Abstract
Homogeneous transition-metal catalysts are usually discrete molecules and can be synthesized by ligand design in a defined and rational way. To improve performance of homogenous catalysts, modification of catalysts is usually carried out within a close proximity of a metal center (within a few angstroms). This is effective way to develop efficient catalysts for various reactions including C-C bond-forming reactions and asymmetric reactions. Inspired by these findings, we set out to expand catalytic environment to nanosize by modification of ligands. Here the recent progress in homogeneous transition-metal catalysts with nanosize ligands is overviewed. To expand a molecular size, dendritic frameworks including flexible or rigid moieties, sterically congested m-terphenyl and its higher dendritic framework were introduced onto N-heterocyclic carbene and phosphine ligands.
