Synthesis and X-ray crystal structure of a heterobimetallic bridged alkynide complex (C5Me5)2Y(μ-CCCMe3)2Li(THF)

Abstract YCl 3 reacts with four equivalents of t-C 4 H 9 Li to form Y(CMe 3 ) 4 Li(THF) 4 ( 1 ) in high yield. 1 reacts with HCCCMe 3 to form Y(CCCMe 3 ) 4 Li(THF) (2) quantitatively. 2 reacts with KC 5 Me 5 to form (C 5 Me 5 ) 2 Y(μ-CCCMe 3 ) 2 Li(THF) ( 3 ) which can also be prepared from (C 5 Me 5 ) 2 YCl(THF) and LiCCCMe 3 . 3 crystallizes from toluene at −34°C in space group Cmcm with a = 13.363(4) A, b = 15.918(7) A, c = 17.453(9) A and D calcd = 1.07 g cm −3 for Z = 4. Least-squares refinement of the model based on 733 reflections converged to a final R F = 0.077. 3 contains a (C 5 Me 5 ) 2 Y bent metallocene unit connected to Li via two alkynide bridges. The proximity of the two CMe 3 groups to Li prevents coordination by more than one THF of solvation.