Reactivities of d0 transition metal complexes toward oxygen: Synthetic and mechanistic studies

Abstract

Transition metals such as Fe in porphyrin complexes are known to bind or react with O 2 , and such reactions are critical to many biological functions and catalytic oxidation using O 2 . The transition metals in these reactions often contain valence d electrons, and oxidation of metals is an important step. In recent years, reactions of O 2 with d 0 transition metal complexes such as Hf(NR 2 ) 4 (R = alkyl) have been used to make metal oxide thin films as insulating gate materials in new microelectronic devices. This feature article discusses our recent studies of such reactions and the formation of TiO 2 thin films. In contrast to the reactions of many d n complexes where metals are often oxidized, reactions of d 0 complexes such as Hf(NMe 2 ) 4 and Ta(NMe 2 ) 4 (SiR 3 ) with O 2 usually lead to the oxidation of ligands, forming, e.g., -ONMe 2 and -OSiR 3 from -NMe 2 and -SiR 3 ligands, respectively. Mechanistic and theoretical studies of these reactions have revealed pathways in the formation of the metal oxide thin films as microelectronic materials.oxygen, amide, metal oxide, gate insulator, theoretical study

Dependence of the Decomposition of Trimethylaluminum on Oxygen Concentration

“…[25][26][27][28][29][30][31][32] Furthermore, in the case of reaction between group IIIB organic compounds including TMA and oxygen, trimethylgallium ͑TMG͒ is reacted with oxygen as below 33 …”

“…Oxygen insertion into M-R bonds has been observed in the reactions of O 2 with alkyl or amide complexes. [25][26][27][28][29][30][31][32] Furthermore, in the case of reaction between group IIIB organic compounds including TMA and oxygen, trimethylgallium ͑TMG͒ is reacted with oxygen as below 33 Ga͑CH 3…”