Perfluorocarbon-Hydrocarbon Discrete Intermolecular Aggregates: An Exceptionally Short N⋯I Contact |
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Authors: | Francesca Fontana Alessandra Forni Pierangelo Metrangolo Walter Panzeri Tullio Pilati Giuseppe Resnati |
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Institution: | 1. Department of Engineering , University of Bergamo , 5, viale Marconi, Dalmine , I-24044 , BG , Italy;2. C.N.R.--Centro Studio Relazioni Struttura Reattività Chimica , Università di Milano , 19, via Golgi, Milano , I-20133 , Italy;3. Department of Chemistry , Polytechnic , 7, via Mancinelli, Milan , I-20131 , Italy;4. C.N.R.--Centro Studio Sostanze Organiche Naturali , Politecnico di Milano, 7 via Mancinelli, Milano , I-20131 , Italy |
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Abstract: | 1-Iodoperfluoroheptane ( 1a ) and tetramethylethylenediamine ( 2 , TMEDA) form the 2:1 ratio stable aggregate 3a and a similar behaviour is shown by 1-iodoperfluoroalkanes 1b-e and iodopentafluorobenzene 1f . These aggregates have been characterised in solution by 1 H/ 19 F-NMR spectroscopy and in the solid state through IR and single crystal X-ray diffraction. The determined structure of 3a (triclinic, a =6.2283(10), b =9.250(2), c =15.098(3) Å, f =81.369(5), g =81.397(5), n = 86.010(5), V =849.3(3) A m 3 , T =175(3) K, space group P-1 (No. 2), Z =1; d (calc)=2.167 g cm m 3 ; 4121 independent reflections, 3665 with I o >2( I o ); final refinement gave R1=0.0400, wR2=0.0901) showed the second shortest N > I interaction found in the crystallographic literature 2.762(3) Å] and the interdigitation of perfluorocarbon and hydrocarbon modules due to co-operative -C-H > F-C- interactions. Calculations to quantify these latter interactions have been also performed. |
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Keywords: | Halogen Bonding Perfluoroalkyl Chains Thin Films -C-H?F-C- Contacts |
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