Methoxy-Functionalized N-Heterocyclic Carbenes

Abstract

The effect of methoxy functionalization of three N-heterocyclic carbene ligands was assessed using a variety of methods. The steric environment of each carbene has been assessed in various coordination environments. The electronic properties, specifically the electron-donating character and πaccepting ability, have been evaluated using nickel and iridium complexes and selenium adducts, respectively. Comparisons with the parent systems have been made with respect to both electronic and steric properties. The carbenes IPr OMe , SIPr OMe , and IPr* OMe have been found to be more electron donating than the parent systems IPr, SIPr, and IPr* and only slightly less π accepting, yet they exhibit similar steric properties.

Thermal, optical and structural properties of disulfide and diselenide salts with weakly associated anions

“…The imidazole moieties in 1-3 are arranged in trans position. The SAS bond length in 1 is 2.1701(15) Å is slightly longer than the previously reported disulfide [13]. Notably the CASe bond length (1.905(6) Å) in 3 is slightly decreased compared to its corresponding ligand IPr'Se (1.942(16) Å).…”

Nickel N-heterocyclic carbene complexes and their utility in homogeneous catalysis

“…complexes were also synthesized by this pathway. Among the imidazole based NHC ligands, the following dimeric [(NHC) 4 Ni 2 (COD)] complexes (8−10), [21,25] (11), [26] and the nickel(0) carbonyl NHC complexes (12−26) [17,27,28] Figure 2). …”

Crystal structure of [2-(4-methoxyphenyl)pyrazine-κ2 C,N) chlorido[N,N′-bis-(2,6-diisopropyl-phenyl)imidazol-2-ylidene-κC)] palladium(II), C38H45ClN4OPd

“…The Pd atom is in a slightly distorted square planar environment bonded to the chlorine atom, the carbon atom of the NHC ligand, the nitrogen atom and the carbon atom of the pyrazine ligand. The Pd-Ccarb bond length of the title complex is similar to those of IPr [N,N′-bis-(2,6-diisopropyl-phenyl)imidazol-2-ylidene] complexes [1,7,10,11], while it is longer than those of the related carbene complexes [12,13] possibly due to the steric bulk of the IPr ligand. The bicyclic system formed by the palladacycle and the pyrazdyl ring is coplanar.…”