Primary Alkyl Amines as Latent Gelators and Their Organogel Adducts with Neutral Triatomic Molecules

Abstract

A series of organogelator salts has been prepared from n-alkylamines by the rapid in situ and isothermal (at room temperature) uptake of a neutral triatomic molecule, CO2, NO2, SO2, or CS2. The organogels have been examined by differential scanning calorimetry, optical microscopy, and X-ray diffraction methods. The efficiency of each gelator has been assessed on the bases of the diversity of liquids it gelled, the minimum amount of it required for gelation, and the temporal and thermal stabilities of its gels. Thus, alkylammonium alkylcarbamates, amine-CO 2 adducts, are the most effective gelators and the amine-NO2 adducts are the least efficient. Salts from longer n-alkylamines are better gelators than those from shorter homologues. Some of the salts are reconverted to their amine and triatomic constituents by heating, while others are transformed into new compounds. In the case of the CS 2 adducts, H2S is expelled and the new species formed, N,N′-dialkylthioureas, are also gelators.

Progress in the studies of low-molecular mass gelators with unusual properties

“…Furthermore, the process can be reversed by simply eliminating CO 2 . Similar observations were also reported by other groups [37,38].…”

Urea and Thiourea Derivatives as Low Molecular‐Mass Organogelators

“…LMOGs containing more than two urea groups have been reported recently, [29,46,47] and a few thiourea derivatives are also known to gelate organic liquids. [34,48] Finally, many structurally more complex LMOGs than those investigated here have been demonstrated to derive their modes of aggregation or solid-state packing in large part from intermolecular hydrogen bonding of urea and thiourea groups. [38,39,45,[49][50] As part of our ongoing effort to design structurally simple LMOGs that are n-alkanes with one inserted heterofunctionality, we report here the gelation properties of some very low molecular mass and structurally simple N-alkyl, N,N'-dialkyl, and N,N-dialkyl ureas and thioureas Abstract: The properties of a series of organogels consisting of a urea or thiourea derivative with one or two n-alkyl substitutuents at the nitrogen atoms (a low molecular-mass organogelator (LMOG)) and an organic liquid are described.…”

Two‐Component Gel‐Phase Materials—Highly Tunable Self‐Assembling Systems

“…This work was extended [41] to assess the impact of different neutral triatomic molecules, i.e., CO 2 , NO 2 , SO 2 and CS 2 , on the gelation properties (Scheme 12). The gelation properties of the products were observed to depend primarily on the nature of the triatomic molecule added to the amine and the length of the alkyl chain: alkylammonium alkylcarbamates were better gelators than the salts formed from other triatomic molecules, and the efficiency within one family of salts increased with increasing alkyl-chain length.…”