PREPARATION OF η2-ACETYLENE- AND η1-VINYLIDENE-MANGANESE COMPLEXES FROM p-DIETHYNYLBENZENE AND CYMANTRENE. X-RAY CRYSTAL AND MOLECULAR STRUCTURE OF Cp(OC)2Mn=C=CHC6H4CBr=CH2

Article abstract of DOI:10.1016/0022-328X(86)80086-9

Cp(OC)2Mn(THF) reacts with p-diethynylbenzene (Deb), yielding Cp(OC)2Mn(Deb) (I) and 2(Deb) (II) with the η²-acetylene coordination of Deb (to both Mn atoms in II).Under the action of PhLi, I and II are isomerized into Cp(OC)2Mn=C=CHC6H4C<*>CH (III) and 2C6H4 (VI).Treatment of I with PhLi, LiBr and an excess of HCl in ether, as well as direct interaction of III with LiBr and HCl/Et2O, gives Cp(OC)2Mn=C=CHC6H4CBr=CH2 (IV), which has been characterized by an X-ray single-crystal diffraction study.III adds PPh3, yielding a zwitterionic complex, Cp(OC)2Mn^--C(P⁺Ph3)=CHC6H4C<*>CH (V).