Limits...
Structural patterns at all scales in a nonmetallic chiral Au133(SR)52 nanoparticle.

Zeng C, Chen Y, Kirschbaum K, Appavoo K, Sfeir MY, Jin R - Sci Adv (2015)

Bottom Line: These complex surface patterns have not been observed in the smaller nanoparticles.We further demonstrate that the Au133(SR)52 nanoparticle exhibits nonmetallic features in optical and electron dynamics measurements.Our work uncovers the elegant self-organization strategies in assembling a highly robust nanoparticle and provides a conceptual advance in scientific understanding of pattern structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

ABSTRACT
Structural ordering is widely present in molecules and materials. However, the organization of molecules on the curved surface of nanoparticles is still the least understood owing to the major limitations of the current surface characterization tools. By the merits of x-ray crystallography, we reveal the structural ordering at all scales in a super robust 133-gold atom nanoparticle protected by 52 thiolate ligands, which is manifested in self-assembled hierarchical patterns starting from the metal core to the interfacial -S-Au-S- ladder-like helical "stripes" and further to the "swirls" of carbon tails. These complex surface patterns have not been observed in the smaller nanoparticles. We further demonstrate that the Au133(SR)52 nanoparticle exhibits nonmetallic features in optical and electron dynamics measurements. Our work uncovers the elegant self-organization strategies in assembling a highly robust nanoparticle and provides a conceptual advance in scientific understanding of pattern structures.

No MeSH data available.


Chiral self-assembly of the carbon tails of the SPh-p-But ligands.(A) The rotative arrangement of phenyl rings results in the formation of fourfold swirls. (B) Carbon-tail swirls on the square unit; top: left-handed isomer; bottom: right-handed isomer. Yellow: sulfur.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4643822&req=5

Figure 4: Chiral self-assembly of the carbon tails of the SPh-p-But ligands.(A) The rotative arrangement of phenyl rings results in the formation of fourfold swirls. (B) Carbon-tail swirls on the square unit; top: left-handed isomer; bottom: right-handed isomer. Yellow: sulfur.

Mentions: Resolving every thiolate ligand by x-ray crystallography allows us to further examine the arrangement of the Ph-p-But carbon tails on the spherical surface. Surprisingly, the carbon tails do not adopt the same helical stripe pattern as that of the underlying –S–Au–S– motifs; that is, the orientation of carbon tails do not follow the all-cis or all-trans conformation in each –S–Au–S– stripe. Instead, the tails tend to self-organize into multiple swirls in accord with the spherical surface of the nanoparticle (Fig. 4A), and each swirl consists of four rotatively arranged phenyl rings (Fig. 4B). Such a twisted arrangement of phenyl rings in Au133(SR)52 is in contrast with the preferred parallel stacking of phenyl rings of p-MBA (that is, SPh-p-COOH) ligands in Au102(p-MBA)44 (6). The swirly arrangement of phenyl rings can be attributed to the combined effects of spherical surface and bulky tert-butyl substituents and is a more compact packing mode compared to the parallel stacking of phenyl rings. It is worth noting that self-assembly of carbon tails of the ligands on the Au133 surface also induces chirality (Fig. 4A), but the chiral pattern is different from that formed by the –S–Au–S– motifs (that is, swirls versus helices). The surface patterns of both the helical ladders of –S–Au–S– motifs and the swirly distribution of carbon tails destroy the perfect symmetry of the spherical gold kernel and may act as specific reaction sites for functionalization (10, 30).


Structural patterns at all scales in a nonmetallic chiral Au133(SR)52 nanoparticle.

Zeng C, Chen Y, Kirschbaum K, Appavoo K, Sfeir MY, Jin R - Sci Adv (2015)

Chiral self-assembly of the carbon tails of the SPh-p-But ligands.(A) The rotative arrangement of phenyl rings results in the formation of fourfold swirls. (B) Carbon-tail swirls on the square unit; top: left-handed isomer; bottom: right-handed isomer. Yellow: sulfur.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643822&req=5

Figure 4: Chiral self-assembly of the carbon tails of the SPh-p-But ligands.(A) The rotative arrangement of phenyl rings results in the formation of fourfold swirls. (B) Carbon-tail swirls on the square unit; top: left-handed isomer; bottom: right-handed isomer. Yellow: sulfur.
Mentions: Resolving every thiolate ligand by x-ray crystallography allows us to further examine the arrangement of the Ph-p-But carbon tails on the spherical surface. Surprisingly, the carbon tails do not adopt the same helical stripe pattern as that of the underlying –S–Au–S– motifs; that is, the orientation of carbon tails do not follow the all-cis or all-trans conformation in each –S–Au–S– stripe. Instead, the tails tend to self-organize into multiple swirls in accord with the spherical surface of the nanoparticle (Fig. 4A), and each swirl consists of four rotatively arranged phenyl rings (Fig. 4B). Such a twisted arrangement of phenyl rings in Au133(SR)52 is in contrast with the preferred parallel stacking of phenyl rings of p-MBA (that is, SPh-p-COOH) ligands in Au102(p-MBA)44 (6). The swirly arrangement of phenyl rings can be attributed to the combined effects of spherical surface and bulky tert-butyl substituents and is a more compact packing mode compared to the parallel stacking of phenyl rings. It is worth noting that self-assembly of carbon tails of the ligands on the Au133 surface also induces chirality (Fig. 4A), but the chiral pattern is different from that formed by the –S–Au–S– motifs (that is, swirls versus helices). The surface patterns of both the helical ladders of –S–Au–S– motifs and the swirly distribution of carbon tails destroy the perfect symmetry of the spherical gold kernel and may act as specific reaction sites for functionalization (10, 30).

Bottom Line: These complex surface patterns have not been observed in the smaller nanoparticles.We further demonstrate that the Au133(SR)52 nanoparticle exhibits nonmetallic features in optical and electron dynamics measurements.Our work uncovers the elegant self-organization strategies in assembling a highly robust nanoparticle and provides a conceptual advance in scientific understanding of pattern structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

ABSTRACT
Structural ordering is widely present in molecules and materials. However, the organization of molecules on the curved surface of nanoparticles is still the least understood owing to the major limitations of the current surface characterization tools. By the merits of x-ray crystallography, we reveal the structural ordering at all scales in a super robust 133-gold atom nanoparticle protected by 52 thiolate ligands, which is manifested in self-assembled hierarchical patterns starting from the metal core to the interfacial -S-Au-S- ladder-like helical "stripes" and further to the "swirls" of carbon tails. These complex surface patterns have not been observed in the smaller nanoparticles. We further demonstrate that the Au133(SR)52 nanoparticle exhibits nonmetallic features in optical and electron dynamics measurements. Our work uncovers the elegant self-organization strategies in assembling a highly robust nanoparticle and provides a conceptual advance in scientific understanding of pattern structures.

No MeSH data available.