Received 29 October 2013
The symmetric title molecule, [Hf(C26H40N4Si)Cl4], lies about a twofold rotation axis. The HfIV and Si atoms lie on the rotation axis with all other atoms being in general positions. The HfIV atom is six-coordinated by two N atoms from the N2,N2'-(dimethylsilanediyl)bis(N-tert-butyl-3-methylbenzimidamidate) ligand and four Cl- ions in a slightly distorted octahedral geometry. The two amidinate moieties are connected through the central Si atom with Si-N bond length of 1.762 (3) Å, generating the characteristic N-C-N-Si-N-C-N skeleton of a silyl-linked ansa-bis(amidine) species.
For reviews of related amidinate ligands and their applications, see: Edelmann (2012); Lei et al. (2011); Münch et al. (2008). For a review of the modification of the steric and electronic properties of amidinate ligands by varying their substitution patterns, see: Liu et al. (2013); Qian et al. (2010). For related silyl-linked bis(amidinate) ligands and the synthesis of their metal complexes, including a closely related Hf complex, see: Bai et al. (2013).
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ5366 ).
We acknowledge financial support by the Natural Science Foundation of China (20702029) and the Natural Science Foundation of Shanxi Province (2008011024).
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