We report the synthesis and crystal structure determination of two novel chiral gold nanoclusters. By utilizing BINAP, we isolate atomically precise intrinsically chiral Au nanoclusters [Au 9 (R-/S-BINAP) 4 ](CF 3 COO) 3 and [Au 10 (R-/S-BINAP) 4 (p-CF 3 C 6 H 4 CC)](CF 3 COO) 3 in high yield with one-pot synthesis. Au 9 has C 2 geometry, while Au 10 is C 1 symmetric. Interestingly, reversible interconversion between Au 9 and Au 10 can be realized by the addition or removal of a RCCAu component. The transformation from Au 9 to Au 10 leads to significant enhancement of CD signals.The maximum anisotropy factor in the visible region of [Au 10 (BINAP) 4 (p-CF 3 C 6 H 4 CC)] 3+ is the hitherto largest (up to 6.6 × 10 −3 ) among gold nanoclusters, which is approximately twice of that of [Au 9 (BINAP) 4 ] 3+ . This work demonstrates that the chiroptical activity of gold nanoclusters can be modulated by structural control through the introduction of second ligands.

Cluster-based functional materials are appealing, because clusters are well-defined building units that can be rationally incorporated for the tuning of structures and properties. Postclustering modification (PCM) allows for tailoring properties through the structural modification of a cluster with preorganized funtional groups. By introducing aldehydes into a robust gold-silver cluster via a protection-deprotection process, we manage to synthesize a new cluster bearing six reactive sites, which are available for PCM through dynamic covalent imine bonds formation with chiral monoamines. Chirality is transferred from the amine to the gold-silver cluster. The homochirality of the resulted cluster has been confirmed by X-ray structural determination and CD spetroscopy. Intense CD signals make it practical for chiral recognition and ee value determination of chiral monoamines. The strategy of prefunctionalizing of cluster and the concept of PCM open a broader prospect for cluster design and applications.

A pair of enantiopure Au13 nanoclusters have been enantioselectively synthesized by chiral ligands with stereogenic centers at the phosphorus atoms. Their structures are determined by X-ray crystallography, which are typical models with a high symmetric core and chiral surface ligand arrangement. Correlation between the crystallographic structure, the calculation, and the circular dichroism (CD) study indicates that helical ligand arrangement inducing the core into chiral distortion accounts for the chiroptical activities in the visible region. A rare example of cocrystallization of a mixture of diastereomers has been observed for the first time for gold nanoclusters, reflecting the lack of chiral self-sorting of the ligands.

Owing to the inherent instability caused by the low Cu(I)/Cu(0) half-cell reduction potential, Cu(0)-containing copper nanoclusters are quite uncommon in comparison to their Ag and Au congeners. Here, a novel eight-electron superatomic copper nanocluster [Cu 31 (4-MeO-PhC�C) 21 (dppe) 3 ](ClO 4 ) 2 (Cu 31 , dppe = 1,2-bis(diphenylphosphino)ethane) is presented with total structural characterization. The structural determination reveals that Cu 31 features an inherent chiral metal core arising from the helical arrangement of two sets of three Cu 2 units encircling the icosahedral Cu 13 core, which is further shielded by 4-MeO-PhC�C − and dppe ligands. Cu 31 is the first copper nanocluster carrying eight free electrons, which is further corroborated by electrospray ionization mass spectrometry, X-ray photoelectron spectroscopy and density functional theory calculations. Interestingly, Cu 31 demonstrates the first near-infrared (750−950 nm, NIR-I) window absorption and the second near-infrared (1000−1700 nm, NIR-II) window emission, which is exceptional in the copper nanocluster family and endows it with great potential in biological applications. Of note, the 4-methoxy groups providing close contacts with neighboring clusters are crucial for the cluster formation and crystallization, while 2-methoxyphenylacetylene leads only to copper hydride clusters, Cu 6 H or Cu 32 H 14 . This research not only showcases a new member of copper superatoms but also exemplifies that copper nanoclusters, which are nonluminous in the visible range may emit luminescence in the deep NIR region.

A gold(i)-silver(i) cluster bearing six carboxylate groups has been synthesized through the oxidation of its aldehyde precursor and the Au6 core of this cluster displays an octahedral or a trigonal prismatic configuration depending on the crystallization conditions. The reversible interconversion between these two isomers can be triggered in the solid state by the addition or removal of acetonitrile solvent molecules. Interestingly, luminescence changes were observed as each configuration shows different emission colors, yellow for octahedral type and red for the trigonal prismatic one.