Synthesis of bis-benzo-15-crown-5 and bis-benzo-18-crown-6-ethers

Bis-crown ethers with benzo-15-crown-5 and benzo-18-crown-6 moieties bridged by different length of polyethylene ethers have been successfully synthesized.     

Structure of the Potassium Hydroxide-Dibenzo-18-crown-6 Complex

Dibenzo-18-crown-6 reacts with potassium hydroxide in methanol to give the C₂₀H₂₄O₆ ⋅ KOH ⋅ MeOH complex which was characterized by the ¹H NMR, UV, and IR spectra. Depending on the conditions, the reaction of the same compounds in toluene gave products with the compositions 4 C₂₀H₂₄O₆ ⋅ KOH ⋅ 3 H₂O (3 h, reflux) and 11C₂₀H₂₄O₆ ⋅ KOH (1 h, 80°C, 1 h).__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 620–625.Original Russian Text Copyright © 2005 by Nosyreva, Mal’kina, Sinegovskaya, Trofimov.     

Crystal Structure of 1,10-Diazonia-18-crown-6 Picrate

The crystal structure of 1,10-diazonia-18-crown-6 picrate (I) was determined in an X-ray diffraction study: space group , a = 10.516(2), b = 11.595(2), c = 15.470(3) , = 78.74(2), = 70.31(2), = 64.38(2)°, Z = 2. The structure was solved by direct methods. The full-matrix least-squares refinement was performed anisotropically to R = 0.060 for all 5275 unique reflections collected (CAD-4 automatic diffractometer, MoK). In crystal, compound (salt) I exists as individual complex (ionic) molecules [H₂DA18C6]²⁺2Pic^– formed by N–HO type hydrogen bonds and counterion electrostatic attraction forces. In the unit cell of crystal I, there are two such centrosymmetric and crystallographically independent molecules; the constituent molecular ions are slightly disordered. The DA18C6 dications exist in two-angle form, which is their typical conformation.     

Temperature study of the intramolecular interactions in 15-crown-5 and 18-crown-6

The Raman CH stretching spectra of 15-crown-5 and 18-crown-6 in water solution are studied in the temperature interval 5–80°C. The method of Fourier deconvolution is applied to resolve the overlapped bands in the complex isotropic and anisotropic spectra. The intramolecular coupling constants and the unperturbed CH stretching frequency are calculated for all studied temperatures. The temperature dependencies are discussed in comparison with the temperature dependencies for 12-crown-4 obtained previously.     

Synthesis and Crystal Structure of 3,3＇-Dimethyl-dibenzo-18-crown-6

1 INTRODUCTION Since the report about unusual coordination num- bers and arrangements to metal ions of crown ether compounds by Pedersen[1], the crown ether compounds have attracted much attention. Due to their novel coordination modes, crown ethers have been widely used in catalyst, solvent extraction, iso- tope separation, bionics, material chemistry, host- guest chemistry and supramolecular chemistry[2~5]. So it is vital to study the synthesis of new crown ethers and their crystal stru…     

The syntheses and complexing properties of oxo-12-crown-3 and oxo-18-crown-5

Derivatives of 12-crown-4 and 18-crown-6 in which one of the ethereal oxygens is replaced by a CO group have been synthesised and their complexing abilities towards both metal and organic cations have been assessed. Variable temperature ¹H decoupled ¹³C n.m.r. spectroscopy reveals the presence of anisometric species in solution when a $\text{1}$:1 complex is formed between oxo-18-crown-5 and (S)-PhCHMeNH₃⁺ClO₄.     

Crystal Structure of 1,10-Diazonia-18-crown-6 Bis(hydrogen oxalate) and 1,10-Diazonia-18-crown-6 Oxalate Dihydrate

An X-ray diffraction study has been performed to study the crystal structure of 1,10-diazonia-18-crown-6 bis(hydrogen oxalate) [H₂DA18C6]²⁺·2C₂HO ₄ ^- (I) and 1,10-diazonia-18-crown-6 oxalate dihydrate [H₂DA18C6]²⁺·2C₂O ₄ ^- ·2H₂O (II). Crystals I are triclinic: space group , a = 7.825, b = 7.861, c = 9.349 , = 97.28, = 110.22, = 99.12°, Z = 1. Crystals II are monoclinic: space group P2 ₁ /n, a = 8.783, b = 10.640, c = 10.225 , = 97.04°, Z = 2. The structures of I and II were solved by direct methods and refined by the full-matrix least-squares procedure anisotropically to R = 0.036 (I) and 0.042 (II) for all 2206 (I) and 1990 (II) unique reflections measured (CAD-4 automatic diffractometer, CuK ). In the crystal structures, the ionic complexes (salts) I and II are not individual guest–host complex molecules but are parts of complex (infinite in two directions) three-dimensional layers of H-bonded molecular anions and DA18C6 dications (and water molecules in II). In structures I and II, the centrosymmetric DA18C6 dications have different conformations: two-angle in I and four-angle in II. The unusual four-angle conformation of the DA18C6 dication was found for the first time.     

Hydration to benzo-15-crown-5, benzo-18-crown-6 and the benzo-18-crown-6-potassium ion complex in the low-polar organic solvents.

The coextraction of water with benzo-15-crown-5 (B1SC5), benzo-18-crown-6 (B18C6) and the B18C6-K+ complex into seven low-polar solvents, i.e., carbon tetrachloride (CTC), chloroform (CF), dichloromethane (DCM), 1,2-dichloroethane (1,2-DCE), benzene (BZ), chlorobenzene (CB) and o-dichlorobenzene (o-DCB), has been investigated. The mean hydration number, nH2O, of these solutes in the water-saturated organic solvents was determined. There is a trend that the nH2O values for any solutes increase with increasing the water concentration in the solvents. Those of B18C6 and B15C5 converge at almost 0.8 for B18C6 and 0.4 - 0.5 for B15C5 in the solvents with the relatively high water concentration, i.e., CF, 1,2-DCE, DCM, and nitorobenzene (NB). The nH2O value of B15C5 is about one-half of that of B18C6 for a given organic solvent. The dominant species of the B18C6-K+ complex in these solvents is non-hydrated. From these results, the hydration equilibrium constants, KH2O, in the organic solvents were estimated.     

Potentiometric study of complexation of phenylaza-15-crown-5, 4-nitrobenzo-15-crown-5 and dibenzopyridino-18-crown-6 and other derivative of 18-crowns-6 with Na+ ion in methanol

The complexation reaction of phenylaza-15-crown-5, and 4-nitrobenzo-15-crown-5, benzo-15-crown-5 and dibenzopyrdino-18-crwon-6, dibenzo-18-crown-6,dicyclohexyl-18-crown-6(cis and trans), and 18-crown-6 with Na⁺ ion in methanol have been studied by potentiometric method. The Na⁺ ion-selective electrode has been used both as indicator and reference electrode. The stoichiometry and stability constants of complexes of these crown ethers with sodium ion were evaluated by MINIQUAD program. The major trend of stability of resulting complexes of these macrocycle with Na⁺ ion varied in the order DCY18C6 > DB18C6 > 18C6 > DBPY18C6 > phenylaza-15C5 > benzo-15C5 > 4-nitrobenzo-15C5. The obtained results in particular stability constant of complexes of DBPY18C6, phenylaza-15C5 and 4-nitrobenzo-15C5 with sodium ion in comparison with other crowns ether are novel, and interesting.