The stability of europium(III) complexes with benzocrown ether derivatives 2−4 containing carboxylic functions with methylene spacers of different length was found to vary surprisingly little. In sharp contrast, the hydrolytic activity of these catalysts against bis(p-nitrophenyl)phosphate (BNPP) varied by a factor of 30. The results show for the first time the efficiency of the carboxylic group as cofactor in phosphate ester hydrolysis, which until now was established only in some enzmyes. Other than with BNPP, the hydrolysis with plasmid DNA (nicking experiments) showed no rate enhancement.

Syntheses of two series of new styryl dyes incorporating thiacrown ether moieties (CSDs 3a-e, 4a-e) are described. 1 H NMR and UV-vis measurements show that these compounds exhibit a strong preference for formation of complexes with heavy metal ions. Polarographic measurements allow conversion of relative complex formation stability constants, determined spectrophotometrically, into absolute values. The photochromic properties of the CSDs are based on reversible trans-cis isomerization and [2+2]-photocycloaddition. The influences of the terminal group of the N-substituent and of the size and composition of the crown ether cavity on metal cation complexation selectivity and on photochromism are evaluated.

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The condensation of 3,4-hi~12-halocthoxy)benzaldehydcs vdth -~cyclic mo)-z,lkancdithiols in the presence of alkali metal c41boflill~2s ill dJT ethanol. DMF, McCN and their ltliXltlrcs with water give,; t'ormyl derivati,,cs of benzothiacmwn c()mpoulld.', ill high yields. ]he best results arc alLHned ,ahcn the radius of the hydrated metal cation ills to tile crown ether cavity. Ill tile caste of Cs". high yield.,, v, crc ob~,cr~cd lbr crown ethers of an} size and compo:,ition: this can bc explained by a spccillc templatc effect of IhJ',; CaHOI1. The illflucncc of the nalurc of the leaving group in 3.4-bist2-halocthoxylbcnz-Hdchydes was established for reactions wilh dithiols conLmfiag no ether oxygen aloms.Key words: 3.4-bis(2-halocthoxy)benzaldchydcs: r alkali metal carbonales: tcn-~ptatc clti:ct: l~.wmyl derivatives of bcnzolhiacrowll ct)lllpoullds..The main types of rltacrncvciic sulfides are thiacrown compounds, thiacryptands, and thiacyclophanes. I-2 ]'he rapt attention to sulft~r-containing macrohclcrocyclcs is due to their capability of sciectivc formation of strong complexes with transition and heavy nletal cations. 3,4The~,c compounds can also be of interest as intermediates in the s vnthesis of polymers with titiacrown fragments, selective chromogcnic arid photochromic reagents for nlclal cati()lls, and cxtractants Ibr the separation of metal sails.Ahhough the first representatives of bcnzocrow~l compounds containing various combinations of sulfur and oxygen in the macrocyclc ,acre synthesized in thc early 70s. 5 it was not tHltil recently that methods lot thc preparation ofbcnzothiacrown con]pounds havil]g a lililCtional group in the benzene ring were developed. 6,7 For example, 4" -tbrmylbcnzodithia-15( I 8)-crown-5(6) were prepared by mctallatkm of bromo benzodithiacrown dcri,,ativcs by n-buLvllithium followed by thc rcaction of organolithium derivatives with DM F.In this work aimed at developing a more convenicnt method for the preparation of the formvl derivatives of benzocrown compounds with different numbers of O. S. and C atoms m the macrocycle, we carried out condensation of 3,4-bisl'2-halocthoxyJbcnzaldehydes la,b with terminal dithiols 2a--e in the presence of alkali metal carbonates ISchemc I).l'hc required dithiols 2a--c are commercial chemicals. 3,6-Dithiaoctane-1,8-dithiol (2d), 3.6.9-trioxaundecanc-1,11 -dithiol (2e). 3.4-bis(2-chloroethoxy)benzaldehyde (la), and 1,2-bis(2-chlomethoxy)bcnzenc (4b) were synthesized by known proccdt, rcs. 8-tl Dichloride la and diiodidc lb were prepared according to Scheme 2.