caa a22 4500 46324026X CHVBK 20180405153310.0 cr unu---uuuuu 170326e20070901xx s 000 0 eng 10.1007/s10947-007-0135-4 doi (NATIONALLICENCE)springer-10.1007/s10947-007-0135-4 Molecular and crystal structure of di-and hexamethine merocyanine dyes — derivatives of 3 H -indole and malononitrile — manifesting positive solvatochromism [Elektronische Daten] [A. Kulinich, A. Ishchenko, S. Shishkina, I. Konovalova, O. Shishkin] Single crystal X-ray diffraction and IR spectroscopy are applied to examine the molecular and crystal structures of 2-[(2E)-2-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidine)ethylidene]-malononitrile (1) and 2-[(2E, 4E,6E)-6-2-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidine)-2,4-hexadienylidene]-malononitrile (2). It is shown that both in solution and crystalline state the studied merocyanines completely retain the trans-conformation and approach a neutral polyene. It is found that the polyene character is increased in transition from di-to hexamethinemerocyanine, which is caused by a partial violation of conjugation with the nitrogen lone pair due to its slight deviation from the plane of the chromophore. It is demonstrated that the stretching vibration frequency of the nitrile group in the IR spectra of malononitrile merocyanines can be used to examine polyene-polymethine electron relaxations. Electronic and spatial structures of merocyanine molecules are calculated by AM1, PM3, and ab initio methods. Theoretical results are compared to experimental ones. Springer Science+Business Media, Inc., 2007 merocyanines nationallicence single crystal X-ray diffraction nationallicence conformation nationallicence IR spectroscopy nationallicence quantum chemical calculations nationallicence Kulinich A. Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv aut Ishchenko A. Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv aut Shishkina S. Scientific Technical Corporation "Institute for Single Crystals”, National Academy of Sciences of Ukraine, Kharkov aut Konovalova I. Scientific Technical Corporation "Institute for Single Crystals”, National Academy of Sciences of Ukraine, Kharkov aut Shishkin O. Scientific Technical Corporation "Institute for Single Crystals”, National Academy of Sciences of Ukraine, Kharkov aut Journal of Structural Chemistry Springer US 48/5(2007-09-01), 914-921 0022-4766 48:5<914 2007 48 10947 https://doi.org/10.1007/s10947-007-0135-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10947-007-0135-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kulinich A. Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv aut NATIONALLICENCE 700 1- Ishchenko A. Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv aut NATIONALLICENCE 700 1- Shishkina S. Scientific Technical Corporation "Institute for Single Crystals”, National Academy of Sciences of Ukraine, Kharkov aut NATIONALLICENCE 700 1- Konovalova I. Scientific Technical Corporation "Institute for Single Crystals”, National Academy of Sciences of Ukraine, Kharkov aut NATIONALLICENCE 700 1- Shishkin O. Scientific Technical Corporation "Institute for Single Crystals”, National Academy of Sciences of Ukraine, Kharkov aut NATIONALLICENCE 773 0- Journal of Structural Chemistry Springer US 48/5(2007-09-01), 914-921 0022-4766 48:5<914 2007 48 10947 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer