401. Asian Academic Seminar December 14-20, 2016

Now in the 57

^th

year

Asian Academic Seminar 2016, December 14-20, 2016 The University of Tokyo

Associate Editor Founder

InnoNano Research Pvt. Ltd.

An IIT Madras Incubated Company

An IIT Madras incubated company

Intercluster reactions between

atomically precise noble metal clusters

Thalappil Pradeep

Institute Professor, IIT Madras

pradeep@iitm.ac.in

Atsushi Suzuki and Mamoru Mitsuishi

Number of atoms

Properties

Metal Clusters

1000 100 10

Diameter

1nm 2nm

Atom

　・ Small is different 　・ Every atom counts

Metal nanoparticles Bulk

From Y. Negishi

Au₂₅PET₁₈

1 2 3

Zhu, M.; Aikens, C. M.; Hollander, F. J.; Schatz, G. C.; Jin, R. J. Am. Chem. Soc. 2008, 130, 5883-5885.

Au S

Au₁₃ core

Au₁₃ core + the exterior 12 Au atoms

Au₂₅(SR)₁₈

Au

₂₅

(SR)

₁₈

S

D_cv D_cf

Ag₄₄SR₃₀ – Nanfeng Zheng and Terry Bigioni 2013

Ammu Mathew and T. Pradeep, Particle, 2014

I. Chakraborty et al, unpublished

Evolution of noble metal clusters

Part I Cluster chemistry is getting increasingly complex Ligand exchange

Isomers Alloys

Supramolecular chemistry Part II Intercluster reactions

Specific examples

Part III How do we understand these systems?

Evolving Science

Part I

Molecular recognition-based chemistry Supramolecular organised structures Early stages of ligand exchange and molecular recognition

Molecular chemistry with clusters is evolving

Summary

Several new methods of synthesis have been introduced Slow reduction

Interfacial synthesis Solid state synthesis Gel cavities

Sunlight-mediated Clusters from clusters Molecular containers

Ag

₉

MSA

₇

- solid state synthesis

TUB Rao and T Pradeep, J. Am. Chem. Soc. 132 (2010) 16304-16307

Ag 152 PET 60

Indranath Chakraborty, et al. Nano Lett. 2012 With Uzi Landman and Rob Whetten

Ag

₇

Au

₆

– 13 atom alloy cluster

T. U. B. Rao et al. Angew. Chem. Int. Ed. 2012 Hot article

Jobin et al. Chem. Phys. Lett. 2004, 390,181

With Tatsuya Tsukuda

a b c

HOMO LUMO

sp-ba nd

d-band

Ammu Mathew et al. ACS Nano 2014.

With Lauri Lehtovaara, Hannu H.kkinen

CD∩BBSH Positive mode MALDI of BBSH∩CD complex

β-CD/BBSH

complex

Substitution chemistry of clusters

R1

R2

Mixed functionalised clusters

Yoshiki Niihori, Miku Matsuzaki, T. Pradeep and Yuichi Negishi, J. Am. Chem. Soc., 135 (2013) 4946-4949

Ligand exchange chemistry – Substitution chemistry

Separation of precise compositions of noble metal clusters protected with mixed ligands

With Niihori and Negishi, Tokyo University of Science

Part II

Some Pointers

Noble Metal Clusters Over Oxides: Aggregation, Separation

and Reaction

Coalescence of Atomically Precise Clusters on Graphenic Surfaces

Schematic of the reaction

Time dependent MALDI MS study of the conversion of Au₂₅. Ghosh, A.; Pradeep, T.; Chakrabarti, J. J. Phys. Chem. C 2014, 118, 13959.

MALDI MS spectra with increasing graphene concentration for a constant Au₂₅ concentration. (a₂) Data at lower concentration (0.005 wt %) of graphene where complete conversion of Au₂₅ to Au₁₃₅ has not taken place. It shows some peaks at lower mass. (a3) At higher concentration (0.01 wt %) of graphene, complete conversion to Au₁₃₅ has happened. Both the spectra were collected after 180 min of mixing the reactants. (B) Time dependent conversion of Au₂₅ for a fixed graphene concentration at different Au₂₅ concentrations. IP and IR represent the intensity of Au₁₃₅ and Au₂₅ in the MALDI MS spectra. Traces b₁, b₂, and b₃ represent final concentrations of Au₂₅ in solutions (3.17, 1.68, and 0.87 μM, respectively).

(A) TEM image of chemically synthesized graphene alone. The nanometer thin folding (marked) indicates that the sheets imaged contain two-three layers of chemically synthesized graphene. (B) Image of graphene surface containing clusters (Au₁₃₅). Some clusters are marked with circles. Outside the graphene surface, there was no cluster. It proves that the conversion happened only on graphene surfaces. Number of folding has decreased significantly in panel B.

Inter-cluster reactions

Au25(PET)

18 + Ag

44(FTP)

30 Au

25-xAg

x(PET)

18-y(FTP)

y + Ag

44-mAu

m(FTP)

30-n(PET)

n

Au25(FTP)

18 + Ag

44(FTP)

30 Au

25-xAg

x(FTP)

18 + Ag

44-mAu

m(FTP)

30

PET :

FTP: MBA:

Clusters tried: [Au

₂₅

(PET)

₁₈

]

^-

[Ag

₄₄

(FTP)

₃₀

]

^4-

[Au

₂₅

(FTP)

₁₈

]

^-

Ag

₁₅₂

(PET)

₆₀

[Au

₂₅

(nBuS)

₁₈

]

^-

Reaction, clusters and ligands used

Ag-Au FTP-PET

(Ag-FTP)-(Au-PET)

FTP

PET

Au₂₅(PET)₁₈ + Ag₄₄(FTP)₃₀

K. R. Krishnadas et al. JACS 2016

A + B 🡪 C + D

40

Temporal changes in the distribution of Au

_25-x

Ag

_x

(PET)

_18-y

(FTP)

_y

during the reaction between [Au

₂₅

(PET)

₁₈

]

^-

and [Ag

₄₄

(FTP)

₃₀

]

^4-

I: Au_25-xAg_x(PET)_18-y(FTP)_y II: Ag_44-mAu_m(FTP)_30-n(PET)_n

M_Au: 197 M_Ag: 108 M_PET: 137 M_FTP: 127

14.0:1.0

7.0:1.0

1.7:1.0 M_Au: 197

M_Ag: 108 MPET: 137 M_FTP: 127

M_Au: 197 M_Ag: 108 MPET: 137 M_FTP: 127

Au

₂₅

(PET)

₁₈

+ Ag

₄₄

(FTP)

₃₀

Au

_25-x

Ag

_x

(PET)

_18-y

(FTP)

_y

; x=0-13

Au

₂₅

:Ag

₄₄

14.0:1.0

7.0:1.0

1.7:1.0

43

Au

_25-x

Ag

_x

(PET)

_18-y

(FTP)

_y

: A closer view

(0, 0)

(1, 0)

Ag-Au (2, 0)

(3, 0) (0, 0)

(0, 1) (0, 2) (0, 3)

FTP-PET

(0, 0) (1, 1) (2, 2)

(Ag-FTP)- (Au-PET)

(0, 0) = Au₂₅(PET)₁₈

Au

₂₅

(FTP)

₁₈

+ Ag

₄₄

(FTP)

₃₀

Au

_25-x

Ag

_x

(FTP)

₁₈

Energies for the substitution reaction of (A) Au in Ag

₄₄

(SR)

₃₀

, (B) Ag in Au

₂₅

(SR)

₁₈

and (C) the overall reaction energies (in eV) as a function of their positions in product clusters, Au

_x

Ag

_44-x

(SR)

₃₀

and

Au

_25-x

Ag

_x

(SR)

₁₈

for x=1

SID incorporation was introduced by Wysocki et al. Angew. Chem. Int. Ed. 2012, 51 (18), 4336-4339.

Laser

Au

₂₅

(PET)

₁₈^-

m/z

m/z

Ag

₄₄

(FTP)

₃₀^4-

Ag

₄₄

(FTP)

₃₀^3-

Ag

₄₄

(FTP)

₃₀^2-

Ag

₄₄

(FTP)

₃₀^2-

Ag

₄₄

(FTP)

₃₀^3-

Ag

₄₄

(FTP)

₃₀^4-

Reaction between Au₂₅ and Ag₄₄

Sreya Sarkar, et al.

J. Phys. Chem. Lett., 5 (2014) 3757–3762

Ag

₄₄

(FTP)

₃₀

:Au

₂₅

(FTP)

₁₈

experiments to show shell closing of

Au

₁₂

Ag

₃₂

(FTP)

₃₀

This is the slide only to show the MS features of individual clusters and a mixture of them, immediately after mixing to show that they react. D is the UV/vis features of Ag44:Au25

mixtures at increasing concentrations of Au25(FTP)18. Here, concentration of Ag44(FTP)30 is kept constant and that of Au25(FTP)18 is increased from a to c.

Incr easing [Au

25

(FTP)

18

]

[Au

_m

Ag

_n

(FTP)

₃₀

]

^4-

; m+n=44

I: icosahedron

D_cf: on the face of the cube (dark green) D_cv: vertices of the cube (light green) S: staple (blue)

57

At various time intervals

[Au

_m

Ag

_n

(FTP)

₃₀

]

^4-

; m+n=44

Immediately after mixing

After 10 min

After 1 h

58

Various unique positions of atoms and M-SR fragments in Au

₂₅

(SR)

₁₈

and Ag

₄₄

(SR)

₃₀

S: Staple

I: Icosahedron

C: Centre of icosahedron

I: icosahedron

D_cf: on the face of the cube (dark green) D_cv: vertices of the cube (light green) S: staple (blue)

A. Desireddy et al., Nature 2013, 501, 399

Ag

₂₅

-Au

₂₅

experiments

K. R. Krishnadas et al. Nature Commun. 2016

Reaction between Au

₂₅

(PET)

₁₈

and Ag

₂₅

(DMBT)

₁₈

DMBT

PET

Ag 25(DMBT) 18 Au 25(PET) 18

[Ag25(DMBT)

18+Au

25(PET)

18]^2-

[Ag

₂₅

(DMBT)

₁₈

+Au

₂₅

(PET)

₁₈

]

^2-

DMBT PET

within 2 min within 5 min Ag₂₅(DMBT)₁₈:Au₂₅(PET)₁₈

0.3:1.0

Evolution of alloy clusters from the dianionic adduct,

[Ag

₂₅

Au

₂₅

(DMBT)

₁₈

(PET)

₁₈

]

^2-

DFT-optimized structure of [Ag

₂₅

Au

₂₅

(DMBT)

₁₈

(PET)

₁₈

]

^2-

64

Ag-rich Au-rich

6.6:1.0 Ag

₂₅

:Au

₂₅

0.3:1.0 Ag

₂₅

:Au

₂₅

After 10 min After 1 h

Immediately

Formation of Ag-rich or Au-rich Ag

_m

Au

_n

(SR)

₁₈

(m+n=25) clusters

Calculated energies for the substitution reaction (∆E

_s

) of Au in Ag

₂₅

(DMBT)

₁₈

(a), Ag in Au

₂₅

(PET)

₁₈

(b) and the overall reaction energies (c), in meV, as a function of their positions in the product

clusters, Ag

₂₄

Au

₁

(DMBT)

₁₈

and Au

₂₄

Ag

₁

(PET)

₁₈

.

What does it mean?

Two kinds of chemistry

Substitution, exchange, conjugation, supramolecular, etc. chemistry and

Cluster chemistry Graphene reaction

No intermediates were prominent.

On oxide surfaces

13 kDa, ~Ag₈₀, n = 34?

20 kDa, ~Ag₁₂₀, n = 58?

Cluster coalescence

Unique inter-cluster reactions, simultaneous transformations

• Cluster science is getting increasingly complex Ligand exchange

Isomers Alloys

Supramolecular chemistry

• How do we comprehend them?

• We need to name them - uniquely

Evolving Science

Structure and name

• Current names

– Au

₂₅

(SR)

₁₈

, Au

₂₅

(SR)

₁₈

, Au@R, or just Au

₂₅

– Au

_25-m

Pd

_m

(SR1)

_18-n

(SR2)

_n

• Complexity: eg. Isomers and chirality

• => Nomenclature

– Organic, inorganic, etc.

– Fullerenes

– Boranes

What does it contain?

• We need:

1. Diagram of the molecule with labels 2. Naming scheme

1. Flexible 2. Unique

3. Structural details

What are these materials?

Aspicules

A view of gold methly thiolate [25]aspicule (Au₂₅(SMe)₁₈).

Gold atoms colored gold, sulfur atoms by yellow, carbon dark gray, hydrogen atoms as white and (b) with the gold and sulfur atoms alone .

x y

S_e

S_c S_c

Au_e Au_e

x y

z

Ball and stick structure

18(methylthiolato)-auro-25 aspicule(1-)

Gana Natarajan et. al. JPC C. 2015

(D1-3,D2-3)-di(2-phenylethylthiolato),16(methylthiolato)-auro-25 aspicule(1-) (D1-3,D2-3)-(PET)₂,(SMe)₁₆-auro-25 aspicule(1-)

x z´

y´

y

x´

³

5

3

1 4

2

1

3 4

4

4 1

1

5

5 4 5

2

2 2 1

4 3 2

5 1

2 3

5

z

3

Au S

4 1

3 2

5 6

7 i

8

9 10

11

12 Ligand Exchange & Alloy

cluster

Au₂₄Pd(SR₁)₁₀(SR₂)₈ isomer 1 (cis) 1, 5-(SBB)₁₀, 3-(SC₆H₁₂)₈

(i, 1, 2, x2)-palladoauro-25 asp (-1)

x y

z

R-(SMe)₄₄-auro-102 aspicule(0) and L-(SMe)₄₄-auro-102 aspicule(0)

Compact aspicule structural names for Au₂₅, Au₃₈ and Au₁₀₂ aspicules and one modification of each.

Aspicule structural names and aspicule names for Au₂₅, Au₃₈ and Au₁₀₂ and one modification of each.

83

Cluster HOMO /eV

LUMO/

eV

Ag₄₄(SH)₃₀ 2.59 3.45 Au₂₅(SH)₁₈ -2.53 -1.24

G. Natarajan et al., J. Phys. Chem. C 2015, 119, 27768

* 85

Summary

• Unusual chemical reactivity of clusters

• Borromean rings diagram of Au 25

• Nomenclature for Au 25 , Au 38 , Au 102 and

Au M (SR) N to describe both structure and

modifications

Thank you

Department of Science and Technology

89

Schematic of the reaction mechanism for Ag-SR/Au-SR substitution

Au₂₅(SR1)₁₈

Ag(SR2)₂