Halil Hoşgören

New copper(II), manganese(III), nickel(II) and zinc(II) complexes with a chiral quadridentate Schiff base

A chiral Schiff base ligand (H2L) was obtained by condensing 2-hydroxynaphthalene-1-carbaldehyde with substituted (1R,2R)-(−)-diaminocyclohexane. Chiral Schiff base complexes [CuL], [NiL], [ZnL] and [MnLOH] have been synthesized and characterized by elemental analyses, ΛM, i.r., u.v.–vis. and 1H-n.m.r. and magnetic measurements.

Novel C2-Symmetric Macrocycles Bearing Diamide−Diester Groups: Synthesis and Enantiomeric Recognition for Primary Alkyl Ammonium Salts

We synthesized a series of novel macrocycles with diamide-diester groups (S,S)-1, (S,S)-2, (S,S)-3, and (R,R)-1, derived from dimethyloxalate and amino alcohols by high dilution technique, and evaluated enantiomeric recognition properties of these macrocycles toward primary alkyl ammonium salts by 1H NMR titration. Taking into account the host employed, important differences were observed in the Ka values of (R)-Am and (S)-Am for (S,S)-1 and (R,R)-1 hosts, KS/KR = 5.55 and KR/KS = 3.65, Delta Delta Go = 0.43 and -0.32 kJ mol-1, respectively. There seems a general tendency for the host to include the guests with the same absolute configuration.

SOLVENT EXTRACTION OF BORON WITH l,2-DIHYDROXY-4-OXADODECANE (DHD) IN n-AMYL ALCOHOL

ABSTRACT In the work presented here, l,2-dihidroxy-4-oxadodecane (DHD) was synthesized and used for the solvent extraction of boron. DHD was prepared from glycidol and octanol by thermal epoxide ring opening reaction without using acid or base catalyst. The structure of this new extracting reagent was identified according to its spectroscopic data i.e. 13C NMR, 1H NMR and elemental analysis results. The fixed standard solution of boron (as borax) of 10−4 M was extracted with different volume ratios of DHD and n-amyl alcohol (AA) at different equilibrium pH values. The best extraction result was obtained at high pH values with a mixture of equal volumes of DHD and n-amyl alcohol. The different equilibrium pH values were plotted against the extraction yields (%R) and the pH0·5 value was determined by using this graph. The extraction of boron from aqueous solutions with equal volumes of DHD and various solvents were studied and it was found that petroluem ether, n-amyl alcohol and diisopropyl ether are convi...

Resolution of (±)-β-methylphenylethylamine by a novel chiral stationary phase for Pirkle-type column chromatography

In this study, a new Pirkle-type chiral column stationary phase for resolution of beta-methylphenylethyl amine was described by using activated Sepharose 4B as a matrix, L-tyrosine as a spacer arm, and an aromatic amine derivative of L-glutamic acid as a ligand. The binding capacities of the stationary phase were determined at different pH values (pH = 6, 7, and 8) using buffer solutions as mobile phase, and enantiomeric excess (ee) was determined by HPLC equipped with chiral column. The ee was found to be 47%.

Effect of 1,3-Diol Structure on the Distribution of Boron Between CHCl3 and Aqueous Phase

The various new aliphatic 1,3-diols, containing primary, secondary, tertiary, and mixed of these groups, were synthesized and used for the solvent extraction of boron. Diols (8a, 8b, 9, 10a, 10b, 11, 12a, 12b, 13) were prepared from (β-hydroxy carbonyl compounds 1–7. The fixed standard solution of boric acid of 1.00×10−2 M was extracted with 0.1 M and 0.5 M diols at equilibrium pH of 2 and at constant ionic strength (I=0.5). The best extracting reagent was found to be 11, which is a primary–tertiary class of -OH groups and methyl groups as a substituent on the second carbon of 1,3-diol.

Synthesis of C 2-Symmetric Chiral Amino Alcohols: Their Usage as Organocatalysts for Enantioselective Opening of Epoxide Ring

A series of β-amino alcohols derivatives were synthesized from (R)-2-amino-1-butanol and (S)-1,2-propanediol, and they have been used as organocatalaysts in the racemic ring opening of epoxide in good yields with high enantiomeric excess (up to 97%).

Synthesis of R-(-)-2-ethyl-N-benzyl (benzo-monoaza-15-crown-5) and the Crystal Structure of Its Sodium Perchlorate Complex

A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-1-azacyclopentadeceane) NaClO4], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P21 with cell dimensions a = 9.480(1), b = 15.978(2), c = 15.816(2) Å, β = 105.51(1)°, Z = 4. The final R value is 0.055 for 2711 observed reflections and 540 parameters. There are twomolecules in the asymmetric unit labelled A and B. The sodium ion is hexacoordinated. The average values for the Na–-Oeth (etheric) distances are 2.364(6), 2.317(7) Å and the Na–N distances are 2.679(6), 2.611(7) Å; the Na–-O(ClO4) contacts are2.497(7) and 2.257(10) Å, for A and B, respectively.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(-)-1-phenyl-ethyl ammonium percholorate

Abstract A new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group P21 with cell dimensions a = 10.0000(8), b = 12.281(2), c = 12.331(1)Å, β = 102.052(7), Z = 2 The host-guest complex is held together by a strong system of hydrogen bonds between the two protons of the ammonium ion as well as the nitrogen and four oxygen atoms of the crown ether The C—O and C—C distances of the 15-membered ring average 1.418 and 1.501 Å while the O—C—C and C—O—C angles average 110.2 and 113.3°. The average N—C distance is 1.476 Å.

Electrical and optical properties of inorganic complexes C36H76N2O9ClNa and C14H12N2O4TeBr2

Abstract The electrical properties of some inorganic samples were studied as functions of temperature and the results were analyzed. These samples activation energies were calculated from the electrical conductivity measurements. Also, a detailed study of optical absorption is presented. The optical absorption spectra are measured in the UV+invisible wavelength range 200–1100 nm. The absorption coefficient and value optical energy gaps were determined from the absorption spectra. The complex C 36 H 76 N 2 O 9 ClNa is characterized by direct optical absorption with an optical edge at 4.49 eV. However, the complex C 14 H 12 N 2 O 4 TeBr 2 is characterized by indirect optical absorption with an optical edge at 1.45 eV, and a nearby direct one at hν =1.80 eV.

The Solvent Extraction of Boron with Synthesized Aliphatic 1,3‐Diols: Stripping and Extraction Behavior of Boron by 2,2,5‐Trimethyl‐1,3‐hexanediol

Abstract A variety of aliphatic 1,3‐diols (4a–c, 5a–c, 6a–c) was synthesized from β‐hydroxy carbonyl compounds (1–3) for potential use in the solvent extraction of boron. Primary‐secondary and primary‐tertiary alcohol structures of 1,3‐diols substituted with isopropyl, isobutyl, and isopentyl groups have been demonstrated to be very efficient for the solvent extraction of boric acid from aqueous solutions. The extraction ability of 2,2,5‐trimethyl‐1,3‐hexanediol (5b) was investigated as a function of 5b concentration, solution pH, solvent properties, and stripping conditions. Extraction efficiency increased with increasing concentration of 5b, and the best extraction of boron (96.8%) was found to be at an equilibrium pH of 2 with 0.5 M of 5b. Chloroform, toluene, chlorobenzene, 2‐octanol, and n‐amyl alcohol were found to be suitable solvents for the solvent extraction of boron. The boron complex can be recovered from the organic phase by treatment with an aqueous solution of sodium hydroxide. The highest ratio (96.7%) of boron was recovered by 0.1 M of sodium hydroxide solution.