Synthesis and Characterization of a 1,2,4-Diazarsolide Anion

Cyclopentadienyl anions ([Cp]−) are
pervasive
ligands in coordination chemistry. In contrast, heavy-element derivatives
of these ligands, particularly those that feature arsenic, are not
as well developed. In this work, a new arsenic-based heterocycle with
a structure analogous to [Cp]− is presented. Reaction
of K3As7 with benzyl azide (BnN3)
leads to fragmentation of the [As7]3– core and C–H activation of two [BnN] units to give the five-membered
arsenic heterocycle [As(NC(Ph))2]−. This
arsenic heterocycle was studied by nuclear magnetic resonance and
UV–vis spectroscopy, X-ray diffraction, and its electronic
structure was investigated computationally.