The Cover Feature shows a watercolor painting of highly stable copper phosphonate frameworks. These frameworks are created by utilizing a tetrahedral-shaped organic building block called methane tetra-p-phenylphosphonic acid, along with different N-ancillary ligands. The main goal of this study is to optimize the binding modes of the ligands on the copper coordination sphere, resulting in the formation of novel secondary building units (SBUs) in metal organophosphonates. More information can be found in the Research Article by Y. Zorlu, G. Yücesan, and co-workers.

Li-S batteries (LSBs) are considered as the attractive candidates for next-generation high-energy system due to their high energy and low cost. However, their practical application is hindered by several stubborn issues, including the poor electric conductivity of sulfur cathodes, the shuttle of lithium polysulfides (LiPSs) and the slow dynamics during charge/discharge cycles. Transitional iron (Fe)-based compounds are regarded as effectively electrocatalysts for polysulfide conversion by accelerating the reaction kinetics and enhancing the electric conductivity electron/charge transfer. In this study, we investigate the typical transition Fe-based compounds (Fe3X, X = B, C, N) known for their high catalytic ability and analyze their roles as sulfur host for LSBs using density functional theory (DFT). Our finding reveal that Fe3C and Fe3B surfaces exhibit more Fe-S bonds compared to Fe3N surface, which explains the different electrochemical behaviors observed during battery testing with sulfur cathode. Additionally, Fe3N demonstrates greater structural stability and effective polysulfide adsorption according to DFT calculations, outperforming the other two compounds in these aspects. We believe that this theoretical investigation will guide the identification of highly efficient hosts for sulfur cathodes and open new avenues for sulfur host selection in LSBs.

BICAAC (bicyclic (alkyl)(amino)carbene) as ambiphilic carbene has been utilized to prepare stable neutral tetrahydrodiborane [BICAAC→(H2)B-B(H2)←BICAAC] and dihydrodiborene [BICAAC→(H)B=B(H)←BICAAC] compounds. The Lewis base stabilized dihydrodiborene is isoelectronic and isolobal to conventional olefins and therefore offers the possibility to explore the formation of π-complexes with transition metals. Reaction of the diborene with coinage metal salts (CuCl, AgBr and CuI) leads to the formation of π-diborene metal complexes via η2 side-on coordination. These are first examples of dihydrodiborene coinage metal complexes. Interestingly, coordination of two CuCl units to the diborene has been observed for the first time with a considerable lengthening of >B=B< and B-CBICAAC bonds manifesting the key role of the BICAAC combined with small steric requirements of hydride substituents in stabilizing these complexes. The energy decomposition analysis (EDA) calculations reveal the interaction between the diborene and Cu(I)/Ag(I) is mainly electrostatic in nature.