Supporting Information Dissociation of Gas Phase Ions of Atomically Precise Silver Clusters Reflects Their Solution Phase Stability

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Supporting Information

Dissociation of Gas Phase Ions of Atomically Precise Silver Clusters Reflects Their Solution Phase Stability

Papri Chakraborty, Ananya Baksi, Esma Khatun, Abhijit Nag, Atanu Ghosh and Thalappil Pradeep*

DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India

*Corresponding author: Fax: + 91-44 2257-0545

*E-mail: [email protected]

Table of Content

Description Page Number

Synthesis of [Ag44(2,4-DCBT)30][PPh4]4 3

List of Figures

Description Page

Number S1 UV-vis and ESI MS characterization of [Ag29(BDT)12(TPP)4]

cluster

3

S2 UV-vis and ESI MS characterization of [Ag44(FTP)30] cluster 4 S3 UV-vis and ESI MS characterization of [Ag25(DMBT)18] cluster 5

S4 MS/MS spectra of [Ag29(BDT)12]^3-ion 6

S5 Experimental and calculated patterns are shown for [Ag24(BDT)9]^2-, [Ag₁₉(BDT)₆]^- and [Ag₂₆(BDT)₁₀]^2-

7

S6 MS/MS spectra of [Ag44(FTP)30]^4- 8

S7 MS/MS spectra of [Ag44(FTP)30]^3- 9

S8 Experimental and calculated isotopic patterns are shown for 10

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S2

[Ag43(FTP)28]^3-, [Ag42(FTP)27]^3-, [Ag43(FTP)28]^2-and [Ag42(FTP)27]^2-

S9 ESI MS of [Ag₄₄(DCBT)₃₀] cluster and collision energy resolved fragmentation curves

11

S10 MS/MS at higher collision energies for [Ag19(DMBT)12]^- 12 S 11 Fitting parameters for the sigmoidal fit of survival yield curves 13 S 12 Solution phase stability comparison of [Ag29(BDT)]12,

[Ag₂₅(DMBT)₁₈] and [Ag₄₄(FTP)₃₀]

14

S 13 Pressure dependence of collision energies 15 S 14 Collision energy resolved fragmentation curves of [Ag29(BDT)12]^3-

ion in presence of Ar and CO gas

16

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S3

Synthesis of [Ag₄₄(2,4-DCBT)₃₀][PPh₄]₄.Approximately 20 mg of AgNO₃ was dissolved in 5 mL methanol and 9 mL DCM. To this reaction mixture, 48 µL of 2,4-DCBT (in 0.5 mL DCM) and 12 mg PPh₄Br (in 0.5 mL DCM) were added at 5 min time interval. After about 20 min, NaBH₄(23 mg in 2 mL ice cold water) was added under stirring condition. The reaction was continued for 11-12 h in an ice bath. The reddish brown colored solution was taken in a round bottomed flask and the solvent was evaporated completely. Then the precipitate was washed with methanol and the cluster was collected by dissolving the precipitate in DCM.

Supporting Information 1

Figure S1: A) UV-vis and B) ESI MS characterization of [Ag₂₉(BDT)₁₂(TPP)₄] cluster.

Structure^† of the cluster is shown in the inset of A). Inset of B) shows the matching of experimental and calculated patterns of the peak for [Ag₂₉(BDT)₁₂]^3-(m/z 1604).

†Structure has been modelled assuming the co-ordinates from the crystal structure. Color codes: red=silver, yellow=sulphur, grey=carbon, hydrogen atoms are not shown for clarity.

2000 4000 6000 8000 10000

Experimental Calculated

m/z

m/z 400 500 600 700 800

0.0 0.2 0.4 0.6 0.8

Wavelength (nm)

Absorbance

A) B)

[Ag29(BDT)12]3-

1600 1605 1610

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S4

Supporting Information 2

Figure S2: Full range ESI MS of [Ag44(FTP)30][PPh4]4 cluster. Experimental and calculated isotopic distributions for [Ag44(FTP)30]^4-and [Ag44(FTP)30]^3-are also shown. Inset a) shows the UV-vis absorption features of the cluster. Structure^† of the cluster is also shown.

† Structure has been modelled assuming the co-ordinates from the crystal structure. Color codes: red=silver, yellow=sulphur, grey=carbon, yellowish green=fluorine, hydrogen atoms are not shown for clarity.

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Supporting Information 3

Figure S3: A) UV-vis and B) Full range ESI MS of [Ag25(DMBT)18] cluster. Structure^†of the cluster is represented in the inset of A) and inset of B) shows the experimental and calculated patterns of the peak for [Ag25(DMBT)18]^-(m/z 5166).

†Structure has been modelled assuming the co-ordinates from crystal structure. Color codes:

red=silver, yellow=sulphur, grey=carbon, hydrogen atoms are not shown for clarity.

2000 4000 6000 8000 10000

m/z

m/z Experimental

Calculated [Ag₂₅(DMBT)₁₈]^-

400 600 800 1000

0.0 0.1 0.2 0.3 0.4 0.5

[Ag₅(DMBT)₆]^-

Wavelength (nm)

Absorbance

A) B)

5150 5160 5170 5180

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S6

Supporting Information 4

Figure S4: MS/MS spectra of [Ag29(BDT)12]^3-ion with increasing collision energy. A) the region between m/z 1500 to 3000, B) an expanded view of the region between m/z 2000 to 3000 and C) expanded view of lower mass region from m/z 300 to 500. Each spectrum is normalized with respect to the most intense peak, and the actual multiplication factor of the intensities as compared to the original full range mass spectrum is indicated in each case. D) shows a plot of TIC vs collision energy (V).

1500 2000 2500 3000 2000 2500 3000

2 V 22 V 24 V 26 V 40 V

30 V 36 V

[Ag24(BDT)9]^2- [Ag29(BDT)12]^3-

[Ag19(BDT)6]^-

[Ag26(BDT)10]^2-

m/z m/z

A) _[Ag B)

19(BDT)6]^-

× 1

× 10

× 100

× 1000

× 6666

× 30000

× 2125

× 1000

× 2700

× 5000

× 3800

× 6666

300 400 500

m/z

18 V 24 V 28 V 32 V 40 V [Ag2(BDT)]^-

[Ag(BDT)2]^-

× 30000

× 5000

× 3500

× 3200

× 3000

C)

0 10 20 30 40 50

0 1x10⁵ 2x10⁵ 3x10⁵

Collision Energy (V)

Total Ion Count (TIC)

D)

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Supporting Information 5

Figure S5: Experimental and calculated mass spectral distributions are shown for A) [Ag₂₄(BDT)₉]^2-, B) [Ag₁₉(BDT)₆]^- and C) [Ag₂₆(BDT)₁₀]^2-.

2880 2900 2100 2110

1920 1930

[Ag₂₄(BDT)₉]^2- [Ag₁₉(BDT)₆]^-

m/z m/z

A) B) C)

[Ag₂₆(BDT)₁₀]^2-

m/z

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Figure S6: A) MS/MS spectra of [Ag44(FTP)30]^4-, B) an expanded view of the higher mass region between m/z 2100 and 2900, C) species [Ag42(FTP)26]^2-and [Ag41(FTP)25]^2-are detected, although, they are at very low intensities. Each spectrum is normalized with respect to the most intense peak, and the actual multiplication factor of the intensities as compared to the original full range spectrum is also indicated.

1500 3000 4500

[Ag(FTP)2]^-

[ Ag44(FTP)30]^4- [Ag43(FTP)28]^3-

2100 2400 2700

[ Ag44(FTP)30]^4-

[Ag43(FTP)28]^3-

[Ag42(FTP)27]^3-

m/z m/z

[Ag2(FTP)3]^-

A) B)

3600 3800 4000 4200

CE 2 CE 4 CE 8 CE 12

CE 0 CE 4 CE 8 CE 12

C)

[Ag₄₂(FTP)₂₆]^2-

[Ag41(FTP)25]^2-

m/z

× 10

× 30

× 50

× 1500

× 52360

× 122962

× 36642

× 13833

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S9

Supporting Information 7

Figure S7: A) MS/MS spectra of [Ag₄₄(FTP)₃₀]^3- with increasing collision energy and B) an expanded view of the region between m/z 3700 and 4300 (multiplication factor of intensities is also indicated).

2000 4000 6000 8000 10000 [ Ag₄₄(FTP)₃₀]^3-

[Ag(FTP)2]^- [Ag₂(FTP)₃]^-

CE 2 CE 8 CE 12 CE 16 CE 20

m/z

3800 4000 4200

[Ag43(FTP)28]^2-

[Ag₄₂(FTP)₂₇]^2- - FTP - FTP

m/z

A) B)

× 1500

× 350

× 1500

× 462

× 245

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S10

Figure S8: Experimental and calculated isotopic patterns for A) [Ag43(FTP)28]^3-, B) [Ag42(FTP)27]^3-, C) [Ag43(FTP)28]^2-and D) [Ag42(FTP)27]^2-.

4090 4100 4110

2650 2655 2660

3980 3990

2730 2735 2740

m/z

Experimental Calculated [Ag₄₃(FTP)₂₈]^3-

m/z

[Ag₄₂(FTP)₂₇]^3-

m/z

[Ag₄₂(FTP)₂₇]^2-

m/z

[Ag₄₃(FTP)₂₈]^2-

A) B)

C) D)

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Figure S9: A) Full range ESI MS of [Ag44(DCBT)30] cluster, B) Collision energy resolved fragmentation curves of [Ag44L30]^4- ion. C) Experimental and calculated isotopic distributions of a) [Ag44L30]^4-, b) [Ag43L28]^3-, c) [Ag42L27]^3-, d) [AgL2]^- and e) [Ag2L3]^-. (L=2,4-DCBT).

2000 4000 6000 8000 10000 0 8 16 24 32 40 48 0.0

0.2 0.4 0.6 0.8

1.0 [Ag₄₄L₃₀]^4-

[AgL2]^-

[Ag₄₃L₂₈]^3- [Ag₂L₃]^- [Ag₄₂L₂₇]^3-

L =

Cl Cl

HS

Collision Energy (eV) Relative Intensity (I/ΣIi)

m/z [Ag₄₄L₃₀]^4-

[Ag43L28]^3-

A) B)

C)

2516 2520 2524 2528 [Ag₄₄L₃₀]^4-

3200 3208 3216

[Ag₄₃L₂₈]^3-

3105 3110 3115 3120 [Ag₄₂L₂₇]^3-

m/z m/z m/z

460 465 470

[AgL₂]^-

m/z

745 750 755 760 [Ag₂L₃]^-

m/z

a) b) c)

d) e)

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S12

Supporting Information 10

Figure S10: MS/MS at higher collision energies showing fragmentation from [Ag19(DMBT)12]^-. The peaks are labelled as (x,y)^-where ‘x’ represents the number of Ag atoms and ‘y’ represents the number of DMBT ligands.

2000 4000 6000

(19, 12)

-

(18, 1 1)

-

(17, 10)

-

(16, 9)

-

(15, 8)

-

(14, 7)

-

(18, 1 1)

-

(16, 9)

-

CE 100 CE 120 CE 150

m/z

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S13

Figure S11: Fitting parameters for the sigmoidal fit of survival yield curves of A) [Ag₂₉(BDT)₁₂]^3-, B) [Ag₂₅(DMBT)₁₈]^- and C) [Ag₄₄(FTP)₃₀]^3-.

Adj. R-Square 0.99867

Value Standard Error

a 0.99946 0.00704

b -9.58389E-4 0.00693

x

₅₀

71.57234 0.15176

dx 3.14822 0.13754

Adj. R-Square 1

a 0.99969 1.95137E-4

b 3.24014E-4 1.7949E-4

x

₅₀

53.87215 0.00479

dx 1.09123 0.00416

Adj. R-Square 0.99963

a 0.96353 0.00607

b -0.00656 0.00417

x

₅₀

10.8473 0.05218

dx 1.74467 0.04673

A) [Ag₂₉(BDT)₁₂]^3-

B) [Ag₂₅(DMBT)₁₈]^-

C) [Ag₄₄(FTP)₃₀]^3-

Equation : y = (a-b)/(1 + exp((x-x

₅₀

)/dx)) + b

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S14

Figure S12: Time dependent UV-vis absorption features of A) [Ag29(BDT)]12, B) [Ag25(DMBT)18] and C) [Ag44(FTP)30]. The less stability of [Ag44(FTP)30] is reflected in its absorption features, the characteristic features are lost after about 6 h. Under ambient conditions [Ag25(DMBT)18] is also less stable compared to [Ag29(BDT)]12, as its absorbance decreases significantly (stability is shown upto 5days)_.

400 600 800 1000

0.0 0.2 0.4 0.6

400 600 800 1000

0.0 0.2 0.4 0.6

400 600 800 1000

0.0 0.2 0.4 0.6

Wavelength (nm)

Absorbance

Wavelength (nm) Wavelength (nm)

A) [Ag₂₉(BDT)₁₂] B) [Ag₂₅(DMBT)₁₈] C) [ Ag₄₄(FTP)₃₀]

0 h 6 h 12 h 0 h

Day 1 Day 5 0 h

Day 1 Day 5

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Supporting Information 13

Figure S13: Collision energy resolved fragmentation curves of [Ag29(BDT)12]^3- cluster ion at two different pressures. Pressure P1 is the normal trap pressure (trap gas flow of 2 mL/min) and P2 is the pressure corresponding to a trap gas flow of 10 mL/min. Ecom50 increases with increase of pressure. There is a slight change in the branching ratios of the fragment ions at higher pressure (trap gas flow of 10 ml/min) as shown in the fragmentation curves in the inset a).

0 20 40 60 80 100 120 140 160 0.0

0.2 0.4 0.6 0.8 1.0

Relative Intensity (I/ΣIi)

Collision Energy (eV) P₁

P₂ P₂> P₁ _E

com50(P1) = 0.59 eV Ecom50(P2) = 0.71 eV

0 30 60 90 120 150 180 0.0

0.2 0.4 0.6 0.8 1.0

Elab(P1) = 72 eV

Elab(P2) = 87 eV

a) [Ag₂₉(BDT)₁₂]^3- [Ag₅(BDT)₃]^-

[Ag24(BDT)9]^2-

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Supporting Information 14

Figure S14: Collision energy resolved fragmentation curves of [Ag29(BDT)12]^3-ion in presence of Ar and CO. Higher energy (in laboratory scale) is required for the dissociation in presence of CO but the calculated true energy in the center-of-mass frame is exactly the same for the two gases (conditions were kept as: capillary voltage 3 kV, cone voltage 50 V and trap gas flow 10 mL/min).Collision energy resolved fragmentation curves for the parent as well the fragment ions in presence of CO gas is also shown in inset a).

0 30 60 90 120 150 180 0.0

0.5 1.0

Ar CO

Relative Intensity (I/ΣIi)

Collision Energy (eV) Elab50(Ar)~ 62 eV Elab50(CO)~ 89 eV

𝐸𝐸_{𝑐𝑐𝑐𝑐𝑐𝑐} = 40

40 + 4809 × 62 = 0.51 𝑒𝑒𝑒𝑒

𝐸𝐸𝑐𝑐𝑐𝑐𝑐𝑐 = 28

28 + 4809 × 89 = 0.51 𝑒𝑒𝑒𝑒 Ar

CO

0 30 60 90 120 150 180 210 0.0

0.2 0.4 0.6 0.8 1.0

[Ag₂₉(BDT)₁₂]^3- [Ag5(BDT)3]^-

[Ag24(BDT)9]^2-

a)