Crystal structure of a NIR‐Emitting DNA‐Stabilized Ag₁₆ Nanocluster

Abstract

DNA has been used as a scaffold to stabilize small, atomically monodisperse silver nanoclusters, which have attracted attention due to their intriguing photophysical properties. Herein, we describe the X‐ray crystal structure of a DNA‐encapsulated, near‐infrared emitting Ag16 nanocluster (DNA–Ag16NC). The asymmetric unit of the crystal contains two DNA–Ag16NCs and the crystal packing between the DNA–Ag16NCs is promoted by several interactions, such as two silver‐mediated base pairs between 3′‐terminal adenines, two phosphate–Ca2+–phosphate interactions, and π‐stacking between two neighboring thymines. Each Ag16NC is confined by two DNA decamers that take on a horse‐shoe‐like conformation and is almost fully shielded from the solvent environment. This structural insight will aid in the determination of the structure/photophysical property relationship for this class of emitters and opens up new research opportunities in fluorescence imaging and sensing using noble‐metal clusters.

Probing the Fluorescence Behavior of DNA‐Stabilized Silver Nanoclusters in the Presence of Biomolecules

“…Photoluminescent DNA-stabilized silver nanoclusters (DNA-AgNCs) have in recent years attracted significant interest. [1][2][3][4][5][6][7][8] This devoted attention is due to the peculiar luminescent properties of some DNA-AgNCs such as high fluorescence quantum efficiencies, resistance to photobleaching and wide wavelength tunability. [6,7,[9][10][11] These DNA-AgNCs consist of few silver atoms and cations (up to 30) enclosed in DNA strands, and their luminescence properties are related to the composition, charge and conformation of the AgNC.…”

“…Photoluminescent DNA‐stabilized silver nanoclusters (DNA‐AgNCs) have in recent years attracted significant interest [1–8] . This devoted attention is due to the peculiar luminescent properties of some DNA‐AgNCs such as high fluorescence quantum efficiencies, resistance to photobleaching and wide wavelength tunability [6,7,9–11] .…”

All-Carboxylate-Protected Superatomic Silver Nanocluster with an Unprecedented Rhombohedral Ag8 Core

“…For instance, Wang et al reported all-nitrogen-donor-protected Ag 21 and Ag 22 that showed interesting optical properties . More excitingly, DNA-stabilized (via nitrogen and oxygen donors on the bases) Ag 8 and Ag 16 nanoclusters with near-IR-emitting properties were characterized by X-ray single-crystal analysis . Using inorganic donors, Mizuno and co-workers reported [SiW 10 O 36 ] 8– protected Ag 6 and Ag 27 clusters, while Zhang et al obtained two unprecedented Ag 6 @Ti 16 -oxo nanoclusters with Ti-oxo clusters as ligands …”

Collective Response in DNA-Stabilized Silver Cluster Assemblies from First-Principles Simulations

“…[17][18][19] Very recent experimental advances allowed to shed light on the structures of these hybrid systems as well. 20,21 For theory these systems represent considerable challenge due to their size. Indeed, the simulations show, that in order to reliably reproduce the experimental results, accurate quantum-chemical calculations are required, 22,23 which include not only a silver cluster core, but also adjacent nucleobases, because the latter can dramatically change the optical properties of the cluster.…”

“…Ligand-stabilized silver clusters represent promising building blocks for novel ultrasmall optical and electronic devices. − The sphere of their proven applications is impressively broad, ranging from biosensing − to photovoltaics. , One of the especially hot topics of modern cluster science is represented by DNA-stabilized few-atom sliver clusters . Experimentally, significant progress has been achieved in the synthesis of these highly fluorescent and photostable complexes, , demonstrating the possibility of creating DNA-embedded silver clusters with absorption and emission spectra tunable in the whole visible range and even beyond it. − Very recent experimental advances shed light on the structures of these hybrid systems as well. , …”