The Aggregated Higher-Structure of 1,3 : 2,4-Di-O-benzylidene-d-sorbitol in Organic Gels

Abstract

1,3 : 2,4-Di-O-benzylidene-d-sorbitol (d-DBS) can cause gelation of organic solvents of a wide range of polarity into a gel state. The aggregated structures of d-DBS/organic solvent systems were studied, mainly by using IR, UV, and circular dichroism (CD) spectroscopy. In the case of the racemate Dl-DBS, no gel state was formed. In IR spectra of d-DBS and Dl-DBS in the solid state, the intensities of νOH and νCO absorption in d-DBS were found to be larger than those in Dl-DBS. It is assumed that the hydrogen bonding formed between an acetal oxygen and a hydroxyl group in the aggregation of d-DBS. From the changes in the IR spectra from solution into a gel state, we can conclude that the chirality and the hydrogen bonding of DBS molecules are essential for the formation of the gel. Comparing the gel-forming ability of d-DBS with its derivatives, 5- or 6-hydroxyl-group-blocked compounds by methyl group, the 6-hydroxyl group seems to be important in the formation of d-DBS aggregates. The results of UV spectra suggest that the benzene rings are ordered in a side by side arrangement. The molar ellipticities in CD spectra increased about 500 times during the change from the solution to the gel state. From these results, it is concluded that d-DBS forms a helical structure of thin fibrous crystals in the gel state.

1,3:2,4-Dibenzylidene-d-sorbitol (DBS) and its derivatives – efficient, versatile and industrially-relevant low-molecular-weight gelators with over 100 years of history and a bright future

“…In further work, Yamasaki and co-workers selectively converted each of the 5-OH group and the 6-OH group into methoxy groups, 39 and observed that no gelation occurred when the terminal (6-OH group) was protected, while gelation still occurred with the 5-OH group protected. As such, they proposed that 6-OH is critical as a hydrogen bond donor for DBS self-assembly.…”

Directed Crystallisation of Synthetic Polymers by Low‐Molar‐Mass Self‐Assembled Templates

“…[6] We have used dibenzylidene sorbitol (DBS), which readily organises, at very low concentrations, into three-dimensional percolation networks in low-molecular-weight organic liquids. [7] DBS is also known to be an efficient clarifying agent for isotactic PP [8] but not for PE.…”

On the Measurement of Phase Transition Temperatures in Physical Molecular Organogels

“…Different spectroscopies can be used specifically for a given gelator. For instance, if paramagnetism is involved, EPR can be used (19); if H-bonds participate in the aggregation mechanism, IR spectroscopy is instructive (20); if luminescence phenomena are implied, fluorescence is then useful (21)(22)(23). These techniques take advantage of the amplitude variation of a spectral feature of the system which is sensitive to the degree of aggregation of the gelator molecules.…”