Reinforcing Supramolecular Bonding with Magnetic Dipole Interactions to Assemble Dynamic Nanoparticle Superlattices

Article abstract of DOI:10.1021/jacs.9b11476

Assembling superparamagnetic particles into ordered lattices is an attractive means of generating new magnetically responsive materials, and is commonly achieved by tailoring interparticle interactions as a function of the ligand coating. However, the inherent linkage between the collective magnetic behavior of particle arrays and the assembly processes used to generate them complicates efforts to understand and control material synthesis. Here, we use a synergistic combination of a chemical force (hydrogen bonding) and magnetic dipole coupling to assemble polymer-brush coated superparamagnetic iron oxide nanoparticles, where the relative strengths of these interactions can be tuned to reinforce one another and stabilize the resulting superlattice phases. We find that we can precisely control both the dipole-dipole coupling between nanoparticles and the strength of the ligand-ligand interactions by modifying the interparticle spacing through changes to the polymer spacer between the hydrogen bonding groups and the nanoparticles' surface. This results in modulation of the materials' blocking temperature, as well as the stabilization of a unique superlattice phase that only exists when magnetic coupling between particles is present. Using magnetic interactions to affect nanoparticle assembly in conjunction with ligand-mediated interparticle interactions expands the potential for synthesizing predictable and controllable nanoparticle-based magnetic composites.

Full text of DOI:10.1021/jacs.9b11476

Subscriber access provided by UNIVERSITY OF CONNECTICUT
Communication
Reinforcing Supramolecular Bonding with Magnetic Dipole
Interactions to Assemble Dynamic Nanoparticle Superlattices
Peter J Santos, and Robert J. Macfarlane
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.9b11476 • Publication Date (Web): 06 Jan 2020
Downloaded from pubs.acs.org on January 7, 2020
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 6
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
Reinforcing Supramolecular Bonding with Magnetic Dipole
Interactions to Assemble Dynamic Nanoparticle Superlattices
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Peter J. Santos and Robert J. Macfarlane*
Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue,
Cambridge, Massachusetts 02139, United States
Supporting Information Placeholder
chemical forces driving nanoparticle assembly to produce novel
structures and structure-property relationships.
Abstract: Assembling superparamagnetic particles into ordered
1
4–18
To achieve a
lattices is an attractive means of generating new magnetically
responsive materials, and is commonly achieved by tailoring
interparticle interactions as a function of the ligand coating.
However, the inherent linkage between the collective magnetic
behavior of particle arrays and the assembly processes used to
generate them complicates efforts to understand and control
material synthesis. Here, we use a synergistic combination of a
chemical force (hydrogen bonding) and magnetic dipole coupling
to assemble polymer-brush coated superparamagnetic iron oxide
nanoparticles, where the relative strengths of these interactions can
be tuned to reinforce one another and stabilize the resulting
superlattice phases. We find that we can precisely control both the
dipole-dipole coupling between nanoparticles and the strength of
the ligand-ligand interactions by modifying the interparticle
spacing through changes to the polymer spacer between the
hydrogen bonding groups and the nanoparticles’ surface. This
results in modulation of the materials’ blocking temperature, as
well as the stabilization of a unique superlattice phase that only
exists when magnetic coupling between particles is present. Using
magnetic interactions to affect nanoparticle assembly in
conjunction with ligand-mediated interparticle interactions
expands the potential for synthesizing predictable and controllable
nanoparticle-based magnetic composites.
self-assembly system with tailorable chemical and magnetic forces,
however, a building block is needed where each interaction can be
independently tuned. Magnetic coupling can be controlled by using
different nanoparticle core sizes or changing interparticle spacings,
while chemical interactions can be dictated by using different
bonding motifs or regulating the degree of multivalency of the
1
9
binding groups.
We have recently described the synthesis of a nanoscale building
block capable of dynamic self-assembly, the nanocomposite tecton
2
0
(NCT) (Figure 1A). NCTs consist of inorganic nanoparticle cores
coated with polymer brushes. Each polymer chain in a brush
terminates in a supramolecular binding group, and when NCTs
with complementary binding groups are mixed, these bonding
interactions drive NCT assembly. Previously reported NCTs have
predominantly used diaminopyridine (DAP) and thymine (Thy)
groups as the supramolecular binding pair, where the hydrogen
bonds between DAP and Thy are thermally labile. As a result,
thermal annealing enables reorganization of the assembled lattices,
allowing NCTs to form crystalline architectures that maximize the
number of DAP-Thy interparticle bonds.
In principle, NCTs are an ideal platform for studying the interplay
between chemical bonding and magnetic coupling in nanoparticle
assembly because the composition of the particle, polymer, and
supramolecular binding group components of the NCT can be
2
1
easily and orthogonally changed. While previous NCTs used gold
nanoparticle cores (AuNPs), it is also possible to use magnetically
responsive nanoparticle compositions to study how magnetic
interactions affect assembly. In this work, NCTs were prepared
with both gold and iron oxide nanoparticle cores functionalized
with polystyrene brushes that terminated in DAP and Thy groups;
the AuNP NCTs served as a non-magnetic control to isolate the
effects of dipole-dipole interactions on particle assembly. AuNP
Superparamagnetic nanoparticles can serve as building blocks for
the synthesis of sophisticated materials, where hierarchical
ordering of the nanoparticle constituents can modulate the
1
collective magnetic response of the resulting structures. This
tunability results from magnetic dipole interactions being affected
by particle composition, size, shape, and local environment.
Therefore, controlling particle distribution within an assembled
solid is critical for fully manipulating structure-property
2
2
based NCTs were synthesized according to prior protocols. The
iron oxide nanoparticles (IONPs) were synthesized through the
decomposition of an iron oleate precursor, resulting in 9, 14, 16, or
2–6
relationships in these magnetic materials.
A strategy for
precisely dictating nanoparticle arrangement involves assembling
superlattices, where the particles are driven towards the
configuration that represents a thermodynamic minimum through a
mixture of intermolecular interactions between the nanoparticles’
2
3 nm diameter magnetite spheres with relative standard deviations
2
3
< 10% (Figures S1-S3, Table S1). DAP and Thy-terminated
polystyrene polymers of 8 kDa and 13 kDa molecular weight with
Ð < 1.1 (Figure S4, Table S2) were synthesized in the same manner
as reported for prior use in AuNP-based NCTs, but were instead
modified with a phosphonate group at their terminus to anchor the
7
–9
ligands and the surrounding solvent.
Importantly, because
magnetic dipole-dipole coupling between particles depends on the
particles’ positions relative to one another, these additional
magnetic interactions could potentially alter the particle self-
2
4,25
polymers to the IONPs (further details in the SI).
TGA
1
0–13
assembly pathways.
In other words, when the dipole-dipole
measurements indicate the polymers graft at a similar density to
both AuNP and IONP NCTs (Figure S5), meaning that the number
of DAP/Thy groups on the particles were equivalent. Isolated
interaction energies and ligand binding energies are balanced to be
of comparable strength, the magnetic force competes with the
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 2 of 6
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Figure 2. NCTs can be synthesized with both gold (AuNP) and iron
oxide nanoparticle (IONP) cores. Small angle x-ray scattering
(SAXS) patterns of superlattices assembled with IO-NCTs
(bottom), Au-NCTs (top), and mixtures of Au and IO-NCTs
(middle two). The lattices composed of just IONP or AuNP cores
possess bcc crystal symmetry, while the combinations of IONP and
AuNP have CsCl symmetry. Notably, the interparticle spacings are
nearly identical, demonstrating that the superlattice crystal
symmetry and lattice parameters can be independently controlled
from the nanoparticle core compositions.
Figure 1. A. Nanocomposite tectons (NCTs) consist of a
nanoparticle core, polymer brush, and supramolecular binding
groups that drive assembly. Here, iron oxide (IO) NCTs are
functionalized with polystyrene chains that are modified with a
terminal phosphonate anchor. Assembly is subsequently directed
via complementary hydrogen bonding moieties, but can be
strengthened with magnetic dipole coupling between aligned spins
when interparticle distances are short. B. Melt profiles of IO-NCTs
containing 16 nm diameter IONPs with 13 kDa polymers and Au-
NCTs containing 15 nm diameter AuNPs with 14 kDa polymers;
the two sets of NCTs show no significant difference in their melt
profiles. C. The melting profile of 16 nm IO-NCTs coated with 8
kDa polymers is shifted ~10℃ above that of 15 nm Au-NCTs
coated with 9 kDa polymers. Spikes in the data at high temperature
are from evaporation and condensation of solvent.
inflection point) was identical to Au-NCTs with similar design
parameters (15 nm core diameter, 14 kDa polymer molecular
weight) (Figure 1B). However, in systems where the ratio of
particle size to interparticle distance was larger (e.g. 8 kDa polymer
on 16 nm IO-NCTs, 9 kDa polymer on 15 nm Au-NCTs), T
m
increased significantly (Figure 1C). We hypothesize that this added
attractive energy arises from magnetic dipole coupling between
particles, and that these magnetic interactions are sensitive to
various nanoscale structural parameters (i.e. interparticle distance
14,16
and particle size, see Figure S7 for additional data).
Dipole-
dipole coupling is insufficient to cause particle aggregation on its
own, but can supplement the supramolecular interactions to further
strengthen NCT-NCT assembly.
solutions of DAP and Thy functionalized IO-NCTs remained stable
for at least a week, and did not noticeably respond when exposed
to a handheld magnet at the concentrations used in these
experiments (~100 nM). After mixing DAP and Thy IO-NCTs,
however, the dark solution became turbid within seconds, and
aggregates became visible within a minute. The aggregates could
be manipulated by a handheld magnet, indicating their collective
magnetic force could overcome Brownian motion.
Because NCT assembly is governed primarily by supramolecular
bonding, the two nanoparticle core compositions should be
structurally equivalent when constructing nanoparticle
superlattices. To confirm this, IO-NCTs and Au-NCTs were
thermally annealed to drive them to their thermodynamically
preferred configurations, which for complementary NCTs of
Hydrogen-bonded NCTs can be cycled between assembled and
melted states by changing the solution temperature; this process
identical size is a body centered cubic (bcc) lattice (Figure 2 red
20
and blue traces).
This crystalline arrangement is the
2
0
was monitored with UV-Vis spectroscopy (Figure S6-S7). For
IO-NCT designs with larger interparticle spacings or smaller
nanoparticle cores (e.g. 16nm core diameter, 13 kDa polymer
thermodynamic product for a range of particle sizes and polymer
19
lengths in both the Au-NCT and IO-NCT assemblies (Figure S8).
Importantly, this also means that an alternating lattice of Au and
IO-NCTs can be assembled if the two NCT compositions are
m
molecular weight) their melting temperature (T , the melt curve
ACS Paragon Plus Environment

Page 3 of 6
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Figure 4. 15 nm Au-NCTs functionalized with ~9 kDa Thy-
-1
terminated polymers exhibit a slight peak at q = 0.023 Å
Figure 3. Blocking temperature (T
assemblies with 8 kDa and 13 kDa polymer shells. T
as the peak of the derivative of the difference between the zero field
cooled (ZFC) and field cooled (FC) curves (see Figure S10 for
experimental data). Upon shortening the polymer length, the T
b
) determination for IO-NCT
is identified
indicating only minor amounts of random aggregation. Conversely,
16 nm IO-NCTs functionalized with ~8 kDa Thy-terminated
polymers show the sharp and clear scatting pattern of a face
centered cubic (fcc) superlattice.
b
b
increases and the transition range broadens, indicating an increase
in dipole-dipole interactions.
measurements). Dipole-dipole interactions are known to increase
28,29
T
b
and broaden the temperature window of this transition.
To
best determine T , the derivative of the difference between the ZFC
b
functionalized with complementary binding groups (Figure 2,
purple traces); this results in lattices structurally equivalent to CsCl
crystals.
and FC curves was taken for both the 8 kDa and 13 kDa linked
30
nanoparticle assemblies mentioned above (Figure 3). The peak,
9
b
signifying T , increased by ~11 K when the shorter polymer was
Based on these structural and thermal data, we conclude that
although the iron oxide cores of the NCTs are interchangeable with
Au-NCTs as a structural element of the superlattices, magnetic
coupling between IO-NCTs can affect the strength of interparticle
bonding when IONPs are in close proximity. At larger interparticle
spacings (surface to surface > 5 nm), the interaction energy is best
used, and the transition significantly broadened, confirming an
enhancement in dipole-dipole interactions.
m b
The observed increases in T and T are consistent with the notion
that shortening the interparticle distance between IO-NCTs allows
the magnetic polarization of each particle to interact and increase
the interparticle attraction. Adding magnetic coupling therefore
contributes another design parameter for controlling nanoparticle
assembly, and consequently it may be possible to stabilize particle
systems that otherwise may not crystallize. Indeed, IO-NCTs
synthesized with the shorter Thy-terminated polymer ligand
formed face centered cubic (fcc) lattices when prepared in the
absence of DAP-NCTs, the first time this phase has been
demonstrated in the NCT system. While Thy-Thy interactions can
2
6
estimated by the Keesom interaction:
1
푚2
)2
푈푑푑 = ― 3
(
(1)
푘퐵푇 4휋휇 푟
3
0
where m is the magnetic moment (proportional to particle size), r
is the interparticle distance, and μ is the magnetic vacuum
0
permeability. When assembled, each NCT is subject to interactions
from neighboring particles, but because the interaction energy is
-6
31
approximated to change as r , only the first few nearest neighbors
be stabilized by hydrogen bonding, these interactions are too
would be expected to contribute to the total binding energy between
neighboring NCTs. Furthermore, polymer ligand length should
significantly affect dipole-dipole coupling strength, as it dictates
weak on their own to cause the Thy-coated NCTs to assemble into
stable lattices. Accordingly, Au-NCTs functionalized with short
Thy polymers (9 kDa) exhibit only a slight scattering peak (Figure
4, red data). However, the well-defined fcc crystals formed by IO-
NCTs imply that an additional magnetic attractive force must be
present (Figure 4, blue data). Consistent with this observation, no
assembly occurs between IO-NCTs functionalized with longer
Thy-terminated polymers (Figure S9).
2
7
the surface-to-surface distance between particles. For example,
6 nm IO-NCTs functionalized with 8 kDa polymer were
1
32
determined by SAXS to have a 29.6 nm interparticle spacing;
Equation 1 predicts that this interparticle distance should result in
a dipole energy of ~5.2 k
is increased to 13 kDa (38.5 nm interparticle spacing), the
calculated interaction energy is 1.1 k T. It is important to note that
these magnetic dipole interaction energies are significantly weaker
than a single DAP-Thy hydrogen bonding pair (12.8 k T in
B
T. When the polymer molecular weight
We have demonstrated that the NCT design concept is easily
adapted to magnetic nanoparticles, making NCTs a powerful
platform for designing magnetic nanocomposites. NCTs can be
appropriately designed to either mask the identity of the core
composition, or take advantage of any inherent interparticle
interactions, with some limitations based on nanoparticle size and
interparticle spacings. Due to the complex sets of interactions
governing self-assembly in these magnetic NCTs, magnetic dipole
coupling between nanoparticles can reinforce the supramolecular
interactions that drive the formation of superlattices. These
synergistic interactions can even stabilize previously unachievable
crystallographic symmetries. Consequently, NCTs can further
B
B
19
toluene), but significant enough to contribute to assembly in
conjunction with the supramolecular bonding.
The existence of enhanced dipole-dipole coupling for NCTs with
smaller interparticle spacings can be further confirmed using zero
field cooled / field cooled (ZFC/FC) measurements to determine
the NCT assemblies’ blocking temperatures (T ), the temperature
b
at which unaligned magnetic spins orient to an applied magnetic
field (Figure 3, Figure S10, see Figure S11 for hysteresis
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 4 of 6
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
clarify the interactions of nanoscale materials, and how the
Nanoparticles.
https://doi.org/10.1039/C7NR05769E.
6) Yeom, J.; Santos, U. S.; Chekini, M.; Cha, M.; Moura, A. F. de;
Kotov, N. A. Chiromagnetic Nanoparticles and Gels. Science 2018, 359
6373), 309–314. https://doi.org/10.1126/science.aao7172.
(7) Shevchenko, E. V.; Talapin, D. V.; Kotov, N. A.; O’Brien, S.;
Nanoscale
2017,
9
(37),
13922–13928.
competition between forces affects self-assembly. Furthermore, the
ability to engineer the magnetic coupling of nanoparticles is a
promising strategy to developing materials with complex
metamaterial properties.
(
(
Murray, C. B. Structural Diversity in Binary Nanoparticle Superlattices.
Nature 2006, 439 (7072), 55–59. https://doi.org/10.1038/nature04414.
(8)
Nayak, S.; Horst, N.; Zhang, H.; Wang, W.; Mallapragada, S.;
ASSOCIATED CONTENT
Supporting Information
Travesset, A.; Vaknin, D. Interpolymer Complexation as a Strategy for
Nanoparticle Assembly and Crystallization. J. Phys. Chem. C 2019, 123 (1),
8
36–840. https://doi.org/10.1021/acs.jpcc.8b09647.
9) Zhang, C.; Macfarlane, R. J.; Young, K. L.; Choi, C. H. J.; Hao,
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Materials and Methods
Scheme S1
Figures S1-S9
Tables S1-S3
Supplementary References 1-7
The Supporting Information is available free of charge on the ACS
Publications website.
(
L.; Auyeung, E.; Liu, G.; Zhou, X.; Mirkin, C. A. A General Approach to
DNA-Programmable Atom Equivalents. Nat. Mater. 2013, 12 (8), 741–746.
https://doi.org/10.1038/nmat3647.
(10)
P.; Klajn, R. Self-Assembly of Magnetite Nanocubes into Helical
Superstructures. Science 2014, 345 (6201), 1149–1153.
https://doi.org/10.1126/science.1254132.
11) Nonappa; Haataja, J. S.; Timonen, J. V. I.; Malola, S.;
Singh, G.; Chan, H.; Baskin, A.; Gelman, E.; Repnin, N.; Král,
(
Engelhardt, P.; Houbenov, N.; Lahtinen, M.; Häkkinen, H.; Ikkala, O.
Reversible Supracolloidal Self-Assembly of Cobalt Nanoparticles to
Hollow Capsids and Their Superstructures. Angew. Chem. Int. Ed. 2017, 56
AUTHOR INFORMATION
Corresponding Author
(
23), 6473–6477. https://doi.org/10.1002/anie.201701135.
12) Ahniyaz, A.; Sakamoto, Y.; Bergström, L. Magnetic Field-
Induced Assembly of Oriented Superlattices from Maghemite Nanocubes.
Proc. Natl. Acad. Sci. 2007, 104 (45), 17570–17574.
https://doi.org/10.1073/pnas.0704210104.
13) Yang, Y.; Wang, B.; Shen, X.; Yao, L.; Wang, L.; Chen, X.; Xie,
(
*
Correspondence to: rmacfarl@mit.edu
Notes
(
The authors declare no competing financial interests.
S.; Li, T.; Hu, J.; Yang, D.; Dong, A. Scalable Assembly of Crystalline
Binary Nanocrystal Superparticles and Their Enhanced Magnetic and
Electrochemical Properties. J. Am. Chem. Soc. 2018, 140 (44), 15038–
15047. https://doi.org/10.1021/jacs.8b09779.
ACKNOWLEDGMENT
(14)
Talapin, D. V.; Shevchenko, E. V.; Murray, C. B.; Titov, A. V.;
This work was primarily supported by an NSF CAREER Grant,
award number CHE-1653289, supported in part by the U.S. Army
Research Office under Grant W911NF-18-1-0197, and made use of
the MRSEC Shared Experimental Facilities at MIT, supported by
the NSF under Award DMR 14-19807. P.J.S. acknowledges
support by the NSF Graduate Research Fellowship Program under
Grant 1122374. SAXS experiments at beamline 12-ID-B at the
Advanced Photon Source at Argonne National Laboratory were
supported by the U.S. Department of Energy, Office of Science,
Office of Basic Energy Sciences, under contract DE-AC02-
Král, P. Dipole−Dipole Interactions in Nanoparticle Superlattices. Nano
Lett. 2007, 7 (5), 1213–1219. https://doi.org/10.1021/nl070058c.
(15)
Dipolar Forces Controlling Mesoscopic Organizations of Magnetic
Nanocrystals. Nat. Mater. 2004, (2), 121.
https://doi.org/10.1038/nmat1054.
16) Chen, J.; Dong, A.; Cai, J.; Ye, X.; Kang, Y.; Kikkawa, J. M.;
Lalatonne, Y.; Richardi, J.; Pileni, M. P. Van Der Waals versus
3
(
Murray, C. B. Collective Dipolar Interactions in Self-Assembled Magnetic
Binary Nanocrystal Superlattice Membranes. Nano Lett. 2010, 10 (12),
5103–5108. https://doi.org/10.1021/nl103568q.
(17)
Frankamp, B. L.; Boal, A. K.; Tuominen, M. T.; Rotello, V. M.
0
6CH11357.
Direct Control of the Magnetic Interaction between Iron Oxide
Nanoparticles through Dendrimer-Mediated Self-Assembly. J. Am. Chem.
Soc. 2005, 127 (27), 9731–9735. https://doi.org/10.1021/ja051351m.
(18)
Yang, Z.; Wei, J.; Bonville, P.; Pileni, M.-P. Beyond Entropy:
Magnetic Forces Induce Formation of Quasicrystalline Structure in Binary
Nanocrystal Superlattices. J. Am. Chem. Soc. 2015, 137 (13), 4487–4493.
https://doi.org/10.1021/jacs.5b00332.
REFERENCES
(
1)
Nanoparticle Assemblies: Formation, Collective Behavior, and Future
Directions. ACS Nano 2011, (8), 6081–6084.
https://doi.org/10.1021/nn202883f.
2) Feld, A.; Koll, R.; Fruhner, L. S.; Krutyeva, M.; Pyckhout-
Majetich, S. A.; Wen, T.; Booth, R. A. Functional Magnetic
(19)
Santos, P. J.; Cao, Z.; Zhang, J.; Alexander-Katz, A.;
Macfarlane, R. J. Dictating Nanoparticle Assembly via Systems-Level
Control of Molecular Multivalency. J. Am. Chem. Soc. 2019, 141 (37),
5
1
4624–14632. https://doi.org/10.1021/jacs.9b04999.
(20) Zhang, J.; Santos, P. J.; Gabrys, P. A.; Lee, S.; Liu, C.;
(
Hintzen, W.; Weiß, C.; Heller, H.; Weimer, A.; Schmidtke, C.; Appavou,
M.-S.; Kentzinger, E.; Allgaier, J.; Weller, H. Nanocomposites of Highly
Monodisperse Encapsulated Superparamagnetic Iron Oxide Nanocrystals
Homogeneously Dispersed in a Poly(Ethylene Oxide) Melt. ACS Nano
Macfarlane, R. J. Self-Assembling Nanocomposite Tectons. J. Am. Chem.
Soc. 2016, 138 (50), 16228–16231. https://doi.org/10.1021/jacs.6b11052.
(21)
Wang, Y.; Santos, P. J.; Kubiak, J. M.; Guo, X.; Lee, M. S.;
Macfarlane, R. J. Multistimuli Responsive Nanocomposite Tectons for
Pathway Dependent Self-Assembly and Acceleration of Covalent Bond
Formation. J. Am. Chem. Soc. 2019, 141 (33), 13234–13243.
https://doi.org/10.1021/jacs.9b06695.
2
017, 11 (4), 3767–3775. https://doi.org/10.1021/acsnano.6b08441.
(3) Cheon, J.; Park, J.-I.; Choi, J.; Jun, Y.; Kim, S.; Kim, M. G.;
Kim, Y.-M.; Kim, Y. J. Magnetic Superlattices and Their Nanoscale Phase
Transition Effects. Proc. Natl. Acad. Sci. 2006, 103 (9), 3023–3027.
https://doi.org/10.1073/pnas.0508877103.
(22)
Ordered Crystals with Disperse Building Blocks. Nano Lett. 2019, 19 (8),
774–5780. https://doi.org/10.1021/acs.nanolett.9b02508.
23) Noh, H.-J.; Park, J.-H.; Kim, J.-Y.; Park, J.-G.; Park, J.; An, K.;
Hwang, N.-M.; Hyeon, T.; Hwang, Y. Ultra-Large-Scale Syntheses of
Santos, P. J.; Cheung, T. C.; Macfarlane, R. J. Assembling
(4)
Yang, Z.; Wei, J.; Bonville, P.; Pileni, M.-P. Engineering the
5
Magnetic Dipolar Interactions in 3D Binary Supracrystals Via Mesoscale
Alloying. Adv. Funct. Mater. 2015, 25 (30), 4908–4915.
https://doi.org/10.1002/adfm.201501499.
(
Monodisperse Nanocrystals. Nat. Mater. 2004,
3
(12), 891.
(5)
Jishkariani, D.; D. Lee, J.; Yun, H.; Paik, T.; M. Kikkawa, J.;
https://doi.org/10.1038/nmat1251.
R. Kagan, C.; Donnio, B.; B. Murray, C. The Dendritic Effect and Magnetic
Permeability in Dendron Coated Nickel and Manganese Zinc Ferrite
(24)
Matyjaszewski, K.; Xia, J. Atom Transfer Radical
ACS Paragon Plus Environment

Page 5 of 6
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
Polymerization.
https://doi.org/10.1021/cr940534g.
25) Turcheniuk, K.; V. Tarasevych, A.; P. Kukhar, V.;
Boukherroub, R.; Szunerits, S. Recent Advances in Surface Chemistry
Strategies for the Fabrication of Functional Iron Oxide Based Magnetic
Chem.
Rev.
2001,
101
(9),
2921–2990.
(29)
Hou, Y.; Yu, J.; Gao, S. Solvothermal Reduction Synthesis and
Characterization of Superparamagnetic Magnetite Nanoparticles. J. Mater.
Chem. 2003, 13 (8), 1983–1987. https://doi.org/10.1039/B305526D.
(30)
(
Bruvera, I. J.; Mendoza Zélis, P.; Pilar Calatayud, M.; Goya, G.
F.; Sánchez, F. H. Determination of the Blocking Temperature of Magnetic
Nanoparticles: The Good, the Bad, and the Ugly. J. Appl. Phys. 2015, 118
(18), 184304. https://doi.org/10.1063/1.4935484.
(31)
Formation of Free Nucleobases and Mononucleosides in the Gas Phase. J.
Am. Chem. Soc. 1994, 116 (20), 9211–9215.
https://doi.org/10.1021/ja00099a042.
(32) Macfarlane, R. J.; Lee, B.; Jones, M. R.; Harris, N.; Schatz, G.
Nanoparticles.
https://doi.org/10.1039/C3NR04131J.
26) Bishop, K. J. M.; Wilmer, C. E.; Soh, S.; Grzybowski, B. A.
Nanoscale
2013,
5
(22),
10729–10752.
(
Dey, M.; Moritz, F.; Grotemeyer, J.; Schlag, E. W. Base Pair
Nanoscale Forces and Their Uses in Self-Assembly. Small 2009, 5 (14),
1600–1630. https://doi.org/10.1002/smll.200900358.
(27)
Boal, A. K.; Frankamp, B. L.; Uzun, O.; Tuominen, M. T.;
Rotello, V. M. Modulation of Spacing and Magnetic Properties of Iron
Oxide Nanoparticles through Polymer-Mediated “Bricks and Mortar” Self-
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
C.; Mirkin, C. A. Nanoparticle Superlattice Engineering with DNA. Science
2011, 334 (6053), 204–208. https://doi.org/10.1126/science.1210493.
Assembly.
https://doi.org/10.1021/cm0495865.
28) Majetich, S. A.; Sachan, M. Magnetostatic Interactions in
Chem.
Mater.
2004,
16
(17),
3252–3256.
(
Magnetic Nanoparticle Assemblies: Energy, Time and Length Scales. J.
Phys. Appl. Phys. 2006, 39 (21), R407–R422. https://doi.org/10.1088/0022-
3727/39/21/R02.
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 6 of 6
Authors are required to submit a graphic entry for the Table of Contents (TOC) that, in conjunction with the manuscript title,
should give the reader a representative idea of one of the following: A key structure, reaction, equation, concept, or theorem,
etc., that is discussed in the manuscript. Consult the journal’s Instructions for Authors for TOC graphic specifications.
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Insert Table of Contents artwork here
6
ACS Paragon Plus Environment