Supplementary Material. Synthesis and Characterization of L, 1,2, 3 and 4

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1 Zinc(II) and Copper(I) Mediated Large Two-Photon Absorption Cross Sections in a bis-cinnamaldiminato Schiff Base Sanjib Das, Amit Nag, Debabrata Goswami * and Parimal K. Bharadwaj * Department of Chemistry, Indian Institute of Technology Kanpur, , India pkb@iitk.ac.in Supplementary Material Synthesis and Characterization of L, 1,2, 3 and 4 Ligand (L): A mixture of 4-(dimethylamino)cinnamaldehyde (0.35 g, 2 mmol) and o- phenylenediamine (0.11 g, 1 mmol) were dissolved in 10 ml absolute ethanol and heated in an oil bath at 40 o C with stirring for 48 h under N 2 atmosphere in the dark. Cooling the reaction mixture at room temperature afforded a deep yellow solid. The yellow solid was collected by filtration, washed thoroughly with absolute ethanol and dried under vacuum. Yield ~80%; mp 160 ; 1 H-NMR (400 MHz, CDCl 3, TMS, 25 C): 2.91(s, 12H), 6.59(bs, 4H), 6.93(br, 6H), 7.07(bs, 2H), 7.32(bs, 4H), 8.08(br, 2H); ES-MS (m/z): 423(25%) [M + H] + ; Anal. Calcd for C 28 H 30 N 4 : C, 79.58; H, 7.15; N, %. Found: C, 79.67; H, 7.23; N, %. [Zn(L) 2 ](ClO4) 2 (1): Zn(ClO 4 ) 2.6H 2 O (0.37 g, 1 mmol) was dissolved in ethanol (10 ml) and added to a solution of L (0.84 g, 2 mmol) in dichloromethane (5 ml) at room temperature with stirring. The solution immediately turned deep red. After addition of

2 diethylether (10 ml), a dark red solid separated that was colleted by filtration. The deep red solid was washed thoroughly with diethylether and finally dried in vacuum. Yield ~80%; 1 H-NMR (400 MHz, CDCl 3, TMS, 25 C): 3.03(s, 24H), 6.72(d, J = 8.80 Hz, 8H), (m, 12H), (m, 4H), (d, J = 8.04 Hz, 8H), (m, 4H); ES-MS, (m/z): 1009(80%) [M (ClO4)] + ; Anal. Calcd for C 56 H 60 N 8 O 8 Cl 2 Zn 1 : C, 60.62; H, 5.45; N, %. Found: C, 60.52; H, 5.55; N, %. [Cu(L) 2 ](BF 4 ) (2): This complex was prepared under argon atmosphere in acetonitrile by using [Cu(MeCN) 4 ]BF 4 and L in 1 : 2 ratio in a manner similar to that for 1. Yield ~85%; 1 H-NMR (400 MHz, CDCl 3, TMS, 25 C): 3.02(s, 24H), 6.70(d, J = 8.80 Hz, 8H), (m, 12H), (m, 4H), 7.45(d, J = 8.04 Hz, 8H), (m, 4H); ES-MS, (m/z): 907(20%) [M (BF 4 )] + ; Anal. Calcd for C 56 H 60 N 8 B 1 F 4 Cu 1 : C, 67.57; H, 6.08; N, %. Found: C, 67.74; H, 6.21; N, %. [Zn(L)Cl 2 ] (3): A mixture of ZnCl 2.2H 2 O (0.14 g, 1 mmol) and L (0.42 g, 1 mmol) were dissolved in 10 ml of a 1:1 mixture (v/v) of dichloromethane/methanol and allowed to stir at room temperature for 1h whereupon a red solid separated after addition of diethyl ether. The red solid was collected by filtration, washed thoroughly with diethylether and dried in vacuum. Yield: ~90%; 1 H-NMR (400 MHz, CDCl 3, TMS, 25 C): 3.01(s, 12H), 6.64(d, J=8.79 Hz, 4H), 7.01(dd, J= 9.99 and 9.79 Hz, 2H) 7.24(bs, 2H), 7.35(d, J=15.16 Hz, 2H), 7.40(bs, 2H), 7.5(d, J=8.56 Hz, 4H), 8.45(d, J=10 Hz, 2H); ES-MS (m/z): 521(15%) [M (Cl)] + ; Anal. Calcd for C 28 H 30 N 4 Cl 2 Zn: C, 60.17; H, 5.41; N, %. Found: C, 60.28; H, 5.32; N, %. [Zn(L)(CN) 2 ] (4): A mixture of Zn(CN) 2 (0.12 g, 1 mmol) and L (0.42 g, 1 mmol) were dissolved in 10 ml of a 1:1 mixture of dichloromethane/methanol (v/v) and allowed to stir 2

3 for 10 h at room temperature. The solution become deep red and after addition of diethyl ether (10 ml) the product is separated as a red solid that was collected by filtration, washed thoroughly with diethylether and finally dried in vacuum. The red solid was dissolved in dichloromethane and layered with diethyl ether. After a few days, red single crystals of 3 appeared that were suitable for X-ray crystallography. Yield: ~80%; 1 H- NMR (400 MHz, CDCl 3, TMS, 25 C): 3.0 (s, 12H), 6.61(d, J=8.75 Hz, 4H), 7.0 (dd, J= 9.92 and 9.74 Hz, 2H) 7.21(bs, 2H), 7.32(d, J=15.13 Hz, 2H), 7.38(bs, 2H), 7.48(d, J=8.53 Hz, 4H), 8.41(d, J=9.95 Hz, 2H); Anal. Calcd for C 30 H 30 N 6 Zn: C, 66.72; H, 5.59; N, %. Found: C, 66.80; H, 5.49; N, %. Figure S1. A perspective view of compound 4 showing 30% probability thermal ellipsoids and atom numbering scheme for the metal and hetero-atoms. Selected bond distances (Å) and angles ( ) are: Zn N (3), Zn N (2), Zn C (4), Zn C (3), N5 C (4), N6 C (4), N1 Zn N (9), N1 Zn C (11), N2 Zn C (11), C30 Zn C (13). 3

4 Crystal data for 4: C 30 H 30 N 6 Zn 1 ; M = ; rectangular, deep red crystals, monoclinic, space group P2 1 /c, a = 8.025(4) Å, b = (11) Å, c = (7) Å, β = (9)º, U = 2878(2) Å 3, T = 100(1) K, Z = 4, µ(mo K α ) = mm -1, F(000) = 1128, ρ calc = mg/m 3, 7033 reflection data with 334 parameters, 4331 [I 2 σ(i)] unique reflections were used in all calculations. The final R1 = , wr2 = , S = Absorbance L L Wavelength (nm) Figure S2. UV-visible spectra () of L and complexes 1 4 in dichloromethane solvent (conc. 1 x 10-5 M) by JASCO, Model V-570, UV/VIS/NIR spectrophotometer. 4

5 Measurement of two photon absorption cross section(σ 2 ): Two-photon absorption cross-section values of these samples are measured by open aperture Z-Scan technique. Our femtosecond experimental scheme involves modelocked Coherent Mira titanium: sapphire laser (Model 900) which is pumped by Coherent Verdi frequency doubled Nd: vanadate laser. The model 900 Mira is tunable from 740 to 900 nm and its repetition rate is 76 MHz. The duration of the pulse is 100 fs as measured by autocorrelation technique. We controlled the average power of the laser pulse as 30 mw by using a quarter waveplate and a polarizer as shown in figure S3. We used 890 nm wavelength here for all the measurements. Using a 20 cm focal length lens, the beam is focused into a 1 cm long cell filled with sample, where it easily produces GW-level intensity at the focal point of the lens. We scan the sample through the focal point using a motorized translation stage (model ESP 300), which can step with a minimum resolution of 0.1µm. This allows a smooth intensity scan for the samples in this wavelength. The transmitted beam, after passing through the sample is focused into the aperture of a UV-enhanced amplified silicon photodetector (Thorlabs DET 210) by using a 7.5 cm focal length lens. We measure the signal in an oscilloscope (Tektronix TDS 224), which is finally interfaced with the computer using GPIB card (National Instruments). The data is acquired using LabVIEW programming. We obtain the nonlinear absorption coefficient β, by fitting our measured transmittance values to the following formula: T (z) = 1 - β I 0 L/ (2(1+ z 2 /z 2 0 )) where, β = nonlinear absorption coefficient, I 0 = on-axis electric field intensity at the focal point in absence of the sample, L= sample thickness, z 0 = Rayleigh range = πw 2 0 /λ, w 0 is the minimum spot size at the focal point. The β values are obtained by curve fitting the measured open-aperture traces with the above equation. After we get the value of β, the TPA cross-section σ 2 (in units of 1 GM = cm 4.s/photon.molecule), of one solute molecule is given by the following expression: σ 2 = β.hν/n.c.10-3, Where ν is the frequency of the incident laser beam, N is Avagadro constant, c is the concentration of the compound in dichloromethane solvent. 5

6 We have taken the known value of σ 2 for Rhodamine-6G as the reference for calibrating our measurement technique. Figure S3 6

7 Theoritically fitted Open aperture Z-Scan Graphs for 3 and 4: [Zn(L)(Cl) 2 ] (3) [Zn(L)(CN) 2 ] (4) (σ 2 = 1,769 GM) (σ 2 = 1,700 GM) Rhodamine 6G (σ 2 = 16 GM) Figure S5 All the reported data in the paper are reported with 1% error bar after our fitting expression was able to reproduce within 1% of the reported value of 16 GM for Rhodamine 6G (Rh6G). Since σ 2 values are directly proportional to β, our error in σ 2 values is reflection of our % accuracy in measured of β, which for Rh6G is an order of 7

8 magnitude less than those of our reported compounds. Thus, the error of 1% represents an upper bound. Figure S6: ES-MS spectra of Schiff Base L Figure S7: ES-MS spectra of complex [Zn(L) 2 (ClO 4 ) 2 ] (1) 8

9 Figure S8: ES-MS spectra of complex [Cu(L) 2 (BF 4 )] (2) Figure S9: ES-MS spectra of complex [Zn(L)(Cl) 2 ] (3) 9

10 Figure S10: TGA spectra of complex [Zn(L) 2 (ClO 4 ) 2 ] (1) Figure S11: TGA spectra of complex [Cu(L) 2 (BF 4 )] (2) 10

11 Figure S12: TGA spectra of complex [Zn(L)(Cl) 2 ] (3) Figure S13: TGA spectra of complex [Zn(L)(CN) 2 ] (4) Reference No. 2 Albota, M.; Beljonne, D.; Brédas, J.-L.; Ehrlich, J. E.; Fu, J. -Y.; Heikal, A. A.; Hess, S. E.; Kogej, T.; Levin, M. D.; Marder, S. R.; McCord-Maughon, D.; Perry, J. W.; Röckel, H.; Rumi, M.; Subramaniam, G.; Webb, W. W.; Wu, X. -L.; Xu, C. Science, 1998, 281,

Supporting Information

Supporting Information Synthesis and characterization of a luminescence metallosupramolecular hyperbranched polymer Bingran Yu, Shuwen Guo, Lipeng He, and Weifeng Bu* Key Laboratory of Nonferrous Metals