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Side‐chain conformations in the isomorphous polyfluorinated {4,4′‐bis[(2,2‐difluoroethoxy)methyl]‐2,2′‐bipyridine‐κ 2 N , N ′}dichloridopalladium and ‐platinum complexes
Author(s) -
Lu Norman,
Zheng Jing-Hung,
Lu Yi-Jing,
Chiang Hsing-Fang,
Chu Chun-Wei,
Thrasher Joseph S.,
Wen Yuh-Sheng,
Liu Ling-Kang
Publication year - 2017
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/s2053229617013857
Subject(s) - dimer , chemistry , crystallography , molecule , hydrogen bond , stereochemistry , platinum , metal , catalysis , biochemistry , organic chemistry
The polyfluorinated title compounds, [ M Cl 2 (C 16 H 16 F 4 N 2 O 2 )] or [4,4′‐(HCF 2 CH 2 OCH 2 ) 2 ‐2,2′‐bpy] M Cl 2 [ M = Pd, ( 1 ), and M = Pt, ( 2 )], have –C(H α ) 2 OC(H β ) 2 CF 2 H side chains with H‐atom donors at the α and β sites. The structures of ( 1 ) and ( 2 ) are isomorphous, with the nearly planar (bpy) M Cl 2 molecules stacked in columns. Within one column, π‐dimer pairs alternate between a π‐dimer pair reinforced with C—H…Cl hydrogen bonds (α,α) and a π‐dimer pair reinforced with C—H β …F(—C) interactions (abbreviated as C—H β …F—C,C—H β …F—C). The compounds [4,4′‐(CF 3 CH 2 OCH 2 ) 2 ‐2,2′‐bpy] M Cl 2 [ M = Pd, ( 3 ), and M = Pt, ( 4 )] have been reported to be isomorphous [Lu et al. (2012). J. Fluorine Chem. 137 , 54–56], yet with disorder in the fluorous regions. The molecules of ( 3 ) [or ( 4 )] also form similar stacks, but with alternating π‐dimer pairs between the (α,β; α,β) and (β,β) forms. Through (C—)H…Cl hydrogen‐bond interactions, one molecule of ( 1 ) [or ( 2 )] is expanded into an aggregate of two inversion‐related π‐dimer pairs, one pair in the (α,α) form and the other pair in the (C—H β …F—C,C—H β …F—C) form, with the plane normals making an interplanar angle of 58.24 (3)°. Due to the demands of maintaining a high coordination number around the metal‐bound Cl atoms in molecule ( 1 ) [or ( 2 )], the ponytails of molecule ( 1 ) [or ( 2 )] bend outward; in contrast, the ponytails of molecule ( 3 ) [or ( 4 )] bend inward.