Metallacarboranes of the Transition and Lanthanide Elements

Interligand Interactions in Half-Sandwich Nickelacarboranes with Phosphine Ligands: Away from Skeletal Rearrangements

“…1 H NMR (acetone-d 6 , ppm): δ 7.93 (4H, m, Ph(dppe)), 7.63 (6H, m, Ph(dppe)), 7.41 (6H, m, Ph(dppe)), 7.28 (4H, m, Ph(dppe)), 6.99 (1H, t, J = 7.5 Hz, p-Ph), 6.79 (2H, t, J = 7.7 Hz, m-Ph), 6.57 (2H, d, J = 8.0 Hz, o-Ph), 2.63 (2H, m, CH 2 P), 2.43 (3H, m, CH 2 P + CH carb ), 3.9− 0.5 (9H, m, BH). 13 3,3-(MePh 2 P) 2 -closo-3,1,2-NiC 2 B 9 H 11 (4). The synthesis was carried out using Cs[7,8-C 2 B 9 H 12 ] (0.40 g, 1.50 mmol), t-BuOK (0.51 g, 4.51 mmol), and [ (MePh 2 P) 2 NiCl 2 ] (0.88 g, 1.65 mmol) in THF (30 mL) to give green solid of 4 (0.61 g, 69% yield).…”

“…Despite its more than 50 year history, the chemistry of nickelacarboranes has received much less development compared to the chemistry of cobalta- and ferracarboranes, which are characterized by the formation of extremely stable bis­(dicarbollide) complexes, − as well as the chemistry of rhoda- and ruthenacarboranes, , which are widely studied as catalysts for various processes. − This is largely due to the increased tendency of nickelacarboranes to skeletal rearrangements, − as well as the often uninformative 11 B NMR spectra of nickelacarboranes, which makes their identification problematic. Certain problems are also associated with the lack of methods for modifying nickel bis­(dicarbollide) and its reduced stability , compared to iron and cobalt bis­(dicarbollides).…”

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

“…The discovery of the decapitation of ortho-carborane under the action of strong nucleophiles with the formation of nido-carborane in the 1960s [1,2] initiated the development of at least two main directions in the development of carborane chemistry. The first one was the use of dicarbollide ligands, which are formed upon the deprotonation of nido-carboranes with strong bases, for the synthesis of π-complexes of transition metals analogous to complexes with cyclopentadiene ligands, the so-called metallacarboranes [3][4][5][6][7][8][9][10][11]. Another direction was the transformation of closo-carborane derivatives into the corresponding nido-carboranes in order to increase their water solubility for use in boron neutron capture therapy for cancer [12][13][14][15][16][17][18][19], radio-immunodiagnostics and radio-immunotherapy [20][21][22], as well as some other medical applications [23][24][25][26][27].…”

Synthesis of Bis(Carboranyl)amides 1,1′-μ-(CH2NH(O)C(CH2)n-1,2-C2B10H11)2 (n = 0, 1) and Attempt of Synthesis of Gadolinium Bis(Dicarbollide)

“…Although at physiological pH 7.4 it is assumed that total excretion of the complexes occurs before any harmful amount of Gd 3+ is released [ 26 ], it has been found that the Gd leakage and retention in body can lead to nephrogenic systemic fibrosis and other health risks [ 27 , 28 ]. Therefore, a real challenge for a boron chemist is to obtain a stable complex in which gadolinium is a part of a metallacarborane cluster, similar to complexes of many other transition metals [ 29 ]. In this contribution we describe an attempt to synthesize such a complex based on two nido -carborane ligands linked by a flexible spacer containing amide groups.…”