A new approach to dissociable chromoionophores 5, 6a-e, aza[ 15lcrown-5 provided binding constants which are about 7 and 8 by reaction of (dicyanomethy1ene)indandione 1 and twenty times lower. These differences depending on the na-(dicyanomethy1ene)pyrazolones 2a-e, respectively, with ture of the crown (aza-crown or benzo-crown with the same aminophenyl crowns 3 and 4 is described. The complexation ring size) are discussed by comparison with a series of known constants were determined by 'H-NMR spectroscopy. For the crowns and also on the basis of molecular modelling technichromoionophores 5 and 6a-e bearing a benzo[l5]crown-5 ques. The ability of the chromophore 6a as extractant for somoiety, K, values between 1100 and 1900 were found, while dium and potassium ions in its ionic form is shown. the chromoionophores 7 and 8 bearing the N-phenylChromoionophores are crown ether derivatives which contain a chromophoric g r o~p [~,~,~] .These functional dyes continue to be a topic of interest for analytical applic a t i o n~ [~~~] .Especially crown ether dyes with proton-dissociable groups are useful as reagents for metal Given this importance, a number of chromoionophores were synthesized by starting from 1 5-aminobenzo[ 15lcrown-5 (3) and N-(4-aminophenyl)aza[ 15lcrown-5 (4). For example, the 2,4,6-trinitrophenyl derivative of 3 r 7 3 * 1 contains an acidic NH group, which dissociates in alkaline solution leading to a color change from orange to red"]. The complex formed with potassium can be extracted into chloroform. Similarly, a series of styryl dyes bearing an aza[l5]crown-5 moiety were synthesized ["]. Only at high concentrations of alkali and alkaline earth metal ions could a shift in the absorption spectra be observed, indicating relatively small complex formation constants. These are important for a critical evaluation of a chromoionophore. They can be determined by different methods [' ' , ' 2 % ' 3 ] , and structure-stability relations were ~tudied['~,'~]. However, a direct comparison of the values is not always possible, and especially the solvent used is important. Usually, the introduced chromophore causes a decrease of the complexing ability because of its electronattracting e f f e~t [ '~* '~I .In contrast, donor substituents in the crown lead to an increase of the complexation con~tants"~1. In this paper we report on the synthesis, UV/Vis spectrophotometrical properties, complexation ability, molecular modelling, and acid-base behavior of chromoionophores derived from dicyanomethylene compounds. Synthesis of the ChromoionophoresFor the synthesis of chromoionophores reported in this paper the known reactivity of (dicyanomethy1ene)indandione 1 and (dicyanomethy1ene)pyrazolones 2a-e towards anilines was utilized. As we showed re~ently['~,'~], these dicyanomethylene compounds are added to N-phenylaza[ 15lcrown-5 and N,N-diphenyldiaza[ 1 Slcrown-6 under mild conditions, and the colorless adducts are converted by heat or photochemically into deeply colored chromoionophores. With 15-aminobenzo[ 15lcrown-...

(N‐Phenyl‐aza‐crown)‐ethenyl‐acridines – Complexing Chromoionophores and Precursors for Deep Blue Coloured Hemicyanines Aromatic aldehyde derivatives of N‐phenyl‐aza‐15‐crown‐5 and N‐phenyl‐aza‐18‐crown‐6 (1a–b) are condensed with 9‐methylacridine to give yellow phenyl‐ethenylacridine derivatives 3a–b which are reversibly converted by protonation into deep blue colored hemicyanines, Using 9,10‐dimethylacridinium perchlorate in the condensation with the crown ether aldehyde 1 the blue hemicyanine 6 is directly obtained. UV/VIS absorption spectra of the basic/acidic forms of the acridine derivatives are presented. The complex formation of the crown ether derivatives with Na+ and K+ are studied using 1H‐NMR and UV/VIS spectroscopy.

Chromoionophores are crown ether derivatives, which contain a chromophoric group [1][2][3]. These functional dyes are of a great interest for analytical applications [4,5], especially in medical diagnostics and therapy. A great number of chromo-and also fluoroionophores, starting from aldehydes of N-phenyl-aza-15-crown-5 or N-phenyl-aza-18-crown-6 are described in the literature [6 -11]. Substitution of the aminic H-atom in aza-crowns leads to nitrogen-pivot lariat crowns, and it was shown that alkyl groups increase the binding strength of the metal complexes [12 -14]. The present paper deals with the synthesis of deeply colored polymethine crown ether derivatives and the influence of the electron acceptor properties of the side chain on the complexation, depending upon conjugation of the chromophore with the nitrogen of the aza-crowns. Abstract. Aromatic aldehyde derivatives of N-phenyl-aza-15-crown-5 2, N-phenyl-aza-18-crown-6 8, and benzo-15-crown-5 10 are condensed with malononitrile and 2-amino-1,1,3-tricyano-1-propene to give light yellow to orange colored crown ether derivatives 4, 5a, 9a, 11, and 12. 5a and 9a were acylated with ethyl chloroformate to give the magenta colored dyes 5b and 9b, respectively. By condensation of N-(4-nitrosophenyl)-aza-15-crown-5 3 with 2-amino-1,1,3-tricyano-1-propene the magenta dye 6a is obtained. Acylation of 6a with ethyl chloroformiate leads to the deep blue colored dye 6b. In these derivatives the nitrogen or oxygen atoms of the crown ethers are part of the chro-mophoric system and binding properties are affected. Further chromophoric derivatives of aza-crown ethers are stu-died in which these are separated from the chromophoric moiety by a spacer. N-(ω-chloroalkyl)-N-alkylanilines 14a -c were attached to aza-15-crown-5 13a and aza-18-crown-6 13b to yield the spacer crown ether derivatives 15a -c and 16a -c, respectively. The formylated spacer crown ether derivatives 17a -c and 18b were condensed with 2-amino-1,1,3-tricyano-1-propene to give the orange spacer-chromoionophores 19a -c and 20. In these crown ether derivatives the extended conjugation is interrupted by the spacer and good binding properties are obtained. The complex formation constants of the crown ether derivatives with Na + and K + are determined using 1 H NMR spectroscopy. dimeric malononitrile (2-amino-1,1,3-tricyanopropene), respectively, is a Knoevenagel condensation which occurs under mild conditions using piperidine as catalyst. The yellow colored chromoionophores 4 and 5a, showing UV/Vis absorption maxima at about λ max = 430 nm, are obtained with a quite good yield.13-(4-Nitrosophenyl)-1,4,7,10-tetraoxa-13-azacyclopentadecane 3 was as well prepared according to Dix and Vögtle [6]. With the dimeric malononitrile it afforded with good yield the magenta colored dye 6a (λ max = 524 nm, CH 3 CN).N-Phenyl-aza-18-crown-6 7 was synthesized according to Dix und Vögtle [6], and the corresponding aldehyde 8 similarly to the crown ether aldehyde 2 prepared by Vilsmeier formylation. Formation of side produc...