On the mechanism of sp C-H borylation using -substituted pyridinium cations.

-Substituted pyridinium cations with the weakly coordinating anion [B(CF)] have been studied and crucial structural features in the sp C-H borylation catalysis of 3-methylthiophene have been identified. The electron-deficiency of the aromatic core of the cation is essential for activity together with accessible protons. The spectroscopic yield of the borylation of 3-methylthiophene with catecholborane (CatBH) was optimized up to 86% and the method was further applied to other substrates such as -alkylbenzenes.

Dicoordinate Au(I)-Ethylene Complexes as Hydroamination Catalysts.

A series of gold(I)-ethylene π-complexes containing a family of bulky phosphine ligands has been prepared. The use of these sterically congested ligands is crucial to stabilize the gold(I)-ethylene bond and prevent decomposition, boosting up their catalytic performance in the highly underexplored hydroamination of ethylene. The precatalysts bearing the most sterically demanding phosphines showed the best results reaching full conversion to the hydroaminated products under notably mild conditions (1 bar of ethylene pressure at 60 °C).

A dicoordinate gold(I)-ethylene complex.

The use of the exceptionally bulky tris-2-(4,4'-di--butylbiphenylyl)phosphine ligand allows the isolation and complete characterization of the first dicoordinate gold(I)-ethylene adduct, filling a missing fundamental piece on the organometallic chemistry of gold. Besides, the bonding situation of this species has been investigated by means of state-of-the-art Density Functional Theory (DFT) calculations indicating that π-backdonation plays a minor role compared with tricoordinate analogues.

Reductive C-C Coupling from Molecular Au(I) Hydrocarbyl Complexes: A Mechanistic Study.

Organometallic gold complexes are used in a range of catalytic reactions, and they often serve as catalyst precursors that mediate C-C bond formation. In this study, we investigate C-C coupling to form ethane from various phosphine-ligated gem-digold(I) methyl complexes including [Au(μ-CH)(PMeAr')][NTf], [Au(μ-CH)(XPhos)][NTf], and [Au(μ-CH)(BuXPhos)][NTf] {Ar' = CH-2,6-(CH-2,6-Me), CH-2,6-(CH-2,4,6-Me), CH-2,6-(CH-2,6-Pr), or CH-2,6-(CH-2,4,6-Pr); XPhos = 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl; BuXPhos = 2-di--butylphosphino-2',4',6'-triisopropylbiphenyl; NTf = bis(trifluoromethyl sulfonylimide)}. The gem-digold methyl complexes are synthesized through reaction between Au(CH)L and Au(L)(NTf) {L = phosphines listed above}.

A Versatile Approach to Access Trimetallic Complexes Based on Trisphosphinite Ligands.

A straightforward method for the preparation of trisphosphinite ligands in one step, using only commercially available reagents (1,1,1-tris(4-hydroxyphenyl)ethane and chlorophosphines) is described. We have made use of this approach to prepare a small family of four trisphosphinite ligands of formula [CHC{(CHOR)], where R stands for Ph (), Xyl (, Xyl = 2,6-Me-CH), Pr (), and Cy (). These polyfunctional phosphinites allowed us to investigate their coordination chemistry towards a range of late transition metal precursors.