Supramolecular Synthon Transferability and Gelation by Diprimary Ammonium Monocarboxylate Salts

Earlier studies revealed that primary ammonium dicarboxylate
(PAD) salts possessed gelling ability, and many such
salts
displayed a 1D columnar hydrogen bonded network (observed in primary
ammonium monocarboxylate (PAM) salts) on either side
of the dicarboxylate end of the anion. In the present study, a new
series of diprimary ammonium monocarboxyate (DPAM) salts
have been prepared with the aim of achieving supramolecular synthon
transferability (the same 1D columnar hydrogen PAM bonded
network on either side of the diammonium cation) in these salts. Single
crystal X-ray diffraction studies revealed that, in 47% of the DPAM salts, such supramolecular synthon transferability indeed
took place. Some of the DPAM salts also showed gelation
ability. The gels were characterized by DSC, rheology, electron microscopy,
and atomic force microscopy. Structure property correlation using
single crystal and powder X-ray diffraction data on a selected gel
was also attempted.

既往研究显示，伯胺二羧酸盐（primary ammonium dicarboxylate，PAD）具备胶凝性能，且该类盐中多数在阴离子的二羧酸盐端两侧呈现出一维柱状氢键网络——该结构此前已在伯胺单羧酸盐（primary ammonium monocarboxylate，PAM）盐中被观测到。本研究制备了一系列新型二伯胺单羧酸盐（diprimary ammonium monocarboxyate，DPAM），旨在实现超分子合成子的可转移性，即让二铵阳离子两侧形成与PAM盐一致的一维柱状氢键网络。单晶X射线衍射研究表明，47%的DPAM盐成功实现了此类超分子合成子的可转移性。部分DPAM盐还展现出胶凝能力，研究团队通过差示扫描量热法（DSC）、流变学、电子显微镜及原子力显微镜对其凝胶进行了表征。此外，本研究还针对选定的凝胶样品，结合单晶与粉末X射线衍射数据开展了构效关系探索。