Can arsine ligands be preferred over similar phosphines to design Cu(I)-based TADF materials? The present study reveals that arsines can indeed be superior to reach shorter decay times of Cu(I)...

A new Csp3–Csp bond forming reaction is reported: the C=N bond of widespread imines reacts with acetylene gas in the presence of superbase KOtBu/DMSO at room temperature to afford terminal α‐aminoacetylenes in up to 94 % yield. The reaction allows nitrogen heterocycles, e.g. 3H‐indoles, to be directly cross‐coupled with acetylene gas.

The coordination behavior of tris(2-pyridyl)arsine (Py3As) has been studied for the first time on the example of the reactions with CuI, CuBr and AgClO4. When treated with CuI in CH2Cl2 medium, Py3As unexpectedly affords the scorpionate complex [Cu(Py3As)I]∙CH2Cl2 only, while this reaction in MeCN selectively leads to the dimer [Cu2(Py3As)2I2]. At the same time, the interaction of CuBr with Py3As exclusively gives the dimer [Cu2(Py3As)2Br2]. It is interesting to note that the scorpionate [Cu(Py3As)I]∙CH2Cl2, upon fuming with a MeCN vapor (r.t., 1 h), undergoes quantitative dimerization into the dimer [Cu2(Py3As)2I2]. The reaction of Py3As with AgClO4 produces complex [Ag@Ag4(Py3As)4](CIO4)5 featuring a Ag-centered Ag4 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 = Py3As; 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).

Aldimines react with aryl- and hetarylacetylenes in the presence of KOBu t /dimethyl sulfoxide (DMSO) or NaOBu t /DMSO systems under exceptionally mild conditions (14 °C, 1 h) to afford C–H-vinylated products, 1-azadienes of E configuration relative to the C–C bond, in up to 72% yield. Vinylation involves the unprecedentedly fast multiposition proton transfer in the intermediate adducts of acetylene to the CN bond. This new Csp2–Csp2 bond-forming reaction opens a straightforward pot-, atom-, step-, and energy-economic access to synthetically valuable 1-azadienes.