Solvent-Induced Structural Changes in Complexes of 1,2-Bis(3-(3-pyridyl)pyrazolyl)ethane

Yuniar P. Prananto; David R. Turner; Jinzhen Lu; Stuart R. Batten

doi:10.1071/CH08483

RESEARCH ARTICLE

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Solvent-Induced Structural Changes in Complexes of 1,2-Bis(3-(3-pyridyl)pyrazolyl)ethane

Yuniar P. Prananto ^A , David R. Turner ^A , Jinzhen Lu ^A and Stuart R. Batten ^A ^B

+ Author Affiliations

- Author Affiliations

^A School of Chemistry, Monash University, Clayton, Vic. 3800, Australia.

^B Corresponding author. Email: stuart.batten@sci.monash.edu.au

Australian Journal of Chemistry 62(2) 108-114 https://doi.org/10.1071/CH08483
Submitted: 5 November 2008 Accepted: 7 December 2008 Published: 19 February 2009

Abstract

A series of complexes have been obtained using the flexible ditopic ligand 1,2-bis(3-(3-pyridyl)pyrazolyl)ethane (L^Et) with M(SCN)₂ (M = Co, Fe) and ZnCl₂. The ligand is observed to exist in a variety of conformations with rotations around the ethane spacer and around the pyridyl/pyrazole bond. The bridging length of the ligand (i.e., distance between pyridyl nitrogen atoms) varies by 3.5 Å depending on its geometry. Three different cobalt(ii) complexes of the general form [Co(L^Et)₂(SCN)₂]·Solv (where Solv is a variable number/type of non-coordinated solvent) have been structurally characterized and form a series of solvent dependant supramolecular isomers. When Solv = 2MeCN a (4,4)-sheet is formed (1), however, when Solv = H₂O an alternate ‘collapsed’ (4,4)-sheet is observed (2). Changing the solvent to two molecules of N,N-dimethylformamide (DMF) leads to a radical change in structure with a one-dimensional (1D) polymer formed (3) that contains two bridging ligands between adjacent metal atoms (i.e., maintaining the same metal/ligand ratio as in the (4,4)-sheet structures). A monomeric thiocyanate complex [Fe(L^Et)₂(SCN)₂(H₂O)₂] (4) is reported in which the bispyridyl ligands are terminal and partake in an extended hydrogen-bonded network. A 1D polymer [Zn(L^Et)Cl₂] (5) is also presented. The structures of the metal complexes are contrasted with that of the free ligand.

Acknowledgements

The authors thank the Australian Research Council for funding and for a post-doctoral fellowship (D.R.T.). Y.P.P. acknowledges an ADS scholarship.

References

Solvent-Induced Structural Changes in Complexes of 1,2-Bis(3-(3-pyridyl)pyrazolyl)ethane

Abstract

Acknowledgements

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