Synthesis of new chiral crown ethers containing a (p-methoxyphenoxy)methyl moiety and their chiral recognition ability towards amino acid esters

Synthesis and spectroscopic characterization of asymmetric Schiff bases derived from 4′-formylbenzo-15-crown-5 containing recognition sites for alkali and transition metal guest cations

“…The zinc(II) complexes are naturally diamagnetic and exhibit no d-d transition; all their UV bands can be assigned to p-p* transitions of the azomethine chromophore of the ligands. (9) C (14) C (3,4) C (2,5,6,(10)(11)(12)(13) C (13) C (18) C (2,5,6,(10)(11)(12)(13)(14)(15)(16)(17) Table 5 UV-vis spectral data for the ligands and complexes a A 2 /A 1 = x/(100 -x) where A 1 = the absorbance of the phenol-imine form (p-p*); A 2 = the absorbance of the keto-amine form (n-p*); x = the percentage of ketoamine form b Keto-amine form 0% in basic medium. Basic medium is attained by addition of NEt 3 (1 mL) to the given solution (ligand concentration: 1 9 10 -5 mol dm -3 ) c Acidic medium is attained by addition of CF 3 COOH (1 mL) to the given solution (ligand concentration: …”

“…Although symmetric diazine ligands have been extensively studied, there is no report on their complexes with bisSchiff bases of hydrazine which are asymmetrical with respect to the two chelating sites [10]. Crown ethers are of interest in the area of molecular recognition [11]. Crown ethers containing hydrophobic exteriors are lipophilic hosts, which can include cations, especially alkali and alkaline earth metal ions, into their cavities via an iondipole interaction [12,13].…”

Synthesis and Enantiomeric Recognition Studies of Novel C2-Symmetrical Chiral Tetra-Amide Compounds

“…Therefore the enantiomeric recognition study of these compounds is of very important. The design of receptors with a chiral recognition ability for chiral amino acids and amines is still receiving considerable attention, although much work on enantiomeric recognition of amino compounds by chiral macrocyclic ligands has been reported (Chadwick et al, 1984;Diederich, 1988;Fitzmaurice et al, 2002;Karakaplan and Aral, 2005;Aydın et al, 2009;Köylü et al, 2011). Especially C2-symmetric ligands have been widely used in chiral recognition (Kizirian et al, 2003;Turgut et al, 2009).…”

Phosphorylated amino derivatives of thiacalix[4]arene as membrane carriers: synthesis and host–guest molecular recognition of amino, hydroxy and dicarboxylic acids

“…[4,5] A number of studies on various analytical methods for mixtures, i.e. capillary electrophoresis [6][7][8] , HPLC, [9] absorption spectrometry [10][11][12] and electrochemistry [13] , have been reported. One of the most promising approaches for the successful separation and concentration of acids is the use of highly selective host molecules able to effectively and selectively interact with a guest.…”