A new family of bis-ureidic receptors for pyrophosphate optical sensing

Abstract

A new family of bis-ureidic receptors (L(1)-L(6)) has been synthesised. The binding properties of L(1)-L(6) towards different anions (acetate, benzoate, glutarate, malonate, dihydrogen phosphate, hydrogen pyrophosphate, triphosphate, AMP and ADP) have been studied by means of (1)H-NMR, UV-Vis and fluorescence spectroscopies and a remarkable affinity for HPpi(3-) has been observed in the case L(3) (in DMSO-d6 and DMSO-d6-5% H2O) which also acts as a fluorimetric chemosensor, even to the naked eye, for this anion. Theoretical calculations helped us explain the binding properties observed.

Anion complexation, transport and structural studies of a series of bis-methylurea compounds

“…Details of the crystallization experiments, both successful and unsuccessful, are 55 provided in ESI † (Table S1). Crystals suitable for single crystal X-ray investigation were only obtained for host-guest complexes involving receptors L 1 -L 4 .…”

Fluorescent asymmetric bis-ureas for pyrophosphate recognition in pure water

“…The formation of a new red-shifted fluorescence band upon addition of HPpi 3-have been previously observed by ourselves and we have attributed it to a possible anion-assisted intramolecular interaction of two naphtalene moieties in the excited state. 27 In this case an interaction between the naphthalene group and the indole group of L1 and L2 brought in proximity in the presence of the anion can be invoked. In order to confirm this interaction theoretical calculation have been performed by means of an empirical forcefield method.…”

“…15,[22][23][24][25][26] We have recently described a new family of symmetric bis-urea receptors which showed a remarkable affinity for Ppi and were able to act as a fluorimetric chemosensors for this anion, even at naked eye. 27 In particular we demonstrated that the presence of naphtyl groups as pendant arms of the ureas, facilitates the binding and the optical fluorimetric selectivity thanks to the uncommon interaction of an aromatic CH from the fluorophore with the Ppi guest. Inspired by these interesting results, we decided to synthesize three new asymmetric bis-urea receptors L1-L3 (Scheme 1) bearing a naphatlene and an indole moiety as pendant arms of the urea moieties.…”

New insights into dihydrogenphosphate recognition with dirhenium(i) tricarbonyl complexes bridged by a thiourea moiety

“…[5][6][7] Low charge selective systems able to operate in aqueous media remains a considerable challenge however. 8,9 The inclusion of urea groups has proved to be particularly successful in the recognition of fluoride, acetate and dihydrogenphosphate [10][11][12] with the development of systems involving two [13][14][15] or three urea or thiourea moieties, [16][17][18] including tripodal architectures [19][20][21][22][23][24][25] which demonstrate considerable selectivity for specific anions, even in protic media.…”