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Recent advances in luminescent materials highlight the significant impact of hydrogen isotope effects on improving optoelectronic properties. However, the research on the influence of the boron isotope effects on photophysical properties remains underdeveloped. This study focused on exploring the boron isotope effects in boron‐cluster‐based luminogens. In doing so, we designed and synthesized carborane‐based luminogens containing 98 % 10B and 95 % 11B, respectively, and observed distinct photophysical behaviors. Compared to the 10B‐enriched luminogens, the 11B‐enriched counterparts can significantly enhance luminescence efficiency, prolong emission lifetime, and reduce full‐width at half‐maximum. Additionally, increased thermal stability, redshifted B−H vibrations, and a fourfold enhanced electrochemiluminescence intensity have also been observed. On the other hand, the biological assessments of a 10B‐enriched luminogen reveals low cytotoxicity, high boron uptake, and excellent fluorescence imaging capability, indicating the potential application in boron neutron capture therapy (BNCT). This work presents the first comprehensive exploration on the boron isotope effects in boron clusters, and provides valuable insights into the rational design of organic luminogens for advanced optoelectronic and biomedical applications. [ABSTRACT FROM AUTHOR]

In this study, we investigated a novel anti-cancer drug design approach by revisiting diclofenac-based carborane-substituted prodrugs. The redesigned compounds combine the robust carborane scaffold with the oxindole framework, resulting in four carborane-derivatized oxindoles and a unique zwitterionic amidine featuring a nido-cluster. We tested the anti-cancer potential of these prodrugs against murine colon adenocarcinoma (MC38), human colorectal carcinoma (HCT116), and human colorectal adenocarcinoma (HT29). The tests showed that diclofenac and the carborane-substituted oxindoles exhibited no cytotoxicity, the dichlorophenyl-substituted oxindole had moderate anti-cancer activity, while with the amidine this effect was strongly potentiated with activity mapping within low micromolar range. Compound 3 abolished the viability of selected colon cancer cell line MC38 preferentially through strong inhibition of cell division and moderate apoptosis accompanied by ROS/RNS depletion. Our findings suggest that carborane-based prodrugs could be a promising direction for new anti-cancer therapies. Inhibition assays for COX-1 and COX-2 revealed that while diclofenac had strong COX inhibition, the re-engineered carborane compounds demonstrated a varied range of anti-cancer effects, probably owing to both, COX inhibition and COX-independent pathways. [ABSTRACT FROM AUTHOR]

A dearomative addition of readily available carboranyllithium reagents to isoquinolinium salts gave a series of carborane cage C‐substituted 1,2‐dihydroisoquinolines in 43–85 % yields. Subsequent hydrogenation enabled the facile synthesis of corresponding carboranyl 1,2,3,4‐tetrahydroisoquinolines in 65–95 % yields. The addition‐reduction pathway is applicable to a wide range of substituted isoquinolinium salts and o‐carborane or m‐carborane. [ABSTRACT FROM AUTHOR]

Carboranes are an interesting class of aromatic molecules with icosahedral geometry, high stability, and unique electronic effects. We herein report a Pd-catalysed coupling reaction of carborane thiols with aryl halides. This protocol was applicable to the controlled synthesis of di(carboranyl) sulfides, and their catalytic performance for aromatic halogenation was examined. [ABSTRACT FROM AUTHOR]

Icosahedral boron clusters-based BODIPY dyes represent a cutting-edge class of compounds that merge the unique properties of boron clusters with the exceptional fluorescence characteristics of BODIPY dyes. These kinds of molecules have garnered substantial interest due to their potential applications across various fields, mainly including optoelectronics, bioimaging, and potential use as boron carriers for Boron Neutron Capture Therapy (BNCT). Carborane clusters are known for their exceptional stability, rigid geometry, and 3D-aromaticity, while BODIPY dyes are renowned for their strong absorption, high fluorescence quantum yields, and photostability. The integration of carborane into BODIPY structures leverages the stability and versatility of carboranes while enhancing the photophysical properties of BODIPY-based fluorophores. This review explores the synthesis and structural diversity of boron clusters-based BODIPY dyes, highlighting how carborane incorporation can lead to significant changes in the electronic and optical properties of the dyes. We discuss the enhanced photophysical characteristics, such as red-shifted absorption and emission poperties, charge and electronic transfer effects, and improved cellular uptake, resulting from carborane substitution. The review also delves into the diverse applications of these compounds. In bioimaging, carborane-BODIPY dyes offer superior fluorescence properties and cellular internalization, making them ideal for cell tracking. In photodynamic therapy, (PDT) these dyes can act as potent photosensitizers capable of generating reactive oxygen species (ROS) for targeted cancer treatment making them excellent candidates for PDT. Additionally, their unique electronic properties make them suitable candidates for optoelectronic applications, including organic light-emitting diodes (OLEDs) and sensors. Overall, carborane-BODIPY dyes represent a versatile and promising class of materials with significant potential for innovation in scientific and technological applications. This review aims to provide a comprehensive overview of the current state of research on carborane-BODIPY dyes, highlighting their synthesis, properties, and broad application spectrum. [ABSTRACT FROM AUTHOR]

In this work, we present our improved protocols for the single batch syntheses of approximately 32 g of [NHMe3][CB11H12] and 10 g of Na[CHB11F11] as well as salt metathesis reactions, granting access to useful starting materials to introduce the [CHB11F11]− anion. This includes the trityl cation [Ph3C]+ and the bis‐1,2‐difluorobenzene‐silver(I)‐complex [Ag(odfb)2]+, as well as some applications of the shown compounds. The described methodology allows the synthesis of large amounts of both the [CB11H12]− and the [CHB11F11]− anion and therefore making them accessible for further reactions. To facilitate the reproducibility, we present video tutorials of the synthetic steps towards Na[CHB11F11]. [ABSTRACT FROM AUTHOR]

Carborane compounds, known for their exceptional thermal stability and non‐toxic attributes, have garnered widespread utility in medicine, supramolecular design, coordination/organometallic chemistry, and others. Although there is considerable interest among chemists, the integration of suitable carborane molecules into ferroelectric materials remains a formidable challenge. In this study, we employ the quasi‐spherical design strategy to introduce functional groups at the boron vertices of the o‐carborane cage, aiming to reduce molecular symmetry. This approach led to the successful synthesis of the pioneering ferroelectric crystals composed of cage‐like carboranes: 9‐OH‐o‐carborane (1) and 9‐SH‐o‐carborane (2), which undergo above‐room ferroelectric phase transitions (Tc) at approximately 367 K and 347 K. Interestingly, 1 and 2 represent uniaxial and multiaxial ferroelectrics respectively, with 2 exhibiting six polar axes and as many as twelve equivalent polarization directions. As the pioneering instance of carborane ferroelectric crystals, this study introduces a novel structural archetype for molecular ferroelectrics, thereby providing fresh insights into the exploration of molecular ferroelectric crystals with promising applications. [ABSTRACT FROM AUTHOR]

Magnitude, similar to concepts like volume, cardinality or Euler characteristic, has become a key focus in combinatorics and topology. Recent advancements in topological data analysis and persistent homology have emphasized its importance. Persistent magnitude, a newly highlighted invariant introduced by Govc and Hepworth, has emerged as a notable subject of interest. In this work, we apply persistent magnitude to analyze and predict the stability of closo-carborane structures. First, we assess the stability of carboranes by employing cross-validation with different magnitude features. The Pearson correlation coefficients for stability predictions using three distinct magnitude features are 0.900, 0.882 and 0.883, respectively. These results are comparable to the Pearson correlation coefficient of 0.881 obtained when using a single feature based on persistent homology. Second, the utilization of magnitude features to predict the HOMO, LUMO and HOMO–LUMO gaps of carboranes involves conducting eight gradient boosting regressions for each scenario. The lowest correlation coefficients observed are 0.9056, 0.9385 and 0.9427, respectively. These findings highlight the promising performance of persistent magnitude features in the analysis of material structure and stability. Magnitude, similar to concepts like volume, cardinality, or Euler characteristic, can be understood as the topological volume of a graph. We apply the persistent magnitude as the topological features to analyze the structure of closo-carborane. Test data show that the persistent magnitude is very effective in predicting the stability and energy of the closo-carborane. [ABSTRACT FROM AUTHOR]

Using the experimentally known aromatic icosahedral superatoms Ih B12H122− and D5d 1,12-C2B10H12 as building blocks and based on extensive density functional theory calculations, we predict herein a series of core–shell superpolyhedral boranes and carboranes in a bottom-up approach, including the high-symmetry Th B12@B152H722− (2), C2h C2B10@B152H72 (3), D3d B12@B144H66 (4), Ih B12@C24B120H722− (6), and D5d C2B10@C24B120H72 (7). More interestingly, the superatom-assembled linear D2h B36H322− (8), close-packed planar D3dB84H602− (10), and nearly close-packed core–shell D3d B12@B144H66 (4) can be extended periodically to form the one-dimensional (1D) α-rhombohedral borane nanowire B12H10 (Pmmm) (9), two-dimensional (2D) α-rhombohedral monolayer borophane B12H6 (P 3 ¯ m 1 ) (11), and the experimentally known three-dimensional (3D) α-rhombohedral boron (R 3 ¯ m ) (12) which can be viewed as an assembly of the monolayer B12H6 (11) staggered in vertical direction, setting up a bottom-up strategy to form low-dimensional boron-based nanomaterials from their borane "seeds" via partial or complete dehydrogenations. Detailed bonding analyses indicate that the high stability of these nanostructures originates from the spherical aromaticity of their icosahedral B12 or C2B10 structural units which possess the universal skeleton electronic configuration of 1S21P61D101F8 following the Wade's n+1 rule. The infrared (IR) and Raman spectra of the most-concerned neutral B12@B144H66 (4) and C2B10@C24B120H72 (7) are computationally simulated to facilitate their experimental characterizations. [ABSTRACT FROM AUTHOR]

Mixed Sn-Pb perovskites have emerged as promising photovoltaic materials for both single- and multi-junction solar cells. However, achieving their scale-up and practical application requires further enhancement in stability. We identify that their poor thermal conductivity results in insufficient thermal transfer, leading to heat accumulation within the absorber layer that accelerates thermal degradation. A thermal regulation strategy by incorporating carboranes into perovskites is developed; these are electron-delocalized carbon-boron molecules known for their efficient heat transfer capability. We specifically select ortho-carborane due to its low thermal hysteresis. We observe its existence through the perovskite layer showing a decreasing trend from the buried interface to the top surface, effectively transferring heat and lowering the surface temperature by around 5 °C under illumination. o-CB also facilitates hole extraction at the perovskite/PEDOT:PSS interface and reduces charge recombination. These enable mixed Sn-Pb cells to exhibit improved thermal stability, retaining 80% of their initial efficiencies after aging at 85 °C for 1080 hours. When integrated into monolithic all-perovskite tandems, we achieve efficiencies of over 27%. A tandem cell maintains 87% of its initial PCE after 704 h of continuous operation under illumination. Mixed Sn-Pb perovskites have emerged as promising photovoltaic materials for both single- and multi-junction solar cells. Here, authors reveal the thermal degradation mechanism and incorporate carboranes for thermal regulation, resulting in stable all-perovskite tandems with efficiency of over 27%. [ABSTRACT FROM AUTHOR]

A carboranylporphyrin of A3B-type bearing a single pentafluorophenyl ring was prepared through the regioselective nucleophilic aromatic substitution reaction of the p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with 9-mercapto-m-carborane. The reaction of this porphyrin with sodium azide led to the selective substitution of the p-fluorine atom in the pentafluorophenyl substituent with an azide functionality which upon reduction with SnCl2 resulted in the formation of the corresponding porphyrin with an amino group. Pentafluorophenyl-substituted A3B-porphyrins were studied and transformed to thiol and amino-substituted compounds allowing for the preparation of porphyrins with different reactive groups such as hydroxy and amino derivatives capable for further functionalization and conjugation of these porphyrins to other substrates. In addition, conjugates containing maleimide or biotin entities in the structure of carborane A3B-porphyrin were also synthesized based on the amino-substituted A3B-porphyrin. The structures of the prepared carboranylporphyrins were determined by UV–vis, IR, 1H, 19F, 11B NMR spectroscopic data and MALDI mass spectrometry.

Herein, we report the unique multiple‐stimuli responsiveness of anthracene‐tethered o‐carborane derivatives. We designed and synthesized anthracene derivatives with different substitution positions and numbers of the o‐carborane units. Two compounds had characteristic crystal structures involving the columnar π‐stacking structures of the anthracene units. From the analysis of crystalline‐state structure–property relationships, it was revealed that the crystals exhibited the photosalient effect accompanied by photochemical [4+4] cycloaddition reactions and temperature‐dependent photophysical dual‐emission properties including excimer emission of anthracene. Those properties were considered as non‐radiative and radiative deactivation pathways through the excimer formation in the excited state and the formation of excimer species was facilitated by the π‐stacking structure of anthracene units. Moreover, we found unusual temperature dependency on the occurrence of the photosalient effect. According to the data from variable temperature X‐ray crystallography, a strong correlation between lattice shrinkage and strain accumulation is suggested. [ABSTRACT FROM AUTHOR]

The effect of substituents of various natures at boron atoms in different positions of the carborane cage on the CH-acidity of carborane derivatives and the electron-withdrawing effect of C-carboranyl groups is considered using 1H NMR spectroscopy data. [ABSTRACT FROM AUTHOR]

Several ortho‐carboranes bearing a phenoxy or a phenylamino group in the B9 position were prepared employing various protection and deprotection strategies. Following established protocols, dendritic compounds were synthesized from a hexachlorocyclotriphosphazene or thiophosphoryl chloride core, and possible anchoring options for the B9‐substituted ortho‐carboranes were investigated experimentally and theoretically (DFT). Furthermore, 1‐ or 1,2‐phosphanyl‐substituted carborane derivatives were obtained. The resulting diethyl‐, diisopropyl‐, di‐tert‐butyl‐, diphenyl‐ or diethoxyphosphines bearing a tunable ortho‐carborane moiety are intriguing ligands for future applications in homogeneous catalysis or the medicinal sector. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: This work describes a general method for the synthesis of a series of sulfenylated and selenylated carboranes at room temperature using readily available iodocarboranes as starting materials via boron‐centered carboranyl radicals. Such hypervalent boron radicals are generated by a visible‐light‐promoted Pd(0)/Pd(I) pathway. They are useful intermediates and can be trapped by disulfides and phenylselenyl chloride for the convenient construction of B—S/Se bonds. [ABSTRACT FROM AUTHOR]

A highly efficient Pd-catalyzed B(9)–H/B(9)–H oxidative dehydrogenation coupling of carboranes to synthesize 9,9′-bis-o-carboranes has been developed. The properties and derivatization of 9,9′-bis-o-carborane were also examined, which provided diverse bis-o-carborane derivatives and bis-nido-carborane. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: This work describes a general method for the synthesis of a series of sulfenylated and selenylated carboranes at room temperature using readily available iodocarboranes as starting materials via boron‐centered carboranyl radicals. Such hypervalent boron radicals are generated by a visible‐light‐promoted Pd(0)/Pd(I) pathway. They are useful intermediates and can be trapped by disulfides and phenylselenyl chloride for the convenient construction of B—S/Se bonds. [ABSTRACT FROM AUTHOR]

Derivatives of the nido‐7,8‐C2B9H12(1‐) (dicarbollide ion) and [3,3′‐Co‐(1,2‐C2B9H11)2](1‐) cobalt sandwich (COSAN) ion represent groups of extremely chemically and thermally stable abiotic compounds. They are being investigated in many research areas, that is, medicinal chemistry, material sciences, analytical chemistry, and electrochemistry. The chirality of these compounds remains still grossly overlooked, what is also reflected in limited number of reports on their chiral separations. Continued progress depends on reliable, fast, and cost‐effective methods for such separations. Recently, chiral separations of COSAN derivatives were achieved in liquid chromatography and supercritical fluid chromatography. Only five anionic derivatives of nido‐7,8‐C2B9H12(1‐) were successfully enantioseparated in liquid chromatography. Efforts to separate anionic nido‐7,8‐C2B9H12(1‐) in supercritical chromatography have failed, and only a few dicarbollide ions were separated using liquid chromatography. Generally, all chiral separations in liquid chromatography took about 30 min. Herein, we identify a versatile column capable of separating both COSAN and nido‐7,8‐C2B9H12(1‐) derivatives and achieve faster analyses times employing commercially available superficially porous chiral stationary phases. The semisynthetic hydroxypropyl β‐cyclodextrin‐based column (CDShell‐RSP) is identified as the column of choice from the tested columns by separating 19 of 27 compounds from each structural motifs tested mainly in less than 10 min. The dihydroxyalkyl, oxygen‐bridged hydroxyalkyl, and bisphenylene‐bridged COSAN derivatives were baseline separated in less than 5 min exceeding the results of supercritical fluid chromatography. Methods developed herein will aid synthetic chemists without the possession of a supercritical fluid chromatograph to achieve fast chiral separations of COSAN and derivatives of nido‐7,8‐C2B9H12(1‐) on a common liquid chromatograph without the need of dedicated instrumentation. [ABSTRACT FROM AUTHOR]

Vinylidene and its heavier analogues are fundamentally important in synthetic chemistry, but their stabilization and structural characterization remains extremely challenging. Herein we describe that the reduction of an NHSi-stabilized stannyl-stannylene (2) with one molar equivalent of [(MesNacnac)Mg]2 affords an NHSi-stabilized distannavinylidene (3). Single-crystal X-ray crystallography and density functional theory (DFT) calculations show that compound 3 features a pronounced Sn=Sn double bond and one lone pair of electrons at the two-coordinate Sn atom. Most strikingly, 3 undergoes an interconversion with distannyne (4) upon the addition and removal of one molar equivalent of N-heterocyclic carbene. Compound 3 readily reacts with Ph2C=C=O, AdC≡P and (AlCp*)4 to give the structurally interesting stannacycles (5, 6) and an aluminyl distannyne (7), demonstrating its unique reactivity derived from the high substituent lability. [ABSTRACT FROM AUTHOR]

Due to their limited capacity for π‐backdonation, isolation of π‐complexes of main‐group elements remains a great challenge. We report herein the synthesis of a homoleptic diphosphene lead complex (2) from the degradation of P4 with a bis(germylene)‐stabilized Pb(0) complex. Structural and computational studies showed that 2 possesses significant π bonding interactions between Pb atom and diphosphene ligands, which is reminiscent of transition‐metal diphosphene complexes. Consistent with its unique electronic structure, complex 2 can deliver Pb(0) atoms to perform redox reaction with an iminoquinone to produce a cyclic plumbylene (4) and perform 2,5‐dimethyl‐3,4‐dimethylimidazol‐1‐ylidene (IMe2Me2) induced phosphorus cation abstraction to give an anionic PbP3 complex (6). [ABSTRACT FROM AUTHOR]

Multi‐metallic multivariate (MTV) rare earth (RE) metal−organic frameworks (MOFs) are of interest for the development of multifunctional materials, however examples with more than three RE cations are rare and obstructed by compositional segregation during synthesis. Herein, this work demonstrates the synthesis of a multi‐metallic MTV RE MOF incorporating two, four, six, or eight different RE ions with different sizes and in nearly equimolar amounts and no compositional segregation. The MOFs are formed by a combination of RE cations (La, Ce, Eu, Gd, Tb, Dy, Y, and Yb) and a 1,7‐di(4‐carboxyphenyl)‐1,7‐dicarba‐closo‐dodecaborane (mCB‐L) linker. The steric bulkiness and acidity of mCB‐L is crucial for the incorporation of different size RE ions into the MOF structure. Demonstration of the incorporation of all RE cations is performed via compositional and structural characterization. The more complex MTV MOF, including all eight RE ions (mCB‐8RE), are also characterized using optical, thermal, and magnetic techniques. Element‐selective X‐ray absorption spectroscopy and X‐ray Magnetic Circular Dichroism measurements allow us to characterize spectroscopically each of the eight RE ions and determine their magnetic moments. This work paves the way for the investigation of MTV MOFs with the possibility to combine RE ions à la carte for diverse applications. [ABSTRACT FROM AUTHOR]

The synthesis of monocarborane sulfonamides is reported. The methodology relies on coupling of the anionic {CB11} boron cluster to sulfonyl azides. Under rhodium catalysis and with the assistance of a pyridine or pyrimidine directing group at the C1 position, the cluster undergoes B−H activation. Conditions have been identified that lead to B2‐selective mono‐sulfonamidation with concomitant loss of N2. The protocol requires no additional ligand, oxidant or base and enables B−N bond formation with various monocarborane and sulfonyl azide inputs. The new products possess the structure [1‐(heteroaryl)‐2‐(NHSO2Ar)−CB11H10]− and have been fully characterized by NMR spectroscopy and mass spectrometry. In addition, three solid state structures confirm the particular B2 substitution pattern. Furthermore, the stoichiometric reaction of the pyridinyl monocarborane precursor with Rh(III) affords a cyclometalated complex with a direct B−Rh bond that has also been characterized by X‐ray crystallography. [ABSTRACT FROM AUTHOR]

Simple Summary: Boron neutron capture therapy (BNCT) is an emerging anticancer treatment. The success of BNCT relies on the delivery of adequate quantities of 10B to tumor cells. Carboranes, polyhedral clusters containing boron, carbon and hydrogen atoms, are promising candidates as boron agents in BNCT. In this review, we provide an overview and state-of-the-art description of applications of carboranes for in vivo BNCT studies. We comprehensively report: (i) the different molecules used, (ii) their formulation and administration strategies, (iii) the tumor models investigated and (iv) qualitative and quantitative methodologies for carborane detection in in vivo experiments. Carboranes have emerged as one of the most promising boron agents in boron neutron capture therapy (BNCT). In this context, in vivo studies are particularly relevant, since they provide qualitative and quantitative information about the biodistribution of these molecules, which is of the utmost importance to determine the efficacy of BNCT, defining their localization and (bio)accumulation, as well as their pharmacokinetics and pharmacodynamics. First, we gathered a detailed list of the carboranes used for in vivo studies, considering the synthesis of carborane derivatives or the use of delivery system such as liposomes, micelles and nanoparticles. Then, the formulation employed and the cancer model used in each of these studies were identified. Finally, we examined the analytical aspects concerning carborane detection, identifying the main methodologies applied in the literature for ex vivo and in vivo analysis. The present work aims to identify the current strengths and weakness of the use of carboranes in BNCT, establishing the bottlenecks and the best strategies for future applications. [ABSTRACT FROM AUTHOR]

This study reports unique luminescent properties of pyrene‐substituted nido‐carborate anion (PYnCA) with two counter cations, tetrabutylammonium (NBu4+) and tetraphenylphosphonium (PPh4+). It is revealed that PYnCA shows twisted intramolecular charge transfer (TICT) emission by the change of the dihedral angle between pyrene and the CcageCcage bond in the carborane unit in the excited state. Although the structure of nCA is almost same as that of ortho‐carborane (oC), the photophysical processes of both pyrene‐substituted compounds are completely different. The study also succeeds in modulating the luminescence species by counter cations in both solution and solid states. To the best of the current knowledge, this is the first report that anion‐based luminescent materials can show the different luminescent species not only in solution but also in the mechanochromic behaviors depending on the type of counter cations. This fundamental research on nCA demonstrates anion‐based emitters as a new platform for stimuli‐responsive materials. [ABSTRACT FROM AUTHOR]

Here, we present composites and materials that can be prepared starting with boron hydride cluster compounds (decaborane, decahydro-closo-decaborate and dodecahydro-closo-dodecaborate anions and carboranes). Recent examples of their utilization as boron protective coatings including using them to synthesize boron carbide, boron nitride, metal borides, metal-containing composites, and neutron shielding materials are discussed. The data are generalized demonstrate the versatile application of materials based on boron cluster anions and carboranes in various fields. [ABSTRACT FROM AUTHOR]

The structure, stability, and intermolecular rearrangements between ortho-, meta-, and para-C2B10H12, and B12H2−12 were investigated using the hybrid density functional B3LYP/6-31G(d) for vibrational frequencies, as well as B3LYP/6-311+G(2d,p) for single-point electronic energies. The general trends in free energies of rearrangement between ortho-C2B10H12 to meta-C2B10H12 and meta-C2B10H12 to para-C2B10H12 presented here are consistent with experimental reaction temperatures. In addition, the majority of the rearrangements can be viewed in terms of concerted diamond–square–diamond steps and triangular-face-rotations. [ABSTRACT FROM AUTHOR]

We report the heterogenization of molecular, electrochemically switchable ortho-substituted carboranes (POCb, POCb-Pyr) for selective metal capture. Films of POCb and POCb-Pyr on glassy carbon and carbon fiber (CF) electrodes demonstrated heterogeneous electrochemical behaviour that was enhanced by the inclusion of single-walled carbon nanotubes (CNTs). Galvanostatically charged CF‖CNT‖POCb and CF‖CNT‖POCb-Pyr electrodes selectively captured and released actinides (Th4+, UO22+) from mixed solutions containing alkali (Cs+), lanthanide (Nd3+, Sm3+) and actinide (Th4+, UO22+) metal ions. [ABSTRACT FROM AUTHOR]

Luminochromic behaviors regarding mechanochromic luminescence (MCL) of o‐carborane‐modified anthracene derivatives are reported. We have previously synthesized bis‐o‐carborane‐substituted anthracene and found that its crystal polymorphs show dual‐emission properties composed of excimer and charge transfer (CT) emission bands in the solid state. Initially, we observed the bathochromic MCL behavior from 1 a originating from emission mechanism alteration from dual emission to CT emission. By inserting the ethynylene spacers between anthracene and o‐carboranes, compound 2 was obtained. Interestingly, 2 showed hypsochromic MCL originating from the emission mechanism alteration from CT to excimer emission. Furthermore, luminescent color of ground 1 a can be recovered to the initial state by allowing to stand at room temperature, meaning that self‐recovery proceeds. Detailed analyses are described in this study. [ABSTRACT FROM AUTHOR]

Visible‐light‐induced photoreaction of carboranes is an effective approach to prepare carborane‐containing compounds. While several methods involving boron‐centered carboranyl radicals have been established, those for carbon‐centered carboranyl radicals are underdeveloped, except for the UV‐light‐promoted photohomolysis. Herein, we describe a simple but effective approach to access carbon‐centered carboranyl radicals by photoreduction of carborane phosphonium salts under blue light irradiation without using transition metals and photocatalysts. The utility of the method was demonstrated by successfully preparing a range of carborane‐oxindole‐pharmaceutical hybrids by radical cascade reactions. Computational and experimental studies suggest that the carbon‐centered carboranyl radicals are generated by single‐electron transfer of the photoactive charge‐transfer complexes between the salts and the additive potassium acetate. [ABSTRACT FROM AUTHOR]

The presence of a large number of boron atoms in boron clusters make them attractive tools for the treatment of cancer using boron neutron capture therapy (BNCT). Since the quantity of boron atoms present in the target cell directly affects the effectiveness of BNCT, the idea of gathering a high number of boron atoms in a single entity has emerged many years ago. In this perspective, using hyper-branched macromolecules such as dendrimers appears as an interesting solution. In this review, we will first present the synthesis of diverse dendritic entities (dendrimers, dendrons, and Janus dendrimers) that incorporate boron clusters, in particular carboranes, anywhere in their structure. Four parts of this review present the synthesis of dendrimers having boron clusters on the surface, or inside their structure, of dendrons and of Janus dendrimers, bearing boron clusters. Practically all these boronated dendritic structures were synthesized with the objective to study their biological properties, but in fact only a few of them have been tested against cancerous cells, and even a smaller number was tested in BNCT experiments. The biological experiments are discussed in the fifth part of this review. A good efficiency is generally observed with the boronated dendrimers, even in animal models, with an increase in their mean survival time (MST). [ABSTRACT FROM AUTHOR]

Reaction of B(4)‐acylmethyl o‐carborane with 2‐azido‐1,3‐dimethylimidazolinium hexafluorophosphate (ADMP) in the presence of 1,8‐diazabicyclo[5.4.0]‐undec‐7‐ene (DBU) in acetonitrile at 25 °C for 3 h produced a wide range of o‐carboranyl‐acyl‐substituted diazo compounds in high yields with good functional group tolerance. [ABSTRACT FROM AUTHOR]

A simple synthetic way to obtain a decachloro derivative of cobalt bis(dicarbollide) has been found. The reaction of cesium salt of cobalt bis(dicarbollide) anion with aluminum chloride in chloroform under reflux conditions results in Cs[3,3′-Co(4,7,8,9,12-Cl5-1,2-C2B9H6)2] of high purity and good yield.

Reexamination of the co‐pyrolysis reactions of B2Cl4 with C2Cl4 at 350 °C and of B2Br4 with CBr4 at 300 °C in vacuo confirmed the carboranes C2B5Cl7 (1), C2B7Cl9 (2), and C2B5Br7 (3) as low‐yield products. While 1 only could be concentrated by repeated vacuum fractionation, 2 and 3 could now be isolated from the conglomerate mixtures for a full spectroscopic characterization and the compounds were verified in their geometries by detailed DFT computations. Surprisingly, the perhalogenated carboranes do not adopt the expected "all‐endo"‐geometries with cluster sizes derived by the sum of the n boron and two carbon atoms (n+2) as known from the syntheses of the parent closo‐carboranes C2BnHn+2. Instead, DFT/GIAO(ZORA)/NMR (GIAO for X=Cl, ZORA for X=Br) computations revealed that the perhalogenated carboranes favor structures with BX2 groups as exo‐skeletal ligands attached to both cage‐carbon atoms yielding the five‐vertex closo‐1,5‐(CBX2)2B3X3 (1: X=Cl; 3: X=Br) and the seven‐vertex closo‐2,4‐(CBCl2)2B5Cl5 for 2. In contrast to these perhalogenated carboranes, analogous computations on the hydrogen substituted carboranes C2BnHn+2, silaboranes Si2BnHn+2 and Si2BnXn+2 (n=5, 7) show in all cases a thermodynamic favorization of structures where all boron atoms of the formula are endo‐skeletally incorporated into the cluster frameworks. [ABSTRACT FROM AUTHOR]

Targeting inflammatory mediators and related signaling pathways may offer a rational strategy for the treatment of cancer. The incorporation of metabolically stable, sterically demanding, and hydrophobic carboranes in dual cycloxygenase-2 (COX-2)/5-lipoxygenase (5-LO) inhibitors that are key enzymes in the biosynthesis of eicosanoids is a promising approach. The di-tert-butylphenol derivatives R-830, S-2474, KME-4, and E-5110 represent potent dual COX-2/5-LO inhibitors. The incorporation of p-carborane and further substitution of the p-position resulted in four carborane-based di-tert-butylphenol analogs that showed no or weak COX inhibition but high 5-LO inhibitory activities in vitro. Cell viability studies on five human cancer cell lines revealed that the p-carborane analogs R-830-Cb, S-2474-Cb, KME-4-Cb, and E-5110-Cb exhibited lower anticancer activity compared to the related di-tert-butylphenols. Interestingly, R-830-Cb did not affect the viability of primary cells and suppressed HCT116 cell proliferation more potently than its carbon-based R-830 counterpart. Considering all the advantages of boron cluster incorporation for enhancement of drug biostability, selectivity, and availability of drugs, R-830-Cb can be tested in further mechanistic and in vivo studies. [ABSTRACT FROM AUTHOR]

Traditionally, drugs were obtained by extraction from medicinal plants, but more recently also by organic synthesis. Today, medicinal chemistry continues to focus on organic compounds and the majority of commercially available drugs are organic molecules, which can incorporate nitrogen, oxygen, and halogens, as well as carbon and hydrogen. Aromatic organic compounds that play important roles in biochemistry find numerous applications ranging from drug delivery to nanotechnology or biomarkers. We achieved a major accomplishment by demonstrating experimentally/theoretically that boranes, carboranes, as well as metallabis(dicarbollides), exhibit global 3D aromaticity. Based on the stability–aromaticity relationship, as well as on the progress made in the synthesis of derivatized clusters, we have opened up new applications of boron icosahedral clusters as key components in the field of novel healthcare materials. In this brief review, we present the results obtained at the Laboratory of Inorganic Materials and Catalysis (LMI) of the Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) with icosahedral boron clusters. These 3D geometric shape clusters, the semi-metallic nature of boron and the presence of exo-cluster hydrogen atoms that can interact with biomolecules through non-covalent hydrogen and dihydrogen bonds, play a key role in endowing these compounds with unique properties in largely unexplored (bio)materials. [ABSTRACT FROM AUTHOR]

Thanks to the tremendous progress in data, computing power and algorithms, AI-based material mining and design have gained much attention. However, building high-performance AI models requires efficient material structure representation. In this work, we propose a structural characterization method based on the neighborhood path complex for the first time. Specifically, we use persistent neighborhood path homology to obtain the structural features by introducing a filtration. This approach preserves more elemental information, as well as the corresponding physicochemical information, through the directed edges of the neighborhood digraph. To validate our model, we perform cross-validation with the carborane structures. The Pearson coefficient for stability prediction is as high as 0.903, which is a 15.5% improvement compared to the traditional persistent homology method. In addition, we constructed a prediction model based on the neighborhood path complex, and the Pearson coefficients for the prediction of carboranes' HOMO, LUMO, and HOMO–LUMO gaps were 0.915, 0.946, and 0.941, respectively. The results show that our proposed method can effectively extract structural information and achieve accurate material property prediction. We propose a structural characterization method based on the neighborhood path complex. Using this approach, elemental information, as well as the corresponding physicochemical information, would be better preserved. Testing results show that the method can effectively extract structural information and achieve accurate material property prediction. [ABSTRACT FROM AUTHOR]

Electrochemical properties of transition metal complexes are important parameters that should be considered for the successful application of these compounds in catalytic reactions. The proper choice of ligands and the type of its coordination allow the construction of a catalyst with high performance. The reversibility of complex oxidation is a prerequisite for successful participation in redox catalysis, while the potential values correlate with the rate of the process and necessary catalyst loading. This work summarizes the results of the exploration of a series of ruthenium carborane complexes based on the nido-C2B9 ligand obtained in our group by cyclic voltammetry and describes the found correlations. The knowledge of the electrochemical properties of the studied ruthenacarboranes is required for the optimization of its structure for successful catalysis of Atom Transfer Radical Polymerization or other applications. It was found that the value of the potential of reversible Ru(II)-Ru(III) transition may vary from −0.501 to 0.389 V versus Fc|Fc+ couple, depending on the nature of auxiliary phosphine, halogen or nitrile ligand, natural bite angle of κ2-diphosphine ligand and the presence of alkyl substituents in the carborane cage. The further oxidation towards formal Ru(IV) may be reversible or not depending on the complex structure. The found trends are in good agreement with the earlier performed findings in the field of coordination chemistry and should be considered as a tool for obtaining of complexes suitable for catalytic applications. [ABSTRACT FROM AUTHOR]

The results of synthesis and study of magnetically-active iron(II) complexes with polynitrogen heterocyclic ligands and outer-sphere boron cluster anions have been considered. Derivatives of 1,2,4-triazole, tris(pyrazol-1-yl)methane, and 2,6-bis(imidazol-2-yl)pyridine have been used as ligands, decahydro-closo-decaborate, dodecahydro-closo-dodecaborate, decachloro-closo-decaborate, and 1,5,6,10-tetra(R)-7,8-dicarba-nido-undecaborates (R = H, Cl, Br) have been studied as outer-sphere anions. A number of iron(II) complexes showing spin crossover accompanied by thermochromism in the majority of cases has been obtained. Effect of ligand nature and cluster anion on temperature (Tc) and spin transition character has been considered. In particular, it has been shown that introduction of substituent increasing electron density over the system of conjugated three-centered two-electron bonds in cluster anion leads to increase in the field strength of ligand bound to anion via network of hydrogen bonds. [ABSTRACT FROM AUTHOR]

Synthesis methods, properties, and application fields of various boron-containing coumarin derivatives are summarized. Particular attention is paid to derivatives with various polyhedral boron clusters as substituents, such as carboranes, metallacarboranes, and the closo-dodecaborate anion. Derivatives of coumarin with simple organoboron compounds, boronic acids and their esters, are also considered. [ABSTRACT FROM AUTHOR]

Direct insertion of unsaturated substrates into a five‐membered borole ring is a useful method to obtain valuable heterocycles containing one or more three‐coordinate boron atoms. A highly Lewis acidic 9‐o‐carboranyl‐9‐borafluorene, in which the o‐carboranyl substituent is connected via one of the cluster carbon atoms to the boron atom of the 9‐borafluorene unit, was found to react with a vast array of unsaturated molecules, such as alkynes, aldehydes and various organic azides, to form larger boraheterocyclic products. The ring expansion reactions of the central borole ring proceed rapidly at room temperature, cementing the role of the o‐carboranyl substituent in enhancing the insertion reactivity of 9‐borafluorenes. [ABSTRACT FROM AUTHOR]

TDDFT scan calculations were performed for s-carborane-anthracene derivatives (o-CB-X-Ant where X=-H, -CH3, -C2H5 and tert-butyl or -tBu) in order to understand the interplay between the steric effects, S1 potential energy surface (PES) and photophysical properties. The results show that all systems exhibit three local minima on the S1 PES, which correspond to the emissive LE and TICT state, along with the nonemissive CT state respectively. In the case of the unsubstituted system (o-CB-H-Ant), and -CH3 and -C2H5 substituted cases, S1 PES is predicted to be quite flat for certain conformations indicating that it is possible for these systems to reach the nonemissive CT state without a large energy penalty. In comparison, conformational pathways for the nonemissive CT state are predicted to be energetically unfavorable for o-CB-tBu-Ant as a result of both steric and electronic effects. These results provide a mechanism for the enhanced emission of s-CB-fluorophore molecules with bulky ligands. [ABSTRACT FROM AUTHOR]

Off-cycle processes in catalytic reactions can dramatically influence the outcome of the chemical transformation and affect its yield, selectivity, rate, and product distribution. While the generation of off-cycle intermediates can complicate reaction coordinate analyses or hamper catalytic efficiency, the generation of such species may also open new routes to unique chemical products. Recently, we reported the Pd-mediated functionalization of carboranes with a range of O-, N-, and C-based nucleophiles. By utilizing a Pd-based catalytic system supported by a biaryl phosphine ligand developed by Buchwald and co-workers, we discovered an off-cycle isomerization process ("cage-walking") that generates four regioisomeric products from a single halogenated boron cluster isomer. Here we describe how several off-cycle processes affect the regioisomer yield and distribution during Pd-catalyzed tandem cage-walking/cross-coupling. In particular, tuning the transmetallation step in the catalytic cycle allowed us to incorporate the cage-walking process into Pd-catalyzed cross-coupling of sterically unencumbered substrates, including cyanide. This work demonstrates the feasibility of using tandem cage-walking/cross-coupling as a unique low-temperature method for producing regioisomers of mono-substituted carboranes.

Modern computational protocols based on the density functional theory (DFT) infer that polyhedral closo ten-vertex carboranes are key starting stationary states in obtaining ten-vertex cationic carboranes. The rearrangement of the bicapped square polyhedra into decaborane-like shapes with open hexagons in boat conformations is caused by attacks of N-heterocyclic carbenes (NHCs) on the closo motifs. Single-point computations on the stationary points found during computational examinations of the reaction pathways have clearly shown that taking the "experimental" NHCs into account requires the use of dispersion correction. Further examination has revealed that for the purposes of the description of reaction pathways in their entirety, i.e., together with all transition states and intermediates, a simplified model of NHCs is sufficient. Many of such transition states resemble in their shapes those that dictate Z-rearrangement among various isomers of closo ten-vertex carboranes. Computational results are in very good agreement with the experimental findings obtained earlier. [ABSTRACT FROM AUTHOR]

Specific features of reactions of complex 5,6,10-{Cl(Ph3P)2Ru}-[5,6,10-(μ-H)3-10-H-exo-nido-7,8-C2B9H8] (1) with 1,2-bis(diphenylphosphino)benzene (dppbz) and bis(diphenylphosphino)methane (dppm) in acetonitrile in the presence of amines were studied. Novel closo-ruthenacarborane complexes containing the metal in a formal oxidation state of +2 were isolated. It was established that the reaction of 1 with dppbz affords a complex containing a coordinated acetonitrile molecule, whereas the reaction with dppm results in a tris(phosphine) complex with strongly sterically shielded ruthenium center. Reactions of the newly obtained compounds with carbon tetrachloride or hydrogen chloride give corresponding 17-electron complexes containing the metal atom in a formal oxidation state of +3. The reversibility of the RuII → RuIII redox transition in the compounds synthesized was investigated by cyclic voltammetry and the influence of the ligand environment on the values of the corresponding redox potentials was assessed. [ABSTRACT FROM AUTHOR]

The syntheses of the first B9‐connected carboranylphosphines (B9‐Phos) featuring two carboranyl moieties as well as access to B9‐Phos ligands with bulky electron‐donating substituents, previously deemed unattainable, is reported. The electrochemical properties of the B9‐Phos ligands were investigated, revealing the ability of the mesityl derivatives to form stabilized phosphoniumyl radical cations. The B9‐Phos ligands display an extremely electron‐releasing character surpassing that of alkyl phosphines and commonly used N‐heterocyclic carbenes. This is demonstrated by their very small Tolman electronic parameters (TEPs) as well as extremely low P−Se coupling constants. Cone angles and buried volumes attest to the high steric demand exerted by the (di)carboranyl phosphines. The dicarboranyl phosphine AuI complexes show superior catalytic performance in the hydroamination of alkynes compared to the monocarboranyl phosphine analogs. [ABSTRACT FROM AUTHOR]

A simple synthetic way to obtain a decachloro derivative of cobalt bis(dicarbollide) has been found. The reaction of cesium salt of cobalt bis(dicarbollide) anion with aluminum chloride in chloroform under reflux conditions results in Cs[3,3′-Co(4,7,8,9,12-Cl5-1,2-C2B9H6)2] of high purity and good yield. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cyclic array of spherical aromatic units. • Each spherical aromatic states retain parent properties. • Interplay between resulting shielding cones. • A central anti-aromatic cyclic bridge. • NMR features for plausible experimental realization. Envisaging cluster-based materials requires a fundamental understanding of the aggregation processes and resulting properties. The inherent spherical aromatic properties of carboranes trigger further evaluation of the persistence of such property in the resulting cluster aggregate. Here, we evaluated the formation of a trimeric species based on the neutral [ o -C 2 B 10 H 12 ] cluster on the [ o -C 2 B 10 H 10 ] 3 form. The obtained results show that the inherent spherical aromatic characteristics of the constituent building units remain in the resulting trimer aggregate as three spherical aromatic states. Thus, cluster-based materials can be envisaged from stable spherical aromatic units, guiding further experimental realization of cluster-based aggregates. [ABSTRACT FROM AUTHOR]

Electrochemical systems offer a versatile means for creating adaptive devices. However, the utility of electrochemical deposition is inherently limited by the properties of the electrolyte. The development of ionic liquids enables electrodeposition in high-vacuum environments and presents opportunities for creating electrochemically adaptive and regenerative spacecraft components. In this work, we developed a silver-rich, boron cluster ionic liquid (BCIL) for reversible electrodeposition of silver films. This air and moisture stable electrolyte was used to deposit metallic films in an electrochemical cell to tune the emissivity of the cell in situ, demonstrating a proof-of-concept design for spacecraft thermal control.

Closo‐carborane anions are prominent, whereas the cations of the same are less abundant in the literature. As these ions have similar size and are weakly coordinating, the ionic liquids of these two ions could have important applications in many areas of chemistry. In view of limited number of polyhedral carborane cations available, we revisited the rearrangement of dicarboranyl methyl cation (7‐CH2 7,9‐nido‐C2B9H10+) using ab initio molecular dynamics calculations with metadynamics. Our simulations confirmed the concerted mechanism of the rearrangement. We believe this work will resume the interest in its synthesis and carborane cations in general. [ABSTRACT FROM AUTHOR]