Zur Umsetzung von Tri(phenylethinyl)arsan und -stiban mit Octacarbonyldicobalt ; Kristallstruktur von (Ph-C≡C)As](η2-C≡C-Ph)Co2(CO)6]2

The synthesis of tri(phenylethynyl)arsane (1) and-stibane (7) is discussed. Octacarbonyldicobalt reacts selectively with 1 or 7 to yield the η 2 -side-on co-ordinated phenylethynyl complexes (Ph-C≡C) n E[(η 2 -C≡C-Ph)Co 2 (CO) 6 ] 3−n which contain sterically hindered carbon-cobalt tetrahedrane cluster units