Themed collection Carboranes

Welcome to this issue of Dalton Transactions featuring the themed issue on Carboranes.

o-Carboryne is a very reactive intermediate and exists in two resonance forms that exhibit significantly different reactivity patterns, leading to the synthesis of a large class of functionalized o-carboranes.

The first ¹H, ¹³C, ³¹P and ¹¹B solid state MAS NMR studies of electron-deficient carborane-containing ruthenium and osmium complexes [Ru/Os(p-cym)(1,2-dicarba-closo-dodecaborane-1,2-dithiolate)] are reported.

Diaryl-substituted ortho-carboranes 1a and 1b, synthesized from the corresponding alkynes by decaborane coupling, inhibited HIF-1α accumulation without affecting HIF-1α mRNA expression under hypoxia.

Reduction of hydroxy-functionalised carbaboranyl carboxylic acids by organolithium reagents yields tertiary alcohols, while reaction of unsubstituted carbaboranyl carboxylic acids leads to cleavage of the exo-polyhedral C–C bond.

A C–C bond formation complex and a Cl⁻/Nu⁻ exchange complex have been obtained through nucleophilic addition by using different nucleophiles.

Carborane-derived inhibitors of prostate specific membrane antigen are reported. Compounds were prepared from C-hydroxy-carboranes and screened in vitro and in vivo.

Base-mediated linear coupling reactions of the agostic (CH₃⋯Rh) (π-allyl)rhodacarborane complexes afforded the structurally novel mononuclear species bearing an open (1-5-η⁵)-pentadienyl ligand at the metal vertex.

Geometric interconversions of metallacarboranes and the derivatives resulting from the redox reaction allow the NLO responses to be switched “ON” or “OFF”.

Active esters of cobalt bis(dicarbollide)(1−) carboxylic acids allow for incorporation of this ion into functional molecules by amidic bonds.

Reactions of lithio-o-carborane with isocyanates give carboranylamides in which the substituent and solvent effects influence the product distribution and yields.

Cobaltabisdicarbollide and its chloroderivatives lack the amphiphilic topology but behave as anionic surfactants in water electrolysis. The worst performing as electrolyte is pristine [3,3′-Co(C₂B₉H₁₁)₂]⁻, whilst the best is [B₁₂H₁₂]²⁻; their difference being the capacity to generate self-assembling ordering by B–H⋯H–C_c dihydrogen bonds.

High boron content gold nanoparticles exhibit complete dispersibility in water, opening the way for their use in medical applications.

A series of diastereomeric sulfonium derivatives of nido-carborane [9-R(Me)S-nido-7,8-C₂B₉H₁₁] were prepared for the first time by alkylation of 9-methylthio-nido-7,8-carborane [9-MeS-nido-7,8-C₂B₉H₁₁]⁻.

Some 1,3,2-dithiaphospholanes with P-organo substituents dimerise reversibly, except R = t-Bu, as shown by NMR, DFT calculations and X-ray analysis.

An efficient synthetic route to novel inorganic ring systems based on dianionic carboranylamidinates is reported.

14-Vertex germa-, stanna-, and plumba-carboranes have been prepared and structurally characterized via polyhedral expansion methodology, which represents the first examples of p-block metallacarboranes of the MC₂B₁₁ system.

Synthesis of carboranylaryl ketones by carbonylative cross-coupling reactions catalyzed by Pd@GOs.

A number of biscarborane precursors to linear metallacarborane-based molecular rods were prepared from 8-iodo-1,2-dicarba-closo-dodecaborane.

The electronic variation of the appended aryl group at the C1-position of o-carborane in the di-o-carborane substituted benzene compounds led to color tuning of aggregation-induced emission.

Bicapped hexagonal antiprismatic bimetallacarboranes with 1,8/13,2,x-Co₂C₂B₁₀ architectures have been characterised including cage C atom identification in crystallographic studies.

The lowest energy CpFeC₃B_n−4H_n−1 (n = 8 to 12) structures are found to have the maximum number of carbon atoms at degree 4 rather than degree 5 vertices and avoid adjacent carbon atoms, i.e., C–C edges. Hexagonal bipyramidal structures are found for CpFeC₃B₄H₇, isocloso structures are found for CpFeC₃B_n−4H_n−1 (n = 8, 9), and polyhedral structures with quadrilateral faces are found for CpFeC₃B_n−4H_n−1 (n = 10, 11).

A unique set of cationic polyhedral boron-based clusters is reported to exhibit remarkable structural non-rigidity with potential in bond activation.

The reaction of Cp*IrS₂C₂B₁₀H₁₀ (1) with 1-azido-3-nitrobenzene affords 2–6 with C–C and C–S bond formation via a radical mechanism.