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When deprotonated, NHOs can be ligands for main group hydrides. E = Ge, Sn. [1] NHOs can stabilize low oxidation state main group hydrides, like GeH 2 and SnH 2 that are coordinated to W(CO) 5. [1] When deprotonated, these NHOs become anionic, four-electron bridging ligands that can bind to two Ge centers, hence displaying carbanion-like ...
Ever since the first crystalline carbene structure was isolated by Arduengo ins 1990, tuning different properties of NHCs has been a popular area of study in main group chemistry. [4] The first NHC boryl anion was synthesized by Segawa in 2006. [1]
In coordination chemistry, a transition metal NHC complex is a metal complex containing one or more N-heterocyclic carbene ligands. Such compounds are the subject of much research, in part because of prospective applications in homogeneous catalysis. One such success is the second generation Grubbs catalyst. [1] IMes is a popular NHC ligand.
This suggests an origin for the efficacy of NHC transfer chemistry from Ag NHC complexes, with weaker M-NHC bonds in addition to the straightforward synthetic route described previously. [5] Further charge-decomposition analysis of the three model complexes suggests that the- major contribution to covalent bonding arises from the NHC to M σ ...
This effect can be used to stabilize highly reactive main group and transition metal compounds. [6] [22] Because excessive steric hindrance can be an issue for some reactivity, NHCs and CAACs bearing substituents with multiple spatial conformations (e.g. cyclohexyl) offer "flexible steric bulk" for catalysis.
NHCs are widely used as ancillary ligand in organometallic chemistry. One practical application is the ruthenium -based Grubbs' catalyst and NHC-Palladium Complexes for cross-coupling reactions. [ 66 ] [ 67 ] [ 68 ] NHC-metal complexes, specifically Ag(I)-NHC complexes have been widely tested for their biological applications.
Adding "steric hindrance" to a molecule's reactive site through bulky groups is a common strategy in molecular chemistry to stabilize reactive moieties within a molecule. [3] In this case bulky ligands like terphenyls, bulky alkoxides, aryl-substituted NHCs, etc. serve as a protective wrapper on the molecule. [1]
No difference in charge sharing is seen in the σ-bond interaction between Si and N of each NHSi, this is also the case with NHCs. In spite of identical Si-N σ bonding, the unsaturated silylene has a lower charge separation in its Si-N bond than the saturated analog: for the unsaturated analog, Si has a charge of +0.87 and each N -1.00, while ...