02391nas a2200205 4500008004100000022001400041245013400055210006900189260000900258300001600267490000700283520164000290100002301930700002301953700001901976700002401995700001702019700002002036856012902056 2022 eng d a2041-652000aRoom temperature chemoselective hydrogenation of C=C, C=O and C=N bonds by using a well-defined mixed donor Mn(I) pincer catalyst0 aRoom temperature chemoselective hydrogenation of CC CO and CN bo cNOV  a13764-137730 v133 a

Chemoselective hydrogenation of C=C, C=O and C=N bonds in alpha,beta-unsaturated ketones, aldehydes and imines is accomplished at room temperature (27 degrees C) using a well-defined Mn(I) catalyst and 5.0 bar H-2. Amongst the three mixed-donor Mn(I) complexes developed, kappa(3)-((PNNPyz)-P-R2-N-3)Mn(CO)(2)Br (R = Ph, Pr-i, Bu-t); the Bu-t -substituted complex ((PNNPyz)-P-tBu2-N-3)Mn(CO)(2)Br shows exceptional chemoselective catalytic reduction of unsaturated bonds. This hydrogenation protocol tolerates a range of highly susceptible functionalities, such as halides (-F, -Cl, -Br, and -I), alkoxy and hydroxy, including hydrogen-sensitive moieties like acetyl, nitrile, nitro, epoxide, and unconjugated alkenyl and alkynyl groups. Additionally, the disclosed method applies to indole, pyrrole, furan, thiophene, and pyridine-containing unsaturated ketones leading to the corresponding saturated ketones. The C=C bond is chemoselectively hydrogenated in alpha,beta-unsaturated ketones, while the aldehyde's C=O bond and imine's C=N bond are preferentially reduced over the C=C bond. A detailed mechanistic study highlighted the non-innocent behavior of the ligand in the ((PNNPyz)-P-tBu2-N-3) Mn(I) complex and indicated a metal-ligand cooperative catalytic pathway. The molecular hydrogen (H-2) acts as a hydride source, whereas MeOH provides a proton for hydrogenation. DFT energy calculations supported the facile progress of most catalytic steps, involving a crucial turnover-limiting H-2 activation.

1 aShabade, Anand, B.1 aSharma, Dipesh, M.1 aBajpai, Priyam1 aGonnade, Rajesh, G.1 aVanka, Kumar1 aPunji, Benudhar uhttps://library.ncl.res.in/content/room-temperature-chemoselective-hydrogenation-cc-co-and-cn-bonds-using-well-defined-mixed01974nas a2200241 4500008004100000245014200041210006900183260000800252300001600260490000600276520110900282653001801391653001801409653002801427653003701455653002501492100001801517700001901535700001701554700001701571700001801588856012601606 2023 eng d00aPd nanoparticles supported on N-incorporated hybrid organosilica as an active and selective low-temperature phenol hydrogenation catalyst0 aPd nanoparticles supported on Nincorporated hybrid organosilica  cJUN a11500-115120 v63 a

A heterogeneous Pd-NPMO hybrid-silicacatalyst is synthesized andits application for aqueous phase selective hydrogenation of phenolto cyclohexanone at near ambient temperature (40 degrees C) and underatmospheric hydrogen pressure is demonstrated. The homogeneously distributedPd nanoparticles on N-bridged hybrid mesoporous organosilica showedremarkable activity and selectivity for cyclohexanone compared tothe unmodified Pd-SBA-15 catalyst. Control experiments strongly claimthe role of nitrogen domains in the organic framework of hybrid silicasupport in stabilizing small Pd nanoparticles and possibly modifyingthe Pd sites responsible for catalysis to activate the substrate moleculesin water. The hybrid silica catalyst was stable and reused severaltimes without any significant drop-in activity, proving the heterogeneityof the bifunctional Pd catalyst. Based on the density functional theorystudy and experimental interventions, a possible reaction mechanismfor the low-temperature phenol hydrogenation explaining the role oforganic domains in the hybrid-silica framework is proposed.

10acyclohexanone10aHybrid silica10apalladium nanoparticles10aPeriodic mesoporous organosilica10aphenol hydrogenation1 aBetsy, K., J.1 aBajpai, Priyam1 aLazar, Anish1 aVanka, Kumar1 aVinod, C., P. uhttps://library.ncl.res.in/content/pd-nanoparticles-supported-n-incorporated-hybrid-organosilica-active-and-selective-low02340nas a2200169 4500008004100000022001400041245014000055210006900195260000900264300001600273490000700289520168600296100001901982700002602001700001702027856012602044 2025 eng d a2041-652000aThe critical helping hand of water: theory shows the way to obtain elusive, granular information about kinetic asymmetry driven systems0 acritical helping hand of water theory shows the way to obtain el cAUG  a14940-149550 v163 a

Kinetic asymmetry is crucial in chemical systems where the selective synthesis of one product over another, or the acceleration of specific reaction(s) is necessary. However, obtaining precise information with current experimental methods about the behavior of such systems as a function of time, substrate concentration and other relevant factors, is not possible. Computational chemistry provides a powerful means to address this problem. The current study unveils a two-pronged computational approach: (i) full quantum chemical studies with density functional theory (DFT), followed by (ii) stochastic simulations with a validated Gillespie algorithm (GA) (using representative model systems where necessary), to study the behavior of a kinetic asymmetry driven unidirectional molecular motor (1-phenylpyrrole2,2 `-dicarboxylic acid) (Nature, 2022, 604 (7904), 80-85). Our approach allows us to understand what is really taking place in the system, underlining the crucial role played by water molecules in facilitating the rotation of the motor. It is seen that water lubricates the motion by increasing the rotation rate constant of the final step by, remarkably, more than ten orders of magnitude! These insights further serve to explain the efficient rotation of the very recently reported gel-embedded molecular motor (Nature, 2025, 637 (8046), 594-600), providing an upper limit for the allowed rotation barrier in such systems, and thus also casts light into the functioning of bio-molecular motors. The current work therefore provides a template for carefully and properly studying a wide variety of important, kinetic asymmetry driven systems in the future.

1 aBajpai, Priyam1 aThulasiram, Shrivatsa1 aVanka, Kumar uhttps://library.ncl.res.in/content/critical-helping-hand-water-theory-shows-way-obtain-elusive-granular-information-about02337nas a2200253 4500008004100000022001400041245006900055210006800124260000800192490000700200520155700207653001501764653001501779653002101794653001601815653001801831100002101849700003301870700001901903700002601922700001701948700002001965856009801985 2025 eng d a1864-563100aDepolymerization of waste polycarbonates to value-added products0 aDepolymerization of waste polycarbonates to valueadded products cJAN0 v183 a

Additive free aminolysis method developed for the depolymerization/upcycling of polycarbonates. We report here chemical recycling of polycarbonate under ambient conditions to get its monomer bisphenol A, monoaminocarbamate and biscarbamates in 1 : 2 : 1 ratio respectively. By employing the secondary amine as the aminating reagent, facilitates the depolymerization to work under additive/catalyst free conditions. The developed method deals with depolymerization of waste polycarbonates and works even with late-stage amine derivatives such as amoxapine and desloratadine which are drugs molecules known to treat neurotic disorders and allergies respectively. The reaction can be scaled up and works with similar efficacy which depicts the efficiency of the depolymerization of wasteend-of-life polycarbonate plastic waste. The biscarbamate and bisphenol-A was further subjected for the post functionalization to obtain amides and phenol in good yields. Developed additive/catalyst free aminolysis of waste polycarbonates to carbamates and monomer BPA at ambient conditions. Variety of secondary amines were screened including the late stage amine derivatives like amoxapine and desloratadine which delivered the expected products successfully. Later the developed methodology was even applied for the different end-of-life polycarbonates with the secondary amine and achieved the depolymerization without any obstacle. Further carried out the scale up reaction and derivatization of carbamates and BPA to amide and phenol synthesis. image

10aAminolysis10acarbamates10adepolymerization10aEnd-of-life10aPolycarbonate1 aPadhi, Ganeshdev1 aPansare, Vaibhav, Ramachandr1 aBajpai, Priyam1 aKrishna, Gamidi, Rama1 aVanka, Kumar1 aBarsu, Nagaraju uhttps://library.ncl.res.in/content/depolymerization-waste-polycarbonates-value-added-products01159nas a2200193 4500008004100000022001400041245013500055210006900190260000800259300001400267490000700281520046000288100001700748700001900765700002600784700001700810700001500827856012300842 2025 eng d a1523-706000aPalladium(II)-catalyzed desymmetrization of 2-alkynylbenzoate-tethered cyclohexadienones for the synthesis of polycyclic compounds0 aPalladiumIIcatalyzed desymmetrization of 2alkynylbenzoatetethere cMAY a5429-54340 v273 a

Pd-catalyzed cascade cyclization of 2-alkynylbenzoate-tethered cyclohexadienone was developed for the single step synthesis of isocoumarin-fused dihydrochromenones. This highly atom economical method proceeds via 6-endo-dig cyclization of tert-butyl benzoate with a tethered alkyne. By modulating the reaction solvent and metal catalyst, the methodology was diverted for the purposeful synthesis of either of the E/Z tetra-substituted alkenes.

1 aRai, Archana1 aBajpai, Priyam1 aGamidi, Rama, Krishna1 aVanka, Kumar1 aDas, Utpal uhttps://library.ncl.res.in/content/palladiumii-catalyzed-desymmetrization-2-alkynylbenzoate-tethered-cyclohexadienones01560nas a2200253 4500008004100000022001400041245015100055210006900206260000900275300001400284490000700298520067500305100001800980700001700998700002801015700001901043700001901062700001601081700001801097700002401115700001701139700001801156856013201174 2025 eng d a1523-706000aUnified photoredox-catalyzed aerobic oxidative dynamic kinetic asymmetric transformation for C-N atropoisomers mediated by chiral organophosphites0 aUnified photoredoxcatalyzed aerobic oxidative dynamic kinetic as cAUG  a8171-81770 v273 a

The synthesis of anilides with a chiral C(=O)-N axis has relied on direct installation of the chiral C(sp2)-N(sp2) bond or enantioselective modification of the peripheral groups. However, these methods are constrained by the size and type of functional groups compatible with each strategy. Herein, we report a dynamic kinetic asymmetric transformation (DYKAT) for the aerobic oxidation of iminium ions to access C(=O)-N axial chirality that addresses those limitations. Furthermore, it eliminates the need for any auxiliary functional groups, which enables us to develop a unified method for the synthesis of atroposelective isoquinolone, lactam, and amide.

1 aSaikia, Pinku1 aAarthika, M.1 aBhattacharjya, Ayantika1 aMaity, Susmita1 aBajpai, Priyam1 aBera, Asish1 aSaha, Arindam1 aGonnade, Rajesh, G.1 aVanka, Kumar1 aMaity, Pradip uhttps://library.ncl.res.in/content/unified-photoredox-catalyzed-aerobic-oxidative-dynamic-kinetic-asymmetric-transformation-c-n