Bis(2,4,7-trimethylindenyl)cobalt(II) and rac-2,2 ',4,4 ' 7,7 '-hexamethyl-1,1 '-biindene

The crystal and molecular structures of bis(eta (5)-2,4,7-trimethylindenyl) cobalt(II), [Co(C12H13)(2)], (I), and rac-2,2',4,4',7,7' hexamethyl-1,1' -b iindene, C24H26, (II), are reported. In the crystal structure of (I), the C o atom lies on an inversion centre and the structure represents the first e xample of a bis(indenyl)cobalt complex exhibiting an eclipsed indenyl confo rmation. The (1R,1'R) and(1S,1'S) enantiomers of the three possible stereoi somers of (II), which form as by-products in the synthesis of (I), cocrysta llize in the monoclinic space group P2(1)/c. In the unit cell of (II), alte rnating (1R,1'R) and (1S,1'S) enantiomers pack in non-bonded rows along the a axis, with the planes of the indenyl groups parallel to each other and s eparated by 3.62 and 3.69 Angstrom.