Synthesis and structure of the first clathrochelate iron(ii) tris-dioximates with inherent nitrile substituent(s) and new dehalogenation – reduction reaction at a quasi-aromatic macrobicyclic framework

Voloshin, Y.Z.; Belov, A.S.; Varzatskii, O.A.; Shul’ga, S.V.; Stuzhin, P.A.; Starikova, Z.A.; Lebed, E.G.; Bubnov, Y.N.

Авторы: Voloshin Yan Z., Belov Alexander S., Varzatskii Oleg A., Shul’ga Sergey V., Stuzhin Pavel A., Starikova Zoya A., Lebed Ekaterina G., Bubnov Yurii N.
Журнал: Dalton Transactions
Том: 41
Номер: 3
Год издания: 2012
Издательство: Royal Society of Chemistry
Местоположение издательства: United Kingdom
Первая страница: 921
Последняя страница: 928
DOI: 10.1039/c1dt11285f
Аннотация: Monoribbed-substituted mono- and dicyano-functionalized iron(II) macrobicycles were obtained for the first time by the reaction of iron(II) diiodoclathrochelate precursor with copper(I) cyanide–triphenylphosphine complex under mild conditions. The target dinitrile clathrochelate is a minor product of this reaction, whereas the major product contains only one cyano group. The clathrochelates obtained were characterized using elemental analysis, 1H and 13C{1H} NMR, IR and UV-vis spectroscopy, MALDI-TOF spectrometry and X-ray diffraction crystallography. The geometry of their FeN6-coordination polyhedra is intermediate between a trigonal prism (TP) and a trigonal antiprism (TAP); the distortion angles, j, are 22.6–24.7◦. In the molecule of the precursor, the Fe–N distances are close, whereas in the mononitrile macrobicycles those for their functionalized chelate fragments are substantially smaller than the corresponding distances in the a-benzyldioximate moieties. The heights, h, of the TP–TAP coordination polyhedra and the average bite angles, a, (2.33A˚ and 39◦, respectively) are the same for the X-rayed clathrochelates. The UV-vis spectra indicate a dramatic redistribution of the electron density in the p-conjugated clathrochelate framework caused by functionalization with inherent nitrile substituents. The proposed mechanism of the dehalogenation–reduction reaction of iron(II) diiodoclathrochelate resulting in substitution of their iodine atoms by a cyano group and hydrogen atom includes the anion-radical hydrodehalogenation of this precursor with acetonitrile as a source of hydrogen atom. Then, the monomethinemonoiodine macrobicyclic product underwent a substitution with a cyano group only. The copper(I) cyanide–triphenylphosphine–acetonitrile system is proposed as a tool for the synthesis of nitrile derivatives of electron-withdrawing heterocycles starting from their halogen-containing precursors.
Добавил в систему: Белов Александр Сергеевич

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Synthesis and structure of the first clathrochelate iron(ii) tris-dioximates with inherent nitrile substituent(s) and new dehalogenation – reduction reaction at a quasi-aromatic macrobicyclic frameworkстатья