Cyclic alkyl ligand

Intramolecular acyl alkylation affords cyclic carbene ligands, e.g., (t 5-C5H5)Ru(CO)2 + C1CH2CH2CH2CC1 -> (t 5-C5H5)(CO)2RuCCH2CH2CH2C1... 

The first example of a chiral carbanionic residual ligand has recently been reported [238]. Chiral mixed cuprates generated from alkyllithium reagents and cyclic a-sulfonimidoyl carbanions transfer alkyl ligands [such as n-Bu, Me, (CH2)30CH(Me)0Etj to cyclic enones with excellent enantioselectivities (77-99% ee). 

In addition to complexes of type 44 with a C2 coordinated NHC ligand, complexes of type 45 with abnormal C4 or C5 bound carbene ligands have recently been described (Fig. 16) [143, 144]. The carbene carbon atom in these complexes is stabilized by only one nitrogen atom. A similar situation has been observed for the cyclic (alkyl)(amino)carbene (type 16, Fig. 6) [38, 39]. 

Tris(ligand) complexes involving ligand (41), or derivatives thereof, have been synthesized and characterized. Appending electron-releasing Ph or cyclic alkyl groups to the ligand leads to a blue... 

The only exception from the binuclear type of coordination of zinc(II) dithiocarbamate complexes is the mononuclear di-cydo-hexyldithiocarba-mate-zinc(II), [Zn S2CN(c-C6Hn)2 2]> with a tetrahedral structure [70]. The presence of two bulky cyclic alkyl substituents in the ligand renders the formation of the binuclear molecular structure sterically impossible h... 

The most definitive examples of heteroleptic organoindium (III) compounds are generally found for mixed alkyl-cyclic systems. Ligand redistribution reactions between InCps... 

Ligands such as phosphines (PRj) and arsines (AsRs) (R = alkyl, aryl, halogen, etc.) form complexes with a variety of metals in various oxidation states. Vibrational spectroscopy has been used extensively to determine the structures of these compounds and to discuss the nature of the metal-phosphorus (M-P) bonding. Verkade reviewed spectroscopic studies of M-P bonding with emphasis on cyclic phosphine ligands. 

Upon treatment with oxygen and carbon nucleophiles, 18-electron ethylene-d2 complex of Pd gave alkyl complexes whose NMR analysis revealed the trans stereochemistry of the nucleophilic attack (Eq. 8.7) [38]. In the case of the reaction of 16-electron alkene complexes of Pd and Pt, both trans and cis attacks occurred depending on the nature of the nucleophile as well as the auxiliary ligand. The trans attack appears to dominate in the reaction of cyclic dialkene ligands (e. 

Cyclic voltammetric studies implied that the mechanism in Scheme 9.5 accounts for the acceleration of CO insertion by oxidation. This process can be catalytic when the 17-electron acyl product is a strong enough oxidant to oxidize the starting alkyl complex. Since an acyl ligand is a weaker electron donor than an alkyl ligand, this condition is often met. 

Cyclic(alkyl)(amino)carbene (CAAC) ligands are unique donor Hgands with an easily tailored steric environment and have yielded a variety of robust gold complexes with unusual catalytic activity with alkyne substrates [179-181]. Here a CAAC-gold complex (23) could mediate the hydroamination of 3-hexyne in a sealed tube at 160° C to give imine product as observed by H NMR spectroscopy (Scheme 15.23) [179]. 

Alkyl ligands with acyl groups form complexes with cyclic 6, 0-coordinated structures 72 and 73. ... 

Figure 5.1 Metal complexes comprising the classical imidazol-2-ylidene ligand (A) and representative non-classical carbene ligands (B-N), including normal carbenes (B-E), abnormal carbenes (F-I), remote carbenes (E, G, I), cyclic alkyl(amino)carbenes (J), acyclic carbenes (K, L, M) and amino(ylide)-carbenes (N). Substituted nitrogen centres may be replaced by oxygen or sulfur. The M=C bond representation— while strongly over-emphasizing the differences in the nature of the metal-carbon bond in these non-classical carbene complexes— was used to accentuate normal and abnormal bonding.

Monoligating NHCs proved extremely successful in ketone arylation. The groups of Nolan and Bertrand reported catalysts 68 and 69-71, respectively (Figure 9.15). Whilst complex 68 was based on commercially available IPr and had a rather unremarkable structure, Bertrand s catalysts were the first reported complexes of so-called cyclic alkyl(amino)carbenes, or CAAC. These ligands display unique steric properties and they are also stronger a-donors... 

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