8-Dioxane ferra(III) bis(dicarbollide): A paramagnetic functional molecule as versatile building block for introduction of a Fe(III) centre into organic molecules

The synthesis of a new, paramagnetic closo-[(8-(-CH2CH2O)2-1,2-C2B9H10)(1′,2′-C2B9H11)-3,3′-Fe]0 (3) is reported. This compound can serve as a versatile building block for construction of both anionic and zwitterionic derivatives, as exemplified by the synthesis of a series of compounds of general formula closo-[(8-X-(CH2CH2O)2-1,2-C2B9H10)(1′,2′-C2B9H11)-3,3′-Fe], bearing organic end groups (X = NC5H5 (4), (C6H5)3P (5), OH (6), and 2-O(1-CH3O–C6H4) (7)) attached to the cluster by a diethyleneglycol spacer. Molecular structures of 3, 4, 5 and 7 were determined by single-crystal X-ray diffraction analysis and by the long-time neglected method of paramagnetic, high field NMR (1H, 13C and 11B) spectroscopy.

Graphical abstractCluster substitution of the ferra(III) bis(dicarbollide)(1-) ion by dioxane followed by ring opening generates conveniently a new series of compounds in which an organic group is attached to the boron cluster via diethyleneglycol spacer. This opens up new synthetic strategies for the preparation of paramagnetic, Fe(III)-labelled compounds which are not accessible by other synthetic methods.Figure optionsDownload full-size imageDownload as PowerPoint slide