Background: During the past few decades

metal nanoclusters have received considerable research interests for their distinct optical

catalytic and electronic properties. However

till today

most studies are focused on the synthesis

structure and properties of Au and Ag clusters

while the studies on Cu nanoclusters are rather rare because of its inherent instability. Purpose: We aim to synthesize the Cu nanocluster that has the tunable photoluminescence. Methods: Through varying the initial legend molar ratio of 2-mercapto-5-n-propylpyrimidine and dodecanethiol

a series of Cu nanoclusters with different emission wavelength were prepared. The photoluminescence property and structure of these nanoclusters were studied by the photoluminescence spectrometry (PL)

X-ray absorption fine structure (XAFS) and Matrix Assisted Laser Desorption Ionization Time of Flight Spectrometer (MALDI-TOF) mass spectrometry. Results: (1) PL spectra showed that with the increase of the proportion of dodecanethiol

the maximum emission wavelength of Cu nanoclusters shifted from 618 nm to 571 nm. (2) Mass spectra results indicated that the main products were changed from Cu5MPP3 (MPP: 2-mercapto-5-n-propylpyrimidine) in the presence of MPP alone to Cu4[MPP][C12SH] when the dodecanethiol was introduced

and remains unchanged with increasing the dodecanethiol. (3) XAFS results showed that with the increase of dodecanethiol

the Cu-S bond length was shortened from 0.228 nm to 0.224 nm. Conclusion: The reduction of the amount of Cu atomic number would lead to the shift of emission wavelength from 618 nm to 597 nm

and the shortening of Cu-S bond length pushed down the HOMO level which was formed by the Cu(I)-S. With the increase of the HOMO-LUMO band gap

the emission wavelength of the products shifted from 597 nm to 571 nm. Abstract