Mutation of position 5 as a crystal engineering tool for a NIR-emitting DNA-stabilized Ag16 nanocluster

Abstract

Mutation of position 5 in a ten-base DNA sequence allowed us to probe its role in the photophysical and structural properties of a DNA-stabilized silver 16 nanocluster (DNA-Ag₁₆NC). A comparison of the original T5 (thymine at position 5) compound with the new modifications: X5 (abasic site), C5 (cytosine), A5 (adenine) and G5 (guanine), was made. All mutants were able to create a similar Ag₁₆NC as formed by the original T5, however diverse packing of the crystal asymmetric units in the crystalline state and minor differences in the spectroscopic properties were observed. We showed that certain nucleotides are essential for stabilizing the Ag₁₆NC, while others are not critical and can be utilized for engineering the arrangement of the asymmetric units in the crystalline state. The latter opens up the possibility to extend the primary role of the DNA as a scaffold for encapsulating the AgNC to a secondary 3D crystal engineering tool.