ARTICLE Studies of two different types of intramolecular C–HF–C interactions from polyfluorinated diiodometal(II) diimine complexes Norman Lu 1,2 | Jing-Hung Zheng 1 | Lei-Chin Lin 1,2 | Ling-Kang Liu 1 | Hsing-Fang Chiang 1 | Ting-You Li 2,3 | Yuh-Sheng Wen 4 | Chung-Kuang Yang 5 | Shih-Wen Chen 5 | Joseph S. Thrasher 3 1 Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei, Taiwan, Republic of China 2 Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei, Taiwan, Republic of China 3 Department of Chemistry, Advanced Materials Research Laboratory, Clemson University, Anderson, South Carolina 4 Institute of Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China 5 Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan, Republic of China Correspondence Norman Lu, Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei 106, Taiwan, Republic of China. Email: normanlu@mail.ntut.edu.tw Funding information Ministry of Science and Technology, Taiwan, Grant/Award Number: MOST 104-2113-M- 027-002-MY3; National Center for High- Performance Computing; Ministry of Science and Technology of Taiwan, Grant/Award Number: MOST 104-2113-M-027-002-MY3 The X-ray crystal structures of the polyfluorinated complexes [5,5 0 -bis (HCF 2 CF 2 CF 2 CF 2 CH 2 OCH 2 )-2,2 0 -bpy]MI 2 (55-8F-PtI 2 and 55-8F-PdI 2 where M = Pt and Pd, respectively) were obtained. These two structures are found to show not only two different types of intramolecular, six-membered cyclic C– HF–C interactions (F 2 C–HF–C and HC–HF–C) as important structural fea- tures but also alternating fluorinated and non-fluorinated layers. The F 2 C–HF–C interactions, which are close to the metal core, are much better structurally charac- terized in this type of complexes with fluorous ponytails at the 5,5 0 positions than those previously reported at the 4,4 0 positions. The molecular planes of (bpy)MI 2 are extended by self-matching, using two C–HI hydrogen bonds and one C– HF–C blue-shifting hydrogen bond. The F 2 C–HF–C hydrogen bonds interact at the supramolecular level such that one polyfluorinated ponytail of the title com- pounds is transoid without an intramolecular C–HF–C interaction, while the other polyfluorinated ponytail is cisoid with an intramolecular C–HF–C interac- tion. Why one ponytail is cisoidal while the other is transoidal will be explained. Furthermore, the second type of C–HF–C interactions involving the methylene H atom has been identified for the first time. In addition, these two metal structures are studied by density functional theory (DFT). KEYWORDS inorganic chemistry, organometallic chemistry, theoretical molecular science 1 | INTRODUCTION Fluorine-containing organic compounds are important because the C–F bond is among the strongest bonds known in organic chemistry, and fluorine-containing molecules exhibit very low polarizability, with the fluoro substituents lying most frequently at the periphery. [1] Fluorine, as the most electronegative element, is ubiquitously present in compounds of relevance to organic and pharmaceutical materials, where weak intramolecular or intermolecular interactions have been reported. [1,2] Compounds with a (bpy)MX 2 skeleton (bpy = 2,2 0 -bipyridine, M = Pt, Pd, X = Cl, Br, I) are interesting building blocks. The molecular connectivity of bpy chelated to Pt or Pd is stable, wherein bpy also allows the attachment of fluorous ponytails as sub- stituents. [3]. Efficient homogeneous catalysis on C–C cross- coupling reactions has been demonstrated using polyfluori- nated (bpy)PdCl 2 catalysts, allowing the recovery and reuse of the precious Pd catalysts multiple times with fluorous biphasic and/or thermomorphic methods. [4] The polyfluori- nated (bpy)MX 2 skeleton [4,5] has a molecular plane that, in the solid state, often exhibits strong ππ interactions with [Correction added on 24 October 2018, after first online publication: the country name for Taiwan has been correctly updated in this version]. Received: 30 April 2018 Revised: 16 August 2018 Accepted: 22 August 2018 DOI: 10.1002/jccs.201800161 © 2018 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim J Chin Chem Soc. 2018;1–10. http://www.jccs.wiley-vch.de 1