Crown ether mediated transport of guanidinium thiocyanate through a bulk liquid membrane and the correlation with the complex stability constants

Abstract

determined by accurate mass measurements. Standard workup of an ethereal solution means washing with 5% HC1 (aqueous), water, and 5% KHC03 (aqueous), drying with Na2S04, and evaporation of the solvent in vacuo. Crystal data: P2U a = 12.962(3) A, (b = 6.260 (1) Ac = 15.711 (3) A, ß = 102.20 (2)°, Z = 2; C^H^O, Mr = 386.67, pcalcd = 1.03 g-cm3, pobed = 1.023 (3) g-cm"3 (flotation in aqueous ZnBr2), platelike crystal, 0.35 X 0.25 X 0.06 mm3. Data collection:36 Syntex P21( Cu Ka radiation ( = 1.54178 A), 2752 unique reflections in the 0 < 2 < 158°r ange, 1304 of them observed with I > 1.96 (7), room temperature, no absorption correction (µ = 4.13 cm"* 1). Structure solution: direct methods and weighted Fourier syntheses, refinement by full-matrix least-squares to R = 0.089, Rw = 0.097 using MAGEX 8036 and SHELX programs. Positions and anisotropic thermal parameters of non-H atoms together with positions and isotropic thermal parameters of H atoms refined in two blocks; average thermal parameters

Self-assembled Structure of Inorganic–Organic Hybrid Crystals Based on Keggin Polyoxometallates [SMo12O402–] and Supramolecular Cations

“…Inorganic–organic hybrids containing POMs and different organic moieties such as tetrathiafulvalene, amino acid, polypeptides, and ferrocenyl derivatives have received considerable attention in the last 20 years because of their intriguing topological structures and potential applications in medical, magnetic, conductive, and nonlinear optical materials. − Recently, crown ethers have been widely used in inorganic–organic hybrids chemistry because of their multiple functions, such as molecular recognition and transportation. − The first oxonium–crown ether compounds were constructed using H 3 O + and the dicyclohexano[18]­crown-6 cation, and the H 3 O + ion was generally located at the center of the crown ether through a hydrogen bonding interaction . Hydrogen bonding can be modified by choosing reasonable and distributing functional groups such as −COOH, −NH 2 , and −OH in the molecular systems.…”

Aza-27-crown-9 Amino Acid

“…The complete analytics for the intermediates 3 and 4 can be found in the supporting information. -3,5,6,8,9,11,12,13,14,15,17,18,20,21,23,24-hexadecahydro-2H-benzo[k] [1,4,7,10,13,16,19,22,25]octaoxaazacycloheptacosine-27,28-dicarboxylate (6) (a) To a mixture of 0.68 g dimethyl-4,5-dihydroxyphthalate (1) (3 mmol) and 1.38 g K 2 CO 3 (10 mmol) in DMF (5 mL), 3.5 g tetraethyleneglykole monotosylate (2) (10 mmol) in DMF (5 mL) were added and stirred under nitrogen at 60 °C overnight. After cooling to room temperature, the mixture was poured into 30 mL of ice-cold saturated NH 4 Cl solution.…”

“…The units can be covalently linked by peptide coupling to more extended receptors showing high specificity for N-terminal lysine in peptides [4,5] or with other recognition motifs binding for example histidine peptides [6,7]. The ability of benzo-27-crown-9 ethers to bind guanidinium ions is known [8,9], was applied in extraction experiments [10] and has been proven by crystal structures [11,12]. Examples of related chemosensors were employed for detecting naturally occurring toxins [13,14].…”

Trimacrocyclic hexasubstituted benzenes for recognition of guanidinium and their anti-cancer and antimicrobial activities

“…For example, Bell et al described a small-molecule guanidinium receptor, that is The Arginine Cork, for strong complexation of guanidinium in water. 14 The Cram and Reinhoudt groups established a series of monocyclic crown ether based cation receptors for guanidinium recognition, [15][16][17][18][19] some of which were found to be useful in selective liquid-liquid extraction of guanidinium from the liquid phase into organic media. [17][18][19] Later, a class of calix [n] arene-based receptors were developed for either selective inclusion and membrane transport of guanidinium salts or selective fluorometric sensing of guanidinium ions by Reinhoudt and Shinkai et al [20][21][22] In 2005, Gong and coworkers reported a collection of six-residue, shape-persistent aromatic oligoamide macrocycles for highly selective binding of guanidinium ions.…”