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Hydrogen bonding and fluorous weak interactions in the non‐isomorphous {4,4′‐bis[(2,2,3,3‐tetrafluoropropoxy)methyl]‐2,2′‐bipyridine‐κ 2 N , N ′}dibromidopalladium and ‐platinum complexes
Author(s) -
Lu Norman,
Kung Chih-Chieh,
Huang Jia-Yu,
Li Yu-Xuan,
Yang Chung-Kuang,
Wen Yuh-Sheng,
Liu Ling-Kang
Publication year - 2018
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618005715
Subject(s) - crystallography , dimer , chemistry , molecule , hydrogen bond , stacking , 2,2' bipyridine , crystal structure , stereochemistry , bipyridine , atom (system on chip) , organic chemistry , computer science , embedded system
The polyfluorinated title compounds, [ M Br 2 (C 18 H 16 F 8 N 2 O 2 )] or [4,4′‐(HCF 2 CF 2 CH 2 OCH 2 ) 2 ‐2,2′‐bpy] M Br 2 , ( 1 ) ( M = Pd and bpy is bipyridine) and ( 2 ) ( M = Pt), have –CH (α)2 OCH (β)2 CF 2 CF 2 H side chains with methylene H‐atom donors at the α and β sites, and methine H‐atom donors at the terminal sites, in addition to aromatic H‐atom donors. In contrast to the original expectation of isomorphous structures, ( 1 ) crystallizes in the space group C 2/ c and ( 2 ) in P 2 1 / n , with similar unit‐cell volumes and Z = 4. The asymmetric unit of ( 1 ) is one half of the molecule, which resides on a crystallographic twofold axis. Both ( 1 ) and ( 2 ) display stacking of the molecules, indicating a planar (bpy) M Br 2 skeleton in each case. The structure of ( 1 ) exhibits columns with C—H (β) …Br hydrogen bonds between consecutive layers which conforms to a static (β,β) linkage between layers. In the molecular plane, ( 1 ) shows double C—H (α) …Br hydrogen bonds self‐repeating along the b axis, the planar molecules being connected into infinite belts. Compound ( 2 ) has no crystallographic symmetry and forms π‐dimer pairs as supermolecules, which then stack parallel to the a axis. The π‐dimer‐pair supermolecules exhibit (Pt—)Br…Br(—Pt) contacts [3.6937 (7) Å] to neighbouring π‐dimer pairs crosslinking the columns. The structure of ( 2 ) reveals many C—H…F(—C) interactions between F atoms and aromatic C—H groups, in addition to those between F atoms and methylene C—H groups.