Molecular recognition-controlled membrane disruption by a bis(crown ether) bola-amphiphile

Abstract

Release of liposome-entrapped carboxyfluorescein is switched 'on' via molecular recognition of barium ion by a bis(crown ether carboxylate) bola-amphiphiie.

Synthetic receptors

“…Fyles and Zeng have reported that the release of liposome entrapped carboxyfluorescein is switched 'on' via molecular recognition of barium ions by a bis(crown ether carboxylate) bola-amphiphile 2. 58 Barboiu et al have Fig. 2 prepared a series of supramolecular complexes of the ammonium salt of a crown ether with different natural and non-natural amino acids (e.g.…”

Einfacher Zugang zu löslichen Polyanionen – Stabilisierung der eindimensionalen Kette1∞[K4Sn9] mit [18]Krone-6 in [K4Sn9([18]krone-6)3]⋅Ethylendiamin

“…Die Kristallstrukturen der entsprechenden Phasen A 4 Sn 9 und A 12 Sn 17 (A Alkalimetall) konnten bisher aufgrund schlechter Kristallqualität nicht aufgeklärt werden. [6] Obwohl in Lösung neunatomige Cluster schon vor über 100 Jahren beobachtet wurden [8] und ein derartiges Anion bereits 1976 erstmals strukturell charakterisiert wurde, [9] gelang die Isolierung von wohldefinierten Produkten aus Lösung nur in kleinen Mengen. Im Rahmen unserer Untersuchungen über lösliche homoatomare Zintl-Ionen [10] berichten wir im folgenden über einen neuen, sehr einfachen und effizienten Zugang zu homoatomaren Polyanionen aus den Elementen bei niedrigen Temperaturen.…”

Easy Access to Soluble Polyanions—Stabilization of the One-Dimensional Chain1∞[K4Sn9] by [18]Crown-6 in [K4Sn9([18]crown-6)3]⋅ethylenediamine

“…The crystal structure of the corresponding phase A 4 Sn 9 or A 12 Sn 17 (A alkali metal) could not be elucidated due to poor crystal quality. [6] Though nine-atom clusters were observed in solution over 100 years ago [8] and the first structural characterization was carried out already in 1976, [9] only small amounts of well-defined products could be isolated from solution. In the course of our studies of soluble, homoatomic Zintl ions, [10] we report here a novel, very simple and efficient access to homoatomic polyanions from the elements at low temperatures.…”

“…[5,6] We selected (2E,7E)-9-chloronona-2,7-dienyl carbamate (6) [7] as substrate in order to compensate for the unfavorable equilibrium state of the cyclization with an irreversible elimination step. [8] Compound 6 was obtained from pentanedial (1) by standard methods (Scheme 2). Treatment of 6 (E:Z 98:2)…”