Halogen bonds in 2,5-dihalopyridine-copper(II) chloride complexes

Abstract
Ten coordination complexes obtained through a facile reaction between 2,5-dihalopyridines and copperIJII) chloride (CuCl2) are characterized using single crystal X-ray diffraction. Two series of dihalopyridine complexes based on 2-chloro-5-X-pyridine and 2-bromo-5-X-pyridine (X = F, Cl, Br and I) were prepared to analyze the C–X2/X5⋯Cl–Cu halogen bonds (XB). The influence of X2- and X5-substituents on the respective interactions was examined by comparing them to the X2/X3⋯Cl–Cu XBs found in mono-substituted halopyridine complexes, (n-X-pyridine)2·CuCl2 (n = 2, 3 and X = Cl, Br and I). Varying the X5-halogens in (2,5-dihalopyridine)2·CuCl2, the C5–X5⋯Cl–Cu XBs follow the order F5 < Cl5 < Br5 < I5 for X2 = Cl and Cl5 < Br5 < I5 for X2 = Br. The C2–X2⋯Cl–Cu XB distances did not follow any particular trends, and are slightly longer compared to corresponding distances in (2-halopyridine)2·CuCl2 complexes due to the competition of X2 and X5-halogen based halogen bonds. The C3–X3⋯Cl–Cu contacts in (3-halopyridine)2 ·CuCl2 have RXB values > 1 and they cannot be considered as halogen bonds. This proves the polarization effect of X2- to X5- rather than X5- to X2-halogen, and the introduction of second halogen substituent in para-position to X5- triggers C2–X2⋯Cl–Cu and C5–X5⋯Cl–Cu XB interactions.
Main Authors
Format
Articles Research article
Published
2018
Series
Subjects
Publication in research information system
Publisher
Royal Society of Chemistry
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-201805222703Use this for linking
Review status
Peer reviewed
ISSN
1466-8033
DOI
https://doi.org/10.1039/C8CE00209F
Language
English
Published in
CrystEngComm
Citation
  • Puttreddy, R., von Essen, C., Peuronen, A., Lahtinen, M., & Rissanen, K. (2018). Halogen bonds in 2,5-dihalopyridine-copper(II) chloride complexes. CrystEngComm, 20(14), 1954-1959. https://doi.org/10.1039/C8CE00209F
License
In CopyrightOpen Access
Funder(s)
Research Council of Finland
Research Council of Finland
Funding program(s)
Akatemiahanke, SA
Tutkijatohtori, SA
Academy Project, AoF
Postdoctoral Researcher, AoF
Research Council of Finland
Additional information about funding
The authors gratefully acknowledge financial support from the Academy of Finland (RP: grant no. 298817, ML: grant no. 277250) and the University of Jyväskylä.
Copyright© The Royal Society of Chemistry 2018

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