A boron analog of diop: synthesis and properties

Tunable carbocation-based redox active ambiphilic ligands: synthesis, coordination and characterization

The synthesis of novel redox active ambiphilic ligands L1-L3 and their coordination chemistry to first-row late transition metal halides (M = Co and Ni) is reported. The heterocyclic carbocation scaffolds act as Lewis acid moieties while the pyridine anchor acts as the coordinating Lewis base. The high synthetic tunability of this ligand scaffold allows for control of its rigidity and electronic properties. Anion exchange and coordination of a chloride anion to the metal center was observed resulting in the formation of [MCl3]- metallate. Upon coordination to the pyridine anchor, the metallate centers adopt a canonical tetrahedral geometry, resulting in an overall neutral complex best described as a zwitterionic metallate trichloride bound to a cationic ligand. Characterization techniques including single crystal X-ray diffraction, cyclic voltammetry, and UV-Vis absorption spectroscopy were employed to better understand the structural and chemical properties of the ligands and metal complexes. A possible weak interaction between one of the chlorides and the carbenium moiety in the ligand is observed in crystals of both of the Co(ii) and Ni(ii) complexes with ligand L1. Density functional theory (DFT) calculations support that this electrostatic interaction for complexes 2a and 2b exists only in the solid state.

Complexes of ambiphilic ligands: reactivity and catalytic applications

This review focuses on the way Lewis acids of ambiphilic ligands influence the reactivity of transition metal complexes and on the new perspectives this opens in catalysis.

Synthesis and structure of Ag(i), Pd(ii), Rh(i), Ru(ii) and Au(i) NHC-complexes with a pendant Lewis acidic boronic ester moiety

Synthesis and characterization of novel NHC-boronic ester ligands and their corresponding TM-complexes.

Synthesis of chiral hydroxyl phospholanes from D-mannitol and their use in asymmetric catalytic reactions

Chiral hydroxyl monophosphane 3 [(2S,3S,4S,5S)-3,4-dihydroxy-2, 5-dimethyl-1-phenylphospholane] and bisphospholanes 5a [1,2-bis[(2S, 3S,4S,5S)-3,4-dihydroxy-2,5-dimethylphospholanyl]benzene] and 5b [1, 2-bis[(2S,3S,4S,5S)-2,5-diethyl-3,4-dihydroxyphospholanyl]benzene] were synthesized from readily available D-mannitol in high yields. Strategies for protection and deprotection of OH-groups in the presence of phosphines have been explored. Rate acceleration in the Baylis-Hillman reaction was observed when a hydroxyl phosphine was used as the catalyst. Rhodium complexes with chiral bisphospholanes are highly enantioselective catalysts for the asymmetric hydrogenation of various kinds of functionalized olefins such as dehydroamino acid derivatives, itaconic acid derivatives, and enamides. An interesting feature of the hydroxyl phospholane system is that hydrogenation of some substrates can be carried out in water with >99% ee and 100% conversion (e.g., itaconic acid).