Passivation of Copper: Benzotriazole Films on Cu(111)

Transcription

1 Supporting Information for Passivation of Copper: Benzotriazole Films on Cu(111) Federico Grillo*, Daniel W. Tee, Stephen M. Francis, Herbert A. Früchtl and Neville V. Richardson EaStCHEM and School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, United Kingdom 1

2 S1. Comparison between HEELS and calculated vibrational spectra After geometrical optimization, the following vibrational spectra for gas phase species were calculated using the Gaussian 03 software package, 1 with the B3LYP hybrid exchange correlation functional and the 6-311G basis set and no symmetry constraints: dimer Cu(BTA) 2, monomers Cu(N 1 )BTA and Cu(N 2 )BTA. Calculated spectra were corrected according to the formula proposed by Matsuura and Yoshida. 2 Figure S1 shows a comparison between the calculated spectra and the experimental HREEL spectrum collected for a nominal 2.5 ML equivalent preparation after annealing to ca. 423 K. The comparison between experimental and calculated spectra shows clear similarities between the observed modes and those calculated for Cu(BTA) 2, less so for CuBTA. The peak at ca. 240 cm -1 is due to the interaction of the Cu(BTA) 2 dimer with the Cu(111) surface. Figure S1. Comparison between the calculated vibrational spectra for gas phase Cu(BTA) 2, Cu(N 1 )BTA, Cu(N 2 )BTA and the experimental HREEL spectrum for a ca. 2.5 ML equivalent preparation collected after annealing to ca. 423 K. 2

3 Table S1 reports the experimentally observed modes, a comparison with the calculated ones and their assignments based also upon reference

4 Table S1. HREELS observed peaks (in cm -1 ), comparison with calculated ones and their assignments. Experimental Experimental Calculated spectra* Assignment HREELS RAIRS 7 BTAH BTA - BTA(N 1 )Cu BTA(N 2 )Cu Cu(BTA) ν N-H ν C-H Aromatic ring in phase ν C 7 -C 7a + ν C 4 -C Aromatic ring out of phase ν C 4 -C 5 + ν C 6 -C δ C 7a Ν 1 Η ν N 1 -C 7a + ν N 1 -Cu ν N 2 -N 3 + ν N 3 -N 3a ν C 6 -C ν N 2 -N 3 + ν N 1 -N w C-H δ N 1 -N 2 -N 3 scissor Aromatic ring breathing + ν N 2 -Cu w C-H ν N 1 -N w N-H Aromatic ring oop deformation Aromatic ring breathing + ν N i -Cu 535 Triazo ring oop deformation Aromatic and triazo ring oop deformation 416 Aromatic ring in plane deformation ν N i -Cu 240 ν N 2 ---Cu surface Symbols: ν, stretching; δ, in-plane bending; w, wagging; oop, out of plane; *calculated spectra are corrected according to the formula proposed by Matsuura and Yoshida. 2 4

5 S2. TPD additional information Figure S2. TPD traces for a ca. 2.5ML equivalent preparation of BTAH/Cu(111). 5

6 S3. Additional STM images Figures S3, S4 and S5 show additional STM images collected for the submonolayer, 1 monolayer and 2.5 monolayers regimes respectively, as prepared and annealed to different temperatures. Figure S3. As prepared molecular structures formed upon adsorption of BTAH on Cu(111); a) ca ML: molecular chains similar to those described in reference 7; nm 2, V, 0.82 na; b) ca. 0.5 ML: higher density of molecular chains; dimers show a fine structure; nm 2, V, 0.79 na; c) ca. 0.5 ML: hexagonal phase beginning to form (left) and (2 1)-Cu(111) reconstruction (right), nm 2, V, 0.91 na; d) ca. 0.7 ML: extended hexagonal phase; nm 2, -0.5 V, 0.25 na. 6

7 Figure S4. Molecular structures formed upon adsorption of BTAH on Cu(111) at ca. 1ML coverage; a) as prepared, local ordering; nm 2, V, 1.12 na; b) annealed to 373 K, upper terraces show local ordering, lower terraces the hexagonal phase; nm 2, V, 0.6 na; c) annealed to 448 K, the hexagonal phase covers the whole surface, some defects are present; nm 2, V, 0.5 na; d) annealed to 498 K, persistence of the hexagonal phase; nm 2, V, 0.25 na. 7

8 Figure S5. Molecular structures formed upon adsorption of BTAH on Cu(111) at ca. 2.5ML coverage; a) as prepared, some hint of local ordering over metastable features; nm 2, V, 0.40 na; b) annealed to 373 K, upper terraces show a distinctly different second phase, lower terraces the hexagonal phase; nm 2, V, 0.50 na; c) annealed to 423 K, hexagonal and centered-rectangular phase coexist; some defects are present; nm 2, V, 0.27 na; d) annealed to 443 K, both phases still coexist; nm 2, V, 0.37 na. 8

9 S4. References (1) Frisch, M.J.; Trucks, G.W.; Schlegel, H.B.; Scuseria, G.E.; Robb, M.A.; Cheeseman, J.R.; Montgomery, Jr., J.A.; Vreven, T.; Kudin, K.N.; Burant, J.C.; et al. Gaussian 03, Revision E.01 Gaussian, Inc., Wallingford CT, (2) Matsuura, H.; Yoshida, H. Handbook of Vibrational Spectroscopy, vol. 3, S4203, Wiley (2001). (3) Popopva, I.; Yates Jr., J. T. Adsorption and Thermal Behavior of Benzotriazole Chemisorbed on γ-al 2 O 3. Langmuir 1997, 13, (4) Törnkvist, C.; Bergman, J.; Liedberg, B. Geometry and Vibrations of the 1,2,3- triazole Anion. A Theoretical and Experimental Study. J. Phys. Chem. 1991, 95, (5) Honesty, N. R.; Gewirth, A. A. Shell-Isolated Nanoparticle Enhanced Raman Spectroscopy (SHINERS) Investigation of Benzotriazole Film Formation on Cu(100), Cu(111), and Cu(poly). J. of Raman Spectroscopy 2012, 43, (6) Salorinne, K.; Chen, X.; Troff, R. W.; Nissinen, M.; Häkkinen, H. One-Pot Synthesis and Characterization of Subnanometre-Size Benzotriazolate Protected Copper Clusters. Nanoscale 2012, 4, (7) Grillo, F.; Tee, D. W.; Francis, S. M.; Früchtl, H.; Richardson, N. V. Initial Stages of Benzotriazole Adsorption on the Cu(111) Surface. Nanoscale 2013, 5,