Multimodal Metal Cation Sensing with Bis(macrocyclic) Dye

Proof of principle of a purine D-A-D' ligand based ratiometric chemical sensor harnessing complexation induced intermolecular PET

A comprehensive photophysical study of a series of purines, doubly decorated at C2 and C6 positions with identical fragments ranging from electron acceptor to donor groups of different strengths, is presented. The asymmetry of substitutions creates a unique molecular D-A-D' structure possessing two independent electronic charge transfer (CT) systems attributed to each fragment and exhibiting dual-band fluorescence. Moreover, the inherent property of coordination of metal ions by purines was enriched due to a presence of nearby triazoles used as spacers for donor or acceptor fragments. New molecules present a bidentate coordination mode, which makes the assembly of several ligands with one metal cation possible. This property was exploited to create a new concept of a ratiometric chemical fluorescence sensor involving the photoinduced electron transfer between branches of different ligands as a mechanism of fluorescence modulation.

FRET-based metal ion sensing by a crown-containing bisstyryl dye

A ratiometric cation FRET system containing two binding centers demonstrates distinct fluorescence changes upon interaction with alkaline, alkaline earth and heavy metal cations.

Synthesis of Novel Ethyl 1-aryl-3-methyl-8-oxo-1,8-dihydropyrano[2′,3′:4,5] Pyrimido[6,1-b]Quinazoline-2-carboxylate Derivatives

In this paper, a new series of ethyl 1-aryl-3-methyl-8-oxo-1,8-dihydropyrano[2′,3′:4,5]pyrimido[6,1-b]quinazoline-2-carboxylate derivatives was synthesised by the cyclisation of methyl anthranilate with ethyl 5-cyano-6-[(ethoxymethylene)amino]-2-methyl-4-aryl-4H-pyran-3-carboxylate derivatives, which were obtained from reaction of triethyl orthoformate with 6-amino-5-cyano-2-methyl-4-aryl-4H- pyran-3-carboxylate derivatives. The title compounds possessed good fluorescence properties. In addition, ethyl 5-cyano-6-[(ethoxymethylene) amino]-2-methyl-4-(p-tolyl)-4H-pyran-3-carboxylate and ethyl 3-methyl-8-oxo-1-(p-tolyl)-1,8-dihydropyrano[2′,3′:4,5]pyrimido[6,1-b] quinazoline-2-carboxylate were further determined by single crystal X-ray diffraction analysis.

Design strategies for lab-on-a-molecule probes and orthogonal sensing

This review highlights the currently exploited working concepts of lab-on-a-molecule probes, with a particular focus on what is required for multianalyte detection and quantification in competitive assays. Both, chemosensor and chemodosimeter approaches are considered. The multifaceted design strategies and the orthogonal protocols are evaluated in order to identify and categorise the successful conceptions and to single out unknown territory and challenges for future work.