Hexyl silane

We now report that in the region of the absorption band the flow linear dichroism of a solution of 1 is positive (Fig. 3). Assuming that the nature of the flow orientation is of the usual kind, i.e., that the polymer chains in a random coil conformation which dominates in solution (34) tend to align with the flow direction, this observation provides additional support for the absolute assignment of the transition moment direction along the chain direction, even in solution. Similar conclusions based on polarization studies on a stretched film of poly(di-n-hexyl silane) have recently been reported (36). 

Dicobaltoctacarbonyl at concentrations about 10-3 M was an excellent catalyst (lib) for hydrosilation of 1-hexene by common silanes, including (MeO)3SiH, Et3SiH, and PhCl2SiH, to give exclusively n-hexyl silanes. The only observable side reaction was formation of hexene-2 and hexene-... 

Kepler, R. G. and Soos, Z. G., Exciton-exciton annihilation and exciton kinetics in poly(di-n-hexyl-silane), Phys. Rev. B, 47, 9253, 1993. 

Polarized EXAFS spectra of oriented thin films can reveal information about the ordering of the molecules, as in the case of poly(di-n-hexyl silane) films. In relevant experiments, spectra were recorded on carbon and silicon edges 17]. 

McCrary, V.R., Sette, F., Chen, C.T., Lovinger , A.J., Robin, M.B., Stdhr, J., and Zeiglet J.M. (1988) Polarization effects in the valence and inner-shell spectra of poly( i-hexyl silane)./. Chem. Phys., 88,... 

Poly(ferrocenyl diethylsilane) Chromatography Poly(ferrocenyl di-n-hexyl silane) Tetrahydrofiiran + 0.1% n-tetrabutylammonium bromide SEC, ultrastyragel... 

Bis(imino)pyridine iron complex 5 acts as a catalyst not only for hydrogenation (see 2.1) but also for hydrosilylation of multiple bonds [27]. The results are summarized in Table 10. The reaction rate for hydrosilylations is slower than that for the corresponding hydrogenation however, the trend of reaction rates is similar in each reaction. In case of tra s-2-hexene, the terminal addition product hexyl (phenyl)silane was obtained predominantly. This result clearly shows that an isomerization reaction takes place and the subsequent hydrosilylation reaction dehvers the corresponding product. Reaction of 1-hexene with H2SiPh2 also produced the hydrosilylated product in this system (eq. 1 in Scheme 18). However, the reaction rate for H2SiPh2 was slower than that for H3SiPh. In addition, reaction of diphenylacetylene as an atkyne with phenylsilane afforded the monoaddition product due to steric repulsion (eq. 2 in Scheme 18). 

PEt3)2]6° When [Pt(PEt3)3] or [Pt(PPr3)3] reacts with the bulkier silane Si( -hexyl)H3, two dimeric products are observed, one with a short Si "Si contact analogous to that shown in (6) and the other with a short Pt- -Pt contact (7).61... 

Figure 4.2 Comparison of UV absorption spectra of four optically active poly silanes in THF at 30°C poly methyl-(iS )-2-methylbutylsilane (1, a of 0.59), poly -hexyl-(5 )-4-methylpentyl-silane (2, a of 0.75), poly -hexyl-(5 )-3-methylpentylsilane (3, a of 0.92), and poly -hexyl-(5)-2-methyl-butylsilane (4, a of 1.25).

Figure 4.9 UV and CD spectra of poly silane homopolymer 4 (solid lines) and copolymers 12 (dotted lines) containing 60 mol % of -hexyl-(5)-2-methylbutylsilane and 40 mol % of n-hexyl-(R)-2-methylbutylsilane in isooctane at —5°C.

We also reported an intriguing chiral termini effect in rodlike poly(n-hexyl-(2-methylpropyl)silane) with (5)-2-me(hylbu(yl termini (15).28g Although the value of gabs is only +1 x 10-5, which indicates a very weak preferential screw sense in 15, it is noted that the preferential screw sense of 15 was opposite to that of 4, bearing the same (5)-2-me(hylbutyl side groups.28d,28f,28k... 

Figure 4.18 CD spectra of (a) poly[ methyl(methoxyphenyl)silane -co- (5 )-2-methylbutyl-(methoxyphenyl)silane ]s (30-32) and (b) poly[ -hexyl(methoxyphenyl)-silane -co- (5)-2-methylbutyl(methoxyphenyl)silane ]s (33 and 34) in THF at 20°C.

Figure 4.22 UV-Vis and CD spectra of poly[ -hexyl(/ -(S)-2-methylbutoxyphenyl)silane] (40) aggregates prepared by methods I and II at 55%/45% THF/methanol volume ratio at 20°C.

Figure 4.27 (a) CD and UV spectra of poly n-hexyl(p- -propoxyphenyl)silane (41) aggregates in toluene/(5> (a solid line) or (R)-2-butanol (b dotted line)/methanol mixtures at 20°C and (.b) plot of CD intensities at 354 nm of the polysilane aggregates in toluene/various ratio of (5)/(i )-2-butanol/methanol mixtures at 20°C. 

Figure 4.28 Plot of CD intensities of poly -hexyl(j -/ -propoxyphenyl)silane (41) aggregates in toluene/series of (S)-primary chiral alkyl alcohols/methanol mixtures at 20°C. [For comparison, CD intensity with (A)-2-butanol is inserted.].

A series of optically active poly alkyl(phenyl)silane derivative copolymers with different chiral molar composition 44 and 45, are shown in Chart 4.7, along with homopolymers poly(methyl(phenyl)silane) (42) and poly(n-hexyl(m-tolyl)silane) (43). 

Figure 4.31 Total energy per Si repeat unit of (a) methyl(phenyl)silane oligomer 42 with 21 Si repeat units and (b) n-hexyl(phenyl)silane oligomer 46 as a model of 43 with 31 Si repeat units as a function of the Si-Si-Si-Si dihedral angle.

Alkyl alkoxy silanes have been found to be very effective in reducing alkali-aggregate expansion [11] (Fig. 6.4). Of the silanes used in the study, hexyl trimethyl siloxane and decyl trimethoxyl silane were found to be more effective in decreasing the expansion than the others. In the same study, Ohama et al. [11] investigated the effect of sodium silicofluoride, alkyl alkoxy silane, lithium carbonate, lithium fluoride, styrene-butadiene rubber latex and lithium hydroxide on compressive strength and the expansion of mortar containing cement with 2% equivalent Na20. The reduction of the level of expansion shown in Fig. 6.4 with the siloxanes was attributed to... 

Ojima has reported a rhodium-catalyzed protocol for the disilylative cyclization of diynes with hydrosilanes to form alkylidene cyclopentanes and/or cyclopentenes. As an example, reaction of dipropargylhexylamine with triethyl-silane catalyzed by Rh(acac)(GO)2 under an atmosphere of CO at 65 °G for 10 h gave an 83 17 mixture of the disilylated alkylidene pyrrolidine derivative 92b (X = N-//-hexyl) and the disilylated dihydro-1/ -pyrrole 92c (X = N-//-hexyl) in 76% combined yield (Equation (60)). Compounds 92b and 92c were presumably formed via hydrosilyla-tion and hydrosilylation/isomerization, respectively, of the initially formed silylated dialkylidene cyclopentane 92a (Equation (60)). The 92b 92c ratio was substrate dependent. Rhodium-catalyzed disilylative cyclization of dipro-pargyl ether formed the disilylated alkylidene tetrahydrofuran 92b (X = O) as the exclusive product in low yield, whereas the reaction of dimethyl dipropargylmalonate formed cyclopentene 92c [X = C(C02Et)2] as the exclusive product in 74% isolated yield (Equation (60)). 

Silane (Tridecafluoro-hexyl)-triinethvl- ElOb,. 412 (Educt)... 

Figure 8b plots the A,max values of 10 and 11 as a function of the molar fraction of n-hexyl(S)-2-methylbutylsilane or n-hexyl(JR)-2-methylbutylsilane. The value of Amax redshifts slightly, but progressively, with increase in the fraction of the silane with chiral side chains in the copolymers. These features are associated with a decrease in screw-pitch of the main chain, because the Si<7-Si<7 absorption is shown from ab initio calculations [45] to blueshift progressively with change in the main chain dihedral angle from planar all-anti (180°) to 4i helix (60°) [52]. 

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