Homogeneous Decomposition Mechanisms of Diethylzinc by Raman Spectroscopy and Quantum Chemical Calculations

Abstract

The gas-phase decomposition pathways of diethylzinc (DEZn), a common precursor for deposition of Zn-VI compounds, were investigated in detail. The homogeneous thermal decomposition of DEZn in N2 carrier was followed in an impinging-jet, up-flow reactor by Raman scattering. Density Functional Theory calculations were performed to describe the bond dissociation behavior using the model chemistry B3LYP/6-311G(d) to estimate optimal geometries and Raman active vibrational frequencies of DEZn, as well as anticipated intermediates and products. Comparison of the measured DEZn decomposition profile to that predicted by a 2-D hydrodynamic simulation revealed that simple bond dissociation between zinc and carbon atoms is the dominant homogeneous thermal decomposition pathway. The calculations suggest several reactions involving intermediates and Raman scattering experiments confirming the formation of the dimer (ZnC2H5)2. In a different set of experiments, photolysis of DEZn gave evidence for decomposition by beta-hydride elimination. The results suggest that beta-hydride elimination is a minor pathway for the gas-phase homogeneous pyrolysis of diethylzinc. A reasonable transition state during beta-hydride elimination was identified, and the calculated energies and thermodynamic properties support the likelihood of these reaction steps.

An Alternative Route Towards Metal–Polymer Hybrid Materials Prepared by Vapor‐Phase Processing

“…bonds and angles present in the linear PTFE, and, at the same time, simplifi es the study of the potential-energy surface of the reacting system, by reducing both the number of atoms and the number of local minima due to conformational changes. According to spectroscopic and theoretical investigations, [ 37 ] diethylzinc undergoes thermal decomposition at elevated temperatures, which proceeds typically in the range 300-600 ° C, but starts already at 150-200 ° C. The main pyrolysis pathway in this case is a homolytic fi ssion of the Zn-C bond with a •Zn(C 2 H 5 ) and •C 2 H 5 radical formation. The free radicals recombine after a short time to the dimer (Zn(C 2 H 5 )) 2 and alkanes.…”

Improvement of the photocatalytic degradation property of atomic layer deposited ZnO thin films: the interplay between film properties and functional performances

“…DEZ has been injected into the reactor chamber under different temperatures, and the by-products of its thermolysis were analysed by RGA. The dominant initial decomposition step of DEZ is known to be the Zn-C bond homolysis 26 , leading to C 2 H 6 , C 2 H 4 , and H 2 . The intensities of C 2 H 4 and H 2 were monitored as a function of the temperature and the obtained results are shown in figure 2.…”

Comparison of Triethylgallium and Trimethylgallium Precursors for GaInP Nanowire Growth

“…This led to a Ga x In 1– x P composition of x = 0.30, which is comparable to the other doped NW samples in this article. Discussing the pyrolysis of TMGa in the presence of DEZn more specifically, ethyl radicals from the pyrolysis of DEZn [ 36,37 ] are expected to attack the partially decomposed Ga compound MMGa via the generation of hydrogen radicals. [ 38 ] Therefore, the presence of DEZn will enhance the supply of elemental Ga to the growth.…”