Transition metal adduct formations with small molecules such as carbon dioxide and carbon monoxide are drawing much attention due to their importance in developing synthetic catalysts. This attention has been in part motivated by a desire to study species possessing uncommon metal-to-carbon multiple bond(s) such as carbene and carbyne via partial or complete group transfer. In this presentation, a particular study of such species will be presented to show their respective roles in small-molecule transformations that include, carbon dioxide transformation for modeling ACS/CODH active site chemistry and carbon monoxide conversion as a key step for Fisher-Tropsch synthesis. To test the validity of hypotheses concerning nickel’s crucial roles in the reversible C-O and C-C bond formation at a single metal center, synthetic nickel model systems are needed. 

A four coordinate (PEP)Ni-L scaffold (E = N, P or Si) where the L site is occupied by ligands such as N2, CO, CO2 and COOR will be described. The systems with a (PNP)Ni scaffold accommodating terminally bound CO in the three formal oxidation states (nickel(0), +1, and +2) and their reactivity toward electrophiles will be illustrated. We also will present the synthesis and characterization of a dinuclear nickel dinitrogen complex {(PPMeP)Ni}2(μ-N2) and a mononuclear nickel carbon dioxide species (PPMeP)Ni(η2-CO2), both fairly uncommon species in organonickel chemistry. Unprecedented methoxy group transfer at a single nickel center mediated by a new type of metal-ligand cooperation with a phosphide based ligand will be presented as well. 

20150924_대학원세미나_이윤호교수.hwp