A Synthetic and X-ray Crystallographic Study of Zinc and Platinum Complexes of 4,5-Diazafluoren-9-one (Dafone) and Dicobalt Hexacarbonyl Derivatives of 9-Phenylethynyl-4,5-Diazafluoren-9-ol: Chelation versus Monocoordination
✍ Scribed by Linda Maguire; Corey M. Seward; Sladjana Baljak; Thea Reumann; Yannick Ortin; Emilie Banide; Kirill Nikitin; Helge Müller-Bunz; Michael J. McGlinchey
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 837 KB
- Volume
- 2009
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
Reaction of 4,5‐diazafluoren‐9‐one (dafone, 6) and zinc dichloride yields [(dafone)ZnCl~2~(H~2~O)] (11) in which the ZnCl~2~ moiety is coordinated to a single nitrogen atom and also to a molecule of water. Hydrogen bonding, not only to the uncomplexed nitrogen atom of dafone but also to the ketonic oxygen atom of a neighbouring molecule, leads to a zigzag chain structure. In contrast, reaction with anhydrous zinc iodide forms cis‐(dafone)~2~ZnI~2~ (12) in which the metal–nitrogen distances – 2.170(5) and 2.456(5) Å – are significantly different. Dafone, in the presence of dimethyl sulfoxide, reacts with K~2~PtCl~4~ to produce square‐planar (dafone)PtCl~2~(dmso) (13), whereas with K~2~PtBr~6~ the octahedral complex (dafone)PtBr~4~ (14) is formed in which the ligand chelates in a symmetrical fashion. Treatment of dafone with phenylethynyllithium furnishes 9‐phenylethynyl‐4,5‐diazafluoren‐9‐ol (7), which forms a square‐planar nitrogen‐bonded PtCl~2~ complex, 15. Reaction of 7 with Co~2~(CO)~8~ yields the (μ‐alkyne)hexacarbonyldicobalt cluster 17, which undergoes protonation at the nitrogen atom to form 20 rather than at the alcohol to form a cobalt‐complexed propargyl cation. Alkynol 7 also reacts with HBr by addition across the triple bond to form Z‐9‐[(2‐bromo‐2‐phenyl)ethenyl]‐4,5‐diazafluoren‐9‐ol (10). X‐ray crystal structures are reported for 6, 7, 10–15, 17 and 20, and their differing hydrogen‐bonding motifs are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)