Redistribution and Exchange Reactions in Groups IIB-VIIB

Prospects for Thermal Atomic Layer Etching Using Sequential, Self-Limiting Fluorination and Ligand-Exchange Reactions

“…The ligand-exchange reactions during thermal ALE are metal-exchange transmetalation or redistribution reactions. Ligands are transferred between adjacent metal centers during the ligand-exchange reaction.…”

“…The thermochemical free energies for the reaction of fluorine-containing gases with Al 2 O 3 at 200 °C are given in Table 1. 10 The ligand-exchange reactions during thermal ALE are metal-exchange transmetalation 8 or redistribution 11 reactions. Ligands are transferred between adjacent metal centers during the ligand-exchange reaction.…”

Role of Redistribution Reactions in the Polymer Route to Silicon–Carbon–Oxygen Ceramics

“…The rates of redistribution reactions depend on the nature of the central atom E, and on the nature of the substituents X and Y. 1,2 The rates are in the order E belonging to Group III Ͼ IV Ͼ V(trivalent) Ͼ V(pentavalent), and First-Row Ͻ Second-Row Ͻ Third-Row Х Fourth-Row. For a given central atom E, the redistributions involving the exchange of EOC bonds are much slower than those involving the exchange of EOH, EOS, EOhalogen, EOO, or EON bonds.…”

“…R EDISTRIBUTION reactions (also called exchange reactions) are common in organometallic chemistry; these equilibrium reactions lead to the exchange of substituents around a central element (reaction (1)): 1,2 EOX ϩ YOEЈ % % EO Y ϩ XOEЈ (1) where E and EЈ ϭ Si, B, Al, Ti, P, Ge, Sn, . .…”

“…It is generally assumed that, at moderate temperatures, the exchange of the substituents proceeds through a four-center intermediate, as depicted in reaction (1). The fact that redistributions, which involve the exchange of good donor substituents around good acceptor central atoms, are rapid is consistent with this mechanism.…”