Abiotic degradation of glyphosate into AMPA in presence of metals

Transcription

1 1 1 Supporting Information 2 3 Abiotic degradation of glyphosate into AMPA in presence of metals J. Ascolani Yael, 1 J. D. Fuhr, 1,2 G. A. Bocan, 2 A. Daza Millone, 3 N. Tognalli, 4 M. dos Santos Afonso 5 and M. L. Martiarena 2 1 Instituto Balseiro, Universidad Nacional de Cuyo, CNEA, Av. Bustillo 9500, 8400 S.C. de Bariloche, Argentina. 2 CONICET and Centro Atómico Bariloche (CNEA), Av. Bustillo 9500, 8400 S.C. de Bariloche, Argentina. 3 CONICET INIFTA, 64 y Diag. 113, 1900 La Plata, Argentina. 4 Centro de Innovación Tecnológica, Empresarial y Social (CITES), Av. Belgrano 758, 2322 Sunchales, Argentina. 5 INQUIMAE and Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Univ. de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina Contents Figure S1: Fitting of the SERS spectra in the P-C frequency region. Table S1: Proportion of molecules according to type and configuration relative to the total number of molecules resulting from the fitting of Fig. S1. Figure S2: SERS spectra of glyphosate deposited on different metal surfaces using the drop-casting method. Figure S3: ATR-FTIR spectra of PMG+Cu samples with different molar ratios. Tables S2 and S3: IR, SERS and DFT frequencies and band assignments for PMG and AMPA.

2 2 27 Fitting procedure of the SERS spectra The amount of AMPA (and PMG) on the samples can be roughly estimated by means of a fitting procedure on the SERS spectra, in the frequency region around the P-C peaks. For AMPA (PMG) we consider two contributions: i) AMPA_c (PMG_c) peaking at the P-C frequency in the molecular crystal and, ii) AMPA/Cu (PMG/Cu) peaking at the P-C frequency of the molecule adsorbed on a Cu surface. We assume equal cross sections for Raman scattering of the P-C mode for all molecules. Therefore, the ratios of fitted areas represent the corresponding ratios of number of molecules. 35

3 Fig. S1: Fitting of the SERS spectra in the region of the P-C peaks. Filled dark green (blue) regions correspond to the total contributions of the AMPA (PMG) P-C mode; dashed green (blue) regions to a contribution peaking at the P-C in the AMPA (PMG) crystal; and filled light green (blue) regions to a contribution peaking at the P-C of AMPA (PMG) adsorbed on Cu. A) Samples prepared with the drop casting method. B) Samples prepared with the dipping method. 44

4 Tab S1: Proportion of molecules according to type and configuration relative to the total number of molecules resulting from the curve fitting. AMPA_T and PMG_T are the total percentage of each molecule. Method AMPA_c AMPA/Cu AMPA_T PMG_c PMG/Cu PMG_T Drop-casting 6,1% 49,9% 56,0% 9,5% 34,5% 44,0% Dipping 46,7% 3,5% 50,2% 41,9% 7,9% 49,8% 49

5 Fig. S2: SERS spectra of glyphosate adsorbed on different metal surfaces using the drop-casting method. Ag (red), Au with Ag NPs (green), Cu UPD/Au with Ag NPs (black). The blue lines indicate the frequency of P-C mode for PMG (full line) and AMPA (dashed line) crystals. 56

6 Fig. S3: ATR-FTIR spectra of PMG+Cu samples with different molar ratios. a) Pure PMG, b) PMG+Cu with a molar ratio 0.7:1 Cu:PMG, c) PMG+Cu with a molar ratio 2.7:1 Cu:PMG.

7 Tables S2 and S3 show a complete band assignment of the IR, Raman and calculated DFT spectra for PMG and AMPA crystals, as well as IR spectra for AMPA+Cu and PMG+Cu. In columns 1 to 6 frequencies for systems involving PMG are displayed. From right to left: PMG crystal (Raman data, IR data and DFT calculation), PMG combined with Cu atoms (IR data), PMG deposited on Cu UPD with the drop-casting method (SERS data) and PMG deposited on Cu UPD with the dipping method (SERS data). In columns 7 to 12 frequencies are portrayed for different systems involving AMPA. From left to right: AMPA crystal (Raman data, IR data and DFT calculation), AMPA combined with Cu atoms (IR data), and AMPA adsorbed on Cu(111) and Cu(100) (DFT calculations for the most stable adsorbed configuration, for which AMPA's phosphonate group is partially deprotonated). In column 13, the corresponding vibration modes (δ for bending, ν for stretching (ν a and ν s for asymmetric and symmetric stretching), ω for wagging, ρ for rocking, τ for twisting, and skel for skeleton) are shown. Regarding notation mark that: a) Curly brackets are used to enumerate frequencies in double-peak structures associated with a single theoretical result. Square brackets are used to delimit structures containing one or several blurry peaks. b) The DFT frequencies for AMPA and PMG crystals are in fact averages over sets of modes in similar vibration states although in some cases there were slight differences either in the atoms involved or in the vibration mode of a given group. For those cases the notation mode-1/mode-2 refers to averages over states some of which include the mode-1 vibration while others present the mode-2 vibration. For brevity, if the atoms involved in modes 1 and 2 are the same, the average mode is described with the two symbols (e.g.: ωτ(ch 2 ) means an average of ω(ch 2 ) and τ(ch 2 ) modes). c) PMG has two CH 2 groups. To tell them apart, CH 2 is the group closest to the phosphonate group (also present in AMPA), while CH 2 * refers

8 to the other one. d) Red and blue asterisks (*) mark vibration modes apparently detected experimentally that correspond respectively to PMG and AMPA in nonzwitterion form. e) The shaded rows indicate SERS peaks that are consistent with the presence of AMPA in the sample

9 Table S2: IR, SERS and DFT frequencies and band Assignments for PMG and AMPA in cm-1 (see text) PMG/Cu Drop-Casting PMG/Cu Dipping PMG+Cu PMG crystal AMPA crystal AMPA+Cu AMPA-H/ Cu111 AMPA-H/ Cu100 SERS SERS IR Raman IR DFT Raman IR DFT IR DFT DFT DFT vibration modes {449;460} {458;466} 460 [440,452] δ(ho-p=o)/δ(o=p=o) δ(po3)+δ(ncco) 465 {461;468} δ(ho-p=o)+ρ(pcn)+ δ(ncc)+δ(oh-c=o)+ ρ(ch2)* 505 [490,520] δ(ho-p=o)+δ(cnc)+ δ(oh-c=o)+ρ(ch2)* [486,500] δ(p-c-n)+ω(ho-p=o) δ(ho-p=o)+ δ(pcn)+δ(c=c-oh) {540;549} [535,553] {537;546} τ(nh3) [560,585] δρ(po3)+skel(ncco2) [630,670] ν(pc)+δ(ncc)+δ(coo) ν(pc) ν(pc) ν(pc)+ρ(ch2) ρ(nh2)+ν(ccoo) {808;840} {814;837} ρ(ch2)+ν(p-oh) * ν(p-oh) ν(cc) CNCC skeleton ν(ho-p) νs(po3)+ν(pc) νs(po3)+τ(ch2) ρ(nh2)+skel(cncc) ν(op) ν(cn) CNCC skeleton (PO3)

10 Table S3: IR, SERS and DFT frequencies and band Assignments for PMG and AMPA in cm -1 (see text) PMG/Cu Drop-casting PMG/Cu Dipping PMG+Cu PMG crystal AMPA crystal AMPA+Cu AMPA-H/ Cu111 SERS SERS IR Raman IR DFT Raman IR DFT IR DFT DFT AMPA-H/ Cu100 DFT vibration modes ν(cn)/cncc skel+ νa(ho-p=o)/νa(poo) CNC skeleton 1116 [1110,1130] 1151 [1150,1167] {1060;1071} δ(hnc)+νa(po2)/ν(po) νa(po3)+ν(nc) νa(o=p=o)+δ(hcnh) νa(p-oh) {1151;1166} [1150,1167] ρ(nh3) (CH2+NH2+ CH2*)/HCNCH+ν(COH) 1167 {1171;1185} ν(p=o) (CH2+NH2+CH2*) ν(cn)+ν(coh) [1195,1221] [1195,1221] 1225 * νa(po3) ν(p-oh)+τ(ch2) {1223;1244} 1238 {1223;1244} 1242 ν(coh)+δ(cnc) [1250,1290] ν(pc)+ν(poh)+ω(ch2) ω(ch2)+ωτ(ch2)* δ(coh)+ν(pc) δ(hop)+ν(pc)+δ(hcnh) ωτ(ch2)*+δ(coh)+δ(cnc)/ν(p OH) δ(hcnh)+δ(pcn) δ(ch2)+ν(ccoh) δ(ch2)+δ(poh) [1405,1430] [1407,1427] [1430,1460] δ(ch2) ν(cc)+δ(cnh)/τ(nh2) ω(nh2)+δ(poh) δ(nh3) {1560;1616} δ(nh2) δ(nh2)

11 {1716;1732} {1715;1730} {1716;1732} 1705 ν(co)