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Based upon global-minimum searches and first-principles electronic structural calculations, we present the perfectly planar B6O50/−/2− (1–3) systems. Notably, the C2v B6O50/− (1–2) clusters mark a groundbreaking advancement as the first boron oxide clusters to feature a five-membered ring. Both structures exhibit remarkable similarity, each characterized by a central B3O2 ring surrounded by three terminal BO groups. However, a notable difference lies in the bond lengths within the B3O2 core, which are uniform in the former but uneven in the latter. Detailed canonical molecular orbital and AdNDP analyses reveal the delocalized π bonds over the B3O2 ring, affirming the π aromaticity of B6O5−. The Cs B6O52− (3) cluster showcases a chain-like arrangement with three terminal BO groups and a typical OBO group linked to a B2 core, emphasizing the crucial role of electrons in shaping the structure. Detailed chemical bonding analyses reveal the presence of dual three-center four-electron (3c–4e) π hyperbonds in 3, shedding further light on its unique bonding characteristics. Moreover, this study comprehensively extends the B(BO)n0/− (n = 1–5) series and provides valuable perspectives on their structural evolution. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Binary polyantimony clusters, namely [Cu2Sb14]4– and [Ag2Sb14]4–, containing coinage metals, were successfully synthesized and characterized, in which two homoatomic Sb73– subunits are bridged by two coinage metals in η4:η1 and η1:η1 coordination modes, respectively. In [Cu2Sb14]4–, two bridging Cu ions and two Sb atoms form a planar rhombic unit, which was revealed to have antiaromatic properties by theoretical calculations. Further electron structure and bonding analysis confirmed the presence of delocalized bonds in the rhombic unit and the metallophilic interaction between two formal M+ ions. [ABSTRACT FROM AUTHOR]

The discovery of cyclic boron oxide clusters has prompted investigations into their distinctive structures and bonding characteristics. Notably, the majority of reported cyclic boron oxide structures consist predominantly of four to six-membered rings. In this study, we employ theoretical methods to predict the global-minimum (GM) structure of B6O62+. Our analyses, including global-minimum searches and calculations using B3LYP, PBE, PBE0, and single-point CCSD(T), reveal that the D2h B6O62+ (1Ag) configuration represents a planar and tricyclic structure, resulting from the fusion of B3O2/B4O2/B3O2 units. Remarkably, this structure establishes the B6O62+ cluster as the smallest boron oxide cluster with a planar tricyclic motif. Further bonding analysis indicates that B6O62+ is a weakly antiaromatic system with 12π delocalized electrons. The reported B6O6 has a planar structure with a 6-membered B3O3 ring and 6 π electrons distributed over the ring. Because of the absence of two electrons from the highest occupied molecular orbital (HOMO) of neutral B6O6, the structure of B6O62+ is distinctly different from that of B6O6. [ABSTRACT FROM AUTHOR]

The modification with alkaline‐earth metals to the energy unfavorable triple‐ring B36 result in a family of stable triple‐ring tubular MB36 (M = Mg, Ca, Sr, Ba). The triple‐ring structures are highly energy favorable than the structures on the basis of the global‐minimum of B36 which is experimentally known as planar structure with dual aromaticity. Basic chemical bonding analysis reveals the σ and dual π aromaticity of these triple‐ring tubes, which refer to threefold aromaticity and result in the chemical stability. Large energy gap and high formation energy support their stability. Highly negative NICS values sustain the same conclusion. This findings hint the possibility of experimental synthesis of triple‐ring tube by importing metals. [ABSTRACT FROM AUTHOR]

A variety of researches on boron oxide clusters have indicated the key role of boronyl (BO) group in the structures and bonding. Based upon global structural searches and electronic structure calculations at the B3LYP and single-point coupled cluster single double (triple) (CCSD(T)) levels, we present the possibility of construction of lithium-doped boron oxide B8O2Li+/0 clusters (1-2). Different from the structures of pure B6+/0/− and B6(BO)20/−, the B8O2Li+/0 which can be formulated as B6(BO)2Li+/0 are not the double-chain structures, they are the crown-like structure, and the Li is like a diamond that links the crown. Detailed AdNDP analyses indicate the π aromaticity of B8O2Li+ (1). The results obtained in this work reveal that the metal could influence the structures and properties of boron oxides significantly. [ABSTRACT FROM AUTHOR]

Both B and Al have high oxygen affinity and their oxidation processes are highly exothermic, hinting at intriguing physical chemistry in ternary Al–B–O clusters. We report a combined photoelectron spectroscopy and density-functional study on the structural, electronic, and bonding properties of AlnBO2− and AlnBO2 (n = 2, 3) clusters. Ground-state vertical detachment energies (VDEs) are measured to be 2.83 and 2.24 eV for Al2BO2− and Al3BO2−, respectively. A weak isomer is also observed for Al3BO2− with a VDE of 1.31 eV. Coalescence-kick global searches allow the identification of candidate structures, confirmed via comparisons with experiment. The Al2BO2− anion is V-shaped in geometry, Cs (1A′), with an Al center connecting to OB and OAl terminals. It can be viewed alternatively as the fusion of BOAl and AlOAl by sharing an Al atom. Al3BO2− has a Cs (2A′′) global minimum in which an Al2 dimer interacts with bridging boronyl (BO) and an OAl unit, as well as a low-lying C2v (2B2) isomer consisting of boronyl and OAl that are doubly bridged by two Al atoms. The BO2 block (linear O=B=O chain) is nonexistent in any of the anion and neutral species. Chemical bonding in these Al–B–O clusters is elucidated via canonical molecular orbitals and adaptive natural density partitioning. The cluster structures are also rationalized using the concept of sequential and competitive oxidation of B versus Al centers in AlnB. The first O atom prefers to oxidize B and form BO, whereas the second O atom has options to interact with a fresh Al/Aln/AlnB unit or a BO group. The former route wins thermodynamically, leading to the observed geometries. [ABSTRACT FROM AUTHOR]

Based on extensive global searches and first-principles theory calculations, we present herein the possibility of double-ring tubular (B2O2)n clusters (n = 6–42) (2–10) rolled up from the most stable one-dimensional (1D) BO double-chain ribbon (1) in boron monoxides. Tubular (3D) (B2O2)n clusters (n≥ 6) are found to be systematically much more stable than their previously proposed planar (2D) counterparts, with a 2D–3D structural transition at B12O12 (2). Detailed bonding analyses on 3D (B2O2)n clusters (2–10) and their precursor 1D BO double-chain ribbon (1) reveal two delocalized B–O–B 3c-2e π bonds over each edge-sharing B4O2 hexagonal unit which form a unique 6c-4e o-bond to help stabilize the systems. The IR, Raman, UV-vis, and photoelectron spectra of the concerned species are computationally simulated to facilitate their experimental characterization. [ABSTRACT FROM AUTHOR]

Based on extensive first-principles theory calculations, we present the possibility of an endohedral charge-transfer complex, Cs Ca@B37− (I), which contains a 3D aromatic fullerene-like Cs B373− (II) trianion composed of interwoven boron double chains with twelve delocalized multicenter π bonds (12 mc–2e π, m = 5, 6) over a σ skeleton, completing the Bnq borospherene family (q = n− 40) in the size range of n = 36–42. [ABSTRACT FROM AUTHOR]