The strong, specific, and directional halogen bond (XB) is an ideal
in crystal engineering, as well as rational catalyst and drug design. These attributes attracted strong growing interest in halogen ...bonding in the past decade and led to a wide range of applications in materials, biological, and catalysis applications. Recently, various research groups exploited the XB mode of activation in designing halogen-based Lewis acids in effecting organic transformation, and there is continual growth in this promising area. In addition to the rapid advancements in methodology development, computational investigations are well suited for mechanistic understanding, rational XB catalyst design, and the study of intermediates that are unstable when observed experimentally. In this review, we highlight recent computational studies of XB organocatalytic reactions, which provide valuable insights into the XB mode of activation, competing reaction pathways, effects of solvent and counterions, and design of novel XB catalysts.
The reversibility of metal anode is a fundamental challenge to the lifetime of rechargeable batteries. Though being widely employed in aqueous energy storage systems, metallic zinc suffers from ...dendrite formation that severely hinders its applications. Here we report texturing Zn as an effective way to address the issue of zinc dendrite. An in‐plane oriented Zn texture with preferentially exposed (002) basal plane is demonstrated via a sulfonate anion‐induced electrodeposition, noting no solid report on (002) textured Zn till now. Anion‐induced reconstruction of zinc coordination is revealed to be responsible for the texture formation. Benchmarking against its (101) textured‐counterpart by the conventional sulphate‐based electrolyte, the Zn (002) texture enables highly reversible stripping/plating at a high current density of 10 mA cm−2, showing its dendrite‐free characteristics. The Zn (002) texture‐based aqueous zinc battery exhibits excellent cycling stability. The developed anion texturing approach provides a pathway towards exploring zinc chemistry and prospering aqueous rechargeable batteries.
An anion texturing approach is developed to achieve an (002) textured Zn with exposed in‐plane orientated basal planes, where the role of anion interaction is explored. Benchmarking against its conventional (101) textured counterpart, Zn (002) texture enables highly reversible dendrite‐free stripping/plating at a high current density of 10 mA cm−2.
Haspin, an atypical serine/threonine protein kinase, is a potential target for cancer therapy. 5-iodotubercidin (5-iTU), an adenosine derivative, has been identified as a potent Haspin inhibitor in ...vitro. In this paper, quantum chemical calculations and molecular dynamics (MD) simulations were employed to identify and quantitatively confirm the presence of halogen bonding (XB), specifically halogen∙∙∙π (aromatic) interaction between halogenated tubercidin ligands with Haspin. Consistent with previous theoretical finding, the site specificity of the XB binding over the
-carbon is identified in all cases. A systematic increase of the interaction energy down Group 17, based on both quantum chemical and MD results, supports the important role of halogen bonding in this series of inhibitors. The observed trend is consistent with the experimental observation of the trend of activity within the halogenated tubercidin ligands (F < Cl < Br < I). Furthermore, non-covalent interaction (NCI) plots show that cooperative non-covalent interactions, namely, hydrogen and halogen bonds, contribute to the binding of tubercidin ligands toward Haspin. The understanding of the role of halogen bonding interaction in the ligand-protein complexes may shed light on rational design of potent ligands in the future.
A new type of chiral β-amino acid catalyst has been computationally designed, mimicking the enzyme catalysis of serine proteases. Our catalyst approach is based on the bioinspired catalytic acid/base ...dyad, namely, a carboxyl and imidazole pair. DFT calculations predict that this designed organocatalyst catalyzes Michael additions of aldehydes to nitroalkenes with excellent enantioselectivities and remarkably high anti diastereoselectivities. The unusual stacked geometry of the enamine intermediate, hydrogen bonding network, and the adoption of an exo transition state are the keys to understand the stereoselectivity.
Protein tyrosine kinase 6 (PTK6), also known as breast tumor kinase (BRK), serves as a non-receptor intracellular tyrosine kinase within the Src kinases family. Structurally resembling other Src ...kinases, PTK6 possesses an Src homology 3 (SH3) domain, an Src homology 2 (SH2) domain, and a tyrosine kinase domain (SH1). While considerable efforts have been dedicated to designing PTK6 inhibitors targeting the SH1 domain, which is responsible for kinase activity in various pathways, it has been observed that solely inhibiting the SH1 domain does not effectively suppress PTK6 activity. Subsequent investigations have revealed the involvement of SH2 and SH3 domains in intramolecular and substrate binding interactions, which are crucial for PTK6 function. Consequently, the identification of PTK6 inhibitors targeting not only the SH1 domain but also the SH2 and SH3 domains becomes imperative. Through an in silico structural-based virtual screening approach, incorporating drug repurposing and a consensus docking approach, we have successfully identified four potential ligands capable of concurrently inhibiting the tyrosine kinase domain and SH2/SH3 domains of PT6K simultaneously. This finding suggests potential pathways for therapeutic interventions in PTK6 inhibition.
We present herein an unprecedented stereoselective synthesis of bridged biaryls with defined axial and central chirality from readily available starting materials. This N-heterocyclic ...carbene-catalyzed method proceeds through propargylic substitution of azolium enolates followed by two-directional cyclization, as supported by DFT calculation. A range of benzofuran/indole-derived bridged biaryls bearing an eight-membered lactone are accessed with uniformly high stereoselectivity (>98:2 dr, mostly >98% ee).
Using DFT calculations, we investigated the use of halogen bonding (XB) interactions to accelerate and control organic reactions, namely Diels–Alder reaction, Claisen rearrangement, and Cope-type ...hydroamination. Our designed triarylbenzene tripodal organocatalyst is characterized by three halogen bond donors, perfluoro-iodophenyl groups. The calculated transition states unravel multiple halogen bonds between the iodine atoms and various types of halogen bond acceptors (lone pair, π and σ bonds). These cooperative noncovalent interactions provide efficient binding between the catalyst and substrate (∼15 kcal/mol binding energy) and are the key factors for transition-state stabilization and molecular recognition. On the basis of our DFT calculations and calculated turnover frequencies, the XB-catalyzed reactions are found to be competitive with the corresponding hydrogen bonding catalysis reported in literature.
We report the generation of cationic N-radicals from Selectfluor® via energy transfer with anthraquinone as a photocatalyst for the fluorination of unactivated C-H bonds.
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•Novel unit-cell based algorithm for generating amorphous SiOC:H structures.•Algorithm automates atomic coordinates, valency, connectivity and cell periodicity.•Algorithm effectively ...removes dangling bonds, enhancing structure reliability.•Validates by comparing calculated mechanical properties with experimental dataset.
Atomistic modeling of amorphous SiOC:H structures is crucial for understanding structure–property relationship and designing of new low-k materials. While a cubic-grid algorithm was previously developed to automatically construct amorphous SiOC:H structures, it required pre-treatment of the cubic grid to meet atomic valency and connectivity criteria. Additionally, the resulting structures suffered from persistent dangling bonds. In this paper, we introduce a novel unit-cell algorithm of generating amorphous SiOC:H structures. It takes the numbers of different types of silicon atoms (Q, T, D, M, and V) and the dimension of the supercell as input parameters. The algorithm ensures automatic handling of atomic coordinates, valency, connectivity, and cell periodicity by modeling the structures on the α-quartz unit cell. Throughout the process, these features are maintained by restricting the types of allowable structural modifications. Amorphous characteristics are introduced by randomly distributing various types of silicon atoms in the supercell. Our algorithm produces structures with amorphous traits, as shown by radial distribution function plots. To validate the effectiveness of the approach, we compare calculated properties of structures generated by the new algorithm to an experimental dataset of SiOC:H films. The good agreement between the two suggests that the new unit-cell algorithm is capable of generating realistic low-k amorphous SiOC:H structures.
We present herein an unprecedented, efficient and enantioselective synthesis of triarylmethanes and 1,1‐diarylalkanes through N‐heterocyclic carbene‐catalyzed acylative desymmetrization of ...bisphenols. This method utilizes readily available substrates, reagents and a simple procedure to deliver the valuable products in excellent enantiopurity. DFT calculations reveal that the selectivity is governed by the C−C bond cleavage step of the tetrahedral intermediate leading to the ester product. A transition state model featuring a combination of intramolecular hydrogen bond and steric effect is developed to explain the enantioselectivity.
Three′s the charm: We present herein a general, efficient and enantioselective synthesis of triarylmethanes and 1,1‐diarylalkanes through N‐heterocyclic carbene‐catalyzed acylative desymmetrization of bisphenols. This method utilizes readily available substrates, reagents and a simple procedure to deliver the valuable products in excellent enantiopurity. DFT calculations provided a transition‐state model featuring a combination of intramolecular hydrogen bond and steric effect to explain the enantioselectivity.
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