A Near-Infrared-Emissive Alkynyl-Protected Au24 Nanocluster.

An alkynyl-protected gold nanocluster [Au24(C≡CPh)14(PPh3)4](SbF6)2 has been prepared by a direct reduction method. Single-crystal X-ray diffraction reveals that the molecular structure contains a Au22 core that is made of two Au13-centered cuboctahedra that share a square face. Two staple-like PhC≡C-Au-C≡CPh motifs are located around the center of the rod-like Au22 core. This Au24 nanocluster is highly emissive in the near-infrared region with λ(max)=925 nm and the nature of the HOMO-LUMO transition is investigated by time-dependent DFT calculations.