An End-on-Coordinated As4 Tetrahedron

摘要

Almost 150 years ago, Bettendorff discovered yellow arsenic as an allotrope of the element but could not isolate it in pure form because of its high instability and fast decomposition into an amorphous form. After 35 years of intense discussions on the existence or non-existence of As4, Erdmann and Unruh were the first to report a large-scale synthesis of yellow arsenic along with its physical properties. However, it took another 75 years until the groups of Sacconi and Scherer used this elusive arsenic allotrope as well as P4 for the synthesis of polyelement ligand complexes (E_n ligand complexes; E = P, As) to demonstrate well the analogy between the two Group 15 homologues. In particular the activation of white phosphorus by transition metals and main-group elements has become an active research field in inorganic chemistry. In contrast, the reactivity of As4 has been much less explored, which is due to its instability, poor solubility, time-consuming synthesis and fast decomposition to grey arsenic, especially when exposed to light.