953400-52-7Relevant academic research and scientific papers
Photochemistry of neutral isonitrile gold(I) complexes: Modulation of photoreactivity by aurophilicity and π-acceptance ability
Elbjeirami, Oussama,Omary, Mohammad A.
, p. 11384 - 11393 (2007)
This work demonstrates for the first time that aurophilicity and ligand π-acceptance ability sensitize the photoreactivity of Au(I) complexes. Photolysis of LAuICl (L = RNC or CO) complexes leads to free L, AuIII, and Au0 photoproducts. Solutions of (p-tosyl)CH2NCAuCl in dichloromethane undergo significant oligomerization leading to dimers and trimers with formation constants of 1.61 × 103 and 6.61 × 103 M-1, respectively, representing the highest values reported to date for complexes that exhibit aurophilic association in solution. The photoproduct quantum yield (Φ) varies with the LAuICl concentration in solution. For (p-tosyl)CH2NCAuCl, metallic gold forms with Φ = 0.0065 and 0.032 in 4.0 × 10-5 and 4.0 × 10-3 M dichloromethane solutions, respectively. Meanwhile, irradiation of t-BuNCAuCl primarily produces t-BuNCAuCl3 with Φ = 0.0045 and 0.013 for 5.0 × 10-5 and 5.0 × 10-3 M dichloromethane solutions, respectively. For Au(CO)Cl, metallic gold forms with Φ = 0.013 and 0.065 upon irradiation of 8.0 × 10-5 and 8.0 × 10-3 M dichloromethane solutions, respectively. Hence, *[LAuX]n oligomeric species are more photoreactive than monomeric species. The results also demonstrate intuitive control of Φ via modulation of the π-acceptance ability of L, as both follow CO > (p-tosyl)CH2NC > (alkyl)NC in LAuCl, a trend that is also commensurate with the relative long-term photosensitivity of the corresponding solids and solutions. A new method for preparing stable small gold nanoparticles is described based on the fundamental findings above. Thus, photolysis of different concentrations of LAuX in solutions containing a primary amine-terminated dendrimer leads to clear solutions exhibiting tunable visible plasmon absorptions of gold nanoparticles; these solutions maintain their colors and stability indefinitely. TEM measurements for representative samples prepared by photolysis of (p-tosyl)CH2NCAuCl solutions give rise to spherical nanoparticles as small as 5 nm.
