Determination of sulfur dioxide residue and some physiochemical properties of raisins varieties produced in Khorasane-Razavi province

In this study, 62 raisin samples including Golden, Green, Teifi and Poloei varieties were purchased from Kashmar, Khalilabad, Bardaskan, Quchan and Shirvan citiy of Khorasan-Razavi province. The sulfur dioxide residue, moisture content, water activity, pH values and total titratable acidity were determined in the samples. According to results, the mean quantity of sulfite residue of Teifi samples of Kashmar, Bardaskan and Khalilabad were 932, 1884 and 2230 mg/kg, respectively. These data for Green variety of the same cities was 1176, 1009 and 658 mg/kg, and for Golden variety were 1226, 2076 and 2484 mg/kg, respectively. In Quchan and Shirvan areas, the mean quantity of sulfite residue of Poloei variety was 1070 and 186 mg/kg, respectively. Among different raisin varieties, the samples collected from Kashmar, Bardaskan and Khalilabad, the Golden samples contained the highest amount of sulfite-residue; moreover, the amount of sulfite-residue in Shirvan’s Poloei sample was higher than Quchan’s. Shirvan Poloei variety showed the lowest pH (3.70) meanwhile, Guchan Poloei variety had the highest (4.05) pH. Golden variety of Khalilabad and Poloei variety of Shirvan had the highest (1.56%) and the lowest (0.8%) acidity, respectively. The highest (12.31%) and lowest (9.66%) moisture content was found in Golden and Teifi varieties of Kashmar, respectively. The highest (0.44) and lowest (0.40) aw value was observed in Poloei variety of Guchan and Teifi variety of Bardaskan. Considering the raisins characteristics, most of the samples were not in accordance with the national/codex standard due to the traditional method of production

Bent Tridentate Receptors in Calamitic Mesophases with Predetermined Photophysical Properties : New Luminescent Lanthanide-Containing Materials.

A new synthetic strategy has been developed to introduce bent and rigid tridentate 2,6-bis(benzimidazol-2‘-yl)pyridine cores into rodlike ligands L11-17. The crystal structure of the nonmesogenic ligand L13 (C39H37N5O4, triclinic, P, Z = 2) shows the expected trans−trans conformation of the tridentate binding unit, which provides a linear arrangement of the semirigid aromatic sidearms. The crystal structure of the related mesogenic ligand L16 (C61H81N5O4, triclinic, P, Z = 2) demonstrates the fully extended conformation adopted by the lipophilic side chains, leading to a slightly helically twisted I-shaped molecule. A rich and varied mesomorphism results which can be combined with the simultaneous tuning of electronic and photophysical properties via a judicious choice of the spacers between the rigid central core and the semirigid lipophilic sidearms. Ligands L13,14 react with Ln(NO3)3·xH2O to give quantitatively and selectively the neutral 1:1 complexes [Ln(Li)(NO3)3] (Ln = La to Lu), which are stable in the solid state at room temperature but partially dissociate in acetonitrile to give the cationic species [Ln(Li)(NO3)2]+. The crystal structure of [Lu(L13)(NO3)3]·3CH3CN (30, LuC45H46N11O13, monoclinic, C2/c, Z = 8) reveals a U-shaped arrangement of the ligand strand arising from the cis−cis conformation of the coordinated tridentate binding unit. This drastic geometric change strongly affects the thermal behavior and the photophysical and electronic properties of the lipophilic complexes [Ln(L14)(NO3)3]. Particular attention has been focused on structure−properties relationships, which can be modulated by the size of the lanthanide metal ions

Extended Rodlike Polyaromatic Receptors with Bent Tridentate Units Complexed to Lanthanide Metal Ions.

A synthetic strategy is developed to attach semirigid lipophilic sidearms to the 6-positions of bent aromatic tridentate 2,6-bis(benzimidazol-2-yl)pyridine cores to produce U-shaped ligands, L6,7. Differential scanning calorimetry (DSC) reveals that entropic contributions severely affect the isotropization processes of these flexible receptors, but no mesomorphism is detected. The attachment of oxygen linkers to the 5- or 6-positions of the benzimidazole sidearms lowers the ligand-centered 1ππ* and 3ππ* excited states, and the semiempirical ZINDO method assigns this effect to a destabilization of the HOMO orbitals resulting from π-interactions. Reactions of L6 with Ln(NO3)3·xH2O provide the rodlike 1:1 complexes [Ln(L6)(NO3)3] (Ln = La−Lu), which are stable in the solid state but partially dissociate in acetonitrile. The crystal structure of [Lu(L6)(NO3)3]·CH3CN (18a, LuC63H84N9O13, monoclinic, P21/n, Z = 4) reveals an I-shaped arrangement of the ligand strand arising from the meridional complexation of the bent tridentate unit to nine-coordinate Lu(III). The replacement of nitrate anions with trifluoroacetate anions gives the centrosymmetric dimer [Lu(L6)(CF3CO2)3]2 (23, Lu2C134H162N10O20F18, triclinic, P, Z = 1), in which the symmetry-related Lu atoms are connected by two bridging carboxylates, leading to an H-shaped dimetallic edifice. These complexes [Ln(L6)(NO3)3] and [Ln(L6)(CF3CO2)3]2 fulfill the geometrical criteria required by precursors of calamitic metallomesogens, but no mesomorphism can be detected, while photophysical studies indicate that the low energies of ligand-centered 3ππ* excited states drastically limit the luminescence of Eu(III) complexes. The relationships between structural and electronic properties resulting from 5- or 6-substitutions of the benzimidazole rings and the effects of these substitutions on photophysical and thermal properties are discussed