Aromatic heterocycles are ubiquitous building blocks in bioactive natural products, pharmaceutical and agrochemical industries. Accordingly, the carborane-fused heterocycles would be potential candidates in drug discovery, nanomaterials, metallacarboranes, as well as photoluminescent materials. In recent years, the transition metal catalyzed B-H activation has been proved to be an effective protocol for selective functionalization of B-H bond of -carboranes, which has been further extended for the synthesis of polyhedral borane cluster-fused heterocycles via cascade B-H functionalization/annulation process. This article summarizes the recent progress in construction of polyhedral borane cluster-fused heterocycles via B-H activation.
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http://dx.doi.org/10.3390/molecules25020391 | DOI Listing |
J Am Chem Soc
October 2024
School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore.
Boranes with closed polyhedral structures feature peculiar bonding and structural characteristics, rendering them widely applicable in diverse research areas ranging from basic functionalization reactions to applications such as medicine, nanomaterials, molecular electronics, and neutron capture therapy. Among the closed borane family, the neutral and cationic heptaborane B clusters have been missing in contemporary boron cluster chemistry to date. Herein, we report a polyhedral expansion protocol to construct a neutral derivative of -heptaborane (B) from -hexaborane (B) mediated by borane.
View Article and Find Full Text PDFAcc Chem Res
October 2024
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
ConspectusUnlike carbon, boron does not usually form ring compounds due to its electron-deficiency-driven affinity toward polyhedral geometries. The polyhedral boranes having -, -, -, or -shapes can be structurally and electronically correlated using various electron counting rules developed by Wade, Mingos, and one of us. However, in the last few decades, boron chemistry progressed significantly toward ring systems.
View Article and Find Full Text PDFAcc Chem Res
August 2024
Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
ConspectusWith three valence electrons and four valence orbitals, boron (2s2p) is an electron-deficient element, resulting in interesting chemical bonding and structures in both borane molecules and bulk boron materials. The electron deficiency leads to electron sharing and delocalization in borane compounds and bulk boron allotropes, characterized by polyhedral cages, in particular, the ubiquitous B icosahedral cage. During the past two decades, the structures and bonding of size-selected boron clusters have been elucidated via combined photoelectron spectroscopy and theoretical investigations.
View Article and Find Full Text PDFChemistry
September 2024
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India.
The ubiquitous chemistry of benzene led us to explore ways to stabilise analogous borozene, by capping them with appropriate groups. The mismatch in overlap of ring-cap fragment molecular orbitals in [(HB)BH] is overcome by replacing the two BH caps with higher congeners of boron. We calculated the relative energies of all the polyhedral structural candidates for [(HE)BH] (E=Al-Tl) and found hexagonal bipyramid (HBP) to be more stable with Al-H caps.
View Article and Find Full Text PDFInorg Chem
July 2024
College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China.
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