A1 Journal article (refereed)
Hydrogen and Halogen Bond Mediated Coordination Polymers of Chloro-Substituted Pyrazin-2-Amine Copper(I) Bromide Complexes (2020)

Mailman, A., Puttreddy, R., Lahtinen, M., Svahn, N., & Rissanen, K. (2020). Hydrogen and Halogen Bond Mediated Coordination Polymers of Chloro-Substituted Pyrazin-2-Amine Copper(I) Bromide Complexes. Chemistry, 2(3), 700-713. https://doi.org/10.3390/chemistry2030045

JYU authors or editors

Publication details

All authors or editors: Mailman, Aaron; Puttreddy, Rakesh; Lahtinen, Manu; Svahn, Noora; Rissanen, Kari

Journal or series: Chemistry

eISSN: 2624-8549

Publication year: 2020

Publication date: 05/08/2020

Volume: 2

Issue number: 3

Pages range: 700-713

Publisher: MDPI AG

Publication country: Switzerland

Publication language: English

DOI: https://doi.org/10.3390/chemistry2030045

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/71366

Abstract

A new class of six mono- (1; 3-Cl-, 2; 5-Cl-, 3; 6-Cl-) and di-(4; 3,6-Cl, 5; 5,6-Cl-, 6; 3,5-Cl-) chloro-substituted pyrazin-2-amine ligands (1–6) form complexes with copper (I) bromide, to give 1D and 2D coordination polymers through a combination of halogen and hydrogen bonding that were characterized by X-ray diffraction analysis. These Cu(I) complexes were prepared indirectly from the ligands and CuBr2 via an in situ redox process in moderate to high yields. Four of the pyrazine ligands, 1, 4–6 were found to favor a monodentate mode of coordination to one CuI ion. The absence of a C6-chloro substituent in ligands 1, 2 and 6 supported N1–Cu coordination over the alternative N4–Cu coordination mode evidenced for ligands 4 and 5. These monodentate systems afforded predominantly hydrogen bond (HB) networks containing a catenated (μ3-bromo)-CuI ‘staircase’ motif, with a network of ‘cooperative’ halogen bonds (XB), leading to infinite polymeric structures. Alternatively, ligands 2 and 3 preferred a μ2-N,N’ bridging mode leading to three different polymeric structures. These adopt the (μ3-bromo)-CuI ‘staircase’ motif observed in the monodentate ligands, a unique single (μ2-bromo)-CuI chain, or a discrete Cu2Br2 rhomboid (μ2-bromo)-CuI dimer. Two main HB patterns afforded by self-complimentary dimerization of the amino pyrazines described by the graph set notation R22(8) and non-cyclic intermolecular N–H∙∙∙N’ or N–H∙∙∙Br–Cu leading to infinite polymeric structures are discussed. The cooperative halogen bonding between C–Cl∙∙∙Cl–C and the C–Cl∙∙∙Br–Cu XB contacts are less than the sum of the van der Waals radii of participating atoms, with the latter ranging from 3.4178(14) to 3.582(15) Å. In all cases, the mode of coordination and pyrazine ring substituents affect the pattern of HBs and XBs in these supramolecular structures.

Keywords: chemical bonds; hydrogen bonds; halogens

Free keywords: hydrogen bond; halogen bond; pyrazine; chloropyrazine; chloropyrazin-2-amine; copper halide

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Ministry reporting: Yes

Reporting Year: 2020

JUFO rating: 1