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   https://doi.org/10.1039/D4CP03716B  

   Scheiner, Steve (November 2024, Physical Chemistry Chemical Physics)

   All metals of the d-block are capable of forming σ and π-hole bonds to a nucleophile. Some of these bonds are typical of noncovalent bonds, but others are strong enough to be characterized as a covalent coordinate bond. 

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2. Dynamic Bonds: Adaptable Timescales for Responsive Materials

   https://doi.org/10.1002/anie.202206938  

   Wanasinghe, Shiwanka V.; Dodo, Obed J.; Konkolewicz, Dominik (November 2022, Angewandte Chemie International Edition)

   Abstract Dynamic bonds introduce unique properties such as self‐healing, recyclability, shape memory, and malleability to polymers. Significant efforts have been made to synthesize a variety of dynamic linkers, creating a diverse library of materials. In addition to the development of new dynamic chemistries, fine‐tuning of dynamic bonds has emerged as a technique to modulate dynamic properties. This Review highlights approaches for controlling the timescales of dynamic bonds in polymers. Particularly, eight dynamic bonds are considered, including urea/urethanes, boronic esters, Thiol–Michael exchange, Diels–Alder adducts, transesterification, imine bonds, coordination bonds, and hydrogen bonding. This Review emphasizes how structural modifications and external factors have been used as tools to tune the dynamic character of materials. Finally, this Review proposes strategies for tailoring the timescales of dynamic bonds in polymer materials through both kinetic effects and modulating bond thermodynamics. 

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3. Complexes of N -chloroquinuclidinium with chloride: strong halogen bonding via chlorine atoms

   https://doi.org/10.1039/d4ce01053a  

   Hardin, Maison; Zeller, Matthias; Rosokha, Sergiy V (December 2024, CrystEngComm)

   The first structures containing bonds between chlorines and tertiary nitrogen atoms and very strong halogen bondsviachlorine (with a substantial contribution of orbital interactions) are reported. 

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4. Chemoselective bond activation by unidirectional and asynchronous PCET using ketone photoredox catalysts

   https://doi.org/10.1039/d3sc04362b  

   Sun, Rui; Ruccolo, Serge; Nascimento, Daniel L; Qin, Yangzhong; Hibbert, Nathaniel; Nocera, Daniel G (December 2023, Chemical Science)

   The triplet excited states of ketones effect selective H-atom abstraction from amide N–H bonds in the presence of weaker C–H bondsviaa proton-coupled electron transfer (PCET) pathway in which the electron and proton transfers are asynchronous. 

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5. Theta‐curves in proteins

   https://doi.org/10.1002/pro.5133  

   Dabrowski‐Tumanski, Pawel; Goundaroulis, Dimos; Stasiak, Andrzej; Rawdon, Eric_J; Sulkowska, Joanna_I (August 2024, Protein Science)

   Abstract We study and characterize the topology of connectivity circuits observed in natively folded protein structures whose coordinates are deposited in the Protein Data Bank (PDB). Polypeptide chains of some proteins naturally fold into unique knotted configurations. Another kind of nontrivial topology of polypeptide chains is observed when, in addition to covalent bonds connecting consecutive amino acids in polypeptide chains, one also considers disulfide and ionic bonds between non‐consecutive amino acids. Bonds between non‐consecutive amino acids introduce bifurcation points into connectivity circuits defined by bonds between consecutive and nonconsecutive amino acids in analyzed proteins. Circuits with bifurcation points can form θ‐curves with various topologies. We catalog here the observed topologies of θ‐curves passing through bridges between consecutive and non‐consecutive amino acids in studied proteins. 

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