Luminescent gold and silver complexes with the monophosphane 1‑(PPh2)‑2-Me‑C2B10H10 and their conversion to gold micro- and superstructured materials

Abstract

Gold and silver complexes containing the monophosphane 1-PPh2-2-Me-l,2-C2B10H10 with different coordination numbers (2, 3) have been synthesized: [M(7,8-(PPh2)2-C2B9H10)(1-PPh2-2-Me- C2B10H10)] (M = Ag, Au) and [Au2(μ-1,n-C2B10H10)(1-PPh2-2-Me- C2B10H10)2] (n = 2, 12). Solid-state pyrolysis of [AuCl(1-PPh2-2-Me- C2B10H10)] and [Au2(μ-1,12-C2B10H10)(1-PPh2-2-Me-C2B10H10)2] in air and of solutions of [AuCl(1-PPh2-2-Me-C2B10H10)] deposited on silicon and silica at 800 °C results in single-crystal Au, confirmed by diffraction and SEM-EDS. The morphology of the pyrolytic products depends on the thermolytic conditions, and different novel 3-D superstructures or microcrystals are possible. We also propose a mechanism for the thermal conversion of these precursors to structural crystalline and phase pure materials. The presence of the carborane monophosphane seems to originate quenching of the luminescence at room temperature in the complexes [Au2(μ-1,n-C2B10H10)(1-PPh2-2-Me-C2B10H10)2], in comparison with other [Au2(μ-1,n-C2B10H10)L2] species (L = monophosphane).