Dimorpholinoacetylene and Its Use for the Synthesis of Tetraaminocyclobutadiene Species

Koerner L, Luong Phong Ho , Puchta R, Stanger A, Tamm M (2022)

Publication Type: Journal article

Publication year: 2022

Journal

DOI: 10.1002/chem.202202737

Abstract

The new diaminoacetylene (DAA) dimorpholinoacetylene (3) was prepared from 1,1-dimorpholinoethene (1) by bromination to form the dibromoketene aminal 2, which upon lithiation afforded 3 through a Fritsch-Buttenberg-Wiechell rearrangement. Heating 3 at elevated temperatures resulted in a complete conversion into the dimer 1,1,2,4-tetramorpholino-1-buten-3-yne (4), which was used for the synthesis of four-membered cyclic bent allene (CBA) transition-metal complexes of the type [(CBA)MLn] (5-7; MLn=AuCl, RhCl(COD), RhCl(CO)2; CBA=1,3,4,4-tetramorpholino-1,2-cyclobutadiene; COD=1,5-cyclooctadiene). The reaction of 3 with tetraethylammonium bromide gave 1,2,3,4-tetramorpholinocyclobutenylium bromide (8), which reacted with bromine to form 1,2,3,4-tetra(morpholino)cyclobutenediylium bis(tribromide) (9). Compound 9 represents the first fully characterized compound containing a tetraaminocyclobutadiene dication and displays a nearly planar C4N4 core as shown by X-ray diffraction analysis. Detailed quantum chemical calculations were performed to assess the aromaticity of tetraaminocyclubutadiene dications by employing the Nucleus Independent Chemical Shift (NICS) method and current density analysis.

Authors with CRIS profile

Ralph Puchta Lehrstuhl für Anorganische und Metallorganische Chemie

Involved external institutions

Technische Universität Braunschweig

Germany (DE) Technion - Israel Institute of Technology

Israel (IL)

How to cite

APA:

Koerner, L., Luong Phong Ho, ., Puchta, R., Stanger, A., & Tamm, M. (2022). Dimorpholinoacetylene and Its Use for the Synthesis of Tetraaminocyclobutadiene Species. Chemistry - A European Journal. https://doi.org/10.1002/chem.202202737

MLA:

Koerner, Lukas, et al. "Dimorpholinoacetylene and Its Use for the Synthesis of Tetraaminocyclobutadiene Species." Chemistry - A European Journal (2022).

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