Size and Structural Evolution of Atomically Precise Thiolated Bimetallic [Au 12+n Cu 32 (SR) 30+n ] 4- (n=0, 2, 4, 6) Clusters

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1 Supporting information for Size and Structural Evolution of Atomically Precise Thiolated Bimetallic [+n (SR) 30+n ] 4- (n=0, 2, 4, 6) Clusters Huayan Yang, 1 Yu Wang, 1 Juanzhu Yan, 1 Xi Chen, 2 Xin Zhang, 1 Hannu Häkkinen, 2 and Nanfeng Zheng 1, * 1 State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen , China 2 Departments of Physics and Chemistry, Nanoscience Center, University of Jyväskylä, FI Jyväskylä, Finland Experimental Details Reagents: Copper(II) perchlorate hexahydrate (Cu(ClO 4 ) 2 6H 2 O, 96%), 4-(trifluoromethyl)thiophenol (C 7 H 5 F 3 S, 97%), tetraphenylphosphonium bromide (PPh 4 Br, 98%), tetrabutyl ammonium bromide (C 16 H 36 BrN, 98%), 2-(diphenylphosphino)pyridine (C 17 H 14 NP, 97%) were purchased from Alfa Aesar. (Tianjin, China), Hydrogen tetrachloroaurate (HAuCl 4 4H 2 O, 99.9%), Triphenylphosphine (C 18 H 15 P, 98%), Sodium borohydride (NaBH 4, 98%), Triethylamine (C 6 H 15 N, 99.5%), dichloromethane (CH 2 Cl 2, A.R.), and methanol (CH 3 OH, A.R.) were purchased from Sinopharm Chemical Reagent Co. Ltd. (Shanghai, China). The water used in all experiments was ultrapure. All reagents were used as received without further purification. Syntheses of AuPPh 3 Cl and AuPPh 2 PyCl were modified by previous report (Acta Cryst.(1976). B32, 962). First dissolve g PPh 3 in 10 ml ethanol (95%) to form a clear solution (one can heat this mixture at 50 C to dissolve all PPh 3 ), and then dissolve 1 g HAuCl 4 4H 2 O in another 20 ml ethanol (95%). Then simply mix the above two ethanol solutions, stir till the formation of white precipitate, and keep stirring the mixture for another 2 hours before filtration. The white fiber-like solid is the AuPPh 3 Cl. Similarly, by using PPh 2 Py, AuPPh 2 PyCl can be made. S1

2 Synthesis of (SPhCF 3 ) 30 4PPh + 4 : For a typical synthesis of (SPhCF 3 ) 30 4PPh + 4, 10 mg AuPPh 3 Cl and 12 mg Cu(ClO 4 ) 2 6H 2 O were dissolved in the mixture solution of dichloromethane and methanol. The solution was cooled to 0 C in an ice bath, and then 5 μl 4-trifluoromethylbenzenethiol and 10 mg tetraphenylphosphonium bromide were added. After 20 minutes, 1 ml NaBH 4 aqueous solution (45 mg/ml) and 60 μl triethylamine were added quickly to above mixture under vigorous stirring. The reaction was aging for 12 hours at 0 C. The aqueous phase was then removed. The mixture in organic phase was then washed several times with water. Black block crystals were crystallized from CH 2 Cl 2 /hexane at 4 C after 10 days. Synthesis of Au 14 (SPhCF 3 ) 32 4NBu + 4 : For a typical synthesis of Au 14 (SPhCF 3 ) 32 4NBu + 4, 10 mg AuPPh 3 Cl and 12 mg Cu(ClO 4 ) 2 6H 2 O were dissolved in the mixture solution of dichloromethane and methanol. The solution was cooled to 0 C in an ice bath, and then 5 μl 4-trifluoromethylbenzenethiol and 8 mg tetrabutyl ammonium bromide were added. After 20 minutes, 1 ml NaBH 4 aqueous solution (45 mg/ml) and 60 μl triethylamine were added quickly to above mixture under vigorous stirring. The reaction was aging for 12 hours at 0 C. The aqueous phase was then removed. The mixture in organic phase was then washed several times with water. Black block crystals were crystallized from CH 2 Cl 2 /hexane at 4 C after 10 days. Synthesis of Au 16 (SPhCF 3 ) 34 4PPh + 4 : For a typical synthesis of Au 16 (SPhCF 3 ) 34 4PPh + 4, 10 mg AuPPh 2 PyCl and 12 mg Cu(ClO 4 ) 2 6H 2 O were dissolved in the mixture solution of dichloromethane and methanol. The solution was cooled to 0 C in an ice bath, and then 5 μl 4-trifluoromethylbenzenethiol and 10 mg tetraphenylphosphonium bromide were added. After 20 minutes, 1 ml NaBH 4 aqueous solution (45 mg/ml) and 60 μl triethylamine were added quickly to above mixture under vigorous stirring. The reaction was aging for 12 hours at 0 C. The aqueous phase was then removed. The mixture in organic phase was then washed several times with water. Black block crystals were crystallized from CH 2 Cl 2 /hexane at 4 C after 12 days. Synthesis of Au 18 (SPhCF 3 ) 36 4NBu + 4 : For a typical synthesis of Au 18 (SPhCF 3 ) 36 4NBu + 4, 10 mg AuPPh 2 PyCl and 12 mg Cu(ClO 4 ) 2 6H 2 O were dissolved in the mixture solution of dichloromethane and methanol. The solution was cooled to 0 C in an ice bath, and then 5 μl 4-trifluoromethylbenzenethiol and 8 mg S2

3 tetrabutyl ammonium bromide were added. After 20 minutes, 1 ml NaBH 4 aqueous solution (45 mg/ml) and 60 μl triethylamine were added quickly to above mixture under vigorous stirring. The reaction was aging for 12 hours at 0 C. The aqueous phase was then removed. The mixture in organic phase was then washed several times with water. Black block crystals were crystallized from CH 2 Cl 2 /hexane at 4 C after 7 days. Crystallization of [Au 13 Cu 12 (SPhCF 3 ) 20 ] 4PPh + 4.The [Au 13 Cu 12 (SPhCF 3 ) 20 ] 4- clusters were found in the degradation products x clusters. Pure single crystals x clusters were dissolved in dichloromethane and subjected to oxidation in air. The solution was then diffused by hexane to crystallize the oxidation products. After 7 days at 4 C, black block crystals of [Au 13 Cu 12 (SPhCF 3 ) 20 ] 4- were obtained with those x clusters. Single Crystal Analysis: The diffraction data x (X=2,4,6) and [Au 13 Cu 12 (SPhCF 3 ) 20 ] 4- were collected on an Agilent Technologies SuperNova system. X-ray single crystal diffractometer with Cu Kα radiation (λ = Å) at 100 K. The data were processed using CrysAlis Pro. S1 The structure was solved and refined using Full-matrix least-squares based on F 2 with program SHELXS-97 and SHELXL-97 S2 within Olex2. S3 Single Crystal Analysis of (SPhCF 3 ) 30 4PPh + 4 :black rodlike crystal, mm, space group P2 1 /n, a = (10) Å, b = (6) Å, c = (8) Å, α = 90, β = (3), γ = 90, V = (10) Å 3, Z = 2, Cu Kα, T = 100 K, 2θ max = reflections were measured, of which were unique with R int = Final R 1 =9.56%, wr 2 = for 2110 parameters and reflections with I > 2σ(I). Single Crystal Analysis of +2 (SPhCF 3 ) NBu + 4 :black block crystal, mm, space group P-1, a = (7) Å, b = (7) Å, c = (7) Å, α = (3), β = (3), γ = (3), V = (6) Å 3, Z = 1, Cu Kα, T = 100 K, 2θ max = reflections were measured, of which were unique with R int = Final R 1 =8.34%, wr 2 = for 2010 parameters and reflections with I > 2σ(I). Single Crystal Analysis of +4 (SPhCF 3 ) PPh + 4 :black block crystal, mm, space group P-1, a = (5) Å, b = (5) Å, c = S3

4 (10) Å, α = (18) β = (2), γ = (18), V = (8) Å 3, Z = 2, Cu Kα, T = 100 K, 2θ max = reflections were measured, of which were unique with R int = Final R 1 = 11.97%, wr 2 = for 4267 parameters and reflections with I > 2σ(I). Single Crystal Analysis of +6 (SPhCF 3 ) NBu4 + :black block crystal, mm, space group P2/n, a = (8) Å, b = (11) Å, c = (2) Å, α = (18) β = (2), γ = (18), V = (8) Å 3, Z = 2, Cu Kα, T = 100 K, 2θ max = reflections were measured, of which were unique with R int = Final R 1 = 8.91%, wr 2 = for 1951 parameters and reflections with I > 2σ(I). Single Crystal Analysis of Au 13 Cu 12 (SPhCF 3 ) 20 4PPh + 4 : black block crystal, mm, space group P-1, a = (8) Å, b = (9) Å, c = (10) Å, α = (5), β = (4), γ =80.078(4), V = (5) Å 3, Z = 1, Cu Kα, T = 100 K, 2θ max = reflections were measured, of which were unique with R int = Final R 1 =4.99%, wr 2 = for 1490 parameters and reflections with I > 2σ(I). Computational Details The calculations were performed with density functional theory code GPAW, S4 which implements projector-augmented wave method in a real-space grid. The real space had a grid spacing of 0.2 Å. Au(5d 10 6s 1 ), Cu(3d 10 4s 1 ), C(2s 2 2p 2 ), S(3s 2 3p 4 ), H(1s 1 ) electrons were regarded as the valence, and the PAW setups for Au and Cu included scalar-relativistic corrections. We chose a simple phenylthiolate (SR = SPh) to model the experimental ligands in all calculations. Total energies were evaluated at the GGA-PBE level (gradient-corrected functional of Perdew, Burke and Ernzerhof). S5 All the atoms were relaxed during the geometry optimization until the maximum force acting on atoms was below 0.05eV/Å. Angular momentum analysis of the Kohn-Sham orbitals was done as projected density of states (PDOS) as described earlier. S6 Optical absorption spectra were calculated with the PBE level using linear-response (LR) time-dependent DFT (LR-TDDFT) formalism in GPAW. S7 The contributions of single particle single hole transitions to selected optical peaks were analyzed using a recently developed method based on time-dependent density functional perturbation theory. S8 S4

5 Reference : S1. CrysAlis Pro Version (2011). Agilent Technologies Inc. Santa Clara, CA, USA. S2. Sheldrick, G. M. (2008). A short history of SHELX. Acta Cryst. A64, S3. Dolomanov et al. (2009). OLEX2: a complete structure solution, refinement and analysis program. J. Appl. Cryst. 42, S4. J. Enkovaara, C. Rostgaard, J. J. Mortensen, J. Chen, M. Dulak, L. Ferrighi, J. Gavnholt, C. Glinsvad, V. Haikola, H. Hansen, H. Kristoffersen, M. Kuisma, A. Larsen, L. Lehtovaara, M. Ljungberg, O. Lopez- Acevedo, P. Moses, J. Ojanen, T. Olsen, V. Petzold, N. Romero, J. Stausholm-Moller, M. Strange, G. Tritsaris, M. Vanin, M. Walter, B. Hammer, H. Hakkinen, G. Madsen, R. Nieminen, J. Norskov, M. Puska, T. Rantala, J. Schiotz, K. Thygesen and K. W. Jacobsen, J. Phys.: Condens.Matter 2010, 22, S5. Perdew, J. P.; Burke, K.; Ernzerhof, M. Phys. Rev. Lett, 1996, 77, S6. M. Walter, J. Akola, O. Lopez-Acevedo, P. D. Jadzinsky, G. Calero, C. J. Ackerson, R. L. Whetten, H. Grönbeck, H. Häkkinen, Proc. Natl. Acad. Sci. USA 2008, 105, S7. Walter, M.; Häkkinen, H.; Lehtovaara, L.; Puska, M.; Enkovaara, J.; Rostgaard, C.; Mortensen, J. J. J. Chem. Phys. 2008, 128, S8. S. Malola, L. Lehtovaara, J. Enkovaara, H. Häkkinen, ACS Nano 2013, 7, S5

6 Figure S1 The structure of (SPhCF 3 ) 30 4PPh + 4 Color C legend: gold sphere, Au; blue sphere, Cu; yellow sphere, S; pink sphere, P; gray sphere, C; green sphere, F; white sphere, H. S6

7 Figure S2 The structure of Au 14 (SPhCF 3 ) 32 4NBu + 4 Color C legend: gold sphere, Au; blue sphere, Cu; yellow sphere, S; cyan sphere, N; grayy sphere, C; green sphere, F; white sphere, H. S7

8 Figure S3 The structure of Au 16 (SPhCF 3 ) 34 4PPh + 4 Color C legend: gold sphere, Au; blue sphere, Cu; yellow sphere, S; pink sphere, P; gray sphere, C; green sphere, F; white sphere, H. S8

9 Figure S4 The structure of Au 18 (SPhCF 3 ) 36 4NBu + 4. Color legend: : gold sphere, Au; blue sphere, Cu; yellow sphere, S; cyan sphere, N; grayy sphere, C; green sphere, F; white sphere, H. S9

10 Figure S5. Top: Projection of the Kohn-Sham electron states to spherical harmonics in the Cu 20 core of [ (SCPhCF 3 ) 30 ] 4-. The HOMO-LUMO gap is centered around zero energy. The HOMO manifold has superatomic 1D-symmetry and the LUMO manifold 1F-symmetry (note that the 2S state is found in the middle of the 1F-states). Bottom: analysis of angular momentum character of the states localized to Au atoms in the core, Cu atoms in the core and Cu atoms in the ligand layer. The electronic structure of the other [+n (SCPhCF 3 ) 30+n ] 4- (n = 2, 4, 6) clusters is similar and is not shown here S10

11 Figure S6 Analysis of the marked peak at 716 nm in the computed absorption spectrum (top panel) of [ (SR) 30 ] 4-. The horizontal and vertical graphs in the lower figure show electronic density of states for occupied and unoccupied states, respectively, with the colors showing their angular momentumm characters (as in Fig. S5). The two-dimensional map shows the weights (squares of the absorption coefficient) of the non-interacting KS transitions (occupied to unoccupied states) contributing to the 716 nm peak. Yellow represents the maximum weight. S11

12 a Abs. (a.u.) b Abs. (a.u.) c Abs. (a.u.) Wavelength d Abs. (a.u.) Wavelength (nm) Wavelength (nm) Wavelength (nm) e A/Ao Heating Time (min) Figure S7 UV-Vis spectra of DMF solutions of (a) (SPhCF 3 ) 30 4PPh 4 +, (b)au 14 (SPhCF 3 ) 32 4NBu 4 +, (c) Au 16 (SPhCF 3 ) 34 4PPh 4 +, and (d) Au 18 (SPhCF 3 ) 36 4NBu 4 + heated in air at 50 o C for different times. (e) shows the comparison change of the absorption at 504 nm with heating time. S12

13 a 0 Abs (a.u.) 1day 2day 3day 4day 5day Abs (a.u.) 1day 2day 3day 4day 5day 6day 6day Wavelength ( nm) c Wavelength ( nm) 6 Abs (a.u.) 1day 2day 3day 4day 5day 6day Abs (a.u.) 1day 2day 3day 4day 5day 6day Wavelength ( nm) Wavelength ( nm) Figure S8 Optical absorption spectra of CH 2 Cl 2 solutions of (a) (SPhCF 3 ) 30 4PPh 4 +, (b)au 14 (SPhCF 3 ) 32 4NBu 4 +, (c) Au 16 (SPhCF 3 ) 34 4PPh 4 +, and (d) Au 18 (SPhCF 3 ) 36 4NBu 4 + at room temperature for different times under N 2 atmosphere. S13

14 Figure S9 The structure of Au 13 Cu 12 (SPhCF 3 ) 20 4PPh + 4 Color legend: gold sphere, Au; blue sphere, Cu; yellow sphere, S; pink sphere, P; gray sphere, C; green sphere, F; white sphere, H. S14

15 Abs (a.u.) 0min 10min 20min 30min 1.5h Wavelength ( nm) + Figure S10 UV/vis absorption spectra of [Au 13 Cu 12 (SPhCF 3 ) 20 ] 4PPh 4 in DMF before and after being heated at 80 C for different times. S15

16 Table S1 A summary of crystallographic data for [+n (SR) 30+n ] 4- clusters and their oxidation product (Au 13 Cu 12 ). a n Composition + 0 [ (SPhCF 3 ) 30 ] 4PPh [Au 14 (SPhCF 3 ) 32 ] 4NBu [Au 16 (SPhCF 3 ) 36 ] 4PPh [Au 18 (SPhCF 3 ) 36 ] 4NBu 4 Ox b + [Au 13 Cu 12 (SPhCF 3 ) 20 ] 4PPh 4 Space group a(å) b(å) c(å) α(o) β(o) γ(o) R(F) P2 1 /n (11) (12) (15) (4) P (7) (7) (7) (3) (3) (3) P (5) (5) (5) (18) (2) (18) P2 1 /n (4) (4) (6) (3) P (5) (12) (7) (3) (4) (11) a Resolutions: 0.88 Å for all compounds. a, b and c, and α, β and γ are unit cell dimensions and angles. R(F)= F obs - F calc / F obs with F obs > 4.0 (F). b The oxidation product of [Au 16 (SPhCF 3 ) 36 ] 4PPh 4 +. S16

17 Table S2. Comparison of PBE-relaxed theoretical structures and the crystal data for [+n (SPhCF 3 ) 30+n ] 4- clusters. Average bond lengths given in Å. n Au-Au Cu-Cu Au-Cu Cu-S Au-S (1 st shell) (2 nd shell) 0 exp calc exp calc exp calc exp calc S17