Serendipitous formation of the first η5-tricyanocyclopentadienyl complex. Crystal and molecular structures of [{C5H4-nX(CN)n}Mn(CO)2PPh3] (X = Br, CN; n = 1, 2)

• Published in: Inorganica Chimica Acta Vol. 528; p. 120619
• Main Authors: Klein-Heßling, Christian, Blockhaus, Tobias, Sünkel, Karlheinz
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2021; Elsevier Science Ltd
• Subjects: Carbon monoxide; Crystal structure; Crystal structure determination; Crystals; Cymantrene; Electrophilic cyanation; Lithium; Molecular structure; Reagents; η5-Cyanocyclopentadienyl complexes; Cymantrene; η5-Cyanocyclopentadienyl complexes; Crystal structure determination; Electrophilic cyanation
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2021.120619

[Display omitted] •Electrophilic cyanation of bromocymantrene gave [{C5HxBry(CN)z}Mn(CO)2PPh3].•The first η5-tricyanocyclopentadienyl–coordination compound was prepared.•“Halogen-dance” reactions of lithiated intermediates lead to complex mixtures.•Key products were characterized by single crystal X-ray diffraction studies. The reaction of [(C5H4Br)Mn(CO)2PPh3] with lithium diisopropylamide and dimethylmalononitrile yields [{1,2-C5H3Br(CN)}Mn(CO)2PPh3] as main product. Further reaction with the same reagents leads to a complex product mixture, with the dicyanocymantrenes [{C5H2X(CN)2}Mn(CO)2PPh3] (X = H, Br) and the η5-1,2,3-tricyanocyclopentadienyl complex [{C5H2(CN)3}Mn(CO)2PPh3] as main components. The crystal structures of these four main products were determined.