Comparing and Correlating Solubility Parameters Governing the Self-Assembly of Molecular Gels Using 1,3:2,4-Dibenzylidene Sorbitol as the Gelator

Abstract

Solvent properties play a central role in mediating the aggregation and self-assembly of molecular gelators and their growth into fibers. Numerous attempts have been made to correlate the solubility parameters of solvents and gelation abilities of molecular gelators, but a comprehensive comparison of the most important parameters has yet to appear. Here, the degree to which partition coefficients (log P), Henry’s law constants (HLC), dipole moments, static relative permittivities (εr), solvatochromic ET(30) parameters, Kamlet–Taft parameters (β, α, and π), Catalan’s solvatochromic parameters (SPP, SB, and SA), Hildebrand solubility parameters (δi), and Hansen solubility parameters (δp, δd, δh) and the associated Hansen distance (Rij) of 62 solvents (covering a wide range of properties) can be correlated with the self-assembly and gelation of 1,3:2,4-dibenzylidene sorbitol (DBS) gelation, a classic molecular gelator, is assessed systematically. The approach presented describes the basis for each of the parameters and how it can be applied. As such, it is an instructional blueprint for how to assess the appropriate type of solvent parameter for use with other molecular gelators as well as with molecules forming other types of self-assembled materials. The results also reveal several important insights into the factors favoring the gelation of solvents by DBS. The ability of a solvent to accept or donate a hydrogen bond is much more important than solvent polarity in determining whether mixtures with DBS become solutions, clear gels, or opaque gels. Thermodynamically derived parameters could not be correlated to the physical properties of the molecular gels unless they were dissected into their individual HSPs. The DBS solvent phases tend to cluster in regions of Hansen space and are highly influenced by the hydrogen-bonding HSP, δh. It is also found that the fate of this molecular gelator, unlike that of polymers, is influenced not only by the magnitude of the distance between the HSPs for DBS and the HSPs of the solvent, Rij, but also by the directionality of Rij: if the solvent has a larger hydrogen-bonding HSP (indicating stronger H-bonding) than that of the DBS, then clear gels are formed; opaque gels form when the solvent has a lower δh than does DBS.

Salicylato Titanocene Complexes as Cooperative Organometallic Lewis Acid and Brønsted Acid Catalysts for Three‐Component Mannich Reactions

“…In that regard, attempts to correlate the E T (30) scale44 and systems involving 9,12 R ‐diol, trans ‐9,10‐diol, and trans ‐13,14‐diol were unsuccessful (Figure S11 in the Supporting Information). The inability of E T (30) to predict the formation of gels within the diol gelators implies that bulk polarity is an insufficient criterion to judge when a gel will or will not be formed;3a specific liquid–gelator interactions at the molecular level must be considered as well.…”

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

“…54 They found that individual HSPs, especially the hydrogen bonding HSP (d h ), strongly influence the physical properties of the DBS organogel -much more so than solvent polarity. 54 They found that individual HSPs, especially the hydrogen bonding HSP (d h ), strongly influence the physical properties of the DBS organogel -much more so than solvent polarity.…”

The key effect of the self-assembly mechanism of dendritic gelators: solubility parameters, generations and terminal effects

“…This is due to their importance for understanding the origin of the driving force for the unique architectural features, to encourage intriguing new forms of gelation behavior, as well as for developing efficient supramolecular gelators. [5][6][7] A wide variety of research articles have tried to understand the mechanism of the self-assembly process from different point of views. 4 However, the mechanisms governing the self-assembly of a number of supramolecular nanostructures, including supramolecular gels, are poorly understood.…”