Tris(2-Pyridyl)Arsine as a New Platform for Design of Luminescent Cu(I) and Ag(I) Complexes

The coordination behavior of tris(2-pyridyl)arsine (Py(3)As) has been studied for the first time on the example of the reactions with CuI, CuBr and AgClO(4). When treated with CuI in CH(2)Cl(2) medium, Py(3)As unexpectedly affords the scorpionate complex [Cu(Py(3)As)I]∙CH(2)Cl(2) only, while this reaction in MeCN selectively leads to the dimer [Cu(2)(Py(3)As)(2)I(2)]. At the same time, the interaction of CuBr with Py(3)As exclusively gives the dimer [Cu(2)(Py(3)As)(2)Br(2)]. It is interesting to note that the scorpionate [Cu(Py(3)As)I]∙CH(2)Cl(2), upon fuming with a MeCN vapor (r.t., 1 h), undergoes quantitative dimerization into the dimer [Cu(2)(Py(3)As)(2)I(2)]. The reaction of Py(3)As with AgClO(4) produces complex [Ag@Ag(4)(Py(3)As)(4)](CIO(4))(5) featuring a Ag-centered Ag(4) tetrahedral kernel. At ambient temperature, the obtained Cu(I) complexes exhibit an unusually short-lived photoluminescence, which can be tentatively assigned to the thermally activated delayed fluorescence of (M + X) LCT type (M = Cu, L = Py(3)As; X = halogen). For the title Ag(I) complexes, QTAIM calculations reveal the pronounced argentophilic interactions for all short Ag∙∙∙Ag contacts (3.209–3.313 Å).