Sterically encumbered dianionic dicarboranyl pincer ligand (C5H3N)(C2B10H11)2 and its CNC Nickel(II) complex

Synthesis, characterization, and crystal structures of organonickel(II) complexes coordinated to novel 1-bromo-2,6-bis{[(λ5-phosphanylidene)imino]methyl}benzene NCN-pincer ligands

“…As expected, the complexes showed an increasing value as more cyclohexyl groups were installed, with the exception of L 2 NiBr. For comparison, a recently described 2,6-bis(carborane)pyridine nickel(II) complex, which is catalytically active for nucleophilic addition of piperdine to acetonitrile and whose pincer ligand was specifically designed to be sterically encumbering, was described in this fashion, with a %V bur = 70.6% (Islam et al, 2018).…”

Room-Temperature Aerobic C–CN Bond Activation in Nickel(II) Cyanomethyl Dicarboranyl Complex

“…As mentioned above, nickel complexes play a significant role in the activation of nitriles through the oxidative addition to zero-valent nickel centers. Recently, we reported the synthesis of a pyridine-backbone bis- ortho –carboranyl CNC dianionic pincer ligand (C 5 H 3 N)­(C 2 B 10 H 11 ) 2 ( 1, L-H ), and its Ni­(II) acetonitrile-ligated complex {(C 5 H 3 N)­(C 2 B 10 H 10 ) 2 }­Ni­(CH 3 CN) ( 2, LNi-NCCH 3 ) . Polyhedral boranes and carboranes are three-dimensional structures that have been used in ligand design due to their unique electronic and steric properties. − For example, the rigidity and extensive steric hindrance of boron clusters can be used to impose control of the coordination modes of a ligand around a metal center.…”

“…100 ( 13 C),128 ( 11 B) MHz, reported in δ (parts per million) and referenced to the residual 1 H/13 C signals of the deuterated solvent or an external BF 3 (Et 2 O) ( 11 B(δ): 0.0 ppm) standard.The starting pro-ligand (C 5 H 3 N)(C 2 B 10 H 11 ) 2(1) and its Ni(II) acetonitrile-ligated complex {(C 5 H 3 N)(C 2 B 10 H 10 ) 2 }Ni(CH 3 CN)(2) were prepared according to the previously reported procedure 34. ortho-Carborane C 2 B 10 H 12 (Boron Specialties) and n-butyllithium solution (n-BuLi, 2.5 M solution in hexane), were used as received.…”

Free three-dimensional carborane carbanions

“…Metalated carborane clusters synthesized in this manner are most of the time not isolated but utilized in situ in subsequent reactions with organic or inorganic electrophiles. [34][35][36][37][38][39] Recently, Duttwyler and co-workers reported the synthesis and structural characterization of a lithiated anionic cluster Li[CB 11 H 11 ] − containing a lithium-carbon bond, which shed light on the structure of these nucleophilic intermediates and can be considered as a 3D analog of phenyllithium. 40 In this work, we report the synthesis, structural, and spectroscopic characterization of deprotonated discrete carboranyl anions, including [C 2 B 10 H 11 ] − , which, containing the "naked" carbanionic center, are the key intermediates in Cvertex functionalization of carboranes.…”