Preparation Of Bromobenzylidene Lab Report

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For the synthesis of P2, a mixture of 1 (500 mg, 0.553 mmol), 2 (252 mg, 0.553 mmol), 3 (760 mg, 1.105 mmol), tris(o-tolyl)phosphine (P(o-tol)3) (13 mg, 0.044 mmol), and tris(dibenzylidene acetone)dipalladium(0) (Pd2(dba)3) (10 mg, 0.011 mmol) in anhydrous chlorobenzene (21 mL) was charged in a 100 mL round bottom flask. The resulting reaction mixture was heated at 150 °C under stirring for 3 days. Compound (2) (38 mg, 0.083 mmol) was added and stirred at 150 °C for 1 h. To that 4-bromobenzotrifluoride (25 mg, 0.111 mmol) was added and stirred at 150 °C for 1 h for end-capping. Next, the mixture was poured in methanol (200 mL), and the precipitate was collected in a Soxhelt thimble filter. The precipitate was then extracted with methanol, ethanol, …show more content…
Similar method was used for the synthesis of the poly(4-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b ']dithiophen-2-yl)-8-(5-(2,6-didodecylbenzo[1,2-d:4,5-d ']bis(thiazole)-4-yl)selenophen-2-yl)-2,6-didodecylbenzo[1,2-d:4,5-d ']bis(thiazole)) [P2] polymer by replacing the 2,5-bis(trimethylstannyl)thiophene with 2,5-bis(trimethylstannyl)selenophene, as shown in Fig. 1. The number-average molecular weights (Mn) of P1 and P2 were 15,710 and 26,220, with polydispersity indexes (PDI) Đ of 1.24 and …show more content…
2c. The UV–vis spectra reveals that the absorption maximum (λmax) of the both polymers P1 and P2 are same at 320 nm, but the absorption onset (λonset) of the both polymers P1 and P2 are different. The λonset of P1 and P2 was 547 and 578 nm, respectively. Fig. 2c shows that P2 polymer red shifted with increasing intensity, as compared to P1 polymer, indicating that P2 polymer has more possibility to harvest the available photons from solar energy. The UV–vis spectra study also reflects that the change in the substitution of sulfur in thiophene with selenium is an effective method to extend the absorption range to longer wavelengths, and this study also supported the previous

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