Iron(II) Mediated Deazotation of Benzyl Azide: Trapping and Subsequent Transformations of the Benzaldimine Fragment

Zars E, Gravogl L, Gau M, Carroll PJ, Meyer K, Mindiola DJ (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Inorganic Chemistry American Chemical Society

DOI: 10.1021/acs.inorgchem.1c03243

Abstract

The mono-benzaldimine (HN=CHPh) complex [((tBu)pyrpyrr2)Fe(HN=CHPh)] (1-HN=CHPh) has been prepared by reaction of [((tBu)pyrpyrr2)Fe(OEt2)] (1-OEt2) ((tBu)pyrpyrr(2) = 2,6-bis(3,5-di-tert-butyl-pyrrolyl)pyridine) with one equivalent of benzyl azide. Compound 1-HN=CHPh retains the cis-divacant octahedral coordination geometry akin to 1, as established by single crystal X-ray diffraction study. A bis-HN=CHPh complex [((tBu)pyrpyrr(2))Fe(HN=CHPh)2] (2) was also prepared by the addition of two equivalents of benzyl azide to 1, and its molecular structure exhibits the two HN=CHPh ligands coordinated trans to each other, thereby forming a square pyramidal coordination geometry at the FeII center. Reaction of 1 with excess benzyl azide yields [((tBu)pyrpyrr(2))Fe(HN=CHPh) 2 center dot PhCHNCH(NH2)Ph] (2-PhCHNCH(NH2)Ph), which contains an unstable benzylideneamino phenyl methanamine fragment, effectively hydrogen bonded to 2. Thermolysis of 2 or 2-PhCHNCH(NH2)Ph releases the HN=CHPh self-coupling products hydrobenzamide (A), N-benzylidine benzylamine (B), and benzonitrile (C). Under catalytic conditions, free HN=CHPh (cis/trans-HN=CHPh mixture) is produced using 2.5 mol % of 1 in 90% spectroscopic yield. These studies provide a clearer understanding for the conversion of the HN=CHPh in 2 or 2-PhCHNCH(NH2)Ph to the C- C and C-N coupled products. Reduction of 1-HN=CHPh with KC8 yields the reductively coupled benzylamide complex [K(OEt2)]2[((tBu)pyrpyrr(2))(2)Fe-2(mu(2)-NHCHPhCHPhNH)] (3) as the result of a new C-C bond formed between two radical benzylamide fragments.

Authors with CRIS profile

Lisa Gravogl Lehrstuhl für Anorganische und Allgemeine Chemie Karsten Meyer Lehrstuhl für Anorganische und Allgemeine Chemie

Involved external institutions

University of Pennsylvania US United States (USA) (US)

How to cite

APA:

Zars, E., Gravogl, L., Gau, M., Carroll, P.J., Meyer, K., & Mindiola, D.J. (2022). Iron(II) Mediated Deazotation of Benzyl Azide: Trapping and Subsequent Transformations of the Benzaldimine Fragment. Inorganic Chemistry. https://dx.doi.org/10.1021/acs.inorgchem.1c03243

MLA:

Zars, Ethan, et al. "Iron(II) Mediated Deazotation of Benzyl Azide: Trapping and Subsequent Transformations of the Benzaldimine Fragment." Inorganic Chemistry (2022).

BibTeX: Download