Synthesis and characterization of amphiphilic poly(p phenylene) based nanostructured materials 6

Experimental details Chapter Experimental Details 166 Experimental details 61 Materials and reagents All reagents were purchased from Aldrich, Fluka, Merck and TCI and were used without further purification unless noted otherwise Tetrahydrofuran (THF) was distilled over sodium and benzophenone under N2 atmosphere prior to use N,N- dimethylformamide (DMF) was dried over activated molecular sieves (4 Å, Aldrich) Toluene, methyl ethyl ketone (MEK), dichloromethane, hexane and diethyl ether were purchased from J T Baker Flash column chromatography was performed using 60-mesh (0.040–0.063 mm) silica gel (Merck) For synthesizing the polymer C6PPPC5Cb, N-alkyl carbazole was synthesized according to the reported procedure.4 Carbazole (Fluka) was recrystallized from absolute alcohol and dibromopentane (Sigma-Aldrich) was used without further purification 6.2 Instrumentation H NMR (300 MHz) and 13 C NMR (75.4 MHz ) spectra were recorded on a Bruker ACF 300 MHz spectrometer MS spectra were obtained using a Finnigan TSQ 7000 spectrometer with ESI or EI ionization capabilities FT-IR spectra were recorded using BIO-RAD FTIR spectrophotometer The thermal properties of the polymers were investigated by thermogravimetric analysis (TGA) using a SDT 2960 TA instrument at a heating rate of 10 °C/min under nitrogen Gel permeation chromatographic (GPC) analyses were performed with a Waters 2696 separation module equipped with a Water 410 differential refractometer HPLC system and Waters Styragel HR 4E columns using THF as eluent and polystyrene as standard The XRD patterns were recorded on an X-ray powder diffractometer with a graphite monochromator using D5005 Siemens X-ray diffractometer with CuKα radiation (40 kV, 40mA) with a wavelength of 1.54 Å at room 167 Experimental details temperature The polymer samples were mounted on a sample holder and scanned between 2θ =1.5ο and 50ο Transmission electron microscopy (TEM) investigations were done on a JEOL 2010 machine at an accelerating voltage of 200 kV All AFM images were recorded using a Nanoacope III AFM (Digital Instruments Inc) in the tapping mode using silicon cantilevers (25 °C, in air) The cyclic voltammetry (CV) experiments were carried out on a Princeton Applied Research Parstat 2263 The electrode surface area was 0.785 cm2 6.3 Details of the amphiphilic poly(p-phenylene)s synthesized and used for the present study 6.3.1 Synthesis and characterization of monomers and polymers The polymers C6PPPOH, C12PPPOH and C18PPPOH were synthesized using Suzuki polycondensation as reported earlier.1,2 Similarly, for C12PPPC11OH, Suzuki coupling was employed In all the cases, bromination of hydroquinone was achieved using a standard procedure.3 In the case of C12PPPC11OH, monoalkylation of was done using 1.0 equiv of dibromohydroquinone and 0.9 equiv of alkyl bromide in the presence of a base, sodium hydroxide (1.5 equiv) at 60° C, with ethanol as solvent Second alkylation of the monoalkylated dibromohydroquinone was carried out at 60 ºC for 10 hours using equivalent of monalkylated hydroquinone and 1.5 equivalents of 11-bromo undecanol in presence of a weak base, potassium carbonate The crude product was reprecipitated from a mixture of 1:4 chloroform and methanol The aliphatic hydroxyl group was then protected using a standard procedure 3, 4-dihydro-2-H-pyran was used for the protection to give tetrahydropyran ether which is stable in strong bases such as lithium aluminum hydride and can be easily removed by acid hydrolysis under mild conditions The 168 Experimental details incorporation of tetrahydropyran protecting groups generally requires protic acid or Lewis acid catalyst We have used p-toluene sulfonic acid (PTSA) as the catalyst PTSA is a weaker acid and this is mild enough to be used in complex systems containing sensitive polyfunctional groups and the reaction is irreversible The crude product was purified using column chromatography with a solvent mixture of hexane: ethyl acetate (9:1) to get the pure product 1, 4-Dialkylated bisboronic acid was synthesized using M solution of butyllithium in hexane and triisopropyl borate under nitrogen atmosphere The crude product was recrystallized from acetone The polymer C12PPPC11OH was synthesized using Suzuki polycondensation under standard conditions The polymerization was carried out using an equimolar mixture of dialkyalted dibromohydroquinone and the bisboronic acid in the biphasic medium of toluene and aqueous 2M potassium carbonate solution with [PdP(Ph3)4] as the catalyst under vigorous stirring for 73 hours Deprotection of the hydroxyl groups were carried out by dissolving the polymer in THF and adding concentrated HCl (10mL) The reaction mixture was stirred at 60 °C for overnight 169 Experimental details 6.3.2 Synthesis of C6PPPOH, C12PPPOH and C18PPPOH OH OH Br (ii) (i) Br OH OH OBn Br (iii) Br Br Br OH (1) OR (2) OR (3) (iv) OH OBn B(OH)2 (v) (vi) n RO (6) OBn n RO (5) OBn Br (HO)2B Br OR OR (4) Scheme 6.1 General synthetic scheme for CnPPPOH (i) Br2 in gl AcOH, 85%; (ii) NaOH in abs EtOH, RBr (1 equiv.), 60 °C for 10 h, 60%; (iii) anhydrous K2CO3 in MEK, BnBr, 40-50 °C for 10 h, 95%; (iv) BuLi in hexanes (1.6 M soln), THF at -78 °C, B(OiPr)3, water stirred at RT for 10 h, 60%, (v) M K2CO3 solution, toluene, mol % Pd(PPh3)4, reflux for days, (vi) H2, 10% Pd/C, EtOH/THF 2,5-Dibromo-4-alkyloxyphenol (2) 2,5-Dibromohydroquinone was synthesized and used for the preparation of 2,5-Dibromo-4-alkyloxyphenol using the procedure reported in the literature.3 2,5-Dibromohydroquinone (25g, 0.093 mol) was dissolved in absolute alcohol under nitrogen atmosphere Sodium hydroxide (5.59g, 0.139 mol) was added to the reaction mixture and warmed to 55 °C Hexyl bromide (10.5 ml, 0.074 mol) was added dropwise to the above reaction mixture After 16 hours, the reaction mixture was cooled to room temperature, filtered and concentrated under reduced pressure Distilled water (1.5 L) was added along with a few drops of concentrated hydrochloric acid until the mixture 170 Experimental details was acidic It was stirred for hours, filtered, washed with water and dried in vacuum The crude product was purified using column chromatography with a mixture of hexane: dichloromethane (6:4) The yield = 60% 2,5-Dibromo-4-hexyloxyphenol (2a) 1H NMR (CDCl3, δ, ppm): 7.23 (s, 1H, aromatic CH), 6.98 (s, 1H, , aromatic C-H), 5.19 (s, 1H, O-H), 3.93 (t, 2H, OCH2), 1.80 (q, 2H, 13 OCH2CH2), 1.48 (m, 6H, CH2), 0.91 (t, 3H, CH3); C NMR (CDCl3, δ, ppm): 150, 146.7, 120.20, 116.6, 112.40, 108.2, 70.31, 31.3, 28.9, 25.5, 22.4, 13.90 MS-ESI: m/z, 351.2 Elemental analysis calculated (%) for C12H16Br2O2: C, 40.94; H, 4.58 Found: C, 40.63; H, 4.84 FT-IR (KBr, cm-1): 3253, 2916, 2852, 1498, 1435, 1388, 1219, 1064, 854, 790, 719 2,5-Dibromo-4-dodecyloxyphenol (2b) 1H NMR (CDCl3, δ, ppm): 7.25 (s, 1H, aromatic C-H), 6.97 (s, 1H, aromatic C-H), 5.16 (s, 1H, O-H), 3.92 (t, 2H, OCH2), 1.62 (q, 2H, OCH2CH2), 1.4 (m, 18H, CH2); 0.88 (t, 3H, CH3) 13 C NMR (CDCl3, δ ppm): 150.01, 146.7, 120.2 116.6, 112.4, 108.2, 70.3, 31.8, 29.5, 29.5, 29.2, 29.2, 28.01, 25.8, 22.6, 14 MS-ESI: m/z, 437 Elemental analysis calcd for C18H28Br2O2: C, 49.56; H, 6.47; Found: C, 49.87; H, 6.73 FT-IR (KBr, cm-1): 3241, 2911, 2853, 2384, 2337, 1498, 1434, 1386, 1211, 1062, 855, 792, 718 2,5-Dibromo-4-octadecyloxyphenol (2c) H NMR (CDCl3, δ, ppm): 7.25 (s, 1H, aromatic C-H), 6.90 (s, 1H, aromatic C-H), 5.11 (s, 1H, O-H ), 3.85 (t, 2H, OCH2), 1.75 (q, 2H, OCH2CH2), 1.4 (m, 30H, CH2); 0.83 (t, 3H, CH3) 13C NMR (CDCl3 δ ppm): 150.01, 146.7, 120.2, 116.2, 112.4, 108.2, 70.3, 31.8, 29.6, 29.5, 29.01, 25.8, 22.6, 14.03 MS-ESI: m/z, 520.1 Elemental analysis calcd for C24H40Br2O2: C, 55.39; H, 7.75 Found: C, 55.66; 171 Experimental details H, 8.16 FT-IR (KBr, cm-1): 3225, 2917, 2848, 2359, 1498, 1466, 1434, 1386, 1211, 1062, 855, 722 2,5-Dibromo-1-benzyloxy-4-alkoxybenzene (3) The monoalkylated 2,5- dibromohydroquinone (15g, 0.042 mol) was dissolved in 200 mL methylethyl ketone, potassium carbonate (20.61g, 0.149 mol) was added and the temperature was raised to 80° C To this solution, benzyl bromide (10.13 ml, 0.085 mol) was added dropowise After 24 hours, the mixture was filtered and the filtrate was concentrated to obtain the crude product The crude product was recrystallized from a mixture of chloroform and methanol (1:4) to get a white precipitate after stirring the mixture in an ice bath for hour and filtered The precipitate was washed thoroughly with deionised water Yield = 95% (17.89 g) 2,5-Dibromo-1-benzyloxy-4-hexyloxybenzene (3a) 1H NMR (CDCl3, δ, ppm): 7.40 (m, 5H, aromatic C-H) 7.17 (s, 1H, aromatic C-H), 7.11 (s, 1H, aromatic C-H), 5.07 (s, 2H, benzylic –CH2), 3.96 (t, 2H, OCH2), 1.81 (q, 2H, OCH2CH2) 1.48 (m, 6H, CH2), 0.92 (t, 3H, CH3) 13C NMR (CDCl3, δ, ppm): 150.5, 149.4, 136.1, 128.5, 128, 127.1, 119.3, 118.3, 111.5, 111.01, 71.9, 70.2, 31.4, 28.9, 25.51, 22.5, 13.9 MS-ESI: m/z, 442 Elemental analysis calcd for C19H22Br2O2: C, 51.61; H, 5.01 Found: C, 51.49; H, 5.00 FT-IR (KBr, cm-1): 3225, 2917, 2848, 2359, 1498, 1466, 1434, 1386, 1211, 1062, 855, 722 2,5-Dibromo-1-benzyloxy-4-dodecyloxybenzene (3b) 1H NMR (CDCl3, δ, ppm): 7.46 (m, 5H, aromatic C-H), 7.21 (s, 1H, aromatic C-H), 7.15 (s, 1H, aromatic C-H), 5.11 (s, 2H, benzylic –CH2), 3.99 (t, 2H, OCH2), 1.85 (q, 2H, OCH2CH2), 1.32 (m, 18H, CH2), 0.95 (t, 3H, CH3) 13 C NMR (CDCl3, δ, ppm): 150.5, 149.5, 136.16, 128.5, 128.1, 127.2, 119.3, 172 Experimental details 118.3, 111.5, 111.01, 71.9, 70.1, 31.8, 29.6, 25.84, 22.6, 14.02 MS-ESI: m/z, 526.2 Elemental analysis calcd for C25H34Br2O2: C, 57.05; H, 6.51 Found: C, 57.16; H, 6.85 FT-IR (KBr, cm-1): 2922, 2848, 2359, 1493, 1466, 1355, 1200, 1073, 1004, 855, 802, 754 2,5-Dibromo-1-benzyloxy-4-octadecyloxybenzene (3c) 1H NMR (CDCl3, δ, ppm): 7.39 (m, 5H, aromatic C-H), 7.15 (s, 1H, aromatic C-H), 7.10 (s, 1H, aromatic C-H), 5.06 (s, 2H, benzylic –CH2), 3.95 (t, 2H, OCH2), 1.82 (q, 2H, OCH2CH2), 1.50 (m, 30H, CH2), 0.88 (t, 3H, CH3 ) 13 C NMR (CDCl3, δ, ppm): 150.5, 149.4, 136.1, 128.5, 128, 119.3, 118.3, 111.5, 110.03, 72, 70.2, 31.8, 29.01, 25.8, 22.6, 14.03 MS (ESI): m/z: 610.3 Elemental analysis calcd for C31H46Br2O2: C, 60.99; H, 7.59 Found: C, 60.49; H, 7.22 FT-IR (KBr, cm-1): 2918, 2854, 1503, 1465, 1365, 1268, 1217, 1058, 1016, 843, 738 1-Benzyloxy-4-alkoxyphenyl-2,5-bis(boronic acid) (4) The benzylated monomer (14.5g, 0.032 mol) was dissolved in freshly distilled tetrahydrofuran (THF) (100 mL) under nitrogen atmosphere at -78 °C, followed by the dropwise addition of 1.6 molar butyllithium (100 mL, 0.147 mol) The reaction mixture was stirred for another hours at -78 °C The mixture was stirred at room temperature for 15 minutes The temperature was again decreased to -78 °C and triisopropylborate (80 mL, 0.328 mol) was added dropwise into the reaction mixture After stirring at -78 °C for hours, the reaction mixture was warmed to RT and stirred overnight deionized water (1L) was added to the reaction mixture and stirred overnight The THF layer was collected and concentrated to get crude product The product was recrystallised from acetone and dried Yield = 60% (7.30g) 1-Benzyloxy-4-hexyloxyphenyl-2,5-bis(boronic acid) (4a) 1H NMR (DMSO-d6, δ, ppm): 7.83 (s, 2H, B-OH), 7.79 (s, 2H, B-OH), 7.48 (m,5H, aromatic C-H), 7.31 (s,1H, aromatic 173 Experimental details C-H), 7.19 (s,1H, aromatic C-H), 5.12 (s, 2H, benzylic –CH2), 4.01(t, 2H, OCH2), 1.74 (q, 2H, OCH2CH2), 1.31 (m, 6H, CH2), 0.89 (t, 3H, CH3) 13 C NMR (DMSO-d6, δ, ppm): 157.05, 156.3, 137.2, 128.4, 127.5, 118.3, 117.8, 70.06, 68.4, 30.8, 28.6, 25.04, 21.9, 13.7 MS (ESI): m/z: 372 Elemental analysis calcd for C19H26B2O6: C, 61.34; H, 7.04 Found: C, 61.81; H, 7.30 FT-IR (KBr, cm-1): 3494, 3352, 2920, 2848, 1498, 1413, 1392, 1296, 1200, 1052, 796, 727 1-Benzyloxy-4-dodecyloxyphenyl-2,5-bis(boronic acid) (4b) 1H NMR (DMSO-d6, δ, ppm): 7.81 (s, 2H, B-OH), 7.76 (s, 2H, B-OH), 7.42 (m, 5H, aromatic C-H), 7.29 (s, 1H, aromatic C-H), 7.16 (s, 1H, aromatic C-H), 5.10 (s, 2H, benzylic –CH2), 3.99 (t, 2H, OCH2), 1.72 (q, 2H, OCH2CH2), 1.24 (m, 18H, CH2), 0.85 (t, 3H, CH3) 13 C NMR (DMSO-d6, δ, ppm): 157.4, 156.7, 137.6, 128.8, 128.2, 127.9, 118.7, 118.1, 70.4, 68.7, 31.6, 29.06, 25.8, 22.4, 14.3 MS (ESI): m/z: 456 Elemental analysis calcd for C25H38B2O6: C, 65.82; H, 8.40 Found: C, 65.87; H, 8.86 FT-IR (KBr, cm-1): 3493, 3350, 2920, 2848, 2359, 1496, 1411, 1392, 1296, 1200, 1052, 796, 727 1-Benzyloxy-4-octadecyloxyphenyl-2,5-bis(boronic acid) (4c) 1H NMR (DMSO-d6, δ, ppm): 7.81 (s, 2H, B-OH), 7.76 (s, 2H, B-OH), 7.46 (m, 5H, aromatic C-H), 7.37 (s, 1H, aromatic C-H), 7.17 (s, 1H, aromatic C-H), 5.10 (s, 2H, benzylic –CH2), 3.99 (t, 2H, OCH2), 1.73 (q, 2H, OCH2CH2), 1.23 (m, 30H, CH2), 0.83 (t, 3H, CH3) 13 C NMR (DMSO-d6, δ, ppm): 157.4, 156.7, 137.6, 128.8, 127.9, 118.7, 118.2, 70.4, 68.7, 31.6, 29.06, 25.8, 22.4, 14.2 MS (ESI): m/z: 540 Elemental analysis calcd for C31H50B2O6: C, 68.91%; H, 9.33 Found: C, 68.41; H, 8.84 FT-IR (KBr, cm-1): 3448, 3363, 2917, 2853, 2359, 1498, 1429, 1392, 1296, 1195, 1057, 781, 722 174 Experimental details Poly(1-benzyloxy-4-alkoxy-p-phenylene) (5) Boronic acid (4a) (6g, 0.016 mol) and benzylated monomer (3a) (7.148g, 0.016 mol) were mixed with toluene (200 ml) under inert atmosphere An aliquot of K2CO3 solution (2 M, 400 mL) was added to this mixture followed by Pd(PPh3)4 (3 mol% of monomer.) The temperature was raised to 80 °C, stirred for 72 hours and precipitated from methanol to yield the crude polymer Poly(1-benzyloxy-4-hexyloxy-p-phenylene) (5a) 1H NMR (CDCl3, δ, ppm): 7.40 (b, aromatic C-H) 5.07 (b, benzylic –CH2), 3.96 (b, OCH2), 1.81 (b, OCH2CH2) 1.48(b, CH2), 0.92 (b, CH3) 13 C NMR (CDCl3, δ ppm): 150.5, 149.4, 136.1, 128.5, 128, 127.1, 119.3, 118.3, 111.5, 111.01, 71.8, 70, 31.3, 28.9, 22.4, 13.95 FT-IR (KBr, cm-1): 2917, 2853, 2367, 1410, 1117, 1112, 727, 715 Poly(1-benzyloxy-4-dodecyloxy-p-phenylene) (5b) 1H NMR (CDCl3, δ, ppm): 7.27 (b, aromatic C-H), 4.97 (b, benzylic –CH2), 3.92 (b, OCH2), 1.60 (b, OCH2CH2), 1.27 (b, CH2), 0.91 (b, CH3) 13C NMR (CDCl3, δ ppm): 150.5, 149.7, 137.7, 128.05, 127, 118.06, 116.8, 71.6, 69.4, 31.8, 29.5, 22.5, 14.02 FT-IR (KBr, cm-1): 2916, 2853, 2367, 1413, 1116, 1114, 727, 715 Poly(1-benzyloxy-4-octadecyloxy-p-phenylene) (5c) 1H NMR (CDCl3, δ ppm): 7.21 (b, aromatic C-H), 4.97 (b, benzylic –CH2), 3.89 (b, OCH2), 1.69 (b, OCH2CH2), 1.24 (b, CH2), 0.88 (b, CH3) 13C NMR (CDCl3, δ ppm): 150.5, 149.6, 137.7, 128.07, 127, 118.06, 116.9, 71.6, 69.4, 31.8, 29.6, 22.59, 14 FT-IR (KBr, cm-1): 2915, 2852, 2365, 1413, 1120, 1114, 727, 715 Poly(1-hydroxy-4-alkoxy-p-phenylene) (6) Precursor polymer (5a) (1.32 g) was dissolved in an equal volume mixture of THF (50 ml) and absolute ethanol (50 mL) at RT 175 Experimental details Pd/C (10%, g) and drops of concentrated HCl were added to the solution and the reaction flask was flushed with nitrogen gas three times to remove traces of oxygen The debenzylation was carried out at RT under positive pressure of hydrogen (using a balloon) for 24 h with constant stirring The reaction mixture was filtered through celite powder; the filtrate was evaporated and dried in vaccuo to yield the desired polymer (0.8 g) Poly(1-hydroxy-4-hexyloxy-p-phenylene) (6a) 1H NMR (CDCl3, δ, ppm): 7.09 (b, aromatic C-H), 6.82 (b, aromatic C-H), 3.94 (b, OCH2), 1.69 (b, OCH2CH2), 1.29 (b, CH2), 0.87 (b, CH3) FT-IR (KBr, cm-1): 3420, 2922, 2844, 2360, 1650, 1466, 1201, 1025, 800 Poly(1-hydroxy-4-dodecyloxy-p-phenylene) (6b) 1H NMR (CDCl3, δ, ppm): 7.03 (b, aromatic C-H), 6.88 (b, aromatic C-H), 3.90 (b, OCH2), 1.77 (b, OCH2CH2), 1.21 (b, CH2), 0.85 (b, CH3) FT-IR (KBr, cm-1): 3415, 2920, 2845, 2362, 1643, 1466, 1205, 1025, 802 Poly(1-hydroxy-4-octadecyloxy-p-phenylene) (6c) 1H NMR (CDCl3, δ, ppm): 7.06 (b, aromatic C-H), 6.85 (b, aromatic C-H), 3.92 (b, OCH2), 1.77 (b, OCH2CH2), 1.24 (b, CH2), 0.85 (b, CH3) FT-IR (KBr, cm-1): 3340, 2917, 2845, 1625, 1470, 1406, 1201, 1054, 796, 720 176 Experimental details 6.3.3 Synthesis of C12PPPC11OH OH OH OH Br (i) (ii) Br OC11H22OH Br Br OH Br (iii) OH Br OC12H25 OC12H25 (2) (1) (3) (iv) OC11H22OTHP Br OC11H22OTHP THPOC11H22O Br B(OH)2 OC12H25 n (6) OC12H25 (vi) Br (v) (HO)2B Br OC12H25 (5) (vii) OC11H22OTHP OC12H25 (4) HOC11H22O n (7) OC12H25 Scheme 6.2 Synthesis of C12PPPC11OH and C12PPPC11OTHP (i) Br2 in glacial AcOH, 85%; (ii) NaOH in absolute EtOH, C12H25Br, 60 °C for 10 h, 60%; (iii) K2CO3 in abs EtOH, BrC11H22OH, 60 °C for 10 h, 80%; (iv) p-toluene sulfonic acid/DHP in THF, °C, 95%; (v) BuLi in cyclohexane (2M solution), THF at -78 °C, B(OiPr)3, water stirred at RT for 10 h, 60%; (vi) M K2CO3 solution, toluene, mol % Pd(PPh3), reflux for days; (vii) HCl/ THF at 60 °C 2,5-Dibromo-1-(ω-hydroxyundecyloxy)-4-dodecyloxybenzene (3) The monoalkylated dibromohydroquinone (2) (11.25 g, 0.025 mol) was dissolved in absolute alcohol (300 mL ) under nitrogen atmosphere Potassium carbonate (8.91 g, 0.064 mol) was added to the reaction mixture and warmed to 70 °C 11-Bromo-1-undecanol (9.73 g, 0.038 mol) dissolved in absolute alcohol (50 mL) was added dropwise to the above reaction mixture, stirred for 10 hours, cooled to room temperature, filtered and concentrated under reduced 177 Experimental details pressure Distilled water (500 mL) was added to the residue and the mixture was acidified with concentrated HCl It was stirred for hours and filtered The crude product was precipitated from a mixture of chloroform and methanol (1:4) under °C The white precipitate obtained was filtered off and dried Yield = 80% (7.82 g) H NMR (CDCl3, δ, ppm): 7.08 (s, 2H, aromatic C-H), 3.94 (t, 4H, OCH2), 3.63 (t, 2H, CH2OH), 1.77 (q, 4H, OCH2CH2), 1.26 (m, 34H, CH2), 0.86 (t, 3H, CH3) 13 C NMR (CDCl3, δ, ppm): 150, 118.4, 111, 70.2, 63, 32.7, 31.8, 29.5, 29.3, 29.1, 25.8, 25.6, 22.5, 13.96 MS-ESI: m/z, 606 (M+) Elemental analysis calculated (%) for C29H50Br2O3: C, 57.43; H, 8.31 Found: C, 57.38; H, 8.32 FT-IR (KBr, cm-1): 3290, 2916, 2850, 1498, 1467, 1388, 1365, 1269, 1219, 1064, 1017, 990, 854, 790, 719 2-[(2,5-Dibromo-1-(ω-tetrahydropyranoxy undecyloxy)-4-dodecyloxy)]benzene (4) Compound (3) (9.76 g, 0.016 mol) was dissolved in anhydrous tetrahydrofuran (50 mL) under nitrogen atmosphere Catalytic amount of paratoluene sulfonic acid was added at °C Dihydropyran (2.5 mL, 0.04 mol) was added to the above reaction mixture, stirred at °C for two hours and at RT overnight Solvent was removed and the crude product was purified using column chromatography with a solvent mixture of hexane: ethyl acetate (9:1) to get the pure product in 95% yield H NMR (CDCl3, δ, ppm): 7.08 (s, 2H, ArC-H), 4.5 (s, 1H, OCHO), 3.96 (t, 4H, ArOCH2), 3.71 (t, 2H, OCH2), 3.57 (q, 2H, CH2O), 3.37 (q, 4H, OCH2CH) 1.77 (m, 6H, CH2), 1.26 (m, 34H, CH2), 0.86 (t, 3H, CH3) 13C NMR (CDCl3, δ, ppm): 155.8, 120.3, 108.2, 100.7, 71.6, 64, 63.6, 33.00, 32.5, 31.2, 30.5, 30.3, 26.6, 23.1, 13.9 MS-ESI: m/z, 691 (M+) Elemental analysis calculated (%) for C34H58Br2O4: C, 59.13; H, 8.46 Found: C, 59.32; H, 178 Experimental details 8.49 FT-IR (KBr, cm-1): 2920, 2850, 1494, 1463, 1392, 1361, 1265, 1211, 1120, 1064, 1027, 807, 722 1-(Dodecyloxy)-4-(ω-tetrahydropyranoxy undecyloxy)-2,5-bis(boronic acid) benzene (5) M solution of butyllithium in hexane (70 mL, 0.141 mol) was added slowly to a solution of dibromide (4) (24.3 g, 0.035 mol) in THF (150 ml) under nitrogen atmosphere at -78 °C The solution was warmed to RT and then cooled to -78 °C, followed by the dropwise addition of triisopropylborate (51 mL) during a h period After complete addition, the mixture was again warmed to RT, stirred overnight and mixed with deionized water (2L) The crystalline precipitate obtained was collected and recrystallized from acetone in 60% yield 1H NMR (CDCl3, δ, ppm): 7.77 (m, 4H, BOH), 7.18 (s, 2H, ArC-H), 4.51 (s, 1H, OCHO), 3.96 (t, 4H, ArOCH2), 3.71 (t, 2H, OCH2), 3.57 (q, 2H, CH2O), 3.4 (q, 4H, OCH2CH2), 1.77 (m, 6H, CH2), 1.26 (m, 34H, CH2), 0.86 (t, 3H, CH3) 13 C NMR (CDCl3, δ, ppm): 156.8, 117.9, 97.80, 68.2, 66.5, 61.1, 31.2, 30.2, 29.1, 28.8, 28.7, 28.6, 25.6, 25.3, 24.9, 22, 19.1, 13.8 MS-ESI: m/z, 621 (M+) Elemental analysis calculated (%) for C34H62B2O8: C, 65.81; H, 10.07 Found: C, 65.49; H, 10.23 FT-IR (KBr, cm-1): 3479, 3358, 2920, 2851, 1495, 1465, 1415, 1389, 1288, 1195, 1047, 1132, 1047, 881, 817, 721, 640 Poly(1-dodecyloxy-4-(ω-tetrahydropyranoxy undecyloxy)-2,5-phenylene) (6) Diboronic acid (5) (13.42 g, 0.023 mol) and dibromo compound (4) (15.75 g, 0.023 mol) were mixed in dry toluene (200 ml ) under nitrogen atmosphere An aliquot of K2CO3 solution (2 M, 400 mL) was added to this mixture followed by tetrakis(triphenylphosphino) palladium (3 mol % with respect to monomer (5)) as catalyst The 179 Experimental details mixture was stirred at 80 °C for 72 h and precipitated twice from methanol to yield a yellowish polymer, which was filtered and dried under reduced pressure Yield 20 g 1H NMR (CDCl3, δ, ppm): 7.08 (b, ArC-H), 4.56 (b, OCHO), 3.85 (b, ArOCH2), 3.69 (b, OCH2), 3.46 (b, CH2O), 3.37 (b, OCH2CH2), 1.66 (b, CH2), 1.24 (b, CH2), 0.87 (b, CH3) 13 C NMR (CDCl3, δ, ppm): 150, 117.1, 98.6, 69.5, 67.5, 62.1, 31.8, 30.6, 29.6, 29.4, 29.2, 26.1, 26, 25.4, 22.6, 19.5, 14 Elemental analysis calculated (%) for C12PPPC11OTHP: C, 76.97; H, 11.02 Found: C, 76.71; H, 11.14 FT-IR (KBr, cm-1): 2921, 2851, 1609, 1471, 1350, 1212, 1066, 1031, 865, 789, 720 Poly(1-dodecylxy-4-(ω-hydroxy undecyloxy)-2,5-phenylene) (7) Precursor polymer (6) (10 g) was dissolved in dry THF (100 ml) Concentrated hydrochloric acid (10 mL) was added to the solution and the reaction mixture stirred at 60 °C overnight The polymer was precipitated by adding methanol 1H NMR (CDCl3, δ, ppm): 7.08 (b, ArCH), 3.88 (b, OCH2), 3.6 (b, CH2OH), 1.60 (b, CH2), 1.22 (b, CH2), 0.84 (b, CH3) 13C NMR (CDCl3, δ, ppm): 149.9, 127.4, 117.2, 69.5, 62.8, 32.7, 31.8, 30.7, 29.6, 29.2, 26, 25.6, 22.5, 13.9 Elemental analysis calculated (%) for C12PPPC11OH: C, 78.02; H 11.29 Found: C, 78.12; H, 11.18 FT-IR (KBr, cm-1): 3317, 2919, 2852, 1600, 1471, 1350, 1212, 1057, 848, 786, 720 180 Experimental details 6.3.4 Synthesis of C6PPPC5Cb (i) NH Br N (1) Br N HO (ii) n OR O N n (2) OR Scheme 6.3 Synthetic scheme of C6PPPC5Cb (i) KOH in dry DMF, 1,5 dibromopentane (28%) (ii) K2CO3 in dry DMF, Bromopentyl pyrrole, 60º C, 24 hours (68%) The polymer C6PPPOH was synthesized as reported before Synthesis of 9-(5bromopentyl)-9H-carbazole and grafting to the C6PPPOH is summarized in Scheme 6.3 9-(5-Bromopentyl)-9H-carbazole (1)4 A mixture of carbazole (6.8 g, 40 mmol), 1,5dibromopentane (7.77g, 40 mmol), and potassium carbonate (16.6 g, 120 mmol) in of DMF (20 mL ) was reacted overnight The reaction mixture was poured into water, extracted with methylene chloride, washed with water and dried over magnesium sulfate The crude product was purified using column chromatography using hexane as the eluent 181 Experimental details After the removal of the dibromohexane, the eluent was changed to a 1% (v/v) ethyl acetate in petroleum ether The 9-(5-bromopentyl)-9H-carbazole was obtained in 26% yield NMR (CDCl3, δ, ppm): 8.09 (d, 2H, ArC-H), 7.48, (t, 2H, ArC-H), 7.38 (d, 2H, ArC-H), 7.21 (t, 2H, ArC-H), 4.32 (t, 2H, -NCH2-), 3.35 (t, 2H, -CH2Br), 1.96-1.83 (m, 4H, alkyl protons), 1.57-1.48 (m, 2H, alkyl protons) 13C NMR (CDCl3, δ, ppm): 140.3, 125.6, 122.8, 120.3, 118.8, 108.5, 42.7, 33.2, 32.4, 28.1, 25.8 MS-ESI: m/z, 315.1 (M+) Elemental analysis calculated (%) for C17H18BrN: C, 64.57; H, 5.74; N, 4.43 Found: C, 64.83; H, 5.96; N, 4.30 C6PPPC5Cb (2) C6PPPOH (0.2 gm) was dissolved in DMF (20 mL) K2CO3 (4.5 equivalents) was added and stirred N-pentyl carbazole (3 equivalents) was added dropwise to the resultant solution and the temperature was raised to 60 ºC and stirred for 24 hours The crude product was washed with water and extracted with chloroform and the polymer was precipitated twice from methanol The yield of the product was 68% H NMR (CDCl , δ, ppm): 8.01 (b, Ar-CH), 7.32 (b, Ar-CH), 7.14 (b, Ar-CH), 7.05 (b, Ar3 CH), 4.11 (b, N-CH2) 3.88 (b, O-CH2-) 2.04 (b, alkyl protons), 1.63-1.22 (b, alkyl protons), 0.82 (b, methyl protons) FT-IR (KBr, cm-1): 3439 (O-H stretching), 2958, 2930, 2862 (saturated C-H stretching), 1598, 1487 (aromatic C-C stretching), 1370 (saturated C-H bending), 1330, 1203 (C-N stretching), 804 (two adjacent aromatic hydrogens) 182 Experimental details 6.4 Langmuir-Blodgett film deposition The Langmuir-Blodgett experiments were performed on a KSV-2000 Langmuir- Blodgett system (KSV Instruments, Helsinki, Finland) equipped with computer controls A Wilhelmy plate was used as the surface pressure sensor placed in the middle of the trough Two barriers compress or expand symmetrically at the same rate from two sides of the trough Monolayers were obtained by spreading 100-150 μL of the polymer in chloroform with a concentration of 0.5 mg/mL onto pure Milli-Q water (resistivity 18.2MΩ/cm) at a neutral pH After 15 for solvent evaporation, the monolayer is compressed at a typical rate of 50 mm/min Isotherms of surface pressure, π, versus the mean molecular area/repeating unit (A) are measured at T = 22 ± 0.2 °C Isobaric creep measurements and compression expansion cycles were also investigated 6.5 Preparation of Substrates The quartz and ITO substrate was cleaned using ultrasonication in hot chloroform (15 min), followed by RCA recipe (H2O/H2O2/NH3::15.1 g/ 26.6 g/ 8.57g), and rinsed with copious amounts of distilled water to get hydrophilic substrates Gold-coated LaSFN9 glass substrates were prepared by thermal evaporation Each glass slide was pre-cleaned using ultrasonication in % Hellmanex solution, water, and ethanol followed by drying in a stream of N2 Gold (~ 50 nm) was deposited onto the substrates by thermal evaporation in a vacuum chamber (Biemtron Co Inc) at ~ x 10-5 torr at a rate of 0.1 nm/s The Au substrates were used as such or modified using 16-mercaptohexadecanoic acid solutions (Aldrich Chemical Co.) to form hydrophilic surfaces The thiol SAMs were assembled from ethanolic solutions at a concentration of mM The surface modification was carried 183 Experimental details out by immersion of a freshly evaporated gold substrate into a freshly prepared thiol solution for 14 hours at room temperature in order to ensure the formation of a high quality film The substrate was then removed from the solution and immediately rinsed with absolute ethanol and dried in a stream of N2 Electrochemical surface plasmon resonance spectroscopy (EC-SPS) measurements were performed using a surface plasmon resonance (SPR) setup combined with a threeelectrode electrochemical cell in a Kretschmann configuration for the excitation of surface plasmons 6.6 Surface Plasmon Resonance Spectroscopy The SPR studies performed were on a set up based on “Kretschmann Configuration A schematic diagrm of the setp up is shown in Figure 6.1 Photodiode Lens Prism Glass substrate Metal layer He-Ne Laser Chopper Polarizer PC Motor controllers Lock-in amplifier Figure 6.1 Schematic diagram of surface plasmon spectroscopy set-up based on Kretchmann configuration 184 Experimental details A Helium-Neon-Laser (Uniphase, mW, λ = 632.8 nm) was used as the light source The laser beam is modulated using a mechanical chopper, and passes through two polarisers in which the first polarizer adjusts the intensity of the incident beam and the second controls the polarisation direction, before it reaches the prism followed by the sample A refractive index-matched immersion oil was applied to avoid light scattering at the interface between the prism and the glass piece The reflected light is focused by a lens before it arrives at a photodiode detector, from where the signal is recorded by a Lock-in amplifier and further evaluated by a computer Sample and detector are moved by two goniometers in θ/2θ geometry Resonance spectrum is obtained by reflecting a polariszed laser beam from the base plane of the prism and plotting the normalized reflected intensity versus the incident angle The obtained scan curve can then be fitted according to Fresnel’s formula in order to calculate the thickness of the metallic and dielectric layers The calculations are carried out using a computer software Winspall 2.0 Parameters that are included in the fitting procedure are the measured reflectivity, the incidence angle, thickness and the dielectric constants of the layers as well as the used laser wavelength and the geometry of the coupling prism By iterative optimization of the parameters, the simulated reflectivity curve is fitted to the measured scan curve and the optical constants of the involved layers are determined Since the thickness and dielectric constant of the layers cannot be determined independently, one of the parameters has to be measured by use of other techniques 185 Experimental details 6.7 Photophysical property measurements The relative PL quantum yields of the polymers in toluene solution were determined using quinine sulfate in 0.1 M sulfuric acid as the reference.5 The absolute PL quantum yield of the polymer films were determined using an integrating sphere (Lab Sphere Com) with He-Cd laser (325 nm; 11 mW) as an excitation source.6,7 To obtain a correct value for absorption, a bare quartz substrate was used when measuring on an empty sphere before measuring the polymer samples Errors due to fluctuation of excitation light and differences in position of the sample inside the sphere were minimized by repeating the measurement several times using polymer film samples of different dimension and different UV absorbance The time resolved photoluminescence measurements were carried out by exciting the spin coated polymer films on quartz substrates using femtosecond laser and measured using FS streak camera The signal to noise ratio was good The obtained decay curves were fitted to single exponential function The charge carrier mobility measurements were done using a conventional time of flight (TOF) photoconductivity measurement on indium-tin-oxide (ITO)/ polymer/aluminum sandwich structures Test devices were prepared by spin coating the polymer solution in toluene (30 mg/mL, 500 rpm) on a transparent ITO (sheet resistance of 20 Ω /square) patterned glass substrate These films were annealed at a temperature of 60 °C for hours in a nitrogen atmosphere to remove residual solvent A 60 nm thick aluminum (Al) electrode was evaporated onto the polymer film by Edwards thermal evaporator (Auto 306) at 10-7 torr pressure The active area of the device was mm2 The thickness of the films was measured using a surface profilometer 186 Experimental details 6.8 Electropolymerization of the polymer C6PPPC5Cb on solid substrates The electropolymerization of the thin films of polymer was carried out in a computer controlled μ-Autolab type II potentiostat/galvanostat controlled by the Autolab GPES software version 4.7 The precursor polymers were transferred onto ITO and bare gold substrates Up to 20 layers were transferred in Z-type deposition to both substrates The substrates were dried under vacuum and were used as working electrodes for the electrochemistry experiments The cyclic voltammetry was performed in a electrode cell containing 0.1 M tetrabutylammonium perchlorate in acetonitrile solution The electropolymerization was performed in each case by sweeping the voltage at a scan rate of 100 mV/s and 20 mV/s from to 1.1 V against Ag/AgCl as a reference electrode and Pt as a counter electrode 187 Experimental details 6.9 References (a) Miyaura, N.; Yanagi, T.; Suzuki, A Synth Commun 1981, 11, 513 (b) Karakaya, B.; Claussen, W.; Gessler, K.; Saenger, W.; Schluter, A D J Am Chem Soc 1997, 119, 3296 (c) Yamamoto, T.; Kimura, T.; Schiraishi, K Macromolecules 1999, 32, 8886 (d) Schlüter, A D J Polym Sci Part A Polym Chem, 2001, 39, 1533 (e) Zhang, C.; Schlaad, H.; Schlüter, A D J Polym Sci Part A: Polym Chem 2003, 41, 2879 Baskar, C.; Lai, Y H.; Valiyaveettil, S Macromolecules 2001, 34, 6255 Tietze, L F Reactions and Synthesis in the Organic Chemistry Laboratory; University Science: Mill Valley, CA, 1989; p 253 Z, Peng, Z Bao, G E Mary, Chem Mater 1998, 10, 2086 Demas, J N.; Crosby, G A.; J Phys Chem 1971, 75, 991 Greenham, N C.; Samuel, I D W.; Hayes, G R.; Philips, R T.; Kessener, Y A R R.; Moratti, S C.; Holmes, A B.; Friend, R H Chem Phys Lett 1995, 241, 89 de Mello, J C.; Wittmann, H F.; Friend, R Adv Mater 1997, 9, 230 188 ... 2 263 The electrode surface area was 0.785 cm2 6. 3 Details of the amphiphilic poly(p- phenylene)s synthesized and used for the present study 6. 3.1 Synthesis and characterization of monomers and. .. 3 .69 (b, OCH2), 3. 46 (b, CH2O), 3.37 (b, OCH2CH2), 1 .66 (b, CH2), 1.24 (b, CH2), 0.87 (b, CH3) 13 C NMR (CDCl3, δ, ppm): 150, 117.1, 98 .6, 69 .5, 67 .5, 62 .1, 31.8, 30 .6, 29 .6, 29.4, 29.2, 26. 1,... NMR (DMSO-d6, δ, ppm): 157.4, 1 56. 7, 137 .6, 128.8, 128.2, 127.9, 118.7, 118.1, 70.4, 68 .7, 31 .6, 29. 06, 25.8, 22.4, 14.3 MS (ESI): m/z: 4 56 Elemental analysis calcd for C25H38B2O6: C, 65 .82; H,