Crystal and molecular structure of tetrakiscyclopentadienylzirconium

Abstract

SwnunaryIn the crystal form of tetrakiscyclopentadienylzirconium, three cyclopentadienyl rings are r-bonded a t a mean Zr-C distance of 2.64 A, the fourth ring being a-bonded with a 2r-C distance of 2-47 A.

Tris(polyalkylcyclopentadienyl) Complexes: The Elusive [(η5‐C5R5)2M(η1‐C5R5)] Structure and Trihapto Cyclopentadienyl Coordination Involving a Methyl Substituent

“…Flexibility in the hapticity of cyclopentadienyl ligands is well known9 and has been theoretically analyzed 10. Examples include [(η 5 ‐C 5 H 5 ) 2 Ti(η 2 ‐C 5 H 5 )],11 [(η 5 ‐C 5 H 5 ) 3 Zr(η 1 ‐C 5 H 5 )],12 [(η 5 ‐C 5 H 5 ) 2 M′(η 1 ‐C 5 H 5 ) 2 ] (M′=Ti,13 Hf14), [(η 1 ‐C 5 Me 4 R) 3 Ga],15 and polymeric [{(η 5 ‐C 5 H 5 ) 2 Sc(μ‐η 1 :η 1 ‐C 5 H 5 )} x ] 16. However, it was unclear if such an η 5 to η 1 transformation could occur in these crowded [(η 5 ‐C 5 Me 5 ) 3 M] complexes. …”

Molecular structures of the bis(.eta.5-indenyl)dimethyl derivatives of titanium, zirconium, and hafnium

“…established: ($-CsHs)~ZrF2,11 ($-CsHs)zZrC12,'2 Structural studies have done much to elucidate the nature of (CHr)3($-CsH4)2ZrC12,13 ($-CsH5)2ZrI2,ll (+-CsHs)-Atwood, Rausch, et al 14.124 ( It is of interest to note that in one of the two complete series to be characterized, (CsH5)4M, two rings are q 5 and two are q' for M = Ti,6 three are 75 and one is 71 for Zr, 16 and two are 75 and two are 71 for Hf. 18 The difference between the zirconium and hafnium analogs is especially surprising in view .…”

Tris(polyalkylcyclopentadienyl) Complexes: The Elusive [(η5‐C5R5)2M(η1‐C5R5)] Structure and Trihapto Cyclopentadienyl Coordination Involving a Methyl Substituent

“…[8] This led to the speculation that [(h 5 [9] and has been theoretically analyzed. [10] Examples include [(h 5 -C 5 H 5 ) 2 Ti(h 2 -C 5 H 5 )], [11] [(h 5 -C 5 H 5 ) 3 Zr-(h 1 -C 5 H 5 )], [12] [13] Hf [14] ),…”

“…Flexibility in the hapticity of cyclopentadienyl ligands is well known [9] and has been theoretically analyzed. [10] Examples include [(h 5 -C 5 H 5 ) 2 Ti(h 2 -C 5 H 5 )], [11] [(h 5 -C 5 H 5 ) 3 Zr-(h 1 -C 5 H 5 )], [12] [(h 5 -C 5 H 5 ) 2 M'(h 1 -C 5 H 5 ) 2 ] (M' = Ti, [13] Hf [14] ), [(h 1 -C 5 Me 4 R) 3 Ga], [15] and polymeric [{(h 5 -C 5 H 5 ) 2 Sc(m-h 1 :h 1 -C 5 H 5 )} x ]. [16] However, it was unclear if such an h 5 to h 1 transformation could occur in these crowded [(h 5 -C 5 Me 5 ) 3…”