The first monoribbed-functionalized tris-dioximate iron(II) clathrochelate with two inherent NH2-substituents, its reactivity, acid–base and coordination-chemical properties

• Published in: Inorganica Chimica Acta 2011-01, Vol.366 (1), p.91-97
• Main Authors: Vershinin, Mikhail A., Burdukov, Aleksei B., Boguslavskii, Evgenii G., Pervukhina, Nataliya V., Kuratieva, Nataliya V., Eltsov, Ilia V., Reznikov, Vladimir A., Varzatskii, Oleg A., Voloshin, Yan Z., Bubnov, Yurii N.
• Format: Article
• Language: English
• Subjects: Acido-ligands; Benzilic rearrangement; Clathrochelates; Copper complexes; Iron complexes; Ligand reactivity
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2010.10.012

The diamine bis-α-benzildioximate iron(II) clathrochelate with two inherent NH2-groups was obtained by nucleophilic substitution of the dichlorine-containing macrobicyclic precursor with liquid ammonia. The amino-groups undergo deprotonation, and the resulted clathrochelate dianions coordinate as the acido-ligands to copper(II) ion giving the heteronuclear copper(II)–iron(II) complex; its reaction with benzil afforded the clathrochelate with annulated heterocyclic piperazinone fragment as a result of benzilic-type rearrangement with 1,2-shift of the phenyl substituent. [Display omitted] ► The iron(II) clathrochelate with two inherent NH2-groups was obtained. ► Clathrochelate NH2-groups have an amide character and undergo deprotonation. ► The clathrochelate dianion is an acido-ligand and coordinates to copper(II) ion. ► The condensation of clathrochelate dianion with benzil gave piperazinone fragment. ► The reaction is benzilic-type rearrangement with 1,2-shift of the phenyl substituent. The diamine bis-α-benzildioximate iron(II) clathrochelate with two inherent NH2-groups at one of the three ribbed fragments was obtained in a high yield by nucleophilic substitution of the dichlorine-containing macrobicyclic precursor with liquid ammonia. These amino-groups have an essential amide character and undergo deprotonation in the presence of strong bases. The resulted clathrochelate dianion behaves as an acido-ligand and coordinates to copper(II) ion giving the heteronuclear copper(II)–iron(II) complexes with the Cu(N−)4 coordination polyhedron. The reaction of this dianion with benzil afforded the clathrochelate product with annulated heterocyclic ribbed piperazinone fragment as a result of benzilic-type rearrangement with 1,2-shift of the phenyl substituent. The complexes obtained have been characterized using elemental analysis, MALDI-TOF, IR, UV–Vis, multinuclear NMR and EPR spectra, and X-ray crystallography. N6-coordination polyhedra of their encapsulated iron(II) ions possess a distorted trigonal-prismatic geometry.