Reactivity Studies of Cyclic Alkyl(Amino) Carbene (cAAC)-Supported Phosphinidenide with AuCl

A neutral octa-nuclear AuI-cluster (2) with molecular formula [(Cy-cAACPAu)4(AuCl)4] [Cy-cAAC=:C(N-2,6-iPr2C6H3)(C6H10)(CMe2)(CH2)] has been isolated, and structurally characterized by single-crystal X-ray diffraction. 2 has been further studied by NMR and ESI-MS. The mu 3-P bridged AuI-cluster 2 possesses a C2 axis that passes through the two Au atoms positioned oppositely of the central AuI4P4 core, and two carbene-P chromophores. The emission spectrum of 2 exhibited a broad band with lambda em at 720 nm, and an average lifetime of 3.36 ns when excited at 388 nm in solid state at room temperature. Cyclic voltammetry (CV) studies revealed that 2 can undergo reversible one-electron oxidation at 0.76 V. The electronic transition in 2 has been further studied by computational methods. A neutral, redox-active AuI8 cluster has been stabilized and isolated in the solid state by employing cyclic alkyl(amino) carbene (cAAC)-supported mono-anionic phosphorus (cAAC=P-) as the ligand. The novel AuI8 cluster has been observed to exhibit orange emission with an average lifetime of 3.36 ns and photoluminescence quantum yield of 0.89 % (in solid state).image

Automated summary

A novel octa-nuclear AuI-cluster has been successfully isolated and structurally characterized. Further studies on its electronic properties have been conducted using NMR, ESI-MS, cyclic voltammetry, and computational methods. Additionally, a new AuI8 cluster has been stabilized and isolated, and its photoluminescence properties have been investigated.