Azza M. Kadry

Flow injection study of the potentiometric lithium selectivity of cyclic dioxadiamides containing oxygen and nitrogen atoms

SummaryFour 15-membered ring cyclic compounds with two oxygen and two nitrogen atoms incorporated in the ring were prepared and evaluated as neutral carriers in lithium ion-selective electrodes. These ionophores, along with potassium tetrakis (p-chlorophenyl)borate and o-nitrophenyloctyl ether (NPOE), were included in the PVC matrix that coated the tip of a silver-wire electrode. The potentiometric selectivities of the electrodes towards lithium over sodium, potassium, calcium and magnesium were determined. Selectivity coefficients, KLi, Napot., as low as 9.5×10−3 were obtained and smaller coefficients for other metals, KLi, Mpot., were found. A calibration curve for lithium in the presence of 140 mmol/l sodium, with a linear portion having a slope of 51 mV/decade, was obtained. The effect of incorporating 1% trioctylphosphine oxide (TOPO) in the electrodes was studied. Comparison with the results obtained with 15-crown-4-ethers is made.

Synthesis and structure of [1,2]thiaphospholo[4,5-e][1,2,4]triazines

Abstract The first syntheses of the novel [1,2]thiaphospholo[4,5-e][1,2,4]triazine ring system, exemplified by the derivatives 3a-c have been accomplished by the action of Lawessons reagent on the 5-arylmethyl-1,2,4-triazin-6-ones 1a-c, their thiones 2a-c or the Mannich bases 4–6. The structure of these new thiaphospholotriazines was established mainly by NMR, and X-ray structural analysis.