4,4′-Bis(trimethylsilyl)-2,2′-bipyridine

In the molecule of title compound, C16H24N2Si2, the pyridine rings are nearly planar (r.m.s. deviation = 0.002 Å).

In the molecule of title compound, C 16 H 24 N 2 Si 2 , the pyridine rings are nearly planar (r.m.s. deviation = 0.002 Å ).
The molecule is placed in centre of symmetry and nealy flat ( Fig. 1) as the C-Si is co-planar with the aromatic rings.

Experimental
All the reagents and solvents empolyed were commercially available. The title compound was synthesized by using 2,2'bipyridine as the starting material with successive polystepreactions (Wenkert & Woodward, 1983). The final product was dissolved in the solution of methanol and methylene chloride, which diffused slowly. After seven days, colourless blockshaped crystals were obtained which were suitable for X-ray analysis.

Refinement
All H atoms were placed in geometrically idealized positions. H atoms of bipyridine constrained to ride on their parent atoms with C-H = 0.94 Å and refined with U iso (H) = 1.2U iso (C). The H atoms of methyl groups constrained to ride on their parent atoms with C-H = 0.97 Å and refined with U iso (H) = 1.5U iso (C). Fig. 1. Molecular structure of title compound with the atom numbering scheme. Displacement ellipsoids are drawn at 40% probability level. H atoms are presented as a small spheres of arbitrary radius. Symmetry code: (i) -x + 1, -y + 1, -z.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σF 2 is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.