Spacer length

As observed in the alkylation with (ro-chloroalkyl)silanes, both the spacer length between the C—Cl and silicon and the substituents on the silicon atom of... 

In the alkylation of benzene with (dichloroalkyl)chlorosilanes in the presence of aluminum chloride catalyst, the reactivity of (dichloroalkyl)silanes increases as the spacer length between the C—Cl and silicon and as the number of chloro-groups on the silicon of (dichloroalkyl)chlorosilanes decreases as similarly observed in the alkylation with (cD-chloroalkyl)silanes. The alkylation of benzene derivatives with other (dichloroalkyl)chlorosilanes in the presence of aluminum chloride gave the corresponding diphenylated products in moderate yields.Those synthetic data are summarized in Table XI. 

Although NHS-LC-biotin and sulfo-NHS-LC-biotin are very popular reagents for biotinylation, they both result in hydrophobic aliphatic biotin modifications on proteins and antibodies. Unfortunately, these groups have a tendency to aggregate in aqueous solution and may cause protein precipitation or loss of activity over time. For this reason, the use of more hydrophilic PEG-based biotin compounds of approximately the same spacer length may be a better alternative for maintaining water solubility of modified proteins (Chapter 18). 

Hashimoto, K., Loader, J.E., and Kinsky, S.C. (1986) Iodoacetylated and biotinylated liposomes Effect of spacer length on sulfbydryl ligand binding and avidin precipitability. Biochim. Biophys. Acta 856, 556-565. 

The corresponding hydrocarbon species with the same spacer length, the dianthrylundecane [6e], forms a radical anion that always exists as a spin-localized species. The esr spectrum obtained for the radical anion of the structurally related ether [7a] (see Fig. 8) is temperature-dependent, which... 

The effects of spacer length on the fluorescence quantum yields of the benzofurazan compounds bearing a donor-acceptor system were reported <2002MI11>. 

Figure 5.12 Dependence of peak frequencies in infrared spectrum of glucosamide bolaam-phiphiles NC( )GN-GLC (14) on methylene spacer length n. (a) The CH2 antisymmetric vas and symmetric vs stretching vibrations reveal gauche-included conformation for short chains and an all-trans conformation for longer chains, (b) Amide I and II frequencies show an even-odd effect for n > 10. Reprinted from Ref. 53 with permission of Wiley-VCH.

E. Lindner, A. Jaeger, F. Auer, W. Wielandt and P. Wegner, Supported organometallic complexes. Part XIII. Catalytic studies on sol-gel processed (ether phosphine)ruthenium(II) complexes with different spacer lengths and different polysiloxane matrices, J. Mol. Catal. A Chem., 1998, 129, 91. 

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