Comparison between Alkalimetal and Group 11 Transition Metal Halide and Hydride Tetramers: Molecular Structure and Bonding

Abstract

A comparison between alkalimetal (M = Li, Na, K, and Rb) and group 11 transition metal (M = Cu, Ag, and Au) (MX)4 tetramers with X = H, F, Cl, Br, and I has been carried out by means of the Amsterdam Density Functional software using density functional theory at the BP86/QZ4P level of theory and including relativistic effects through the ZORA approximation. We have obtained that, in the case of alkalimetals, the cubic isomer of Td geometry is more stable than the ring structure with D4h symmetry, whereas in the case of group 11 transition metal tetramers, the isomer with D4h symmetry (or D2d symmetry) is more stable than the Td form. To better understand the results obtained we have made energy decomposition analyses of the tetramerization energies. The results show that in alkalimetal halide and hydride tetramers, the cubic geometry is the most stable because the larger Pauli repulsion energies are compensated by the attractive electrostatic and orbital interaction terms. In the case of group 11 transition metal tetramers, the D4h/D2d geometry is more stable than the Td one due to the reduction of electrostatic stabilization and the dominant effect of the Pauli repulsion.

The activation strain model and molecular orbital theory

“…Conveniently, there is no special computer code required to perform activation strain analyses: all necessary quantities can be computed using any of the regular quantum‐chemical software packages available. As a result, the activation strain model has been applied by various research groups, on a range of chemical processes, such as nucleophilic substitution, cycloaddition, oxidative addition, isomerization, and many other processes from organic and organometallic chemistry.…”

“…9 Conveniently, there is no special computer code required to perform activation strain analyses: all necessary quantities can be computed using any of the regular quantum-chemical software packages available. As a result, the activation strain model has been applied by various research groups, on a range of chemical processes, such as nucleophilic substitution, 1,[10][11][12][13][14][15][16][17][18][19] cycloaddition, [20][21][22][23][24][25][26][27][28][29][30][31][32][33] oxidative addition, [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] isomerization, [50][51][52][53][54][55] and many other processes from organic…”

Planar vs. three-dimensional X62−, X2Y42−, and X3Y32− (X, Y = B, Al, Ga) metal clusters: an analysis of their relative energies through the turn-upside-down approach

“…For instance, using this method we provided an explanation of why the cubic isomer of T d geometry is more stable than the ring structure with D 4h symmetry for (MX) 4 tetramers (X = H, F, Cl, Br, and I) if M is an alkalimetal and the other way round if M belongs to group 11 transition metals. 38 Therefore, the application of this type of analysis to B 6 2À and Al 6 2À clusters will disclose the factors that make the planar D 2h structure more stable for boron and the octahedral one for aluminium. As said before, boron clusters favour localised covalent bonds whereas aluminium clusters prefer a more delocalised bonding.…”

Aromaticity and Magnetic Properties of 1‐ and 2‐Indenones and Their Aza Derivatives

“…The relative stabilities discussed above can be further analyzed by means of an energy decomposition analysis (EDA) 57–62. Scheme shows that the 1‐oxo and the corresponding 2‐oxo isomers can be formed from the same two fragments by simply turning the fragment on the right upside‐down 4,63,64. Thus, each pair of isomers have been analyzed through the EDA analysis, with the corresponding values enclosed in Table 8.…”