Influence of the Nature of Group 15 Element on [Au^I]-C≡E/Azide 1,3-Dipolar Cycloaddition Reaction

The impact of the nature of the Group 15 element on both the bonding situation and the reactivity of gold(I)-C ≡ E (E = N to Bi) complexes has been studied quantum chemically within the density theory functional framework. For this purpose, the 1,3-dipolar cycloaddition reaction involving tBuN₃ as dipole has been selected and its main features, including the regioselectivity of the transformation and the in-plane aromaticity of the corresponding transition structures, have been investigated. It is found that the reactivity of the complexes is increased as one moves down Group 15 (N ≪ P < As < Sb < Bi). This reactivity trend has been rationalized by using the combined activation strain model and energy decomposition analysis methods, which indicate that the process is mainly dominated by the strain energy required by the reactants to reach the corresponding transition state geometries.