A large-scale,
easy synthesis of red fluorescent copper nanoclusters
(CuNCs) from a cheap source copper acetate, monohydrate has been reported.
A proteinaceous amino acid cysteine has been used to stabilize these
clusters at room temperature. These nanoclusters have been thoroughly
characterized by UV–vis absorption, fluorescence spectroscopy,
matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF)
spectrometry, transmission electron microscopy (TEM), X-ray powder
diffraction analysis, cyclic voltametry (CV), and X-ray photoelectron
spectroscopy. MALDI-TOF analysis indicates that the nanocluster is
a Cu5(Cys)3 species. Computational studies revealed
the energy optimized structure of Cu5(Cys)3 with
most possible arrangements of Cu atoms and their interactions with
stabilizing ligands. It is evident from the structure that vacant
Cu sites are available; hence, these sites can be used for binding
with substrate molecules for catalytic reactions. Interestingly, these
as-synthesized red-emitting nanocluster catalyze the degradation of
4-nitrophenol (toxic chemical used in industries) to almost nontoxic
4-aminophenol at room temperature. These nanoclusters (powdered) can
also be recycled as catalyst for another time. This type of new nanocatalyst
for the organic transformation of a toxic to nontoxic material holds
future promise for the development of novel large-scale nanocatalytic
materials.