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  • 1
    Electronic Resource
    Electronic Resource
    Dependence of metal ion complexation and intermolecular aggregation on photoinduced geometric isomerism in a crown ether styryl dye (1992)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 114 (1992), S. 6381-6385 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00042a013
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  • 2
    Electronic Resource
    Electronic Resource
    Derivatization and Template-Guided Ligation of Oligodeoxyribonucleotides Using Cyanogen Bromide and N-Substituted Morpholines (1997)
    Springer
    Origins of life and evolution of the biospheres 27 (1997), S. 555-566 
    Details
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Cyanogen bromide has been found to induce the template-guided condensation of oligonucleotides only in the presence of N-substituted morpholines. Based on 31 P,1 H and13 C NMR spectroscopy data, the mechanism of the phosphomonoester group activation by cyanogen bromide in N-substituted morpholine buffers is suggested. It has also been shown that BrCN can be used for the synthesis of oligonucleotide derivatives in aqueous solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006577107354
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  • 3
    Electronic Resource
    Electronic Resource
    Crown-ether styryl dyes (1995)
    Springer
    Russian chemical bulletin 44 (1995), S. 2131-2136 
    Details
    ISSN: 1573-9171
    Keywords: crown ether styryl dyes ; complex-formation ; [2+2]-photocycloaddition ; cyclobutane derivatives ; 1H NMR spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Styryl dyes (4a,b) containing a 15-crown-5 fragment and isomeric 2- and 4-quinolinium residues with anN-sulfopropyl substituent undergo [2+2]-autophotocycloaddition to give cyclobutane derivatives (9a,b) in acetonitrile only in the presence of Mg(ClO4)2 or Ca(ClO4)2. The stereospecificity of both pathways of photocycloaddition and its efficiency are explained by the preorganization of the supramolecular dimers derived from thetrans-isomers of the dyes when they are bound into complexes with Mg and Ca cations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00696719
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  • 4
    Electronic Resource
    Electronic Resource
    Novel synthesis of benzocrown ethers formylated in the benzene ring (1993)
    Springer
    Russian chemical bulletin 42 (1993), S. 960-961 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698974
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  • 5
    Electronic Resource
    Electronic Resource
    Crown-containing styryl dyes (1993)
    Springer
    Russian chemical bulletin 42 (1993), S. 1385-1389 
    Details
    ISSN: 1573-9171
    Keywords: crown-containing styryl dyes ; complexes with Mg2+ ; photocyclodimerization ; cyclobutane derivatives ; 1H and13C NMR spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Styryl dyes containing a crown ether group and a heteroaromatic moiety with a sulfoalkylN-substituent (1a,b) undergo photocyclodimerization in acetonitrile in the presence of Mg(ClO4)2 to give only the typeA isomer of cyclobutane derivative (2a,b). The photochemical regio- and stereoselectivity of the cycloaddition is explained by self-organization of thetrans-isomers of the styryl dyes upon complexation with the Mg2+ cations into dimers with a fixed mutual arrangement of multiple bonds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00699938
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis of formyl derivatives of benzocrown ethers containing N, S, and O heteroatoms in the macrocycle (1995)
    Springer
    Russian chemical bulletin 44 (1995), S. 116-123 
    Details
    ISSN: 1573-9171
    Keywords: 4′-bromobenzocrowns, synthesis, metallation ; 4′-formylbenzocrown ethers ; semicarbazones and oximes of 4′-formylbenzocrown ethers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method for the synthesis of 4′-bromobenzodithia-15(18)-crown-5(6) and 4′-bromobenzodiaza-15 (18)-crown-5(6) by condensation of 3,4-di(2′-haloethoxy)bromobenzene with polyoxaalkanes containing terminal SH or NHMe groups was suggested. The method for the synthesis of formyl derivatives of benzocrowns containing N, S, and O heteroatoms in the macrocycle based on the metallation of appropriate bromo derivatives with BunLi followed by treatment of the resulting organolithium intermediates with DMF was developed. Oximes and semicarbazones of benzaldehydes containing a crown ether fragment were obtained, and their transformation into the original aldehydes by treatment with KNO2 in an acid medium was studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00696971
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  • 7
    Electronic Resource
    Electronic Resource
    Crown-ether styryl dyes (1995)
    Springer
    Russian chemical bulletin 44 (1995), S. 2323-2330 
    Details
    ISSN: 1573-9171
    Keywords: surface enhanced Raman scattering (SERS) ; crown-ether styryl dyes ; complexes with Mg2+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The surface enhanced Raman scattering (SERS) spectra of styryl dyes containing a crown-ether group and a heteroaromatic residue with sulfoalkyl (1a) or alkyl (1b)N-substituent and of their complexes with Mg2+ cations were recorded in the 10−4–10−8 mol L−1 concentration range. A model for the interaction of compoundsla,b with a silver surface during their adsorption on an electrochemically treated electrode was suggested. Fastcis-trans relaxation of the adsorbed molecules1a,b and complexes (1a,b)Mg2+ was found. It was shown that at [1a] = 10−5 mol L−1 and moderate molar ratios (C Mg/[1a] = 3/1 to 9/1) in acetonitrile solutions, (trans-1a)Mg2+ complexes are joined into head-to-tail type dimers. An excess of Mg2+ cations (CMg/[1a] 〉 100) leads to dissociation of the dimers yielding (trans-1a)(Mg2+)2 complexes. The formation of dimers from complexes (trans-1a)Mg2+ is accompanied by a substantial distortion of the planar structure oftrans-1a. This may be an important factor influencing the efficiency of photocycloaddition involving dimers of (trans-1a)Mg2+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713602
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  • 8
    Electronic Resource
    Electronic Resource
    Crown ether styryl dyes (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 564-572 
    Details
    ISSN: 1573-9171
    Keywords: crown ether styryl dyes ; Mg2+, Ca2+, and Ba2+ complexes ; stability constants ; dimerization constant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The stoichiometry of complexation of crown ether styryl dyes with Mg2+, Ca2+, and Ba2+ ions and the dependence of the stability constants of these complexes on the length of theN-sulfoalkyl substituent were investigated. Introduction of a terminal sulfo group into theN-ethyl substituent had but a small effect on the stability constant for the complexes with 1 : I stoichiometry. Increase in the length of theN-substituent by one or two methylene groups resulted in a jumpwise rise of this constant. The effect observed was attributed to the formation of the intramolecular ion pair. The dimerization constant for Mg2+ complexes increased dramatically when passing from the sulfopropylN-substituent to the sulfobutyl one. The increase in the constant results from the decrease in steric strains in the dimeric complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01435783
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  • 9
    Electronic Resource
    Electronic Resource
    Macrocycle opening in crown ethers (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 648-653 
    Details
    ISSN: 1573-9171
    Keywords: 4′-formylbenzocrown ethers ; macrocycle opening ; alkylamines ; podands ; complex formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Macrocycle opening in derivatives of benzocrown ethers under the action of amines is affected by the nature of the heteroatoms in the macrocycle, the nature of the functional group in the benzene ring of the crown ether, and the length, branching, and number of hydrocarbon radicals at the amine nitrogen atom. A distinguishing feature of this reaction is the template effect of MeNH3 +, Me2NH2 +, Na+, and K+ ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01435799
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  • 10
    Electronic Resource
    Electronic Resource
    Crown ether styryl dyes (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 654-661 
    Details
    ISSN: 1573-9171
    Keywords: crown ether styryl dyes ; synthesis ; complexation ; anion-“capped” complexes ; [2+2] photocycloaddition ; cyclobutane derivatives ; 1H NMR spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract New crown ether styryl dyes (trans-1c,d) containing the 18-crown-6 ether fragment were synthesized. Interaction oftrans-1c,d dyes, as well as their analogs,trans-1a,b containing the 15-crown-5 ether fragment, with Ca(ClO4)2 in MeCN afforded supramolecular structures (dimeric complexes). Competing reactions,trans-cis-photoisomerization with the formation of anion-“capped” complexes ofcis-1a—d and [2+2] autophotocycloaddition with the formation of cyclobutane derivatives8a—d and9c, were observed on photolysis of solutions of complexes oftrans-1a—d with Ca2+. Preorganization oftrans-isomers in dimeric complexes with Ca2+ determined the regio- and stereoselectivity of each of the two directions of the photocycloaddition and the efficiency of the reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01435800
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