Novel Polydiacetylenes as Materials for Second and Third Order Nonlinear Optics
- PDF / 297,500 Bytes
- 6 Pages / 414.72 x 648 pts Page_size
- 45 Downloads / 168 Views
third order NLO properties. Further, enhancement of the third order properties through cascade effects may be possible. The electroactive sidegroups may be used to modify and modulate the backbone electronic structure as well. This investigation is centered around two unsymmetrical diacetylene monomers in which each contained a highly flexible urethanyl side group (RI' = R 2 ' = (CH2)40(CO)NHCH2(CO)OC4H9) and a chromophoric substituent. The chromophoric substituents chosen were: R1 = -CH20(CO)NH(C6H4)2NO2 (I) and R 2 = CH20(CO)NH(C6H4)N=N(C6H4)NO2 (II) (Fig. 1). The high entropy flexible urethanyl side group was chosen to satisfy the monomer packing requirements for polymerization and enhance the solubility of the PDAs. This paper will focus on the synthesis and polymerization of the diacetylene monomers and the NLO properties of the corresponding polymers.
NO2 -
-NH(CO)OCH 2C= C-C-C(CH2)40(CO NHCH 2(CO)OC 4H9 MONOMER I
NO 2 --
N=N-O-NH(CO)OCH 2C= C-CGC(CH2)4 O(CO)NHCH 2(CO)OC 4 H9 MONOMER 2
Figure 1. Chemical Structure of the Diacetylene Monomers EXPERIMENTAL Chemicals Butyl isocyanatoacetate was obtained from Eastman Kodak Company, 4,4'dinitrobiphenyl was obtained from TCI America Organic Chemicals, and trichloromethylchlorofromate was obtained from Lancaster Synthesis. All of the aforementioned chemicals were used as received. All other chemicals were obtained from Aldrich Chemical and used as received. Synthesis of 6-Bromo-5-Hexyn-l -ol Bromine (0.1M) was added dropwise to a NaOH/H20 solution (0.02M/100ml) under stirring at 0-5 °C. A pale yellowish solution of NaOBr was observed to form immediately. 5-Hexyn-l-ol (0.01M) was added to 25mL of 1,4 Dioxane to increase the solubility of the compound. The NaOBr solution was added dropwise to the above mixture
668
over 30 minutes at 5-10 °C under nitrogen and vigorously stirred for 30 minutes. This mixture was extracted with ethyl ether, dried with MgSO4, and a pale yellow liquid was obtained by removing the solvent. Yield: 55% IR(KBr): 3338cm- 1 (OH), 2217cm- 1 (C=-C) Synthesis of ((6-Butoxy carbonyl) methyl urethanyl)-l-bromo-l-hexyne To a solution of butyl isocyanatoacetate (0.055M) and 6-Bromo-5-Hexyn-l-ol (0.05M) in 5OmL of dry THF, 3-5 drops of dibutyltin dilaurate and 3-5 drops of triethylamine were added. The mixture was stirred for 3 hours at room temperature. A brown liquid is obtained after removal of the solvent. Yield: 90 % IR(KBr): 3305cm-1 (NH), 1690cm-1 (C=O) Synthesis of ((9-Butoxy carbonyl) methyl urethanyl) nona-2.4-diyn-l-ol (BNDO) BNDO was prepared via the Cadiot-Chodkiewicz coupling [6] of ((6-Butoxy carbonyl) methyl urethanyl)-1-bromo-1-hexyne and propargyl alcohol. A catalytic solution of CuCl, 70% aqueous ethylamine (20 mL), NH2OHoHC1 in H2 0 (2g/20ml), and 100 mL of methanol was prepared in a 3-necked round bottomed flask. The reaction was carried out in a nitrogen atmosphere. The propargyl alcohol (0.075M) was added to the catalytic solution in one portion with the formation of a yellow solution. ((6-Butoxy carbonyl) methyl urethany
Data Loading...
