1. Difluorenylsilanes, -germanes, and -stannanes Exhibiting an Unprecedented Parallel Arrangement of the Fluorene Units
- Author
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Gabriela Nemes, Kieran C. Molloy, Ioan Silaghi-Dumitrescu, Mary F. Mahon, Luminita Silaghi-Dumitrescu, Julio Zukerman-Schpector, Henri Ranaivonjatovo, Jean Escudié, Babes bolyai, UNIVERSITE KOGALNICEANU, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), department of Chemistry, University of Bath [Bath], DEPARTAMENTO DE QUIMICA, and Universidade Federal de Sao Carlos
- Subjects
Carbon group ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,010405 organic chemistry ,Chemistry ,Stereochemistry ,Aryl ,Organic Chemistry ,Supramolecular chemistry ,Crystal structure ,Fluorene ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,NMR spectra database ,chemistry.chemical_compound ,Crystallography ,Intramolecular force ,Molecular orbital ,Physical and Theoretical Chemistry ,ComputingMilieux_MISCELLANEOUS - Abstract
New, yet unprecedented molecular structures with parallel fluorene units were found by X-ray diffraction in (9,9'-disubstituted difluorenyl)(dimethyl) derivatives of group 14 elements Me 2 E(CR'R 2 )(CR"R 2 ) (E = Si, R' = Me, R" = SiMe 3 , 6a; E = Ge, R' = Me, R" = SiMe 3 , 6b; and E = Sn, R' = R" = SiMe 3 , 5c; CR 2 = fluorene units). This is in sharp contrast with the structure of monosubstituted Me 2 Ge(CHR 2 )(CR 2 -SiMe 3 ) (3b) and disubstituted Me 2 E(CMeR 2 ) 2 (E = Ge, 4b; E = Sn, 4c) derivatives where the two fluorene units are almost perpendicular. Intramolecular C-H...π interactions are revealed by solution 1 H NMR spectroscopy and supported by the AM1 molecular orbital calculations. Intermolecular (aryl, alkyl)C-H...π interactions leading to supramolecular associations are shown by the crystal structures of 3b, 4b, 4c, 5c, and 6a. In 4b and 5c rather unusual CH...HC distances resembling the "dihydrogen" bonds are noticed. Synthesis, NMR spectra, and gas phase conformations predicted on the basis of AM1 semiempirical molecular orbital calculations are discussed for Me 2 E(CR"R 2 )(CR"R 2 ) (E = Si, R' = R" = SiMe 3 , 5a; E = Ge, R' = R" = SiMe 3 , 5b; E = Sn, R' = H, R" = Me, 2c; R' = H, R" = SiMe 3 , 3c; R' = Me, R" = SiMe 3 , 6c; CR 2 = fluorene units).
- Published
- 2005
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