We show that using the same reaction procedure, by hindering or allowing the formation of a reaction intermediate, the Ag+dodecanethiolate polymeric complex, it is possible to selectively obtain Ag dodecanethiolate nanoparticles or Ag dodecanethiolate nanoclusters in the size range 4-2 nm. Moreover, the Ag dodecanethiolate nanoclusters display a lamellar superstructure templated from the precursor Ag+dodecanethiolate polymeric complex. A plausible formation mechanism is illustrated where, starting from the precursor and scaffold lamellar Ag+thiolate polymeric complex, first the nanocluster Agn0core is formed by reduction of isoplanar Ag+ions, followed by Ag+thiolate units that build protection, the nanocluster shell, around the core. The nanoclusters are characterized by elemental analyses, XRD, ATR-FTIR, XPS, XAS, MALDI, ESI, UV-Vis and fluorescence measurements. The luminescent Ag15(dodecanethiolate)11·2H2O nanocluster is achieved in good yield after 4 hours of reaction whereas after 2 hours, the luminescent Ag35(dodecanethiolate)16is isolated. Both Ag nanoclusters present emission bands in the range 330-450 nm, the shifting depending on the excitation wavelength. This phenomenon is attributed to a possible dipolar state causing distribution in energies due to variability of dipole-dipole interactions. Moreover, both nanoclusters further present a NIR emission at about 700 nm independent from the excitation wavelength. Thanks to their optical and structural properties, the synthesized nanoclusters, perfect molecular/nanoparticle hybrids, have great potentiality for new applications in nanotechnologies.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
Suber, L., Imperatori, P., Pilloni, L., Caschera, D., Angelini, N., Mezzi, A., Kaciulis, S., Iadecola, A., Joseph, B., & Campi, G. (2018). Nanocluster superstructures or nanoparticles? the self-consuming scaffold decides. Nanoscale, 10(16), 7472 - 7483. https://doi.org/10.1039/c7nr09520a