Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Catalysis & Excited state. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Pd Nanoparticles Decorated on Hypercrosslinked Microporous Polymer: A Highly Efficient Catalyst for the Formylation of Amines through Carbon Dioxide Fixation

Abstract: CO2 fixation reaction is one of the most challenging chemical transformations not only in the context of environmental remediation but also for effective utilization of abundant carbon sources in nature. Here, we have stabilized palladium nanoparticles (NPs) at the surfaces of a hypercrosslinked porous polymer bearing carbazole and α,α′-dibromo-p-xylene monomeric units to obtain a Pd@HMP-1 nanocatalyst. The material has been thoroughly characterized by powder XRD, high-resolution (HR)-TEM, field-emission (FE)-SEM, Brunauer–Emmett–Teller (BET), thermogravimetric (TGA), and FTIR analysis. Pd@HMP-1 showed excellent catalytic activity towards formylation of amines by carbon dioxide fixation under mild reaction conditions. The high surface area and nitrogen-rich porous surface make the polymer a suitable support for the palladium nanoparticles and endow it with high recycling efficiency in this CO2 fixation reaction.

A companion perturbation theory for state-specific multireference coupled cluster methods

Abstract: A partitioning scheme is applied to the state-specific Mukherjee multireference coupled cluster method to derive a companion perturbation theory (Mk-MRPT2). A production-level implementation of Mk-MRPT2 is reported. The effectiveness of the Mk-MRPT2 method is demonstrated by application to the classic F2 dissociation problem and the lowest-lying electronic states of meta-benzyne, including computations with up to 766 atomic orbitals. We show that Mk-MRPT2 theory is particularly useful in multireference focal point extrapolations to determine ab initio limits.

Cell penetrating thiazole peptides inhibit c-MYC expression via site-specific targeting of c-MYC G-quadruplex

Abstract: The structural differences among different G-quadruplexes provide an opportunity for site-specific targeting of a particular G-quadruplex structure. However, majority of G-quadruplex ligands described thus far show little selectivity among different G-quadruplexes. In this work, we delineate the design and synthesis of a crescent-shaped thiazole peptide that preferentially stabilizes c-MYC quadruplex over other promoter G-quadruplexes and inhibits c-MYC oncogene expression. Biophysical analysis such as Forster resonance energy transfer (FRET) melting and fluorescence spectroscopy show that the thiazole peptide TH3 can selectively interact with the c-MYC G-quadruplex over other investigated G-quadruplexes and duplex DNA. NMR spectroscopy reveals that peptide TH3 binds to the terminal G-quartets and capping regions present in the 5'- and 3'-ends of c-MYC G-quadruplex with a 2:1 stoichiometry; whereas structurally related distamycin A is reported to interact with quadruplex structures via groove binding and end stacking modes with 4:1 stoichiometry. Importantly, qRT-PCR, western blot and dual luciferase reporter assay show that TH3 downregulates c-MYC expression by stabilizing the c-MYC G-quadruplex in cancer cells. Moreover, TH3 localizes within the nucleus of cancer cells and exhibits antiproliferative activities by inducing S phase cell cycle arrest and apoptosis.

Synthesis of Well-Defined Amphiphilic Poly(ε-caprolactone)-b-poly(N-vinylpyrrolidone) Block Copolymers via the Combination of ROP and Xanthate-Mediated RAFT Polymerization

Abstract: Well-defined amphiphilic poly(e-caprolactone)-b-poly(N-vinylpyrrolidone) (PCL-b-PNVP) block copolymers were successfully prepared via the combination of ring-opening polymerization (ROP) and xanthate-mediated reversible addition−fragmentation chain transfer (RAFT) polymerization. Well-defined poly(e-caprolactone) (PCL−OH) was synthesized by ROP in bulk at 110 °C using benzyl alcohol as initiator and stannous octate [Sn(Oct)2] as catalyst . The −OH end group was then converted into its corresponding xanthate (PCL−X) via the conversion to its corresponding bromide (PCL−Br). These are verified by 1H NMR spectroscopy. PCL-b-PNVP block copolymers were synthesized via RAFT polymerization in tetrahydrofuran (THF) at 80 °C using PCL−X as macro-chain transfer agent and characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). The amphiphilic diblock copolymer PCL63-b-PNVP90 forms spherical micelles of ∼34 nm diameter in water as shown by transmission electron microscopy (TEM), supported by 1H N...