The energy-transfer luminescence of complexes of Tb3+ with calix- (CAS), thiacalix- (TCAS), and sulfonylcalix[4]arene-p-tetrasulfonates (SO2CAS), in which four p-phenolsulfonates are jointed by –CH2–, –S–, and –SO2–, respectively, was applied to an ultratrace determination of the Tb3+ ion. Based on the complexation behavior of each calix ligand, a determination procedure was established. A time-resolved measurement was conveniently employed to separate the background fluorescence from the luminescence of the calix-Tb3+ complexes. An improved sensitivity was attained by sulfur-bridged calixes, TCAS and SO2CAS, as compared to CAS, owing to the photophysical properties of the Tb3+-complexes. The detection limits for Tb3+ ion by CAS, TCAS, and SO2CAS ligands were estimated to be 8.2×10−10 mol dm−3 (131 ppt), 2.0 × 10−10 mol dm−3 (32 ppt), and 2.3 × 10−10 mol dm−3 (37 ppt) at S/N = 3, respectively. In terms of the selectivity, the effect of diverse coexisting ions on the luminescence intensity of the Tb3+ complexes was studied. The luminescence of the TCAS complex was interfered by the presence of a 5-fold amount of other lanthanide ions, while that of the SO2CAS complex was more tolerant for those metal ions, allowing the presence of as much as 50 to 100-fold amounts. Also, 10 to 1500-fold amounts of other common ions were tolerated by using SO2CAS. Thus, SO2CAS was proved to be a practical reagent for determining the Tb3+ ion at the sub-ppb level.
In the presence of metallic strontium, the Barbier-type alkylation of aldehydes with alkyl iodides proceeded smoothly at −15 °C under an argon atmosphere to afford the corresponding alkylated alcohols in moderate to good yields. The unusual addition reaction of ethyl benzoate with tert-butyl iodide took place to give the p-tert-butylated alkylated product (the 1,6-adduct of the benzoate) in 55% yield. Using strontium isopropoxide, the Meerwein–Ponndorf–Verley-type reduction of the aldehyde proceeded smoothly under reflux conditions in 2-propanol.
Addition reactions
Addition reactions O 0060The Barbier-Type Alkylation of Aldehydes with Alkyl Halides in the Presence of Metallic Strontium. -In the presence of metallic Sr the Barbier-type alkylation of aldehydes (I) with iodides (II) proceeds smoothly to afford the corresponding alkylated alcohols (III) in moderate to good yields. Using strontium isopropoxide, the Meerwein-Ponndorf-Verley-type reduction of aldehyde (Ia) gives the primary alcohol (IV). -(MIYOSHI*, N.; KAMIURA, K.; OKA, H.; KITA, A.; KUWATA, R.; IKEHARA, D.; WADA, M.; Bull. Chem. Soc. Jpn. 77 (2004) 2, 341-345; Dep. Chem., Fac. Integr. Arts Sci., Univ. Tokushima, Minamijosanjima, Tokushima 770, Japan; Eng.) -M. Paetzel 22-042
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