Stepwise B–H bond activation of a meta-carborane

Abstract

Stepwise, multiple B-H bond activation is a major challenge in synthetic chemistry. Herein, we have developed a time-controlled method to monitor the process of B-H bond activation based on a...

Octanuclear Palladacycles with B(3)–H Bond Activation of o‐Carborane†

“…The average length of B—Pd bonds is 203.4 pm, which is comparable to previous reported 204.4 pm. [ 17 ] However, the C=S "double" bond length increases from 162.6 pm on the free ligand [ 14 ] to 175.7 pm on complex 1 , which can be considered as an increasing single bond character and hence suggests a strong influence from the side bonded palladium atom. The (S=)C—Pd bonds have a length of 206.9 pm and the (C=)S—Pd bonds are 226.3 pm, which are close to the sum of elements' covalent radii and can be compared to previous work, [ 13,17 ] thus it can be speculated that the bonding between central side‐on coordinated palladium atoms and methyldithiocarboxyl group is more close to "cyclopropane" motif with Pd—C and Pd—S single bonds than a common π‐complex motif.…”

“…[ 17 ] However, the C=S "double" bond length increases from 162.6 pm on the free ligand [ 14 ] to 175.7 pm on complex 1 , which can be considered as an increasing single bond character and hence suggests a strong influence from the side bonded palladium atom. The (S=)C—Pd bonds have a length of 206.9 pm and the (C=)S—Pd bonds are 226.3 pm, which are close to the sum of elements' covalent radii and can be compared to previous work, [ 13,17 ] thus it can be speculated that the bonding between central side‐on coordinated palladium atoms and methyldithiocarboxyl group is more close to "cyclopropane" motif with Pd—C and Pd—S single bonds than a common π‐complex motif. Besides, all sulfur atoms of the carborane moiety are three‐coordinated with a dative bond to palladium, while S(‐CH 3 ) bonds to another central palladium atom and C=S side bonds to the central palladium atom as well as directly bonds to the surrounding palladium atom, which combines with the same carborane moiety.…”

Improved Methods for the Synthesis of KB3H8, NH3B3H7, and N-Alkyl Analogues of NH3B3H7

“…As a reagent, KB 3 H 8 has certain advantages over other salts of the B 3 H 8 – anion such as relatively high stability in air and in organic solvents. ,, Meanwhile, the coordination between the K + ion and solvent is weak, thus the unsolvated salt can be readily isolated and purified as described above. , In the present work, THF·B 3 H 7 was prepared according to two modified literature methods using KB 3 H 8 as a starting material. The first one is based on the reaction of KB 3 H 8 with HCl (1 M solution in diethyl ether) in THF to form the solution of THF·B 3 H 7 (eq ), in which the H δ+ ···H δ− dihydrogen bond interaction (which can also be considered proton acting as an oxidant) assists dehydrogenation . The formed KCl was identified by X-ray diffraction (XRD) (Figure S3) and the solution of THF·B 3 H 7 by 11 B NMR spectroscopy (Figure b).…”

Migration Mechanism of the B−H Activation of Carboranes

“…The distinctive three-dimensional structure and unique electronic properties of carborane cause the different activities of hydrogen atoms in the carborane cage. [1][2][3][4][5][6][7][8] BÀ H functionalisation on carborane has developed rapidly in recent years; [9][10][11][12][13][14] however, the selective BÀ H activation reaction still faces many challenges. The challenges are principally reflected in two aspects: the polarity and nucleophilicity of BÀ H bonds are greatly lower than those of the corresponding CÀ H bonds because of the electron-deficient characteristic of boron.…”