Synthesis and characterization of functional polysilanes [RMe₂Si(CH₂)_x(Me)Si]_n (R = 2‐Fu, 5‐Me‐2‐Fu, 2‐Th, 4‐Me‐2‐Th; x = 2, 3) with appended furyl/thienyl groups on the carbosilyl side chains and their application in the generation and stabilization of palladium nanoparticles

Abstract

The polysilanes [RMe2Si(CH2)x(Me)Si]n [x = 2, 3; R = 2‐Fu (1, 2), 5‐Me‐2‐Fu (3, 4)] bearing furyl‐substituted carbosilyl side chains have been synthesized by dehalocondensation reaction (Wurtz coupling) of the corresponding carbosilanes using sodium dispersion in refluxing toluene. On the other hand, analogous polysilanes with appended thienyl groups [x = 2, 3; R = 2‐Th (5, 6), 4‐Me‐2‐Th (7, 8)] are only accessible by the reaction of the corresponding carbosilane precursors under mild Wurtz coupling conditions (THF, RT). These polysilanes reveal monomodal molecular weight distribution with Mw/PDI = 3.3–5.4 × 104/1.22–1.47 (1–4) and 9.1–14.4 × 104/1.45–1.61 (5–8) and are characterized by FT‐IR, multinuclear (1H, 13C{1H}, 29Si{1H}) NMR, and UV/PL spectral studies as well as thermogravimetric analysis (TGA). Preliminary studies on the reactivity of polysilane 2 with palladium acetate (toluene, RT) reveal the formation of spherical palladium nanoparticles of size 8.2 ± 0.6 nm, which remain stable in solution for several weeks. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7816–7826, 2008

Catalytic dehydrocoupling of thienyl/furyl-substituted carbosilanes – Synthesis and characterization of functional poly(hydrosilane)s [RMe2Si(CH2)xSiH]n, (R=2-Th, 4-Me-2-Th, 2-Fu, 5-Me-2-Fu; x=2 and 3)

“…The synthesis of 2-thienylsilane [29] and the hydrosilanes, RMe 2-SiH [R = 2-Fu, 5-Me-2-Fu, 2-Th, 4-Me-2-Th/3-Me-2-Th (regioisomers)] [20,[30][31][32][33][34] was carried out by following the procedure reported earlier.…”

“…To address this issue, we have undertaken a systematic study to explore viable synthetic protocols for this class of functional polymers. As shown in Chart 1, a number of such polysilanes have been successfully prepared by involving dehalocondensation (Wurtz coupling) of appropriate dichlorosilanes or chemical modification of preformed poly(n-hexylsilane) [19,20]. It has also been observed that the thienyl/furyl groups on the appended side chains in these polymers contribute towards stabilization of in situ generated silver and palladium nanoparticles.…”

“…129.32, 126.15 (Th),20.97 (b-CH 2 ),19.82 (c-CH 2 ),16.56,15.05 (MeTh),10.12 (a-CH 2 ), À1.90 (SiMe 2 ).29 Si{ 1 H} NMR (CDCl 3 , 79.5 MHz): d À6.22 (SiMe 2 ), À60.16 (SiH 3 ); IR (KBr, cm À1 ): 2146 (mSiH), 925 (dSiH 2 ), 3089 (Si-Th), 1252 (Si-Me). ES-MS: m/z Calc.…”

Scope of network polysilanes in the synthesis of fluorescent silver and gold nanoparticles/nanoclusters‐modulations of their optical properties in the presence of Hg(II) ions

“…A few copolymer templates incorporating polysilane units [R 2 Si] n have been utilized for the synthesis of silicon‐based polymer–metal nanocomposites which exhibit excellent catalytic properties in many organic transformations, including hydrogenation, Suzuki, Sonagashira coupling, and hydrosilylation reactions 6–11. It has been shown that donor ability of the appended 2‐theinyl/2‐furyl groups on the sila‐alkyl side chains in linear polysilanes imparts better stabilization of Ag and Pd nanoparticles 12, 13. Poly(alkyl‐arylsilane)s, [R(C 6 H 4 R 1 )Si] n (R 1 = H, p ‐Me, p ‐OMe, p ‐NMe 2 ) with electron withdrawing/electron releasing substituents on the phenyl groups are found to be interesting precursors for “size controlled” synthesis of Ag and Pd nanoparticles 14.…”

“…The formation of AgNCs in conjunction with AgNPs in these nanocomposites has been substantiated by their fluorescent characteristics in green light region. Our continued interest in silicon‐based polymers and their applications in the synthetic domain of metal nanoparticles12–14 has prompted us to undertake a systematic study on network polysilanes (polysilyne) frameworks, [RSi] n (R = alkyl or aryl) which are known to possess two dimensional sheet‐like structures comprising of linear, branched, and cyclic components and are associated with both direct and indirect band gaps of the order of 2–3 eV 31–38. Herein we describe the synthesis of polysilynes [RMe 2 SiCH 2 CH 2 Si] n [R = Ph ( 1 ), 2‐Furyl ( 2) ] and their reactivity studies toward Ag(I) and Au(III) ions.…”