Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106, Braunschweig, Germany.
Department Chemie und Pharmazie, Friedrich-Alexander Universität Erlangen-Nürnberg, Egerlandstr. 1, 91058, Erlangen, Germany.
Chemistry. 2022 Nov 21;28(65):e202202737. doi: 10.1002/chem.202202737. Epub 2022 Nov 3.
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)ML ] (5-7; ML =AuCl, RhCl(COD), RhCl(CO) ; 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 C N 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.
新的二氨基乙炔（DAA）二吗啉乙炔（3）由 1,1-二吗啉乙（1）溴化制成二溴代亚酮亚胺 2，后者经锂化通过 Fritsch-Buttenberg-Wiechell 重排得到 3。将 3 在高温下加热会导致完全转化为二聚体 1,1,2,4-四吗啉基-1-丁烯-3-炔（4），4 用于合成四元环弯曲烯丙基（CBA）过渡金属配合物的类型[(CBA)ML]（5-7；ML=AuCl、RhCl(COD)、RhCl(CO)；CBA=1,3,4,4-四吗啉基-1,2-环丁二烯；COD=1,5-环辛二烯）。3 与四乙基溴化铵反应得到 1,2,3,4-四吗啉环丁烯鎓溴化物（8），8 与溴反应生成 1,2,3,4-四（吗啉基）环丁二烯二鎓双（三溴化物）（9）。化合物 9 代表了第一个完全表征的含有四氨环丁二烯二阳离子的化合物，并通过 X 射线衍射分析显示出几乎平面的 C N 核心。通过使用核独立化学位移（NICS）方法和电流密度分析，进行了详细的量子化学计算，以评估四氨环丁二烯二阳离子的芳香性。
