Published data on the synthesis and structural modification of spiropyrans and bisspiropyrans and production of the heteroanalogs of spiropyrans are classified and analyzed. The chemical characteristics of spiropyrans, including complexation of the open-chain isomers and cyclic forms are examined. Special attention is paid to the photochromic characteristics of spiropyrans at interfaces between phases.

In mammals, a C2H2 zinc finger (C2H2) protein, CTCF, acts as the master regulator of chromosomal architecture and of the expression of Hox gene clusters. Like mammalian CTCF, the Drosophila homolog, dCTCF, localizes to boundaries in the bithorax complex (BX-C). Here, we have determined the minimal requirements for the assembly of a functional boundary by dCTCF and two other C2H2 zinc finger proteins, Pita and Su(Hw). Although binding sites for these proteins are essential for the insulator activity of BX-C boundaries, these binding sites alone are insufficient to create a functional boundary. dCTCF cannot effectively bind to a single recognition sequence in chromatin or generate a functional insulator without the help of additional proteins. In addition, for boundary elements in BX-C at least four binding sites for dCTCF or the presence of additional DNA binding factors is required to generate a functional insulator.

Complexation of lanthanide ions {Ln(III) ions [Tb(III), Eu(III), or Sm(III)]} with the spiropyran-derived merocyanine obtained in dark and under steady irradiation of indoline spiropyran (1,3,3-trimethyl-5′-hydroxy-6′-formyl-indoline-spiro-2,2′-[2H]chromene) induces a noticeable hypsochromic shift of about 10–110 nm of its visible absorption band concomitant with hypochromic effect and influences its thermal bleaching in the dark. The effect of lanthanide ions and medium on photochromic, spectral-and-kinetic, and luminescence properties of the spiropyran and its complexes in solution and polymer matrix of polymethylmethacrylate (PMMA) is studied. Efficient energy transfer from the spiropyran moiety results in efficient typical luminescence from the Ln(III) ion that becomes more pronounced in polar nonalcoholic solvents and PMMA solid matrix. Moreover, luminescence mappings for pattern recognition analysis have been obtained from which the nature of the solvent and/or the ligand is clearly identified.

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