ja305198p_si_001.pdf (7.67 MB)
Radical-Involved Photosynthesis of AuCN Oligomers from Au Nanoparticles and Acetonitrile
journal contribution
posted on 2016-02-20, 06:56 authored by Renhong Li, Hisayoshi Kobayashi, Jiawei Tong, Xiaoqing Yan, Yu Tang, Shihui Zou, Jiabin Jin, Wuzhong Yi, Jie FanWe show here the first radical route for the direct photosynthesis
of AuCN oligomers with different sizes and shapes, as evidenced by
TEM observations, from an Au nanoparticle/benzaldehyde/CH3CN ternary system in air under UV-light irradiation. This photochemical
route is green, mild, and universal, which makes itself distinguishable
from the common cyanidation process. Several elementary reaction steps,
including the strong C–C bond dissociation of CH3CN and subsequent •CN radical addition to Au, have been suggested
to be critical in the formation of AuCN oligomers based on the identification
of •CN radical by in situ EPR and the radical
trapping technique, and other reaction products by GC-MS and 1H NMR, and DFT calculations. The resulting solid-state AuCN
oligomers exhibit unique spectroscopic characters that may be a result
of the shorter Au–Au distances (namely, aurophilicity) and/or
special polymer-like structures as compared with gold cyanide derivatives
in the aqueous phase. The nanosized AuCN oligomers supported on mesoporous
silica showed relatively good catalytic activity on the homogeneous
annulation of salicylaldehyde with phenylacetylene to afford isoflavanones
employing PBu3 as the cocatalyst under moderate conditions,
which also serves as evidence for the successful production of AuCN
oligomers.