An efficient naphthalimide based receptor for selective detection of Hg2+and Pb2+ions

Naphthalimide based receptor 1 with N-substituted benzothiazole and pyrrolidine subunit is designed, synthesized, and characterized using FT-IR,1H and 13C NMR spectroscopy and mass spectrometry techniques. The receptor 1 exhibits prominent optical response for Hg2+and Pb2+ions allowing the detection of these ions in acetonitrile (ACN). The formation of the receptor 1:cation complexes have been investigated using UV-Vis and fluorescence emission titration. Further, the selectivity of the receptor 1towards Hg2+and Pb2+ ions on the presence of various interfering cations such as Mg2+, Ba2+, Ni2+, Co2+, Cu2+, Ag2+, Fe2+, Fe3+and Cr3+ has been confirmed by UV-Vis and fluorescence spectroscopy. The binding constant between receptor 1 and Hg2+ and Pb2+ was estimated by Benesi-Hildebrand plot and equations. The binding constants have been found to be Ka= 3.43286 ´ 10−6 and Ka= 2.84079 ´ 10−6 M for Hg2+ and Pb2+, respectively. The limit of detection (LOD) for Hg2+and Pb2+by receptor 1are down to 7.44 ´ 10−10 M and 1.26 ´ 10−9 M, respectively. In addition, Job’s plot analysis reveals 1:2 binding stoichiometry between the receptor 1 and Pb2+ and Hg2+ cations.

Hydrophobe und hydrophile Yoctobrunnen für das molekulare Sortieren und als dreidimensionale Liganden

Title pages and Table of Contents Acknowledgements List of Publications 1\. Introduction 2\. Constituents of Yoctowells 3\. Slow Motion of Water- and Chloroform-Soluble Porphyrins in Yoctowells 4\. Trapping and Sorting of Water- and Chloroform-Soluble Porphyrins in Yoctowells 5\. Functional Yoctowells as Receptors Chapter 6 doesn't exist! 7\. Experimental Part 8\. References English Summary and German Zusammenfassung Curriculum VitaeSmooth aminated silica gel particles were synthesized from tetraethoxy orthosilicate and characterized by electron and force microscopy. The typical diameter of the particles was 100± 10 nm, AFM showed no roughness above 1nm. The particles were then partly occupied with covalently bound tetracarboxy- porpyrins (e.g. 32), which lied flat on the surface and were then surrounded with rigid walls made of diamido- bolaamphiphiles (e.g. 10, 16 or 42) to form stable membrane gaps were thus formed with a volume between 10 and 20 yoctoliters ( 10 24 L) and a porphyrin bottom. These so-called yoctowells reacted in colloidal solutions of the silica particles in water or chloroform with dissolved manganese (III) porphyrins having the same diameter as the bottom porphyrin, complete fluorescence quenching of the later occurred only after about 2000 seconds, which means an apparent diffusion constant of 10 24 m2s-1. This extreme slowness is explained by a slowly reversible adsorption of the quencher porphyrin to the walls of the yoctowells ( page 80). The phenomenon of slow and irreversible adsorption to the bottom was then used in a sorting process of water and chloroform soluble porphyrins within the wells. Too big quencher molecule did not enter the yoctowell at all, small quenchers reached their bottom immediately. The yoctowells resemble protein receptor with respect to molecular size selectivity. DMSO or heat destroy the wells reversibly. Finally the prepared oligoethylene glycol yoctowells, which acted like 3D- crown ethers in the binding of oligoamines in water. The equilibrium constant were near 107 M-1 showing in water. A triglycinyl wall of the yoctowells fixated a fluorescence labeled triglycine derivative with a similar binding constant in ethanol.Glatte, aminierte Kieselgelpartikel wurden aus Tetraethoxysilan und 3 -Aminopropyl-triethoxysilan hergestellt und durch TEM und AFM charakterisiert. Der typische Durchmesser der Partikel lag bei 100 ± 10 nm, AFM zeigte Rauigkeiten nur im 1-Nanometerbereich. Diese Partikel wurden mit Inseln aus flach liegenden Tetracarboxyporphyrinen (32) versehen und danach mit starren Monoschichten aus den Diamidobolaamphiphilen 6, 10 oder 42 bedeckt. So entstanden formstabile Membranlücken mit einem Porphyrinboden und einem Inhalt von 10-20 Yoctolitern (yl; 10-24 L). Diese so genannten Yoctobrunnen wurden in kolloidaler wässriger Lösung mit Mangan(III) porphyrin versetzt, das etwa den gleichen Durchmesser aufwies wie das Bodenporphyrin. Vollständige Fluoreszenzlöschung trat erst nach etwa 2000 Sekunden auf, die apparente Diffusionskonstante war mit etwa 10-24 m2s-1 extrem niedrig. Ein Modell zur Erklärung dieses Tatbestands erläutert es mit Wandabsorptionen, die nur langsam wieder gelöst werden (S.80). Das Phänomen der langsamen Eingliederung wurde dann zum Sortieren wasser- und chloroformlöslicher Porphyrine benutzt. Zu große Porphyrine traten gar nicht in die Brunnen ein, kleinere Löschungsmoleküle wirken sofort. Die Yoctobrunnen sind ähnlich Proteinrezeptoren extrem größenselektiv. DMSO und Hitze zerstören die Brunnen in reversibler Weise. Schließlich wurden auch Oligoethylenglykol-Yoctobrunnen als 3-dimensionale Kronenether zur Bindung von Oligoamin in Wasser entwickelt. Die Gleichgewichtskonstante mit tobramycin lag bei etwa 107 M-1. Eine Tripeptidbrunnenwand band fluoreszeinmarkiertes Triglycin etwa mit der gleichen Bindungskonstante

Phosphonic acid appended naphthalenediimide molecular receptor for saccharides and aminoglycoside antibiotics recognition

Design of symmetric phosphonic acid functionalized naphthalene diimide bolaamphiphile (NDI 1) is reported. NDI 1 based molecular recognition of saccharides and aminoglycoside antibiotics in aqueous media was investigated. UV-vis and fluorescence measurements revealed an efficient protocol for NDI 1 as molecular receptor. The sensor successfully recognises saccharides and aminoglycoside antibiotics kanamycin and neomycin in terms of both absorbance intensity and binding affinity. This protocol provides new platform for the design and synthesis of phosphonic acid appended NDI sensor for recognition of multifunctional biomolecules