Recent advances in the chemistry of 1,1’-bis(ortho-carborane)

Chemistry of 1,1'-bis(ortho-carborane) is rapidly developing during the last years when convenient method of itssynthesis was elaborated. Here we review the recent progress in this field with main imphasis on synthesis of 1,1'-bis(ortho-carborane) based transition metal complexes and heterocycles

Combining Two Types of Boron in One Molecule (To the 60th Anniversary of the First Synthesis of Carborane)

This review is an attempt to bring together the data from the literature on the synthesis and properties of icosahedral carborane derivatives, in which exo-polyhedral three- and four-coordinated boron substituents are attached directly to the carborane cage through boron–carbon or boron–boron bonds. Various classes of compounds are considered, including carboranyl aryl boranes, boronic acids and their derivatives, boroles, diazaboroles, etc. Particular attention is paid to carborane-fused heterocycles containing boron atoms

Ferrocene and Transition Metal Bis(Dicarbollides) as Platform for Design of Rotatory Molecular Switches

Design of rotatory molecular switches based on extremely stable sandwich organometallic complexes ferrocene and bis(dicarbollide) complexes of transition metals is reviewed. The “on”–“off” switching in these systems can be controlled by various external stimuli such as change of the solution pH, interactions with coordinating species or redox reactions involving the central atom or substituents in the ligands

Charge-Compensated Derivatives of Nido-Carborane

This review summarizes data on the main types of charge-compensated nido-carborane derivatives. Compared with organic analogs, onium derivatives of nido-carborane have increased stability due to the stabilizing electron-donor action of the boron cage. Charge-compensated derivatives are considered according to the type of heteroatom bonded to a boron atom

How the Position of Substitution Affects Intermolecular Bonding in Halogen Derivatives of Carboranes: Crystal Structures of 1,2,3- and 8,9,12-Triiodo- and 8,9,12-Tribromo <i>ortho</i>-Carboranes

The crystal structures of two isomeric triiodo derivatives of ortho-carborane containing substituents in the three most electron-withdrawing positions of the carborane cage, 1,2,3-I3-1,2-C2B10H9, and the three most electron-donating positions, 8,9,12-I3-1,2-C2B10H9, as well as the crystal structure of 8,9,12-Br3-1,2-C2B10H9, were determined by single-crystal X-ray diffraction. In the structure of 1,2,3-I3-1,2-C2B10H9, an iodine atom attached to the boron atom (position 3) donates its lone pairs simultaneously to the σ-holes of both iodine atoms attached to the carbon atoms (positions 1 and 2) with the I⋯I distance of 3.554(2) Å and the C-I⋯I and B-I⋯I angles of 169.2(2)° and 92.2(2)°, respectively. The structure is additionally stabilized by a few B-H⋯I-shortened contacts. In the structure of 8,9,12-I3-1,2-C2B10H9, the I⋯I contacts of type II are very weak (the I⋯I distance is 4.268(4) Å, the B8-I8⋯I12 and B12-I12⋯I8 angles are 130.2(3)° and 92.2(3)°) and can only be regarded as dihalogen bonds formally. In comparison with the latter, the structure of 8,9,12-Br3-1,2-C2B10H9 demonstrates both similarities and differences. No Br⋯Br contacts of type II are observed, while there are two Br⋯Br halogen bonds of type I

Charge-Compensated Derivatives of Nido-Carborane

This review summarizes data on the main types of charge-compensated nido-carborane derivatives. Compared with organic analogs, onium derivatives of nido-carborane have increased stability due to the stabilizing electron-donor action of the boron cage. Charge-compensated derivatives are considered according to the type of heteroatom bonded to a boron atom

How to Protect ortho-Carborane from Decapitation&mdash;Practical Synthesis of 3,6-Dihalogen Derivatives 3,6-X2-1,2-C2B10H10 (X = Cl, Br, I)

The 3-halogen and 3,6-dihalogen derivatives of ortho-carborane 3-X-1,2-C2B10H11 and 3,6-X2-1,2-C2B10H10 (X = Cl, Br, I) were prepared by Cu-assisted halodeboronation of the corresponding pinacolborate derivatives 3-Bpin-1,2-C2B10H11 and 3,6-(Bpin)2-1,2-C2B10H10. It was shown that decapitation of 3-Cl-1,2-C2B10H11, similarly to the corresponding bromo and iodo derivatives, proceeds regioselectively with the retention of the B-Cl bond. Crystal structures of 3,6-Cl2-1,2-C2B10H10 and Cs [3-Cl-7,8-C2B9H11] were determined by single crystal X-ray diffraction

Crystal Structure of 9-Dibenzylsulfide-7,8-dicarba-nido-undecaborane 9-Bn2S-7,8-C2B9H11

The crystal structure of 9-dibenzylsulfide-7,8-dicarba-nido-undecaborane 9-Bn2S-7,8-C2B9H11 was determined by a single-crystal X-ray diffraction. One of the benzyl groups is located above the open face of the carborane cage with a short H···H distance (2.29 and 2.71 Å for two symmetrically independent molecules) between the BHB-bridging hydrogen atom of the carborane fragment and the ortho-CH group of the aromatic ring. Topological analysis has revealed the existence of a critical bond point with a calculated energy of −0.8 kcal/mol in accordance with an X-ray diffraction molecular geometry. The crystal packing analysis revealed that this benzyl group is also involved in π-stacking interactions, while another benzyl group participates in numerous weak H···π, H···H and van der Waals interactions

The First Nickelacarborane with closo-nido Structure

The first nickelacarborane with closo-nido structure [10&prime;,11&prime;-(Py)2-3,9&prime;-Ni(1,2-C2B9H11)(7&prime;,8&prime;-C2B8H8)] was isolated from the reaction of nickel(IV) bis(dicarbollide) with pyridine. The molecular structure of this complex was determined by single crystal X-ray diffraction. The nickel atom is a common vertex for the closo-NiC2B9 cluster and the nido-NC2B8 cluster where it is located together with carbon atoms in the open NiC2B2 pentagonal face. It is assumed that its formation proceeds through the nucleophile-induced removal of the B(6)H vertex followed by rearrangement of the forming 11-vertex cluster, which most likely proceeds through a sequence of closing and opening reactions

How to Protect <i>ortho</i>-Carborane from Decapitation—Practical Synthesis of 3,6-Dihalogen Derivatives 3,6-X₂-1,2-C₂B₁₀H₁₀ (X = Cl, Br, I)

The 3-halogen and 3,6-dihalogen derivatives of ortho-carborane 3-X-1,2-C2B10H11 and 3,6-X2-1,2-C2B10H10 (X = Cl, Br, I) were prepared by Cu-assisted halodeboronation of the corresponding pinacolborate derivatives 3-Bpin-1,2-C2B10H11 and 3,6-(Bpin)2-1,2-C2B10H10. It was shown that decapitation of 3-Cl-1,2-C2B10H11, similarly to the corresponding bromo and iodo derivatives, proceeds regioselectively with the retention of the B-Cl bond. Crystal structures of 3,6-Cl2-1,2-C2B10H10 and Cs [3-Cl-7,8-C2B9H11] were determined by single crystal X-ray diffraction