Chiral Dirhodium(II) Carboxylates: New Insights into the Effect of Ligand Stereo-Purity on Catalyst Structure and Enantioselectivity

Heteroleptic dirhodium(II,II) paddlewheel complexes as carbene transfer catalysts

This review highlights the applications of dirhodium(II,II) paddlewheel complexes with a heteroleptic scaffold. Dirhodium(II,II) paddlewheel complexes are well known as highly efficient and selective carbene transfer catalysts. While the majority of described complexes are homoleptic, comparatively fewer studies have concerned heteroleptic complexes. Here, we emphasise the use of heteroleptic complexes in order to highlight their benefits as carbene transfer catalysts and spur future research. Methods to synthesise heteroleptic dirhodium(II,II) paddlewheel complexes are discussed as well as a categorical review of their types of heteroleptic complexes and the carbene reactions in which they have been used.

Transition Metal Catalyzed Insertion Reactions with Donor/Donor Carbenes

Donor/donor carbenes are relatively new in the field of carbene chemistry; although applications in C-H and X-H insertion reactions are few in number, they demonstrate exquisite chemo- and stereo-selectivity. Recent reports have shown that C-H, N-H, B-H, O-H, S-H, Si-H, Ge-H, Sn-H and P-H insertion reactions are feasible with a variety of transition metal catalysts, both inter- and intramolecularly. Furthermore, high degrees of diastereo- and enantioselectivity have been observed in several cases. Methods typically involve the formation of a diazo-based carbene precursor, but procedures using diazo-free metal carbenes have been developed with significant success. This Minireview covers transition-metal catalyzed insertion reactions with donor/donor and donor carbenes, providing context for future developments in this emerging field.

Linear One-Dimensional Coordination Polymers Constructed by Dirhodium Paddlewheel and Tetracyanido-Metallate Building Blocks

In this article, we describe the preparation of anionic heteronuclear one-dimensional coordination polymers made by dirhodium paddlewheels and tetracyanido-metallatate building blocks. A series of complexes of (PPh4)2n[{Rh2(µ-O2CCH3)4}{M(CN)4}]n (M = Ni (1), Pd (2), Pt (3)) formulae were obtained by reaction of [Rh2(μ-O2CCH3)4] with (PPh4)2[M(CN)4] in a 1:1 or 2:1 ratio. Crystals of 1−3 suitable for single crystal X-ray diffraction were grown by slow diffusion of a dichloromethane solution of the dirhodium complex into a chloroform solution of the corresponding tetracyanido–metallatate salt. Compounds 1 and 2 are isostructural and crystallize in the triclinic P-1 space group, while compound 3 crystallizes in the monoclinic P21/n space group. A detailed description of the structures is presented, including the analysis of the packing of anionic chains and PPh4+ cations.