Theoretical study of the bonding between aminocarbene and main group elements

Abstract

International audienceB3LYP/6-31G* calculations were carried out on adducts formed by the interaction of a cyclic unsaturated aminocarbene with carbenoid moieties CH2, SiH2, NH, PH, O or S. The bonding mode has been described using the Natural Bond Orbital (NBO) partitioning schemes, the Charge-Decomposition Analysis (CDA) and the topological analysis of the Electron Localization Function (ELF). A donor–acceptor interaction with a substantial π backbonding of the carbenoid moiety is observed in the case of CH2, SiH2, PH and S. The bond-description has been correlated with the bond length, the bond dissociation energy and the aromaticity of the carbene ring obtained by Nucleus-Independent Chemical Shift (NICS) calculation

16‐Electron (Arene)ruthenium Complexes with Superbasic Bis(imidazolin‐2‐imine) Ligands and Their Use in Catalytic Transfer Hydrogenation

“…In contrast to the ecliptic orientation of the benzene ring in 6 with respect to the imine C-N and arene C-H bonds, the cymene ligand in 8 is oriented in a stag- Figure 5. ORTEP diagram of the cation in [8](BF 4 ) 2 ·CH 2 Cl 2 with thermal displacement parameters drawn at 50 % probability; the ethylene bridge is disordered. gered fashion, allowing the iPr and Me substituents to adopt the sterically least hindered positions between the two imidazole sites.…”

“…These characteristics become even more pronounced in poly(imidazolin-2-imine) ligands, since the imidazole ring is particularly effective in stabilizing a positive charge. This induces a strong polarization of the exocyclic C=N bond, [8,9] which can be described by the two resonance structures A and B for the BL iPr and BL Me ligands (Scheme 1). Upon metal coordination, the contribution of the ylidic form B can be expected to increase considerably, and thus these ligands exhibit a particularly strong electron-donating capacity toward transition metal atoms.…”

Facile synthesis of benzimidazolin-2-chalcogenones: Nature of the carbon–chalcogen bond

“…This also renders CeTe bond relatively weak as compared to CeS or CeSe bond. Also, it is reported in the literature that the donoreacceptor bonding mode not only comprises of a s donation from the carbene, but also significant p back-bonding from the main group elements [34]. The benzimidazolium systems are considered to be more robust in comparison to the imidazolium as they can provide more stability by further enhancing conjugation in the system.…”

Rare Earth and Alkaline Earth Metal Complexes with Me2Si‐Bridged Cyclopentadienyl‐Imidazolin‐2‐Imine Ligands and Their Use as Constrained‐Geometry Hydroamination Catalysts

“…[18,[20][21][22][23][24][25] Monoalkyl complexes have been of particular importance, and this contribution establishes the corresponding type III rare earth metal dialkyl complexes and compares their properties with those of their silylene-linked cyclopentadienyl-amido counterparts. diene (2) with two equivalents of 1,3-diisopropyl-4,5-dimethylimidazolin-2-imine, Im iPr NH (1). One equivalent of the imine serves as a hydrochloric acid scavenger and precipitates from the reaction mixture as the corresponding 2-aminoimidazolium chloride, 1·HCl (Scheme 2).…”

“…[1][2][3] We have recently established a general method for the preparation of these ligands from stable carbenes of the imidazolin-2-ylidene type and trimethylsilyl azide. This procedure resembles the Staudinger reaction [4] between phosphanes and azides and furnishes 2-trimethylsilyliminoimidazolines (X = SiMe 3 ), [3] which are suitable precursors for the synthesis of transition metal complexes incorporating ancillary imidazolin-2-iminato ligands (X = N -).…”