Octafluor‐1, 2‐dimethylencyclobutan, ein perfluorierter Dien‐Komplexligand — Carbonyl(η 5 ‐cyclopentadienyl)(η 4 ‐octafluor‐1, 2‐dimethylencyclobutan)mangan

Octafluoro‐1, 2‐dimethylenecyclobutane, a Perfluorinated Diene Ligand — Carbonyl(η 5 ‐cyclopentadienyl)(η 4 ‐octafluoro‐1, 2‐dimethylenecyclobutane)manganese The [2+2]‐cycloaddition product of tetrafluoroallene ( 1 ), octafluoro‐1, 2‐dimethylenecyclobutane ( 2 ) reacts with tricarbonyl(η 5 ‐cyclopentadienyl)manganese ( 4 ) replacing two carbonyl ligands to give carbonyl(η 5 ‐cyclopentadienyl)(η 4 ‐octafluoro‐1, 2‐dimethylenecyclobutane)manganese ( 5 ). According to the IR spectrum of 5 , the ligand 2 is a strong π acceptor. Among the less volatile by‐products of the dimerizationof 1 , the hydrolysis product of its trimer could be structurally characterized by X‐ray diffraction as the spirocyclic compound decafluoro‐5‐methylene‐spiro[3.3]heptane‐2‐carboxylic acid ( 3 ). The structure of 5 was also determined by an X‐ray crystal structure determination.