There are more chances for interfacial engineering when Janus particles with different properties and compositions are spread out on the surface of a single objector. Janus particles are a new type of interfacial active material that combines the amphiphilic properties of molecular surfactants with the Pickering effect of uniform particles. Find out more in the review article written by Fuxin Liang and co-workers.
Attempts to form a tethered-N-heterocyclic Carbene Aluminium hydride complex resulted in the unexpected formation of a bicyclic N-heterocyclic aminal Aluminium hydride.
Tethered N-heterocyclic carbenes (NHCs) are an emerging class of ligand, as they feature all the desirable aspects of NHCs (ease of synthesis, high tunabilty) but also enable metal-ligand cooperativity when combined with Lewis acidic metal centres due to the donor-acceptor nature of the complexes formed. Herein we report a simple ethoxy-tethered NHC for the stabilisation of Al(III) hydrides, resulting in the unexpected formation of a bicyclic N-heterocyclic aminal (1). Compound 1 behaves as a metal hydride, capable of reducing benzophenone and carbodiimide to yield compounds 2 and 3, respectively. Furthermore, we show that 1 behaves as an efficient catalyst in the dehydrocoupling of amine-boranes due to the hemi-labile nature of the supporting ligand.
A five-step approach was developed for the synthesis of a series of substituted indole-pyrido-indene pentacyclic compounds. Reaction proceeded via domino radical-mediated processes in the presence of the radical reagents LDA/TTMSS and AIBN/TTMSS.
A five-step approach, starting from simple 1,5-disubstituted indoles, has been implemented for the synthesis of diversely substituted indole-pyrido-indene pentacyclic compounds up to 54 % yield via domino radical-mediated processes in the presence of the radical reagents DLP/TTMSS and AIBN/TTMSS. Reactions proceeded with diverse key starting radical cyano-precursors strategically synthesized which were subsequently transformed into the target pentacyclic compounds through an aryl/iminyl radical-mediated domino reactions sequence. In addition to the routine spectroscopic techniques, the structure of radical precursors, as well as, the target pentacyclic products were unequivocally established by single crystal X-ray diffraction, confirming the effectiveness of the proposed synthetic sequence.
![HSA over BSA: Selective detection of Human Serum Albumin via a naphtho [2,1-b] furan-based system](https://onlinelibrary.wiley.com/cms/asset/5500421e-72d3-4c6b-b2b5-adb0cf25870c/asia202301055-toc-0001-m.png)
Development of a naphtho[2,1-b] furan probe for fluorescence-assisted micromolar detection of Human Serum Albumin (HSA). The probe displays exclusive selectivity towards HSA compared to its congeners from other mammalian/non-mammalian sources. Its unique behavior is analyzed using anisotropy and time-resolved studies. The practical application of the probe is demonstrated in HSA-spiked human urine samples.
Human serum albumin (HSA) is an important biomarker that can be used for the early diagnosis of many diseases. In this work, a TICT probe bearing fused naphtho-furan scaffold (NPNF) was developed and employed in the selective turn-on sensing of HSA. The probe's selectivity towards HSA was observed using steady-state fluorescence experiments, with limit of quantitation in micromolar levels. NPNF's capability to exclusively detect HSA over BSA was further studied/rationalized using anisotropy and time-resolved studies. Molecular docking was used to shed light on the location of NPNF in the subdomain IB of HSA. The practical application of the probe was also demonstrated by the detection of HSA in urine and the HSA-assisted detection of cerium.
Nickel complexes with rare pentagonal bipyramidal structures were synthesized via ligand-exchange reactions. The complexes were water- and acid-resistant. With the aid of theoretical calculations, the crystal structures showed that the pentagonal bipyramidal structures comprised electrostatic rings of cyclic pentapyridyls and threaded linear metal complexes.
The coordination chemistries of transition metal complexes with pentagonal bipyramidal geometries were investigated, and the highly stable nature of a cyclic pentapyridyl ligand was disclosed. A NiCl2 complex with the pentapyridyl ligand was found to be stable toward water and acidic conditions. The stable complex underwent ligand-exchange reactions with nucleophilic reagents, and a series of pentagonal bipyramidal complexes with different apical ligands was prepared. Crystallographic analyses with the aid of theoretical calculations revealed that the complexes were constructed by electrostatic threading of a divalent linear nickel complex into the ring of the neutral, cyclic pentapyridyl, which resulted in robust water- and acid-resistant complexes with unique pentagonal bipyramidal structures. A reductive metal exchange reaction was then discovered, which enabled “linear divalent metal + electrostatic ring” formulations with different metal atoms.
Selective oxime formation of 2-substituted indoles and malonates has been developed. Notwithstanding lack of ability to dissolve reactants, water exhibited superior performance to other media. 2-Methoxyethyl nitrite, which has been tailored for reactions in water, empowered this protocol. Chemoselective transformations of the products opens up access to a new chemical library. These results support the power of running organic reactions in water.
Water is not a good solvent for most organic compounds, yet water can offer many benefits to some organic reactions, hence enriching organic chemistry. Herein, the unique divergent reactivity of 2-substituted indoles with ⋅NO sources is presented. The amount of water solvent was harnessed for a scalable, benign, and expedient synthesis of indolenine oximes, albeit with water's inability to dissolve the reactants. 2-Methoxyethyl nitrite, which has been tailored for reactions in water, empowered this protocol by enhancing the product selectivity. We further report on chemoselective transformations of the products that rely on their structural features. Our findings are expected to offer access to an underexplored chemical space. The platform is also applicable to oximinomalonate synthesis. Mechanistic studies revealed the important role of water in the reversal of stability between oxime and nitroso compounds, promoting the proton transfer.
A rapid and practical synthesis of gem-dibromoalkanes has been developed. A variety of alkyl and aromatic aldehydes are converted into their corresponding gem-dibromoalkanes within 10 minutes by using tribromide reagent. The protocol is also appliable to the bromination of alcohols, accessing alkyl bromides with inversion of configuration.
gem-Dibromoalkanes are important synthetic building block in organic chemistry, but their preparation is still troublesome. Herein, we have developed a simple and practical protocol for the synthesis of gem-dibromoalkanes from aldehydes using tetrabutylammonium tribromide and triphenyl phosphite. A variety of alkyl and aromatic aldehydes can be transformed into the corresponding products within 10 minutes. This protocol is also applicable to alcohols, and the configuration of chiral alcohol is inverted during the process with excellent enantiopurity.
Time for new functional groups: A new ferrocenyl-functionalized bis(phosphinimino)methane ligand with redox-active properties was synthesized and introduced into tetrylene chemistry, leading to unprecedented coordination behaviour.
Herein, we report the synthesis of a novel ferrocenyl-functionalized bis(phosphinimino)methane ligand (CH2(PPh2NFc)2). Deprotonation of CH2(PPh2NFc)2 with KN(SiMe3)2 gave the dimeric species [K{CH(PPh2NFc)2}]2, which was further reacted with ECl2 (E=Ge, Sn) to yield the tetrylene compounds [{CH(PPh2NFc)2}ECl]. The ligand and the resulting tetrylenes were examined for their electrochemical properties with the aid of cyclic voltammetry. Furthermore, the reaction of the tetrylenes [{CH(PPh2NFc)2}ECl] with [AuC6F5(tht)] resulted in the bimetallic complexes [{(AuC6F5)CH(PPh2NFc)2}ECl] with an unusual Au coordination on the ligand backbone.
A domino double cyclization of N-benzyltryptyl-4-pentenamide has been developed for rapid assembly of a novel azepane-fused tetrahydro-β-carboline framework. With a serendipitous stereocontrolled alkylation, the total synthesis of (±)-20-epi-Kopsiyunnanine K have been successfully accomplished.
A one-pot route to a novel azepane-fused tetrahydro-β-carboline framework from tryptyl-4-pentenamide derivatives has been developed, featuring the Rh-catalyzed hydroformylation double cyclization. Subsequent alkylation in the tetracyclic system proceeded stereoselectively to form a quaternary carbon. The synthesis of (±)-20-epi-kopsiyunnanine K was accomplished through the strategy.
From Bigger to Smaller: Unraveling the influence of size and Pauli repulsion on halogen bond directionality. The potential energy landscape is shaped by anisotropic electron density through Pauli repulsion in larger halogens, whereas the influence of electrostatic forces on bond orientation becomes more pronounced in smaller halogens.
Halogen bonds are typically observed to have a linear arrangement with a 180° angle between the nucleophile and the halogen bond acceptor X−R. This linearity is commonly explained using the σ-hole model, although there have been alternative explanations involving exchange repulsion forces. We employ two-dimensional Distortion/Interaction and Energy Decomposition Analysis to examine the archetypal H3N⋯X2 halogen bond systems. Our results indicate that although halogen bonds are predominantly electrostatic, their directionality is largely due to decreased Pauli repulsion in linear configurations as opposed to angled ones in the I2 and Br2 systems. As we move to the smaller halogens, Cl2 and F2, the influence of Pauli repulsion diminishes, and the energy surface is shaped by orbital interactions and electrostatic forces. These results support the role of exchange repulsion forces in influencing the directionality of strong halogen bonds. Additionally, we demonstrate that the 2D Energy Decomposition Analysis is a useful tool for enhancing our understanding of the nature of potential energy surfaces in noncovalent interactions.