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Cobalt(II) coordination polymers with 4 '-substituted 4,2 ':6 ',4 ''- and 3,2 ':6 ',3 ''-terpyridines : engineering a switch from planar to undulating chains and sheets

Constable, Edwin C. and Housecroft, Catherine E. and Neuburger, Markus and Vujovic, Srboljub and Zampese, Jennifer A. and Zhang, Guoqi. (2012) Cobalt(II) coordination polymers with 4 '-substituted 4,2 ':6 ',4 ''- and 3,2 ':6 ',3 ''-terpyridines : engineering a switch from planar to undulating chains and sheets. CrystEngComm, 14 (10). pp. 3554-3563.

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Official URL: http://edoc.unibas.ch/dok/A6056195

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Abstract

Two new ligands 4`-(1H-imidazol-4-yl)-4,2`:6`,4 ``-terpyridine (3) and 4`-(4-dimethylaminophenyl)-3,2`:6`,3 ``-terpyridine (4) are described. Structure determination of 3 center dot CHCl3 reveals the assembly of hydrogen-bonded chains of molecules of 3; the preference for NHimidazole center dot center dot center dot N-tpy over NHimidazole center dot center dot center dot N-imidazole hydrogen bonds is consistent with the relative basicities of the heterocyclic rings. Reactions of Co(NCS)(2) with 4`-phenyl-4,2`:6`,4 ``-terpyridine (1), 4`-(4-ethynylphenyl)-4,2`:6`,4 ``-terpyridine (2) or 3, produce two-dimensional networks. In each, the Co2+ ion is in an octahedral trans-Co(N-tpy)(4)(NCS)(2) environment. [2Co(1)(2)(NCS)(2)center dot 5H(2)O(n)] and [Co(3)(2)(SCN)(2)center dot 2MeOH(n)] exhibit (4,4) nets. In [Co(2)(2)(NCS)(2)center dot 0.67C(2)H(4)Cl(2)center dot MeOH center dot H2O(n)], a (6,3) net is present. In all three coordination networks, there is substantial twisting of the 4,2`:6`,4 ``-terpyridine backbone and as a consequence, the dominant packing interactions are not the face-to-face pi-stacking of tpy domains that are ubiquitous in many solid-state structures containing metal-bound tpy domains. As a preliminary investigation of the effects of altering the directionality of the donor set in the terpyridine domain, Co(SCN)(2) was reacted with ligand 4, and the one-dimensional coordination polymer [Co(4)(MeOH)(2)(NCS)(2)(n)] was isolated. Ligand 4 adopts a trans, trans-arrangement and the zig-zag chains are undulating. The buckled sheets that result from the intermeshing of the chains contrast with the planar sheets observed in [Cd(5)(OH2)(2)(ONO2)(O2NO)center dot H2O(n)] (5 = 4`-(4-dimethylaminophenyl)-4,2`:6`,4 ``-terpyridine). The observed packing interactions suggest that the change from planar to undulating chains and sheets on going from 5 to 4 is a consequence of optimizing face-to-face pi-stacking interactions.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Anorganische Chemie (Constable)
05 Faculty of Science > Departement Chemie > Chemie > Anorganische Chemie (Housecroft)
UniBasel Contributors:Constable, Edwin Charles and Housecroft, Catherine Elizabeth and Neuburger, Markus
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Royal Society of Chemistry
e-ISSN:1466-8033
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:17 Nov 2016 14:34
Deposited On:01 Feb 2013 08:41

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