01339nas a2200193 4500008004100000022001400041245006100055210006100116260000800177490000700185520073500192100002300927700002000950700002700970700002200997700001901019700001901038856008801057 2024 eng d a1477-922600aActivation of carbon disulfide by a hypersilyl germylene0 aActivation of carbon disulfide by a hypersilyl germylene cJUL0 v533 a

In this work, the insertion of CS2 into the Ge-Si bond of PhC(NtBu)2Ge-Si(SiMe3)3 (1) has been investigated, resulting in the formation of PhC(NtBu)2Ge-C( 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 S)-S-Si(SiMe3)3 (2). Interestingly, the addition of NHC to 2 allows the release of NHCCS2 with concomitant regeneration of 1. Addition of another equivalent of 1 or an analogous hypersilyl silylene, [PhC(NtBu)2Si-Si(SiMe3)3], to 2 led to the formation of compounds with a GeS (3) or a SiS (4) bond. In this work, the insertion of CS2 into the Ge-Si bond of PhC(NtBu)2Ge-Si(SiMe3)3 (1) has been investigated, resulting in the formation of PhC(NtBu)2Ge-C(S)-S-Si(SiMe3)3 (2).

1 aAjithkumar, V., S.1 aKhilari, Nripen1 aGhanwat, Pratiksha, B.1 aVenugopal, Geethu1 aKoley, Debasis1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/activation-carbon-disulfide-hypersilyl-germylene02427nas a2200277 4500008004100000022001400041245012800055210007000183260000900253490000700262520147600269653003801745653001001783653001801793653001701811653000901828100002201837700001801859700003001877700002401907700002001931700002001951700001801971700003001989856013002019 2024 eng d a0947-653900aBoron- and oxygen-doped π-extended helical nanographene with circularly polarised thermally activated delayed fluorescence0 aBoron and oxygendoped πextended helical nanographene with circul cAPR 0 v303 a

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

10acircularly polarized luminescence10aDOBNA10adual emission10ananographene10aTADF1 aVenugopal, Geethu1 aKumar, Viksit1 aJadhav, Ashok, Badrinaray1 aDongre, Sangram, D.1 aKhan, Abujunaid1 aGonnade, Rajesh1 aKumar, Jatish1 aBabu, Sukumaran, Santhosh uhttps://library.ncl.res.in/content/boron-and-oxygen-doped-%CF%80-extended-helical-nanographene-circularly-polarised-thermally01511nas a2200193 4500008004100000022001400041245011000055210007000165260000900235300001600244490000700260520080300267100001801070700002401088700002201112700002201134700003001156856013101186 2024 eng d a1359-734500aTailoring helical ends of π-extended [6]heterohelicenes to control optical, and electrochemical features0 aTailoring helical ends of πextended 6heterohelicenes to control  cOCT  a11944-119470 v603 a

The inherent helical chirality and improved pi-stacking capabilities endow helicenes with fascinating photophysical characteristics when decorated with lateral pi-extensions. Here, we report the synthesis and physicochemical characterization of expanded hetero[6]helicenes fused with thiadiazole and selenadiazole rings at the helical ends. Comparing these heterohelicenes revealed the impact of the heteroatom-embedded aromatic rings on the excited state and redox features. A small structural variation of the terminal rings from thiadiazole to selenadiazole caused a striking change in the heterohelical nanographenes. The inherent helical chirality and improved pi-stacking capabilities endow helicenes with fascinating photophysical characteristics when decorated with heteroatoms.

1 aKumar, Viksit1 aDongre, Sangram, D.1 aVenugopal, Geethu1 aNarayanan, Aswini1 aBabu, Sukumaran, Santhosh uhttps://library.ncl.res.in/content/tailoring-helical-ends-%CF%80-extended-6heterohelicenes-control-optical-and-electrochemical02168nas a2200253 4500008004100000245009100041210006900132260000900201300001500210490000700225520131300232653003801545653002301583653001301606653001701619653001801636100002401654700002201678700001801700700003001718700001801748700003001766856011801796 2025 eng d00aChiroptical amplification of [7]-helicene nanographene by additional helical chirality0 aChiroptical amplification of 7helicene nanographene by additiona cFEB  ae2024207670 v643 a

Nanographenes have captivated scientific interest since the pioneering discovery of graphene. Recently, attention has shifted towards exploring chiral and nonplanar nanographenes, for their distinct optical, chiroptical, and electronic properties. Despite the growing acceptance of helicenes, the research on inducing helical chirality on pi-extended derivatives to boost chiroptical properties remains unattended. In our study, we introduce a new pi-extended [7]-helicene resulting from the condensation of diamines with 3,6-dibromophenanthrene-9,10-dione, complemented by two hexabenzocoronene arms in the periphery. Notably, the nanographene containing binaphtho-[1,4]diazocine, compared to the corresponding phenazine, exhibits a remarkable average 2.5, 5, and 10-fold enhancements in quantum yield, dissymmetry factor, and brightness, respectively, when measured in five different solvents. These improvements underscore the significance of the induced helical chirality by the antiaromatic binaphtho-[1,4]diazocine in influencing the chiroptical properties of the helical nanographene. Our research represents a significant stride toward unlocking the potential of pi-extended helicenes and lays the groundwork for further exploration in designing and synthesizing new chiral nanomaterials.

10acircularly polarised luminescence10adissymmetry factor10ahelicene10ananographene10aquantum yield1 aDongre, Sangram, D.1 aVenugopal, Geethu1 aKumar, Viksit1 aJadhav, Ashok, Badrinaray1 aKumar, Jatish1 aBabu, Sukumaran, Santhosh uhttps://library.ncl.res.in/content/chiroptical-amplification-7-helicene-nanographene-additional-helical-chirality01776nas a2200253 4500008004100000245009800041210006900139260000900208490000700217520092400224653001401148653002501162653001501187653002301202100001801225700002101243700002501264700002901289700002201318700001701340700001901357700001901376856012701395 2025 eng d00aGermylene mediated reductive C-C and C-N coupling of an isocyanide and its device application0 aGermylene mediated reductive CC and CN coupling of an isocyanide cFEB 0 v643 a

We have demonstrated a unique reductive coupling of 4-iodophenyl isocyanide, facilitated by a perimidine-based N-heterocyclic germylene (NHGe), which yields a bis-spirogerma compound featuring simultaneous C-C and C-N bond formation. This reaction, which leads to the oxidation of germanium from +2 to +4, represents a significant departure from previously documented isocyanide-germylene interactions. The product exhibits extensive conjugation across its bicyclic C4Ge2N2 framework, conferring distinct photophysical properties, including prominent orange luminescence in both solution and solid states. The photophysical properties are supported by the TD-DFT calculations confirming an n ->pi* transition. The potential application of this compound in optoelectronic devices, particularly as a hole transport layer in PbS quantum dot solar cells, is also explored, with promising preliminary results.

10aGermylene10ahole transport layer10aIsocyanide10areductive coupling1 aGour, Kritika1 aPramanik, Debjit1 aDash, Soumya, Ranjan1 aShinde, Dipak, Dattatray1 aVenugopal, Geethu1 aVanka, Kumar1 aRath, Arup, K.1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/germylene-mediated-reductive-c-c-and-c-n-coupling-isocyanide-and-its-device-application02407nas a2200313 4500008004100000245008500041210007000126260000800196300001500204490000700219520144500226653001401671653000801685653001401693653001701707653002001724653000901744100001801753700002201771700003001793700002401823700002001847700001801867700001901885700001901904700002101923700003001944856011901974 2025 eng d00aRegioisomeric π-extended nanographene with long-lived phosphorescence afterglow0 aRegioisomeric πextended nanographene with longlived phosphoresce cFEB ae2024221250 v643 a

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.

10aAfterglow10aCPL10aHelicenes10ananographene10aPhosphorescence10aTADF1 aKumar, Viksit1 aVenugopal, Geethu1 aJadhav, Ashok, Badrinaray1 aDongre, Sangram, D.1 aGonnade, Rajesh1 aKumar, Jatish1 aRuer, Paul, C.1 aHupp, Benjamin1 aSteffen, Andreas1 aBabu, Sukumaran, Santhosh uhttps://library.ncl.res.in/content/regioisomeric-%CF%80-extended-nanographene-long-lived-phosphorescence-afterglow02695nas a2200241 4500008004100000022001400041245014400055210006900199260000800268300001600276490000800292520183600300100002102136700002002157700002202177700002402199700002302223700002002246700002202266700001902288700001802307856012802325 2026 eng d a0002-786300aHarnessing strong chiroptical nonlinearity in carbene-copper-amides through center-specific chirality: an approach to amplified dissymmetry0 aHarnessing strong chiroptical nonlinearity in carbenecopperamide cJUN a23238-232530 v1483 a

We present the design, synthesis, and photophysical characterization of a new class of chiral N-heterocyclic carbene (NHC)-copper(I)-amide (CMA) complexes with enantiomerically pure phenylethylamine motifs within the amide framework. These chiral CMA complexes represent a new class of mononuclear molecular Cu(I) complexes exhibiting pronounced chiral nonlinear optical (NLO) activity, which are actively being researched for advanced optoelectronic applications such as advanced photonics, biosensing, and security. The intrinsic molecular chirality and noncentrosymmetric crystal packing collectively enable strong second-harmonic generation (SHG) responses in the presence of circularly polarized (CP) light. Notably, these complexes display impressive SHG circular dichroism factors (g SHG-CD) as high as +/- 0.40 at 1000 nm, equaling or surpassing state-of-the-art chiral perovskites in this domain. Beyond their exceptional NLO response, the complexes exhibit dual emissive behavior, originating from both singlet and triplet excited states, with absolute quantum yields reaching 30%, and validated by TD-DFT calculations. The air-sensitive phosphorescence (similar to 550 nm) efficiently generates singlet oxygen (1O2), confirmed by PPh3 photooxidation and TEMPO radical generation. Remarkably, the emission can be reversibly switched between pure singlet and mixed singlet-triplet states by external modulation of O2, maintaining photostability over multiple oxic-anoxic cycles up to 5 days. These findings establish chiral CMA complexes as a new class of NHC-ligated molecular Cu(I) systems to display circularly polarized NLO activity with reversible photoluminescent switching, opening new avenues for exploring main-group organometallic compounds in next-generation polarization-sensitive photonic devices.

1 aGhosh, Moushakhi1 aTanwar, Riteeka1 aPanwaria, Prakash1 aChatterjee, Abhijit1 aPanday, Rishukumar1 aAkhtar, Ruksana1 aVenugopal, Geethu1 aMandal, Pankaj1 aKhan, Shabana uhttps://library.ncl.res.in/content/harnessing-strong-chiroptical-nonlinearity-carbene-copper-amides-through-center-specific