Oxazoles XXII.* The Cobalt(ii) Coordination Chemistry of 2-(ortho-Anilinyl)-4,4-dimethyl-2-oxazoline: Syntheses, Properties, and Solid-State Structural Characterization

Felix J. Baerlocher; Robert Bucur; Andreas Decken; Charles R. Eisnor; Robert A. Gossage; Sarah M. Jackson; Leslie Jolly; Susan L. Wheaton; R. Stephen Wylie

doi:10.1071/CH09259

RESEARCH ARTICLE

Oxazoles XXII.* The Cobalt(ii) Coordination Chemistry of 2-(ortho-Anilinyl)-4,4-dimethyl-2-oxazoline: Syntheses, Properties, and Solid-State Structural Characterization

Felix J. Baerlocher ^A , Robert Bucur ^B , Andreas Decken ^C , Charles R. Eisnor ^D ^E , Robert A. Gossage ^B ^F , Sarah M. Jackson ^D , Leslie Jolly ^B , Susan L. Wheaton ^A and R. Stephen Wylie ^B

+ Author Affiliations

- Author Affiliations

^A Department of Biology, Mount Allison University, 63B York Street, Sackville NB E4 L 1G7, Canada.

^B Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto ON M5B 2K3, Canada.

^C Department of Chemistry, University of New Brunswick, Fredericton NB E3B 6E2, Canada. Corresponding author for the crystallographic work. Email: adecken@unb.ca

^D Department of Chemistry, Acadia University, Wolfville NS B4P 2R6, Canada.

^E Deceased 10 September 2006.

^F Corresponding author. Email: gossage@ryerson.ca

Australian Journal of Chemistry 63(1) 47-55 https://doi.org/10.1071/CH09259
Submitted: 30 April 2009 Accepted: 13 June 2009 Published: 8 January 2010

Abstract

Ethanol solutions of the cobalt(ii) halides react with an excess of 2-(ortho-anilinyl)-4,4-dimethyl-2-oxazoline (1: i.e. 2-(2′-anilinyl)-4,4-dimethyl-4,5-dihydro-1,3-oxazole) to give isolable κ²-N,N′-bonded species of 1 in good to excellent yields. The complexes CoX₂(1-κ²-N,N′)·(H₂O)_n have been isolated for X = Cl (2: n = 1/2), X = Br and I (3 and 4, respectively; n = 0); the solid-state structures (X-ray) are in accordance with those suggested by UV-visible spectroscopy and conductivity measurements (i.e. non-ionic complexes with a pseudo-tetrahedral coordination motif around Co). In contrast, reaction of excess 1 with Co(NCS)₂ forms the octahedral (UV-visible, X-ray) bis-isothiocyanato complex Co(NCS-κ¹-N′)₂(1-κ²-N,N′)₂ (5) with cis-oriented NCS groups and trans-disposed oxazolines. Calculations at the PM3(tm) level of theory suggest that this isomer is close in energy to the four other possible (gas-phase) isomers. Treatment of ethanol solutions of hydrated cobaltous nitrate with excess 1 yields a material analyzed as [Co(NO₃)(1)(H₂O)₂](NO₃) (6a) and a small amount (less than 1%) of a second complex (6b); the latter has been characterized (X-ray) as the hydrated octahedral complex [Co(NO₃-κ¹-O)(1-κ²-N,N′)₂(OH₂)](NO₃). In this case, the nitrato and aqua groupings are located cis to one another and trans to the coordinated –NH₂ groups. Complex 6a is surmised to have a [Co(NO₃-κ²-O,O′)₂(1-κ²-N,N′)(OH₂)₂]NO₃ structure. Cobalt compounds 2–5 and 1 have also been screened for their antifungal properties against Aspergillus niger, Aspergillus flavus, Candida albicans, and Saccharomyces cerevisiae but were found to be inactive in this regard.

Acknowledgements

The authors are indebted for the support of Ryerson University, Acadia University and the Natural Sciences and Engineering Research Council (NSERC Canada). Mr. K. E. Kershaw and Mr. M. J. Hughes (Acadia University) are thanked for their syntheses of samples of 1 that were used in this study. Dr Jenny Field (Cambridge Crystallographic Data Centre) is also thanked for her contributions to this research. R.A.G. is further indebted to the Royal Society of Chemistry for provision of a J. W. T. Jones Travelling Fellowship that allowed the author to complete sections of this manuscript during sabbatical leave at the University of Tasmania.

References

^* Part XXI: R. A. Gossage, H. A. Jenkins, J. W. Quail, J. Chem. Crystallogr., accepted pending minor revisions.

Oxazoles XXII.* The Cobalt(ii) Coordination Chemistry of 2-(ortho-Anilinyl)-4,4-dimethyl-2-oxazoline: Syntheses, Properties, and Solid-State Structural Characterization

Abstract

Acknowledgements

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