Peer review of: A Keplerian Ag90 nest of Platonic and Archimedean polyhedra in different symmetry groups (2020)

Reviewers' comments: 

Reviewer #1 (Remarks to the Author): 

In this manuscript, the authors reported the synthesis and structure of a novel atomically precise Ag90 
nanocluster that consists of three well defined concentric shells, each with high symmetry, including an 
octahedral Ag6 core, a middle Ag24 shell with truncated octahedron shape, and an outer Ag60 
rhombicosidodecahedron shell. Another nontrivial feature of this Ag90 cluster is that the three highly 
symmetric shells are aligned around multiple symmetry elements due to the presence of S2- and PO43- 
templates. Overall, this study provides important insight into the design of highly symmetric and 
complex atomically precise clusters via ligand template strategy, and will attract a broad interest from 
inorganic chemists, materials scientists, and in general those who are interested in structure design of 
crystalline materials . I recommend that the manuscript be accepted after a minor revision that 
addresses the following concerns: 
1. In Figure 1 it is very difficult to appreciate the morphology of Ag90b crystals from the microscope 
image. If possible, please make the images larger or have image with larger magnification. Scale bars are 
also missing. 

2. In the last paragraph of page 3, it is stated that “Ag6 octahedron with six 3.3.3 vertices …” I think it 
should be “3.3.3.3 vertices”. 

3. Where is the mirror plane in the D2h arrangement of the five platonic solids. I can only see the three 
orthogonal 2-fold axes. Please make sure if it has mirror planes or not, and point out the mirror plane 
explicitly. If no mirror planes are present, the symmetry would be D2. 

4. When discussing how the three shells are aligned around rotation axes in Ag90, would it be 
meaningful to discuss the positions of S2- and PO43- templates again? I think they play an important 
role in aligning the three shells. For example, PO43- ions seems to help align the 3-fold axes of the Ag6, 
Ag24 and Ag60. And S2- also seems to align C2 of Ag60 with C4 of Ag24. 



Reviewer #2 (Remarks to the Author): 

This paper from Sun group reports quite interesting results about the synthesis, geometry, and 
properties of atomically precise Keplerian Ag90 nanoclusters that possess a three-shell nested metallic 
framework with each showing very charming aesthetic appreciation value. The cluster was synthesized 
by a unique anion template combination method (S2- and PO43-) to control the formation and 
separation of the different polyhedral shells of nanocluster, which gives very clean interfaces between 
different shells. More interesting, authors viewed these three polyhedral shells in a brand-new 
perspective which is related to the symmetry compatibility of polyhedra when posing them together. 
They found three polyhedra with apparent incompatibility also can be encaged one-by-one together and 
explained such an uncommon mathematic issue using a product of chemistry as model through the 
geometrics method. Excepting for these fundamental science aspects, another noteworthy point of this 
work is the positive photocurrent responses by on-off cycling irradiation with LED light, which 
guarantees the possible applications of these clusters in the future. I thus believe that this manuscript 
shows important advances in the fields of chemistry, materials and mathematics and is suitable for 
publishing in such a prestigious comprehensive journal----Nature Comm after minor revision. Thus, I 
would like the authors to address these points shown below. 

(1)Some names of abbreviated journals are wrong such as ref. 31 and 32, please carefully check and 
revise them. 
(2)Authors have missed the page numbers for refs. 16 and 35. 
(3)The proposed mixed anions strategy is fascinating. This method requires two different anions as 
templates. It would be good for the authors to provide a short comment on the underlying chemistry 
about why selecting PO43- in this system. 
(4)What is the special roles of S2- and PO43- on shaping the polyhedral silver shell? Some comments 
about this should be added into main text, which will be help for us to understand some intrinsic 
assembly rule in silver cluster chemistry. 
(5)The innermost Ag6 octahedron has been widely observed in silver cluster family for example in J. Am. 
Chem. Soc. 2019, 141, 19550 and Chem. Commun., 2013, 49, 376. Is this one also subvalent as reported 
by the same group? How to determine the valence of the inner core? 
(6)In synthesis section, no mol amount was provided for Na3PO4, why? 



Reviewer #3 (Remarks to the Author): 

In this paper, Sun and Schein performed a detailed and in-depth investigations on a pair of polymorphic 
Ag90 nanoclusters under the direction of mixed anion templates, S2- and PO43-. It is thrilled to find that 
the as-synthesized Ag90 nanoclusters have three polyhedral shells from inner to outer, octahedron, 
truncated octahedron, and rhombicosidodecahedron, respectively. The former two have Oh symmetry 
whereas the latter has Ih symmetry. The nesting of three polyhedra in one compound thus arouses an 
interesting mathematic problem that is how they can align together by fitting some unmatched 
symmetry elements such as 2-, 3-, or 4-fold axis. This problem was well explained in this work based on 
geometric principles. The manuscript is well written with solid data to support their conclusions. The 
quality of single crystal x-ray data was quite good in this work, although I know the huge difficulty for 
collecting satisfactory crystallographic data for structural analysis of such large nanoclusters. Moreover, 
temperature-dependent emission and photocurrent response properties were also studied, providing an 
insight of the self-assembly and demonstrating the potential application of such high-nuclearity clusters. 
I am sure that the synthetic protocol, structural aspects and new findings in math included in this work 
will be of interest to heterogeneous readers from communities of coordination chemistry, nanocluster 
chemistry, materials science, nanoscience, and even mathematics. I should not hesitate to recommend 
the acceptance of this paper in Nature Comm but after the authors have addressed the following minor 
issues. 

1. Why PhCOOAg and CH3SO3Ag can produce two Ag90 nanoclusters packing in the different unit cell? 
How about the synthesis results if other silver salts used instead? Some comments about this will be 
welcomed in main text. 
2. Are these silver nanoclusters stable in air or light? 
3. The discussion of optical properties of the title compound raises concerns. They apply the Kubelka-
Munk function to calculate the optical band gap as if they had a band semiconductor. But the authors 
did not show which type of the function used, which is important because different functions are used 
for direct-gap and indirect-gap semiconductors. 
4. In this work, I found that single-crystal X-ray diffraction was used as a main technique to 
resolve/refine the structure and determine the molecular composition of the as-synthesized Ag90 
nanoclusters. However, it has been already well accepted in the nanocluster field that ESI-MS is an 
alternative powerful method to determine the molecular formula, charge state, solution behavior, 
cluster transformation reaction, even the assembly mechanism of the metal nanoclusters. What is the 
ESI-MS result of Ag90 nanoclusters in the current work? Some possible discussions on ESI-MS may 
benefit the readers, especially to those lack of extensive research experiences on metal nanoclusters. 
5. As stated by authors, all S2- ions are from in situ decomposition of tBuSH. I think there should have 
some references to support this hypothesis. 
6. The text needs polishing or proof-reading due to the existence of several typos.