Chloral oligomers

The helical structure of polychloral was proposed by Vogl in 198028 and was demonstrated by Ute, Hatada, and Vogl via a detailed conformational analysis of chloral oligomers.29 As an example of a helical polymer with an inorganic backbone, polysilanes bearing a chiral side chain were synthesized and their conformational aspects were studied. A helical conformation with an excess screw sense for this class of polymers in solution was found in 1994 independently by Fujiki30a and by Moller.300 Matyjaszewski had pointed out such a conformation for chiral polysilanes in the solid state in 1992.30c... 

The stereostructures of the linear chloral oligomers have been determined by X-ray single-crystal analysis (Fig. 26).280 The chloral oligomers from dimer to hexamer were isolated by distillation and by GPC fractionation from the oligomer mixture prepared with t-C4H9OLi initiation and acetate endcapping. The dimer fraction was a diastereomeric mixture of the racemo and meso isomers (m/r = 3/1). Subsequent propagating steps of monomer addition force the reaction to become stereospecific toward meso addition... 

Fig. 26. X-ray molecular structure of the isotactic chloral oligomers from dimer to...

Fig. 35. The Rl-detected (a) and H NMR-detected (b) GPC curves of the mixture of chloral oligomers. (From Ref. 339.)...

K+ ionization of desorbed species (K+IDS) spectrometry, linear 1-butoxide-initiated, acetate-capped chloral oligomers, ion source pressure < 10 Torr, source temperature = 200°C Amine-initiated chloral oligomers, K+IDS mass spectrometry and... 

H and C NMR, chloral oligomers prepared by lithium t-butoxide (21) initiation... 

Amine-initiated chloral oligomers, K+IDS mass sjrectrometry and capillary GC (22)... 

Figure 6. Gas Chromatogram of Tertiary Butoxide Initiated Acetate Endcapped Chloral Oligomers...

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