2,2,4,4-Tetra­phenyl-1,3-bis­(3,3,5,5-tetra­methyl-1,1-diphenyl-5-vinyl­trisilox­an-1-yl)­cyclo­disilazane

Zhen Lv; Lina Dai; Xuezhong Zhang; Zhijie Zhang; Zemin Xie

doi:10.1107/S1600536811014863

. 2011 Apr 29;67(Pt 5):o1234. doi: 10.1107/S1600536811014863

2,2,4,4-Tetraphenyl-1,3-bis(3,3,5,5-tetramethyl-1,1-diphenyl-5-vinyltrisiloxan-1-yl)cyclodisilazane

Zhen Lv ^a, Lina Dai ^a, Xuezhong Zhang ^a, Zhijie Zhang ^a,^*, Zemin Xie ^a

PMCID: PMC3089304 PMID: 21754530

Abstract

The title molecule, C₆₀H₇₀N₂O₄Si₈, lies on an inversion center. In the asymmetric unit, one of the phenyl rings is disordered over two sets of sites with refined occupancies 0.58 (2) and 0.42 (2). In addition, in two substitution sites of the terminal dimethyl(vinyl)silyl unit, a methyl group and the vinyl group are disordered over the same site with refined occupancies 0.523 (13) and 0.477 (13).

Related literature

For similar cyclodisilazanes to the title compound and their synthesis, see: Zhu et al. (2007 ▶).

Experimental

Crystal data

C₆₀H₇₀N₂O₄Si₈
M _r = 1107.90
Triclinic,
a = 10.731 (2) Å
b = 11.021 (2) Å
c = 13.859 (3) Å
α = 88.320 (9)°
β = 76.120 (6)°
γ = 78.860 (8)°
V = 1561.0 (6) Å³
Z = 1
Mo Kα radiation
μ = 0.22 mm⁻¹
T = 173 K
0.41 × 0.28 × 0.22 mm

Data collection

Rigaku Saturn724+ CCD diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2007 ▶) T _min = 0.916, T _max = 0.954
12950 measured reflections
6338 independent reflections
5389 reflections with I > 2σ(I)
R _int = 0.040

Refinement

R[F ² > 2σ(F ²)] = 0.072
wR(F ²) = 0.169
S = 1.11
6338 reflections
390 parameters
74 restraints
H-atom parameters constrained
Δρ_max = 0.55 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: CrystalClear (Rigaku, 2007 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811014863/lh5235sup1.cif

e-67-o1234-sup1.cif^{(40.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811014863/lh5235Isup2.hkl

e-67-o1234-Isup2.hkl^{(310.2KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors would like to thank the National Natural Science Foundation of China (grant No. 50803070) for financial support.

supplementary crystallographic information

Comment

Organocyclodisilazanes exhibit high thermal stability, and have been used to enhance the thermal properties of silicone rubbers (Zhu et al., 2007). Different functional groups can be introduced to cyclodisilazanes to improve their reactivity.

The molecular structure of the title compound is shown in Fig. 1. The molecule lies on an inversion center. In the asymmetric unit, one of the phenyl rings is disordered over two sets of sites with refined occupancies 0.58 (2) and 0.42 (2). In addition, in the the terminal dimethyl(vinyl)silyl group one of the methyl groups and the vinyl group are disordered over their respective sites with refined occupancies 0.523 (13) and 0.477 (13).

Experimental

The reaction scheme is shown in Fig. 2. 2 g 1,3-bis-(hydroxydiphenylsilanyl)-2,2,4,4-tetraphenylcyclodisilazane was dissolved in 20 ml tetrahydrofuran and added dropwisely to 2 ml n-butyllithum (2.5 mol/L solution in n-hexane) at 263K, then warmed to room temperature. An excessive amount of 1-vinyl-3-chloro-1,1,3,3-tetramethyldisiloxane was added to the mixture. After stirring for 30 min, solvents and unreacted disiloxane were removed under reduced pressure. The crude product was recrystallized from n-hexane to give colorless crystal.