Facile purification of the N-heterocyclic carbene precursor [IMesH][Cl] and chloride binding in the solvates [IMesH][Cl]·acetone and [IMesH][Cl]·H₂O (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene)

1,3-Bis(2,4,6-trimethylphenyl)-3H-imidazol-1-ium tetraoxidorhenate(VII)

“…The compound has crystallographic mirror symmetry with the Re1, O1, O2 and the imidazolium C1 and H1 atoms all lying in a mirror plane. The geometry of the imidazolium cation is similar to those observed for previously reported structures of 1,3-Bis(2,4,6-trimethylphenyl)-3H-imidazolium salts, for example halide (Cl -, Br -) salts (Arduengo et al, 1995;Cole et al, 2002;Cole & Junk, 2004;Lorber &Vendier, 2009). The imidazolium C1-H1 is hydrogen bonded to…”

“…were observed between the cation and the anion in the halide salts (Cole & Junk, 2004). The Re-O2 bond is somewhat longer (1.714 (5) Å) than the other (nominally double) Re-O bonds (mean 1.690 (6) Å) and may indicate some localization of the anion negative charge on O2.…”

“…For related structures of some halide salts, see: Arduengo et al (1995); Cole et al (2002); Cole & Junk (2004); Lorber & Vendier (2009).…”

Synthesis, structure and catalysis of a NHC–Pd(ii) complex based on a tetradentate mixed ligand

“…29 All the reagents for synthesis and analyses were of analytical grade and used without further purification. N-Picolyl-benzimidazole was prepared according to the literature method.…”

Expedient syntheses of the N-heterocyclic carbene precursor imidazolium salts IPr·HCl, IMes·HCl and IXy·HCl

“…Thus, the synthesis of IMes·HCl ( 2 ) according to the Arduengo protocol is followed by extensive solvent washes, resulting in a low yield (40%). [ 6 , 7 ] Both the Arduengo and Nolan groups noted that this synthetic protocol cannot be extended to the sterically more hindered IPr·HCl ( 1 ). [ 8 , 9 ] Instead, Arduengo and coworkers found that the reaction of the 1,4-diaryl-1,4-diazadienes (DADs, or glyoxal imines) 4 and 5 with chloromethyl-ethylether (THF, 40°C/16 h or 23°C/5 d) gave pure IPr·HCl ( 1 ) or IMes·HCl ( 2 ) in 47% or 40% yield, respectively (Scheme 2b ).…”