}, volume = {4}, year = {2019}, month = {OCT }, pages = {11518-11522}, type = {Article}, abstract = {

We describe herein design, synthesis and conformational investigations of polypeptides attached on a rigid dimedone template. Two identical peptide chains are attached on a single carbon containing dimedone as a scaffold. Dimedone assists in controlling the secondary interactions through strong intramolecular helical C-12 and C-15 membered bifurcated hydrogen bonding on both the peptide chains along with propagating the helical architecture of the peptide chains attached. There exists a C-6 hydrogen bonding for the single stranded peptides attached to dimedone. Extensive structural investigations involving single crystal X-ray diffraction, solution-state NMR and CD studies of oligopeptides have been undertaken.

}, keywords = {dimedone, Helical, hydrogen bonding, Peptides, template}, issn = {2365-6549}, doi = {10.1002/slct.201903087}, author = {Madica, Krishnaprasad and Lakshmi, Jerripothula K. and Madhu, Suresh and Nadimpally, Krishna Chaitanya and Gonnade, Rajesh and Jagadeesh, Bharatam and Sanjayan, Gangadhar J.} } @article {46203, title = {Synthesis of hexaphenylbenzene-based template assembled synthetic proteins}, journal = {Tetrahedron Letters}, volume = {60}, year = {2019}, month = {AUG}, type = {Article}, abstract = {

Template-assembled synthetic proteins (TASPs) synthesized from rigid templates have attracted attention due to their interesting structural architectures and potential biomedical applications. Herein, we report the design, synthesis and characterizations of TASPs based on hexaphenylbenzene template (HPB) having twelve peptide attachable axial-arms in its structure. The peptides were attached to all the axial-arms of the template in a single step using simple solution phase peptide coupling strategy. The reaction conditions were standardized systematically using simple amines from smaller size to larger ones. (C) 2019 Elsevier Ltd. All rights reserved.

}, doi = {10.1016/j.tetlet.2019.07.011}, author = {Madhu, Suresh and Madica, Krishnaprasad and Gonnade, Rajesh and Sanjayan, Gangadhar J} } @article {46091, title = {Tf2NH catalyzed 1,6-conjugate addition of 2-hydroxy-p-quinone methides with -functionalized ketones: access to 2,3,4,9-Tetrahydro-1H-xanthenones and 4H-Chromene Derivatives}, journal = {European Journal of Organic Chemistry}, year = {2019}, month = {JUN }, pages = {3127-3133}, type = {Article}, abstract = {

A Bronsted acid catalyzed tandem 1,6-conjugate sequential cycloaddition reaction using 2-hydroxy-p-quinone methides and -functionalized ketones is reported. The method allows xanthenones and chromenes to be accessed in moderate to excellent yield with broad substrate scope, which could be further functionalized to give a versatile set of products.

}, keywords = {-Functionalized ketone, 1, 6-Conjugated addition, Bronsted acid, Chromenes, Xanthenones}, issn = {1434-193X}, doi = {10.1002/ejoc.201900370}, author = {Satbhaiya, Shruti and Khonde, Nilesh S. and Rathod, Jayant and Gonnade, Rajesh and Kumar, Pradeep} } @article {46864, title = {Synthesis and biological activity of imidazole based 1,4-naphthoquinones}, journal = {New Journal of Chemistry}, volume = {44}, year = {2020}, month = {MAY }, pages = {6889-6901}, type = {Article}, abstract = {

Design and development of drugs in multi-drug resistant (MDR) infections have been of growing interest. We report the syntheses, and antibacterial and antifungal activities of imidazole-based 1,4-naphthoquinones (I-1 to I-4; 1-alkyl-2-methyl-1H-naphtho[2,3-d]imidazole-4,9-dione (alkyl = methyl to butyl)) and their precursors (B-3; N-(3-chloro-1,-dioxo-1,4-dihydronaphthalen-2-yl)acetamide) and A-1 to A-4; N-(3-(alkylamino)-1,4-dioxo-1,4-dihydronaphthalen-2-yl)acetamide (alkyl = methyl to butyl). Crystal structures of B-3, A-1 to A-3 and I-2 to I-4 were obtained through single crystal X-ray diffraction experiments. Electronic structure and charge distribution have further been characterized with the use of Density Functional Theory. Seven of these derivatives display a broad spectrum of antibacterial activity against few selected bacterial strains (Gram-positive and Gram-negative). As demonstrated MIC values with B-2 and B-3 against bacterial isolates were 8-64 mu g ml(-1) and those against pathogenic yeast, C. albicans, were observed in the range of 128-256 mu g ml(-1). MIC data of these derivatives suggest them to be promising against pathogens.

}, issn = {1144-0546}, doi = {10.1039/c9nj04339j}, author = {Choudhari, Dinkar and Salunke-Gawali, Sunita and Chakravarty, Debamitra and Shaikh, Samir R. and Lande, Dipali N. and Gejji, Shridhar P. and Rao, Pradeep Kumar and Satpute, Surekha and Puranik, Vedavati G. and Gonnade, Rajesh} } @article {47587, title = {Intramolecularly double-donor-stabilized stannylene and its coordination towards Ag(I) and Au(I) centers}, journal = {Chemistry-An Asian Journal}, volume = {16}, year = {2021}, month = {AUG }, pages = {2118-2125}, type = {Article}, abstract = {The intramolecularly double-donor-stabilized stannylene 1 has been synthesized from the salt-metathesis reaction between two equivalents of lithium pyridine ene-amide L1 and SnCl2. Compound 1 exhibits dipolar behavior when reacted with B(C6F5)(3) leading to the zwitterionic compound 2. The reaction of 1 with one equivalent and 0.5 equivalent of AgOTf (OTf=trifluoromethane sulfonate) result in the formation of a stannylene-AgOTf complex 3 and a homoleptic distannylene-silver ionic complex 4, respectively. Analogous to complex 4, the gold(I) complex 5 has been synthesized from the reaction between two equivalents of 1 and 0.5 equivalent of AuCl.SMe2/Me3SiOTf. Complex 5 is the first example of homoleptic stannylene-Au(I) ionic complex among the very scarce reports on stannylene-gold(I) coordination complexes. All compounds have been structurally characterized using single crystal X-ray crystallography. Solution-state characterization have been performed using multinuclear NMR techniques. Detailed DFT calculations on the optimized geometries 1 o, 3 o-5 o reveal the change in sp- hybridization on the pyramidal Sn(II) center upon metal coordination and their bonding overlaps.}, keywords = {coordination, gold cation, hybridization, intramolecular donor, stannylene}, issn = {1861-4728}, doi = {10.1002/asia.202100523}, author = {Chibde, Purva and Raut, Ravindra K. and Kumar, Vikas and Deb, Rahul and Gonnade, Rajesh and Majumdar, Moumita} } @article {48114, title = {Enceleamycins A-C, furo-naphthoquinones from amycolatopsis sp. MCC0218: isolation, structure elucidation, and antimicrobial activity}, journal = {Journal of Natural Products}, volume = {85}, year = {2022}, month = {MAY}, pages = {1267-1273}, type = {Article}, abstract = {

Three novel furo-naphthoquinones, enceleamycins A-C (1-3), and a new N-hydroxypyrazinone acid (4) were identified from the strain Amycolatopsis sp. MCC 0218, isolated from a soil sample collected from the Western Ghats of India. Their chemical structure and absolute and relative configurations were established by 1D and 2D NMR spectroscopy, single-crystal X-ray crystallography, and high-resolution mass spectrometry. Compounds 1 and 3 were active against methicillin-susceptible and -resistant Staphylococcus aureus with MIC values of 2-16 mu g/mL.

}, issn = {0163-3864}, doi = {10.1021/acs.jnatprod.1c01160}, author = {Khan, Abujunaid and Said, Madhukar S. and Borade, Balasaheb R. and Gonnade, Rajesh and Barvkar, Vitthal and Kontham, Ravindar and Dastager, Syed G.} } @article {48058, title = {Regioselective synthesis of 1,4,5-trisubstituted 1,2,3-triazole derivatives from alpha,beta-unsaturated carbonyls}, journal = {European Journal of Organic Chemistry}, volume = {2022}, year = {2022}, month = {JUL}, pages = {e202200317}, type = {Article}, abstract = {

The copper-catalyzed oxidative azide-olefin cycloaddition (OAOC) reaction of differently substituted alpha,beta-unsaturated carbonyls with azides provided an efficient method for preparing biologically active 1,4,5-trisubstituted 1,2,3-triazoles. In this study, the cycloaddition reaction was found to be a simple and powerful method for constructing diverse mono- and bis-(1,4,5-trisubstituted 1,2,3-triazole) functionalized heterocyclic compounds in moderate to high yields with great regioselectivity. The XRD-analysis data of one of the bis-triazole derivatives supported the regioselectivity as well as the conformity of the method in the construction of the triazole nucleus. The preliminary antifungal profile against C. albicans was observed with cinnamaldehyde-based triazole derivatives demonstrating promising results.

}, keywords = {alpha, antifungal, beta-Unsaturated carbonyls, Cycloaddition, Dibenzalacetone, Triazole}, issn = {1434-193X}, doi = {10.1002/ejoc.202200317}, author = {Verma, Naimish K. and Bera, Smritilekha and Gonnade, Rajesh and Mondal, Dhananjoy} } @article {48771, title = {Donor strapped perylene bisimide macrocycle and its lemniscate dimer with extended charge separation}, journal = {Inorganic Chemistry Frontiers}, volume = {10}, year = {2023}, month = {OCT }, pages = {5099-5107}, type = {Article}, abstract = {

Macrocyclic structures are fascinating due to their unique design and capability to place chromophores in specific orientations, resulting in exciting optoelectronic properties. However, the synthetic challenges limit the broad exploration of such systems. Herein, we report a thiophene-diacetylene-based ring strapped perylene bisimide macrocycle and its notably different electron transfer features. Single-crystal analysis of the macrocycle pointed to the nearly orthogonal placement of donor-acceptor units, facilitating better electronic communication between them. Interestingly, introduction of an alkyl substituent on the peripheral thiophene ring opened the possibility of forming a higher oligomer macrocycle consisting of two strapped perylene bisimide units. Diffusion and two-dimensional NMR experiments provided insight into the structure of the figure-eight-shaped lemniscate dimer. Transient absorption measurements showed faster electron transfer and extended stabilization of the charge-separated state. The thiophene-diacetylene-based ring is a better donor unit to facilitate rapid electron transfer and extended charge separation in the macrocycle and its lemniscate dimer. The new macrocycle design enables the formation of higher analogs equally capable of stabilizing the charge-separated state. Donor-acceptor (D-A) macrocycle designs position the respective units to achieve ultrafast electron transfer precisely and an extended charge-separated state. Here, we report a D-A macrocycle and its lemniscate dimer molecule with exciting electron transfer features.

}, issn = {2052-4129}, doi = {10.1039/d3qo01060k}, author = {Veer, Sairam Dnyaneshwar and Goswami, Tanmay and Ravindranathan, Sapna and Gonnade, Rajesh and Kharbanda, Nitika and Ghosh, Hirendra N. and Babu, Sukumaran Santhosh} } @article {48939, title = {Isomer effect on energy storage of π-extended S-shaped double[6]heterohelicene}, journal = { Angewandte chemie-international edition}, volume = {62}, year = {2023}, month = {NOV}, type = {Article}, abstract = {

Recently, chiral and nonplanar cutouts of graphene have been the favorites due to their unique optical, electronic, and redox properties and high solubility compared with their planar counterparts. Despite the remarkable progress in helicenes, pi-extended heterohelicenes have not been widely explored. As an anode in a lithium-ion battery, the racemic mixture of pi-extended double heterohelical nanographene containing thienothiophene core exhibited a high lithium storage capability, attaining a specific capacity of 424 mAh g-1 at 0.1 A g-1 with excellent rate capability and superior long-term cycling performance over 6000 cycles with negligible fade. As a first report, the pi-extended helicene isomer (PP and MM), with the more interlayer distance that helps faster diffusion of ions, has exhibited a high capacity of 300 mAh g-1 at 2 A g-1 with long-term cycling performance over 1500 cycles compared to the less performing MP and PM isomer and racemic mixture (150 mAh g-1 at 2 A g-1). As supported by single-crystal X-ray analysis, a unique molecular design of nanographenes with a fixed (helical) molecular geometry, avoiding restacking of the layers, renders better performance as an anode in lithium-ion batteries. Interestingly, the recycled nanographene anode material displayed comparable performance. A pi-extended double heterohelical nanographene of thienothiophene core fused with two hexabenzocoronene units exhibits excellent performance as an anode in a lithium-ion battery. The isomer (PP and MM) with more interlayer distance exhibited a high lithium storage capability compared to the other isomer and racemic mixture. Helical nanographene anodes display excellent rate capability, superior long-term cycling performance, and recyclability.image

}, keywords = {Battery, graphene, Li-ion battery, nanographene, Organic Electrode Material}, issn = {1433-7851}, doi = {10.1002/anie.202311657}, author = {Kumar, Viksit and Bharathkumar, H. J. and Dongre, Sangram D. and Gonnade, Rajesh and Krishnamoorthy, Kothandam and Babu, Sukumaran Santhosh} } @article {48451, title = {Oligothiophene-ring-strapped perylene bisimides: functionalizable coaxial donor-acceptor macrocycles}, journal = {Angewandte Chemie-International Edition}, volume = {62}, year = {2023}, month = {JAN}, type = {Article}, abstract = {

Aesthetic designs from nature enable new knowledge to be gained and, at the same time, inspire scientific models. In this context, multicomponent macrocycles embody the advantage of precisely positioning the structural units to achieve efficient communication between them. However, the construction of a functionalizable macrocycle for ultrafast charge separation and stabilization has not been attempted. Herein, we report the synthesis, crystal structure, and transient absorption of a new functionalizable macrocycle consisting of an oligothiophene-ring-strapped perylene bisimide. Transient absorption results point to a sequential improvement in charge separation and stabilization from the macrocycle to the corresponding linear dimer and 2D polymer due to the unique design. Our macrocycle design with a supportive spatial arrangement of the donor and acceptor units will inspire the development of more complex synthetic systems with exciting electron-transfer and charge-separation features.

}, keywords = {Charge Separation, Donor-Acceptor Systems, Electron Transfer, Macrocycles, Perylene Bisimides}, issn = {1433-7851}, doi = {10.1002/anie.202212934}, author = {Dnyaneshwar Veer, Sairam and Chandrakant Wakchaure, Vivek and Asokan, Kiran and Dixit, Ruchi and Goswami, Tanmay and Saha, Ramchandra and Gonnade, Rajesh and Ghosh, Hirendra N. and Santhosh Babu, Sukumaran} } @article {49100, title = {Boron- and oxygen-doped π-extended helical nanographene with circularly polarised thermally activated delayed fluorescence}, journal = {Chemistry-A European Journal}, volume = {30}, year = {2024}, month = {APR }, type = {Article}, abstract = {

Helical nanographenes have garnered substantial attention owing to their finely adjustable optical and semiconducting properties. The strategic integration of both helicity and heteroatoms into the nanographene structure, facilitated by a boron-oxygen-based multiple resonance (MR) thermally activated delayed fluorescence (TADF), elevates its photophysical and chiroptical features. This signifies the introduction of an elegant category of helical nanographene that combines optical (TADF) and chiroptical (CPL) features. In this direction, we report the synthesis, optical, and chiroptical properties of boron, oxygen-doped pi-extended helical nanographene. The pi-extension induces distortion in the DOBNA-incorporated nanographene, endowing a pair of helicenes, (P)-B2NG, and (M)-B2NG exhibiting circularly polarized luminescence with glum of -2.3x10-3 and +2.5x10-3, respectively. B2NG exhibited MR-TADF with a lifetime below 5 mu s, and a reasonably high fluorescence quantum yield (50 \%). Our molecular design enriches the optical and chiroptical properties of nanographenes and opens up new opportunities in multidisciplinary fields. B, O-doped pi-extended helical nanographene has been explored for its optical and chiroptical properties. The presence of helical and nanographene segments stabilize the helicity and imparts tunable optical properties. Helical nanographene display circularly polarized thermally activated delayed fluorescence. image

}, keywords = {circularly polarized luminescence, DOBNA, dual emission, nanographene, TADF}, issn = {0947-6539}, doi = {10.1002/chem.202304169}, author = {Venugopal, Geethu and Kumar, Viksit and Jadhav, Ashok Badrinarayan and Dongre, Sangram D. and Khan, Abujunaid and Gonnade, Rajesh and Kumar, Jatish and Santhosh Babu, Sukumaran} } @article {49042, title = {Solid-state NMR method for characterization of pharmaceutical eutectics}, journal = {Physical Chemistry Chemical Physics}, volume = {26}, year = {2024}, month = {JAN }, pages = {3800-3803}, type = {Article}, abstract = {

Pharmaceutical eutectics are extremely useful for designing formulations, and currently, there are no techniques other than differential scanning calorimetry (DSC) that can confirm their formation. In this study, we demonstrate that 1H fast magic angle spinning (MAS) solid-state NMR (SSNMR) experiments can confirm the formation of eutectics by detecting their intermolecular hydrogen bonding interactions. 2D 1H-1H double quantum single quantum (DQSQ) correlation SSNMR experiment is demonstrated which can confirm the formation of pharmaceutical eutectics for which there are no techniques other than differential scanning calorimetry (DSC).

}, issn = {1463-9076}, doi = {10.1039/d3cp05615e}, author = {Hareendran, Chaithanya and Shaligram, Parth S. and Gonnade, Rajesh and Ajithkumar, T. G.} } @article {49552, title = {Investigating the visible range photoresponse of an organic single-crystal analogue of the green fluorescent protein}, journal = {Nanoscale}, volume = {17}, year = {2025}, month = {APR}, pages = {8614-8623}, type = {Article}, abstract = {

The growing demand for lightweight, flexible, semi-transparent and low-cost photodetectors (PDs) in wearable electronics and optical communication systems has prompted studies to investigate organic materials as feasible alternatives to conventional inorganic PDs. However, modern organic PDs often face responsivity, detectivity, and photoresponse speed limitations, particularly in the visible range. Here, we present the photoresponse of an organic single-crystal analogue of the green fluorescent protein (GFP) chromophore photodetector, fabricated on a silicon nitride substrate. A significant increase in photocurrent was detected upon illumination with visible wavelengths (532 nm, 630 nm, and halogen light). A remarkably consistent and repeatable photoresponse was obtained during the ON and OFF illumination cycles. The device showed the dependence of photocurrent on the applied bias voltages. The measured photocurrent, responsivity, detectivity, rise time, decay time, noise equivalent power and external quantum efficiency are studied for different wavelengths. Strikingly, the fabricated device demonstrates excellent performance in the visible region compared to several conventional organic and inorganic PDs. The observed responsivity and detectivity values for the device are 98 mA W-1 and 7.94 x 108 Jones, respectively. Furthermore, the device also exhibits rapid photoresponse dynamics with a rise time of 180 ms and a decay time of 152 ms. The excellent photodetection features indicate that the single crystal GFP could serve as a versatile broadband material for future applications in optoelectronics.

}, issn = {2040-3364}, doi = {10.1039/d4nr05252h}, author = {Virole, Vishal and Dabke, Niteen and Verma, Sahil and Kumar, Ajay and Pandya, Rinu and Husale, Sudhir and Vanka, Kumar and Gonnade, Rajesh and Kanawade, Rajesh} } @article {49568, title = {Regioisomeric π-extended nanographene with long-lived phosphorescence afterglow}, journal = {Angewandte Chemie-International Edition}, volume = {64}, year = {2025}, month = {FEB}, pages = {e202422125}, type = {Article}, abstract = {

The cutouts of graphene sheets, particularly those with a nonplanar topology, present vast opportunities for advancement. Even a slight deviation from the planar structure can lead to intriguing (chiro)optical features for helically twisted nanographenes. In this context, we introduce two regioisomeric pi-extended nanographenes that exhibit distinct excited-state characteristics. The helicene structure and the photophysical features can be easily tuned by changing the connecting position of the nanographene to the carbazole core (2,7- and 3,6-). Single-crystal X-ray diffraction analysis confirmed the formation of nanographenes with bent and helical conformations. Both derivatives exhibited thermally activated delayed fluorescence at room temperature and phosphorescence at low temperatures. Notably, the nanographene with the bent structure displayed an impressive red afterglow lasting over 30seconds, in contrast to the very weak afterglow observed in the helical structure. DFT calculations revealed the existence of an isoenergetic higher triplet state (T-8) and comparatively weak spin-orbit coupling (T-1-S-0), thereby enabling the bent nanographene to exhibit a long-lived component and strong afterglow. Our findings highlight the significance of regioisomeric nanographenes with exceptional optical properties and offer a deeper understanding of the structure-property relationship in nonplanar nanographenes.

}, keywords = {Afterglow, CPL, Helicenes, nanographene, Phosphorescence, TADF}, doi = {10.1002/anie.202422125}, author = {Kumar, Viksit and Venugopal, Geethu and Jadhav, Ashok Badrinarayan and Dongre, Sangram D. and Gonnade, Rajesh and Kumar, Jatish and Ruer, Paul C. and Hupp, Benjamin and Steffen, Andreas and Babu, Sukumaran Santhosh} }