Organometallics 1996, 14, 1089-1091
1089
Polymeric Organosilicon Systems. 24. Anionic Polymerization of 4,5,lO-Trisilabicyclo[6.3.01undeca-1(1l),&diene-2,6-diynes Eiji Toyoda, Atsutaka Kunai, and Mitsuo Ishikawa* Department of Applied Chemistry, Faculty of Engineering, Hiroshima University, Higashi-Hiroshima 724,Japan Received November 4, 1994@ Summary: Anionic ring-opening polymerization of cyclic silole derivatives has been reported. The reaction of 45,1O-trisilabicycl~[6.3.Olundeca-l(ll),8-diene-2,6-diynes with a catalytic amount of tetrabutylammonium fluoride afforded polymers that have a regular alternating arrangement of a disilanylene unit and 3,4-diethynylenesubstituted silole system. Current interest has focused on the synthesis of silicon-containing polymers that can be used as functionality materia1s.l It is of interest to us to synthesize alternating disilanylene polymers that have an electrondeficient group such as a silole unit in the polymer backbone, because these polymers might produce n-type conducting materials.2 Recently, we have found that 1,2,5,6-tetrasilacycloocta-3,7-diynes undergo anionic,3a thermal,3band radi~al-induced~~ ring-opening polymerization to give poly[(disilanylene)ethynylenesl with high molecular weights. As a part of our continuing investigations concerning the design and synthesis of siliconcontaining functionality materials, we have prepared a new type of the polymer that has a regular alternating arrangement of a disilanylene unit and 3,4-diethynylene-substituted silole system in the polymer backbone. Our strategy for the synthesis of this type of polymer involves the anionic ring-opening reaction of the cyclic silole derivatives 4,5,10-trisilabicycl0[6.3.01undeca-1(11),8-diene-2,6-diynes. To our knowledge, only two types of polymers involving silole rings in the main chain have been prepared so far.4,5 The starting siloles 4,4,5,5,10,10-hexamethyl-, 4,433tetraethyl-lO,lO-dimethyl-,and 4,5-dibutyl-4,5,10,10Abstract published in Advance ACS Abstracts, February 1, 1995. (1)For example: (a) Ishikawa, M.; Nate, K. In Inorganic and Organometallic Polymers; Zeldin, M., Wynne, K. J., Allcock, H. R., Eds.; ACS Symposium Series 360;American Chemical Society: Washington, DC, 1988;Chapter 16.(b) Nate, K.; Ishikawa, M.; Ni, H.; Watanabe, H.; Saheki, Y. Organometallics 1987,6,1673.(c) Ohshita, J.; Kanaya, D.; Ishikawa, M.; Yamanaka, T. J . Organomet. Chem. 1989,369,C18. (d) Hong, H.; Weber, W. P. Polym. Bull. 1989,22, 363. (e) Hu, S.; Weber, W. P. Polym. Bull. 1989,21,133.(f) Ishikawa, M.;Hasegawa, Y.; Kunai, A. J . Organomet. Chem. 1990,381,C57. (g) Ohshita, J.; Kanaya, D.; Ishikawa, M.; Koike, T.; Yamanaka, T. Macromolecules 1991,24,2106.(h) Ohshita, J.; Ohsaki, H.; Ishikawa, M. Bull. Chem. SOC.Jpn. 1993,66, 1795.(i) Ohshita, J.; Kanaya, D.; Ishikawa, M. J . Organomet. Chem. 1994,468,55. (2)Although the conducting polymers with semiconducting levels have been obtained by treating the alternating disilanylene polymers having various n-electron systems with SbFe, FeC13, and 12, all of them are p-type conducting (see ref 3a and also see: Ishikawa, M.; Sakamoto, H.; Ishii, M.; Ohshita, J . J . Polym. Sci. A: Polym. Chem. 1993,31, 3281. Fukushima, M. Industrial Science and Technology Frontier Program: The 2nd Symposium on Silicon-Based Polymers; Japan High Polymer Center: Tokyo, 1994;extended abstracts pp 183-191). (3)(a) Ishikawa, M.; Hatano, T.; Hasegawa, Y.; Horio, T.; Kunai, A.; Miyai, A.; Ishida, T.; Tsukihara, T.; Yamanaka, T.; Koike, T.; Shioya, J . Organometallics 1992,11, 1604.(b) Ishikawa, M.; Horio, T.; Hatano, T.; Kunai, A. Organometallics 1993,12, 2078. (4)Tamao, K.; Yamaguchi, S.; Shiozaki, M.; Nakagawa, Y.; Ito, Y. J . Am. Chem. SOC.1992,114,5867. @
0276-733319512314-1089$09.OO/O
tetramethyl-4,5,10-trisilabicyclo[6.3.Olundeca-l(ll),8diene-2,6-diynes (Sa-c) were prepared by the series of reactions shown in Scheme 1. Treatment of 1,4-bis(trimethylsilyl)butadiyne6with 1,1,2,24etramethyldisilane7 in the presence of a catalytic amount of dichlorobis(triethylphosphine)nickel(II)in THF at reflux temperature for 26 h gave a mixture of 1,l-dimethyl-2,5bis(trimethylsilyl)-3,4-bis((trimethylsilyl)ethynyl)silole (1) and 1,1,4,4-tetramethyl-2,5-bis(trimethylsilyl)-3,6-bis((trimethylsilyl)ethynyl)-l,4-disilacyclohexa-2,5-diene (2h8 The reaction of this mixture with methanol in the presence of a catalytic amount of potassium hydroxide at 50 "C for 1 h afforded the respective desilylated products (3 and 4). Diethynylsilole 3: thus formed, could be readily separated from 41° by column chromatography. Compounds 3 and 4 were obtained in 27% and 11%isolated yields, respectively, from the starting 1,4-bis(trimethylsilyl)butadiyne. Treatment of 3 with 2 equiv of lithium diisopropylamide at -70 "C for 0.5 h, followed by the reaction of the resulting dilithio compound with 1,2-dichlorotetramethyldisilane,ll produced the cyclic silole derivative 5a, with a 4,5,10-trisilabicyclo[6.3.0lundeca-l(ll),8diene-2,6-diyne ring structure,12 in 8% yield. Similar treatment of the dilithio compound with 1,2-dichlorotetr a e t h ~ land - ~ ~1,2-dibutyl-l,2-dichlorodimethyldi~ilane~~ afforded the respective siloles (5b13and 5c14)in 54% and 39% yields. (5) (a) Corriu, R. J . P.; Douglas, W. E.; Yang, Z.-X. J . Organomet. Chem. 1993,456,35. (b) Brefort, J . L.; Corriu, R. J. P.; Gerbier, P.; GuBrin, C.; Henner, B. J. L.; Jean, A.; Kuhlmann, T. Organometallics 1992,11,2500. (6)Walton, D. R. M.; Waugh, F. J. Organomet. Chem. 1972,37,45. (7)Urenovitch, J. V.;West, R. J . Organomet. Chem. 1965,3,138. For 1,1,2,24etramethyldisilane:MS m/z 118 (M+); 'H NMR (6 in CDC13) 0.14(d, 12H,MeSi, J = 3.3 Hz), 3.69 (m, 2H, HSi). (8)Okinoshima, H.; Yamamoto, K.; Kumada, M. J . Am. Chem. SOC. 1972,94,9263. (9)Compound 3: mp 49-50 "C; MS mlz 302 (M+); UV I, (THF solution) 238 nm ( E = 18 6001,333nm ( E = 2700);IR V C ~ 3303, H Y-C 2094 cm-l; 'H NMR (6 in CDC13) 0.21 (6, 18H,Me&), 0.24 ( s , 6H, Me&), 3.33(s, 2H, ethynyl protons); 13CNMR (6 in CDC13) -3.88 (MezSi). -0.75(Me&). 82.57.82.95(CsC). 144.44.156.10(C=C): %Si NMR (6 in CDC13) -8.07 (Me&), 24.97 (hie&). Anal. Calcd for ' C I ~ H Z ~ S ~ ~ : C, 63.50;H, 8.66.Found: C, 63.34;H, 8.66. (10)Compound 4: mp 136-138 "C; MS mlz 360 (M+);IR VCWH 3282 cm-'; 'H NMR (6 in CDC13) 0.25(s, 18H, Measi), 0.30(s, 12H, MezSi), 3.70 (s, 2H, ethynyl protons); 13C NMR (6 in CDC13) -0.84 (Me&), 0.70 (Measi), 86.25,89.94(CIC), 154.10,172.36(C-C); 29SiNMR (6 in CDC13) -7.71 (Me&), -24.47 (MezSi). Anal. Calcd for C18H32Si4: C, 59.92;H, 8.94.Found: C, 59.88;H, 8.91. (11)Kumada, M.; Yamaguchi, M.; Yamamoto, Y.; Nakajima, J.; Shiina, K. J . Org. Chem. 1956,21,1264. (12)Compound 5a: mp 198-199 "C dec; MS mlz 416 (M+);UVI,, (THF solution) 225 nm (c = 36 goo),250 nm ( E = 24 400),340 nm ( E = 3400);IR VC-C 2108 cm-1; 'H NMR (6 in CDCl3) 0.206(s, 18H, Measi), 0.214(s, 6H, MezSi in silole ring), 0.30 (s, 12H,MezSi-Si); 13C NMR (6 in CDC13)-3.65 (MezSi in silole ring), -2.78 (MezSi-Si), -0.34(MeaSi), 105.40,115.28(CrC), 147.15,149.86(C=C); 29SiNMR (6 in CDC13) -31.48 (MezSi-Si), -7.63 (Me&), 27.40 (MezSi in d o l e ring). Anal. Calcd for C20H36Si5:C, 57.62;H, 8.70.Found: C, 57.55;H, 8.58.
0 1995 American Chemical Society
Communications
1090 Organometallics, Vol. 14, No. 3, 1995 Scheme 1 Me3SiCE C- C m CSiMe3
+
1/2 HMefii-SiMqH
5b
Et 1
Et
2
H 7
3
+
Sa, R'=RZ=Me Sb, R'=RZ=Et 5c. R h - B u , RkMe
6a, R'=RZ=Me
6b,R'=RZ=Et 6c, R'=n-Bu, RZ=Me
Compounds 5a-c readily undergo the anionic ringopening polymerization in the presence of a catalytic amount of tetrabutylammonium fluoride (2 mol %) t o give the respective alternating polymers with high molecular weights in high yields. In a typical experiment, a mixture of 195 mg (0.412mmol) of silole 5b and 0.008 mmol(2 mol %) of tetrabutylammonium fluoride in 1 mL of THF dried over Na-K alloy was stirred in a sealed tube a t room temperature for 20 h. After addition of a few drops of MeI, the mixture was poured into ca. 50 mL of methanol. Then, the resulting solid was filtered off and dried under reduced pressure to give 169 mg (87% yield) of poly[(l,2-diethynylenetetraethyldisilanylene)(l,l-dimethyl-l-silacyclopentaS,4-diene3,4-diyl)l (6b)15with a molecular weight of M, = 30 300 (M,/M, = 1.66). Similar treatment of 5a and 5c with (13) Compound 5b: mp 104-105 "C; MS m/z 472 (M+); UV I,, (THF solution) 227 nm (E = 39 3001,250 nm (E = 26 500), 340 nm ( e = 3700); IR Y C 2112 ~ cm-'; 1H NMR (6 in CDC13) 0.23 (s, 18H, Me&), 0.24 (8,6H, MezSi), 0.72-0.91 (m, 8H, C H ~ C H Z S 1.07 ~ ) , (t, 12H, CH3CHzSi, J = 7.8 Hz); 13C NMR (6 in CDC13) -3.54 (Me&), -0.34 (Me&), 4.55, 8.59 (EtzSi), 104.37, 116.01 ( C I C ) , 147.66, 149.08 (C=C); 29Si NMR (6 in CDC13) -20.54 (Et&), -7.35 (Measi), 27.66 (Me&). Anal. Calcd for C Z ~ H ~C,~ 60.94; S ~ ~H, : 9.38. Found C, 60.75; H, 9.47. (14) Compound 5c (mixture of cis and trans isomers): MS mlz 500 (M+);UV I,, (THF solution) 227 nm (c = 33 8001,251 nm (E = 24 3001, 340 nm ( E = 3800); IR vclc 2112 cm-l; 'H NMR (6 in CDC13) 0.20 (s, 18H, Me&), 0.22 (s, 6H, MezSi in silole ring), 0.28 (s, 6H, n-BuMeSi), 0.69-0.91, 1.30-1.50 (m, 18H, n-Bu); 13C NMR (6 in CDC13) -4.48, -4.40 (n-BuMeSi), -3.63, -3.61, -3.58 (Me&), -0.36 (Me&), 13.76, 26.09,26.84,26.94 (n-Bu), 105.21,115.45 (CSC), 147.41,149.40 (C=C); 29Si NMR (6 in CDC13) -28.82, -28.61 (n-BuMeSi), -7.60 (Me$%), 27.27 (Me&). Anal. Calcd for C2,&48Si5: C, 62.32; H, 9.66. Found: C, 62.10; H, 9.76.
the fluoride anion in THF afforded polymers 6a ( M w= 9400,MwIMn= 1.38)16 and 6~ ( M w= 46 300,M w l M n = 1.76)17in 75% and 80% yields, respectively. That monomers 5a-c undergo anionic ring-opening reactions, giving the polymers 6a-c, was confirmed by the fact that treatment of 5b with a catalytic amount of methyllithium produced polymer 6b (M, = 47 900, MwlMn= 1.26)in 77% yield. IR, lH NMR, and 13CN M R spectra for this polymer were identical with those for 6b obtained from the fluoride anion-catalyzed polymerization of 5b. Furthermore, the reaction of 5b with 1 equiv of methyllithium at -90 "Cfor 1 h, followed by treatment of the resulting mixture with dilute hydrochloric acid, produced 3-ethynyl-4((2-methyltetraethyldisilany1)ethynyl)1,l-dimethyl2,5-bis(trimethylsilyl)silole(7)18in 60% yield as the sole volatile product. This result clearly indicates that methyl anion attacks a t a silicon atom in the disilanylene unit to give a ring-opened lithioethynylsilole (Scheme 2). The I3CNMX spectrum for 6b reveals resonances at 6 -3.64,-0.55,4.93,and 8.67ppm, attributed to Me2Si, MesSi, and EtnSi carbons, as well as resonances at 6 97.39,107.32,145.98,and 155.21ppm, due to sp and sp2carbons, respectively. Its 29SiNMR spectrum shows three resonances a t 6 -30.11, -8.76,and 24.02 ppm, (15)Polymer 6b: mp 79-82 "C; M , = 30 300 (M,IM, = 1.66); W I,,, (THF solution) 255 nm (E = 25 OOO), 300 nm (sh, E = 9400); IR Y C 2130 ~ cm-l; 'H NMR (6 in CDC13) 0.21 (s, 18H, Measi), 0.23 (s, 6H, Me&), 0.90 (9,8H,C H ~ C H Z SJ~= , 7.6 Hz), 1.12 (t, 12H, CH3CHzSi, J = 7.6 Hz); 13C NMR (6 in CDC13) -3.64 (Me&), -0.55 (Me&), 4.93, 8.67 (EtSi), 97.39, 107.32 (CEC), 145.98, 155.21 (C=C); 29Si NMR (6 in CDC13) -30.11 (Et&), -8.76 (Measi), 24.02 (MezSi). Anal. Calcd for ( C Z ~ H ~ ~ SC,~60.94; S ) ~ : H, 9.38. Found: C, 60.56; H, 9.65. (16) Polymer 6a: mp 90-98 "C; M , = 9400 ( M J M n = 1.38);W I,, (THF solution) 254 nm (E = 16 loo), 292 nm (sh, E = 7800); IR YCSC 2136 cm-'; lH NMR (6 in CDCl3) 0.19 (s, 18H, Measi), 0.21 (s, 6H, MezSi in silole ring), 0.36 (s, 12H, MezSi-Si); 13C NMR (6 in CDC13) -3.75 (MezSi in silole ring), -2.53 (MezSi-Si), -0.65 (Me&), 98.60, 106.69 (CsC), 145.64, 155.36 (C-C); 29SiNMR (6 in CDC13) -37.32 (MezSi-Si), -8.51 (Me&), 24.57 (MezSi in silole ring). Anal. Calcd for ( C Z O H ~ ~ C, S ~57.62; ~ ) ~ :H, 8.70. Found: C, 56.81; H, 8.80. (17) Polymer 6c: mp 46-50 "C; M , = 46 300 (MJM,= 1.76);UV I,, (THF solution) 254 nm (e = 25 goo), 301 nm (sh, E = 12 300); IR YCW 2134 cm-l; lH NMR (6 in CDC13) 0.19 ( 8 , 18H, Me&), 0.21 (s, 6H, MezSi in silole ring), 0.35 (5, 6H, BuMeSi), 0.81-0.89, 1.32-1.47 (m, 18H, n-Bu); 13C NMR (6 in CDC13) -4.00 (BuMeSi), -3.73 (MezSi), -0.60 (Me&), 13.81, 14.01, 14.12,26.54, 26.73, 26.78 (n-Bu), 98.24, 106.86 (C=C), 145.89, 154.82, 154.85, 154.88 (C-C); 29SiNMR (6 in CDCl3) -34.93, -34.75 (BuMeSi), -8.17 (Messif, 24.79 (MezSi). Anal. Calcd for (Cz~H48Si5)~: C, 62.32; H, 9.66. Found: C, 61.66; H, 9.61. (18)Compound 7: MS m/z 488 (M+);IR UCWH 3307, u c e 2132 cm-'; lH NMR (6 in CDC13) 0.11 (s, 3H, MeSi), 0.20, 0.21, 0.23 (3 s, 24H, 2 Me&i and Me@), 0.68-1.23 (m, 20H, EtSi), 3.23 (s, l H , ethynyl proton); 13C NMR (6 in CDC13) -6.00 (EtzMeSi), -3.75 (MezSi), -0.68 (Me&), 5.00,5.38,8.21,8.66(Et),82.95,98.99,106.65(C=C), 145.12, 146.02, 153.41, 155.54 (C-C); 29SiNMR (6 in CDCl3) -28.47, -11.49 (Si-Si), -8.42, -8.23 (Me&), 24.79 (Me&). Anal. Calcd for (C25H48Si&: C, 61.40; H, 9.89. Found: C, 61.40; H, 9.87.
Organometallics, Vol. 14,No.3, 1995 1091
Communications due to EtzSi, Me&, and MeaSi. No other resonances are detected in its 13C and 29SiNMR spectra. These results indicate that 6b has a regular alternating arrangement of a disilanylene unit and 3,4-diethynylenesilole system in the polymer main chain. The structures of 6a and 6c were also verified by spedrometric and elemental analysis. Polymers 6a-c are solids, melt without decomposition, and are soluble in aromatic hydrocarbons, ethers, and chlorocarbons but insoluble in alcohols.
We are continuing to explore the use of the present polymers as functionality materials. Supplementary Material Available: Text giving experimental details and spectroscopic data €or 1 and 2 and figures giving 'H,W, and 29SiNMR spectra for polymers 6a-c (12 pages). Ordering information is given on any current masthead page.
OM940839L
