On the relative stability of cobalt‐ and nickel‐based amidinate complexes against β‐migration

Abstract

ABSTRACT:We present a first-principles study on the relative stability of cobaltand nickel-based amidinate complexes against ␤-migration using density functional theory. Factors that influence the reactivity of these compounds were carefully addressed and the calculated molecular structures are in excellent agreement with the available crystal structural data. Reaction energies as well as activation barriers of ␤-migration were evaluated. The predicted relative stability of the selected compounds is consistent with experimental observations.

Competing reactions during metalorganic deposition: Ligand-exchange versus direct reaction with the substrate surface

“…162 Previous calculations indicate that the most stable state for Ni[Pr-amd] 2 precursor molecule corresponds to the tetrahedral geometry; 162,163 however, our calculations indicate that the planar geometry is the most stable for this compound. 162 Previous calculations indicate that the most stable state for Ni[Pr-amd] 2 precursor molecule corresponds to the tetrahedral geometry; 162,163 however, our calculations indicate that the planar geometry is the most stable for this compound.…”

“…The use of amidinates as deposition precursors was established only recently. 162 In this section, special emphasis is placed on comparing the results for amidinates with those for diketonates. Amidinates featured an improved thermal stability, higher vapor pressure, and, more importantly, produced films that were practically free of contamination.…”

Modeling Mechanism and Growth Reactions for New Nanofabrication Processes by Atomic Layer Deposition

“…[ 73 ] A quantum chemical study of the decomposition pathway of amidinate precursors for Co or Ni ALD shows that thermal and kinetic stability can be substantially enhanced by locating a CH 3 group at the β position, rather than H, which is consistent with experimental data. [ 74 ] Furthermore, chelation enhances the stability of the complex against β-H migration and decomposition.…”

Synthesis of 5,5-Bicyclic Amidines as Ligands for Thermally Stable Vapor Deposition Precursors

“…DFT calculations on the mechanism and the transition state through which this takes place revealed that, in the transition state, the transferred H atom, the metal atom, and the N−C−N functional group of the ligand all lie in the same plane. 12,13 Barry et al have come partway to solving the problem with their careful study of tert-butylimino-2,2-dimethylpyrrolidine as the ligand. 14 A copper(I) complex with this ligand, which can be thought of as a monocyclic amidine, showed improved thermal stability in comparison to N′,N″-diisopropyl-Ndimethyl-guanidinatocopper(I).…”