caa a22 4500 605545618 CHVBK 20210128100936.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00723-015-0690-3 doi (NATIONALLICENCE)springer-10.1007/s00723-015-0690-3 Investigations on Carboxy Dibenzylidene Sorbitol Hydrogels Using EPR Spectroscopy [Elektronische Daten] [Ana Ariciu, Teodora Staicu, Marin Micutz, Maria Neacsu, Petre Ionita, Victorita Tecuceanu, Cornel Munteanu, Gabriela Ionita] Low-molecular-weight organic gelators generate physical gels by the formation of three-dimensional fibrous network structures as a response to various physicochemical stimuli such as heat, light, ultrasound and chemical environments. Dibenzylidene sorbitol (DBS) represents a typical compound able to generate gels because of some prerequisite structural features: the presence of functional groups to form intermolecular hydrogen bonds and of aromatic groups to be involved in π-π interactions, or chirality. Herein, we present the synthesis of three derivatives of DBS-bearing carboxy groups attached to phenyl rings and the corresponding spin-labelled compounds. We studied the formation of physical gels resulting from self-assembly of DBS derivatives with the aim of highlighting the influence of the position of the carboxy group on the gel properties. These types of compounds can form gels in polar solvents (such as water, DMSO) by either temperature treatment or variation of the pH. In this study, the systems were investigated by rheological measurements, SEM analysis and EPR measurements. The results showed that the introduction of carboxy groups into the structure of DBS generates weaker gels compared with the parent gelator, DBS. The spin probes used in this study (spin-labelled DBS derivatives and 5-doxyl stearic acid) demonstrated that assembly of gelator molecules is a highly selective process. The two-component feature of EPR spectra of spin probes in gels is proof that EPR spectroscopy is sensitive to the non-homogeneity of these systems. Springer-Verlag Wien, 2015 Ariciu Ana Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut Staicu Teodora Department of Physical Chemistry, University of Bucharest, 4-12 Regina Elisabeta Bvd., 030018, Bucharest, Romania aut Micutz Marin Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut Neacsu Maria Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut Ionita Petre Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut Tecuceanu Victorita Organic Chemistry Centre of the Romanian Academy, 202B Splaiul Independentei, 060023, Bucharest, Romania aut Munteanu Cornel Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut Ionita Gabriela Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut Applied Magnetic Resonance Springer Vienna 46/12(2015-12-01), 1395-1407 0937-9347 46:12<1395 2015 46 723 https://doi.org/10.1007/s00723-015-0690-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00723-015-0690-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ariciu Ana Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut NATIONALLICENCE 700 1- Staicu Teodora Department of Physical Chemistry, University of Bucharest, 4-12 Regina Elisabeta Bvd., 030018, Bucharest, Romania aut NATIONALLICENCE 700 1- Micutz Marin Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut NATIONALLICENCE 700 1- Neacsu Maria Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut NATIONALLICENCE 700 1- Ionita Petre Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut NATIONALLICENCE 700 1- Tecuceanu Victorita Organic Chemistry Centre of the Romanian Academy, 202B Splaiul Independentei, 060023, Bucharest, Romania aut NATIONALLICENCE 700 1- Munteanu Cornel Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut NATIONALLICENCE 700 1- Ionita Gabriela Romanian Academy, ‘Ilie Murgulescu' Institute of Physical Chemistry, 202 Splaiul Independentei, 060021, Bucharest, Romania aut NATIONALLICENCE 773 0- Applied Magnetic Resonance Springer Vienna 46/12(2015-12-01), 1395-1407 0937-9347 46:12<1395 2015 46 723