Bronislaw P. Czech

Novel Liphophilic crown car☐ylic acids

Abstract Four novel ionizable crowns are formed from reactions of methyl 5-( n -decyl)salicylate with tosylates from hydroxymethyl-12-crown-4, -15-crown-5, -18-crown-6 and -21-crown-7 followed by hydrolysis.

Synthesis of hydroxymethyl-21-crown-7 and hydroxymethyl-24-crown-8

Abstract Reactions of 3,6-dioxa-4-(benzyloxymethyl)-1,8-octanediol with appropriate ditosylates followed by hydrogenolysis produced two new functionalized crown ethers.

New lipophilic ionizable crown ethers

Abstract Two new ionizable crown ethers which bear lipophilic groups are synthesized and found to exhibit selectivity for complexation of K+ in competitive solvent extractions of alkali metal cations.

CHROMOGENIC CRYPTAHEMISPHERAPLEXES FOR THE DETERMINATION OF POTASSIUM IN AQUEOUS SOLUTIONS

Abstract A series of novel chromogenic cryptahemispheraplexes whose core structures are hybrids between those of cryptands and spherands were designed and synthesized for the selective complexation of potassium in aqueous solutions. Two different cavity sizes obtained by combining diaza-18-corand-6, [2.2], and diaza-21-corand-7, [3.2], with the half spherand were explored. These compounds bear various picrylamine-type chromophoric groups for generating a spectrophotometric response. The resulting compounds having the [2.2] cavity are 2,4-dinitro-6-(trifluoromethyl)anilino ( 2 ), 2,6-dinitro-4-(trifluoromethyl)anilino ( 3 ), 4-cyano-2,6-dinitroanilino ( 4 ) and 6-( N,N -diethylsulfonamide)-2,4-dinitroanilino ( 5 ) and having the [3.2] cavity 2,4,6-trinitroanilino ( 6 ). A decrease in the p K a of the chromogenic compound is observed with complexation of potassium ion, which results in an increase in absorbance observed at the characteristic wavelength of the ionized form of the chromophoric group. The p K a values for the NaBr complexes (the original form of the chromogenic cryptahemispheraplexes) ranged from 7.93 to 9.27 with Δp K a [p K a (KL) - p K a (NaL)] values of −0.39 ( 6 ), −0.59 ( 3 ), −0.99 ( 4 ), −1.30 ( 5 ), and −1.69 ( 2 ). The best responses to potassium were obtained with compounds 2 , 5 and 6 , which also had the best molar absorptivities, 1.9 × 10 4 −2.0 × 10 4 l mol −1 cm −1 Compound 6 , owing to the larger cavity size, was less sensitive towards potassium and suitable for use with potassium solutions of higher concentration.

SOLVENT EXTRACTION OF RADIUM AND BARIUM CATIONS INTO CHLOROFORM BY A LIPOPHILIC ACYCLIC POLYETHER DICARBOXYLIC ACID

The lipophilic acyclic polyether carboxylic acid bls-l,8(2 -carboxy-3-naphthoxy)-3,6-dioxaoctane exhibits selectivity for Ra2+ over Ba2+ in competitive extractions into chloroform. Solubility characteristics of the compound suggest that the addition of branched alkyl substituents would be required to make it a practical separation agent.

Synthesis of a New Cyclophane Host and Crystal Structures of Its Compounds with Neutral Guests

A new cyclophane host molecule 3 is prepared by connecting the oxygenatoms of twoα,α′-di(4-hydroxyphenyl)-1,4-diisopropylbenzene units withtwo trimethylene spacers. Solid-state structures are determined forcompounds of 3 with dichloromethane and p-xylene guests. The crystals of thetwo host-guest compounds are isomorphous.

Effect of crown-ether surfactants on flame atomic absorption and flame emission signals of some monovalent cations

Abstract Two surface-active and one surface-inactive 18-crown-6 derivatives were synthesized and evaluated for their abilities to enhance flame atomic absorption and flame emission signals of monovalent cations. Enhancement of potassium signals were noted for the surface-active compounds but not for the surface-inactive compound. The critical micelle concentration was determined and compared to the degree of enhancement. Surfactant-induced signal enhancements are not due to the slight or moderate decrease in the size of the aerosol first produced in the nebulizing chamber. Additional mechanistic considerations are discussed.

Functionalized large ring crown ethers

Abstract Reactions of 3,6,9,12-tetraoxa-7-(benzyloxymethyl)-1,14-tetradecanediol with appropriate ditosylates followed by hydrogenolysis produce hydroxymethyl-27-crown-9 and hydroxy- methyl-30-crown-10. Alkali metal cation complexation by lipophilic dodecyl ether derivatives of these crowns is examined.

Crystal and molecular structure of the meso-diastereoisomer of 1,12-dimethyl-2,11-dithia-5,8-dioxa[12](1,1′)ferrocenophane

Abstract The meso-diastereoisomer of 1,12-dimethyl-2,11-dithia-5,8-dioxa[12](1,1′)ferrocenophane crystallizes in space group P 1 with a 8.879(2), b 10.135(2), c 12.030(2) A, α 100.14(1), β 99.02(1), γ 103.93(1)°; the ferrocenyl moiety has an eclipsed conformation and the bridging chain a steric arrangement of the type aag+ aag− g+ aag− a.

Synthesis, Metal Ion Complexation Properties, and Electrochemical Behavior of Ferrocenyl Thioacetal Crown Compounds

Abstract Condensation of ferrocenecarboxyaldehyde with dithiols under Lewis acid catalysis produces ferrocenyl thioacetal crown compounds in good to excellent yields. Complexation behavior of several ferrocenyl thioacetal crown compounds toward alkali metal cations, Ag(I), Tl(I), Cu(II), Pb(II) and Zn(II) is assessed by picrate extractions from aqueous solutions into chloroform. Electrochemical behavior of several ferrocenyl thioacetal crown compounds in the absence and presence of sodium ions is investigated by cyclic voltammetry.