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1. From Carbene-Dithiolene Zwitterion Mediated B–H Bond Activation to BH ₃ ·SMe ₂ -Assisted Boron–Boron Bond Formation

   https://doi.org/10.1021/acs.organomet.3c00361  

   Wang, Yuzhong; Tran, Phuong M.; Lahm, Mitchell E.; Wei, Pingrong; Adams, Earle R.; Schaefer, III, Henry F.; Robinson, Gregory H. (October 2023, Organometallics)
2. B ₄₈ ⁻ : a bilayer boron cluster

   https://doi.org/10.1039/D0NR09214B  

   Chen, Wei-Jia; Ma, Yuan-Yuan; Chen, Teng-Teng; Ao, Mei-Zhen; Yuan, Dao-Fu; Chen, Qiang; Tian, Xin-Xin; Mu, Yue-Wen; Li, Si-Dian; Wang, Lai-Sheng (February 2021, Nanoscale)

   null (Ed.)

   Size-selected negatively-charged boron clusters (B n − ) have been found to be planar or quasi-planar in a wide size range. Even though cage structures emerged as the global minimum at B 39 − , the global minimum of B 40 − was in fact planar. Only in the neutral form did the B 40 borospherene become the global minimum. How the structures of larger boron clusters evolve is of immense interest. Here we report the observation of a bilayer B 48 − cluster using photoelectron spectroscopy and first-principles calculations. The photoelectron spectra of B 48 − exhibit two well-resolved features at low binding energies, which are used as electronic signatures to compare with theoretical calculations. Global minimum searches and theoretical calculations indicate that both the B 48 − anion and the B 48 neutral possess a bilayer-type structure with D 2h symmetry. The simulated spectrum of the D 2h B 48 − agrees well with the experimental spectral features, confirming the bilayer global minimum structure. The bilayer B 48 −/0 clusters are found to be highly stable with strong interlayer covalent bonding, revealing a new structural type for size-selected boron clusters. The current study shows the structural diversity of boron nanoclusters and provides experimental evidence for the viability of bilayer borophenes. 

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3. Probing copper-boron interactions in the Cu ₂ B ₈ ⁻ bimetallic cluster

   https://doi.org/10.1116/6.0001833  

   Kulichenko, Maksim; Chen, Wei-Jia; Choi, Hyun Wook; Yuan, Dao-Fu; Boldyrev, Alexander I.; Wang, Lai-Sheng (July 2022, Journal of Vacuum Science & Technology A)

   Borophenes are atom-thin boron layers that can be grown on coinage metal substrates and have become an important class of synthetic 2D nanomaterials. The interactions between boron and substrates are critical to understand the growth mechanisms of borophenes. Here, we report an investigation of copper-boron interactions in the Cu 2 B 8 − bimetallic cluster using photoelectron spectroscopy and quantum chemical calculations. Well-resolved photoelectron spectra are obtained at several photon energies and are combined with theoretical calculations to elucidate the structures and bonding of Cu 2 B 8 − . Global minimum searches reveal that Cu 2 B 8 − consists of a Cu 2 dimer atop a B 8 molecular wheel with a long Cu–Cu bond length close to that in Cu 2 + . Chemical bonding analyses indicate that there is clear charge transfer from Cu 2 to B 8 , and the Cu 2 B 8 − cluster can be viewed as a [Cu 2 + ]-borozene complex, [Cu 2 + ][B 8 2– ]. In the neutral cluster, no Cu–Cu bond exists and Cu 2 B 8 consists of two Cu + centers interacting with doubly aromatic B 8 2− borozene. The charge transfer interactions between Cu and boron in the Cu 2 B 8 − cluster are analogous to charge transfer from the copper substrate to the first borophene layer recently reported to be critical in the growth of bilayer borophenes on a Cu(111) substrate. 

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4. B ₃₁ ⁻ and B ₃₂ ⁻ : chiral quasi-planar boron clusters

   https://doi.org/10.1039/C9NR01524H  

   Chen, Qiang; Chen, Teng-Teng; Li, Hai-Ru; Zhao, Xiao-Yun; Chen, Wei-Jia; Zhai, Hua-Jin; Li, Si-Dian; Wang, Lai-Sheng (May 2019, Nanoscale)

   Chirality plays an important role in nature. Nanoclusters can also exhibit chiral properties. We report herein a joint experimental and theoretical investigation on the geometric and electronic structures of B 31 − and B 32 − clusters, using photoelectron spectroscopy in combination with first-principles calculations. Two degenerate quasi-planar chiral C 1 enantiomers ( I and II , 1 A) with a central hexagonal vacancy are identified as the global minima of B 31 − . For B 32 − , two degenerate boat-like quasi-planar chiral C 2 structures ( VI and VII , 2 A) with a central hexagonal vacancy are also found as the global minima, with a low-lying chair-like C i B 32 − ( VIII , 2 A u ) also present in the experiment as a minor isomer. The chiral conversions in quasi-planar B 31 − and B 32 − clusters are investigated and relatively low barriers are found due to the high flexibility of these monolayer clusters, which feature multiple delocalized σ and π bonds over buckled molecular surfaces. 

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5. Probing Relaxation Dynamics and Stepped Domain Switching in Boron‐Alloyed VO ₂

   https://doi.org/10.1002/aelm.202100932  

   Bradicich, Adelaide; Clarke, Heidi; Braham, Erick_J; Yano, Aliya; Sellers, Diane; Banerjee, Sarbajit; Shamberger, Patrick_J (November 2021, Advanced Electronic Materials)

   Abstract The characteristic metal–insulator phase transition (MIT) in vanadium dioxide results in nonlinear electrical transport behavior, allowing VO₂devices to imitate the complex functions of neurological behavior. Chemical doping is an established method for varying the properties of the MIT, and interstitial dopant boron has been shown to generate a unique dynamic relaxation effect in individual B‐VO₂particles. This paper describes the first demonstration of an electrically stimulated B‐VO₂proto‐device which manifests a time‐dependent critical transformation temperature and switching voltage derived from the coupling of dopant diffusion dynamics and the metal–insulator transition of VO₂. During quasi‐steady current‐driven transitions, the electrical responses of B‐VO₂proto‐devices show a step‐by‐step progression through the phase transformation, evidencing domain transformations within individual particles. The dynamic relaxation effect is shown to increase the critical switching voltage by up to 41% (ΔV_crit =0.13 V) and also to increase the resistivity of the M1 phase of B‐VO₂by 14%, imbuing a memristive response derived from intrinsic material properties. These observations demonstrate the dynamic relaxation effect in B‐VO₂proto‐devices whose electrical transport responses can be adjusted by electronic phase transitions triggered by temperature but also by time as a result of intrinsic dynamics of interstitial dopants. 

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