Impact of“half-crown/two carbonyl”–Ca²⁺metal ion interactions of a low molecular weight gelator (LMWG) on its fiber to nanosphere morphology transformation with a gel-to-sol phase transition

Abstract

We report here a smart functional low molecular weight gelator (LMWG) L, containing an unusual metal ion coordination site, i.e. "half-crown/two carbonyl". The gelator L shows excellent gelation behavior with typical fibrillar morphology in acetonitrile, methanol and ethanol media. Upon Ca2+ ion binding with its "half-crown/two carbonyl" coordination site, the acetonitrile gel of L exhibits a fiber to nanosphere morphology transformation along with a gel-to-sol phase transition as confirmed by microscopic investigation and by direct naked eye visualization, respectively. The mechanism involved in this morphology transformation and gel-to-sol phase transition process was studied thoroughly with the help of computational calculations and various spectroscopic experiments and discussed.

Harnessing Activated Alkyne-Hydroxyl “Click” Chemistry for Degradable and Self-Healing Poly(urea vinyl ether ester)s

“…It is noteworthy that in the FT-IR spectrum of P1a2a , the ester carbonyl stretching from 1a as well as the urea N–H stretching and bending vibration peaks from 2a remain present, appearing at 1702, 3357, and 1554 cm –1 , respectively. The urea stretching vibration peak in P1a2a exhibits a broader shape compared to that of monomer 2a , which can be attributed to the H-bonded nature of the urea groups in the polymer structure. ,, This interpretation aligns well with the 1 H NMR results of P1a2a (Figure A). The aliphatic (−CH 2 ) groups, which are common to monomers 1a , 2a , and polymer P1a2a , display characteristic C–H stretching vibrations that can be observed in their respective IR spectra between 2966 and 2876 cm –1 (Figure ).…”

“…The urea stretching vibration peak in P1a2a exhibits a broader shape compared to that of monomer 2a, which can be attributed to the H-bonded nature of the urea groups in the polymer structure. 59,91,92 This interpretation aligns well with the 1 H NMR results of P1a2a (Figure 1A). The aliphatic (−CH 2 ) groups, which are common to monomers 1a, 2a, and polymer P1a2a, display characteristic C−H stretching vibrations that can be observed in their respective IR spectra between 2966 and 2876 cm −1 (Figure 2).…”

Dosimetric gelator probes and their application as sensors

“…[27,49,50] Typically, a gel-based detection technique involves interaction between the externally added chemical analyte and the gelator molecules which can produce three different responses from the system (Figure 1). [49,51,52] An initially formed gel can…”