@article {1592,
	title = {Conformational stability, molecular structure, and intramolecular hydrogen bonding of thenoyltrifluoroacetone},
	journal = {J. Theor. Comput. Chem.},
	volume = {5},
	number = {3},
	year = {2006},
	note = {ISI Document Delivery No.: 098FUTimes Cited: 3Cited Reference Count: 52Tayyari, Sayyed Faramarz Nekoei, Abdo-Reza Vakili, Mohammad Hassanpour, Masoud Wang, Yan Alexander},
	month = {Sep},
	pages = {647-664},
	type = {Article},
	abstract = {<p>Complete conformational analysis of all possible keto and enol forms of thenoyltrifluoroacetone (TTFA) was carried out using density functional theory with the B3LYP functional and the 6-31G**, 6-311G**, and 6-311++G** basis sets. In addition, the geometries and energies of the four most stable chelated conformers and their corresponding open structures were obtained at the MP2/6-31G** level of theory. The energy differences between the four stable chelated enol conformers, in the gas phase, calculated at the B3LYP levels are negligible. However, calculations at the MP2 level indicate that the B2 conformer (the hydroxyl group in the -CF3 side) is significantly more stable than others, in agreement with the X-ray diffraction results. The calculated intramolecular hydrogen bond (IHB) energy E-HB and the strength of the bond have been compared, and an imperfection in the prevalent method of evaluating E-HB has been perceived. The IHB of TTFA was compared with those in several beta-dicarbonyls.</p>},
	keywords = {ACETYLACETONE, beta-diketone, BETA-DIKETONES, conformational analysis, CRYSTAL-STRUCTURE, EQUILIBRIUM CONSTANTS, INFRARED-SPECTRA, intramolecular hydrogen bond, KETO-ENOL-TAUTOMERISM, nuclear magnetic resonance, PROTON CHEMICAL, SHIFTS, SYNERGISTIC EXTRACTION, thenoyltrifluoroacetone, VIBRATIONAL ASSIGNMENT},
	isbn = {0219-6336},
	url = {<Go to ISI>://000241507200011},
	author = {S. F. Tayyari* and A.-R. Nekoei and Vakili, M. and Hassanpour, M. and Wang, Y. A.}
}
@article {3061,
	title = {BINDING AND TRANSPORT OF CALCIUM-IONS BY SYNTHETIC ANALOGS OF IONOMYCIN},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {72},
	number = {6},
	year = {1994},
	note = {ISI Document Delivery No.: NV309Times Cited: 4Cited Reference Count: 66},
	month = {Jun},
	pages = {1512-1524},
	type = {Article},
	abstract = {The transport of calcium ions across an organic barrier by a series of synthetic analogues of ionomycin was measured in a cylindrical glass cell using chloroform as the artificial membrane. The presence of a beta-diketone and carboxyl group in the same molecule and a sufficient Lipid solubility of the compounds were shown to be necessary and sufficient conditions for Ca2+ transport. Small and no transport of Ca2+ were found for analogues 5 and 6, respectively, due to the low lipid solubility of these compounds. The Ca2+ transport rate for analogues 8 and 13-15 followed the order of 8 > 13 > 14 > 15, which demonstrated that optimal Ca2+ transport was achieved when the beta-diketone was separated from the carboxyl group by seven methylene units, identical to that found in ionomycin. Analogues 8-10 were comparable to ionomycin and calcimycin in terms of Ca2+ transport. Ca2+ transport by the analogues was found to be a saturable process that obeyed Michaelis-Menten kinetics. It was dependent on the pH in the aqueous source phase and independent of the pH in the receiving phase. Both the carboxyl and the beta-diketo groups were ionized in the transport of Ca2+, indicating that the stoichiometry of Ca2+ complex in transport was 1:1. The pK(a) of the beta-diketone of the analogues was determined to be in the range of 10.90-11.16 in 80\% MeOH-H2O. The pK(a) values were related to the lipid solubility of the compounds and the hydrocarbon chain length between the beta-diketone and the carboxyl group. The binding constants of the analogues with Ca2+ and Mg2+ in 80\% MeOH-H2O were determined to be in the order of 10(2) M(-1) and 10(3) M(-1), respectively, using the pK(a) method. The stoichiometry of Mg2+ binding was found to be 1:1 by the mole ratio method. The selectivity in binding and in transport followed the same order, being Mg2+ > Ca2+ >> Na+, K+.},
	keywords = {A23187, ACETYLACETONE, ALKALINE-EARTH CATIONS, COMPLEXATION, COUNTERTRANSPORT, COUPLED, DIVALENT-CATION IONOPHORE, FORMATION-CONSTANTS, MEMBRANE, METAL-IONS, SYSTEMS},
	isbn = {0008-4042},
	url = {<Go to ISI>://A1994NV30900011},
	author = {Hu, Thomas Q. and Weiler, L.}
}
