Abstract
The synthesis of new calix[4]arenes adopting a cone stereoisomeric form bearing two or four azide fragments on the upper rim and water-soluble triazolyl amphiphilic receptors with two or four polyammonium headgroups via copper-catalyzed azide–alkyne cycloaddition reaction has been performed for the first time. It was found that the synthesized macrocycles form stable aggregates with hydrodynamic diameters between 150–200 nm and electrokinetic potentials about +40 to +60 mV in water solutions. Critical aggregation concentration (CAC) values were measured using a micelle method with pyrene and eosin Y as dye probes. The CAC values of tetraalkyl-substituted macrocycles 12a,b (5 µM for both) are significantly lower than those for dialkyl-substituted macrocycles 10a,b (790 and 160 µM, respectively). Premicellar aggregates of macrocycles 10a,b and 12a,b with the dye eosin Y were used for nucleotides sensing through a dye replacement procedure. It is unusual that disubstituted macrocycles 10a,b bind more effectively a less charged adenosine 5'-diphosphate (ADP) than adenosine 5'-triphosphate (ATP). A simple colorimetric method based on polydiacetylene vesicles decorated with 10b was elaborated for the naked-eye detection of ADP with a detection limit of 0.5 mM.
Highlights
During the last two decades many researcher groups have paid much attention to the synthesis of host molecules with high affinity to biologically important anions [1,2,3,4,5]
In this investigation more rigid arylazide calixarene derivatives were chosen as precursors for the synthesis of the targeted macrocycles having an enlarged cavity for the effective binding of large biomolecules (Scheme 1)
Macrocyclic receptors have a number of advantages in the design of molecular receptors, providing preorganization of the binding sites offering multipoint interactions with a substrate for the effective complexation [13]
Summary
During the last two decades many researcher groups have paid much attention to the synthesis of host molecules with high affinity to biologically important anions [1,2,3,4,5]. Polyammonium cation receptors bind the nucleotides according to their negative charge values: ATP > ADP > AMP. It is accompanied with increasing complex stability, which depends on charge–charge interactions between the receptor and the nucleotide. Kuchelmeister et al synthesized a receptor with two symmetric peptide arms decorated with guanidinium-based anion binding sites This receptor showed a stronger binding of AMP in comparison with ADP and ATP [11]. Another polyammonium receptor synthesized by Mascaros et al [12] showed selective recognition of ADP in the presence of ATP in water
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
