organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890
Volume 67| Part 5| May 2011| Page o1233

1,1,3,3,5,5,7,7-Octa­phenyl-2,6-dioxa-4,8-di­aza-1,3,5,7-tetra­sila­cyclo­octa­ne

aInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
*Correspondence e-mail: zhangzj@iccas.ac.cn

(Received 11 April 2011; accepted 20 April 2011; online 29 April 2011)

The title mol­ecule, C48H42N2O2Si4, lies on a twofold rotation axis. The eight-membered ring has a slightly distorted boat conformation.

Related literature

For the hydrolysis of 1,3-bis-(hy­droxy­diphenyl­silan­yl)-2,2,4,4-tetra­phenyl­cyclo­disilazane, see: Voronkov et al. (1977[Voronkov, M. G., Varezhkin, Yu. M., Zhinkin, D. Ya., Morgunova, M. M., Gurkova, S. N., Gusev, A. I. & Alekseev, N. V. (1977). Dokl. Akad. Nauk SSSR, 237, 102-104.]).

[Scheme 1]

Experimental

Crystal data
  • C48H42N2O2Si4

  • Mr = 791.20

  • Monoclinic, C 2/c

  • a = 12.1188 (18) Å

  • b = 17.016 (3) Å

  • c = 20.621 (3) Å

  • β = 93.216 (3)°

  • V = 4245.8 (11) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.18 mm−1

  • T = 173 K

  • 0.35 × 0.35 × 0.05 mm

Data collection
  • Rigaku MM007-HF CCD (Saturn 724+) diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2007[Rigaku (2007). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.939, Tmax = 0.991

  • 14029 measured reflections

  • 4833 independent reflections

  • 4411 reflections with I > 2σ(I)

  • Rint = 0.039

Refinement
  • R[F2 > 2σ(F2)] = 0.052

  • wR(F2) = 0.120

  • S = 1.10

  • 4833 reflections

  • 253 parameters

  • H-atom parameters constrained

  • Δρmax = 0.39 e Å−3

  • Δρmin = −0.30 e Å−3

Data collection: CrystalClear (Rigaku, 2007[Rigaku (2007). CrystalClear. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

The title compound is one of the hydrolysis products of 1,3-bis-(hydroxydiphenylsilanyl)-2,2,4,4-tetraphenylcyclodisilazane. Voronkov et al. (1977) reported that the hydrolysis of 1,3-bis-(hydroxydiphenylsilanyl)-2,2,4,4-tetraphenylcyclodisilazane in base medium could give 1,1,3,3,5,5,7,7-octaphenyl-2,4-dioxa-6,8,-diaza-1,3,5,7-tetrasilacyclo-octane and we have found that the title compound was also produced. Its crystal structure is presented herein. The molecular structure of the title compound is shown in Fig. 1. The eight-membered ring has a slightly disorted boat conformation.

Related literature top

For the hydrolysis of 1,3-bis-(hydroxydiphenylsilanyl)-2,2,4,4-tetraphenylcyclodisilazane, see: Voronkov et al. (1977).

Experimental top

The reaction scheme is shown in Fig. 2. 1 ml aqueous solution of sodium hydroxide (0.1 mol/L) was added to a solution of 1,3-bis-(hydroxydiphenylsilanyl)-2,2,4,4-tetraphenylcyclodisilazane (1 g) in tetrahydrofuran (10 ml). After stirring for 30 min at room temprature, the solvents were removed under reduced pressure. The crude product was recrystallized from n-hexane to give colorless crystals.

Refinement top

All the H atoms were located in difference maps but were subsequently placed in calculated positions with C-H = 0.95Å and constrained in a riding-model approximation with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: CrystalClear (Rigaku, 2007); cell refinement: CrystalClear (Rigaku, 2007); data reduction: CrystalClear (Rigaku, 2007); 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 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with 30% ellipsoids. H atoms are not shown (symmetry code (A): -x+1, y, -z+3/2).
[Figure 2] Fig. 2. The hydrolysis reaction of 1,3-bis-(hydroxydiphenylsilanyl)-2,2,4,4-tetraphenylcyclodisilazane
2,2,4,4,6,6,8,8-octaphenyl-1,5,3,7,2,4,6,8-dioxadiazatetrasilocane top
Crystal data top
C48H42N2O2Si4F(000) = 1664
Mr = 791.20Dx = 1.238 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 7324 reflections
a = 12.1188 (18) Åθ = 2.1–27.5°
b = 17.016 (3) ŵ = 0.18 mm1
c = 20.621 (3) ÅT = 173 K
β = 93.216 (3)°Platelet, colorless
V = 4245.8 (11) Å30.35 × 0.35 × 0.05 mm
Z = 4
Data collection top
Rigaku MM007-HF CCD (Saturn 724+)
diffractometer
4833 independent reflections
Radiation source: rotating anode4411 reflections with I > 2σ(I)
Confocal monochromatorRint = 0.039
ω scans at fixed χ = 45°θmax = 27.5°, θmin = 2.1°
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2007)
h = 1513
Tmin = 0.939, Tmax = 0.991k = 1822
14029 measured reflectionsl = 2624
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.052Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.120H-atom parameters constrained
S = 1.10 w = 1/[σ2(Fo2) + (0.0442P)2 + 4.974P]
where P = (Fo2 + 2Fc2)/3
4833 reflections(Δ/σ)max = 0.001
253 parametersΔρmax = 0.39 e Å3
0 restraintsΔρmin = 0.30 e Å3
Crystal data top
C48H42N2O2Si4V = 4245.8 (11) Å3
Mr = 791.20Z = 4
Monoclinic, C2/cMo Kα radiation
a = 12.1188 (18) ŵ = 0.18 mm1
b = 17.016 (3) ÅT = 173 K
c = 20.621 (3) Å0.35 × 0.35 × 0.05 mm
β = 93.216 (3)°
Data collection top
Rigaku MM007-HF CCD (Saturn 724+)
diffractometer
4833 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2007)
4411 reflections with I > 2σ(I)
Tmin = 0.939, Tmax = 0.991Rint = 0.039
14029 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0520 restraints
wR(F2) = 0.120H-atom parameters constrained
S = 1.10Δρmax = 0.39 e Å3
4833 reflectionsΔρmin = 0.30 e Å3
253 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Si10.34094 (4)0.15720 (3)0.71343 (2)0.02431 (13)
Si20.55767 (4)0.21644 (3)0.65217 (2)0.02461 (13)
O10.44552 (11)0.16871 (8)0.66768 (6)0.0324 (3)
N10.35191 (13)0.21530 (9)0.78113 (7)0.0282 (3)
H1A0.30080.25200.78180.034*
C10.21399 (15)0.18949 (11)0.66561 (8)0.0269 (4)
C20.21930 (18)0.23932 (15)0.61226 (10)0.0437 (5)
H2A0.28950.25340.59750.052*
C30.12476 (19)0.26890 (15)0.58017 (11)0.0471 (6)
H3A0.13100.30360.54450.057*
C40.02258 (18)0.24847 (14)0.59954 (10)0.0415 (5)
H4A0.04220.26840.57720.050*
C50.01439 (18)0.19908 (15)0.65148 (12)0.0478 (6)
H5A0.05640.18450.66510.057*
C60.10912 (17)0.17011 (13)0.68447 (11)0.0390 (5)
H6A0.10190.13630.72070.047*
C70.33633 (15)0.05141 (11)0.73523 (9)0.0284 (4)
C80.29044 (18)0.02462 (12)0.79170 (11)0.0405 (5)
H8A0.25990.06130.82040.049*
C90.2889 (2)0.05507 (14)0.80646 (12)0.0503 (6)
H9A0.25730.07250.84500.060*
C100.3333 (2)0.10885 (13)0.76511 (13)0.0492 (6)
H10A0.33350.16320.77560.059*
C110.3772 (2)0.08378 (13)0.70882 (12)0.0481 (6)
H11A0.40620.12090.67990.058*
C120.37953 (19)0.00461 (12)0.69411 (10)0.0390 (5)
H12A0.41110.01210.65530.047*
C130.61490 (16)0.16531 (11)0.58150 (8)0.0289 (4)
C140.5520 (2)0.11582 (13)0.54049 (10)0.0416 (5)
H14A0.47660.10680.54850.050*
C150.5975 (2)0.07921 (15)0.48789 (12)0.0550 (6)
H15A0.55310.04610.46000.066*
C160.7078 (2)0.09105 (15)0.47616 (12)0.0545 (7)
H16A0.73990.06470.44120.065*
C170.7700 (2)0.14071 (17)0.51506 (12)0.0543 (6)
H17A0.84510.15010.50650.065*
C180.72369 (18)0.17780 (15)0.56732 (11)0.0434 (5)
H18A0.76790.21250.59380.052*
C190.52733 (15)0.32134 (11)0.63098 (9)0.0306 (4)
C200.5545 (2)0.38324 (14)0.67257 (12)0.0515 (6)
H20A0.59090.37250.71360.062*
C210.5299 (3)0.46049 (16)0.65572 (16)0.0752 (9)
H21A0.55150.50190.68460.090*
C220.4745 (3)0.47717 (17)0.59751 (16)0.0731 (9)
H22A0.45580.52990.58660.088*
C230.4461 (2)0.41749 (17)0.55499 (13)0.0591 (7)
H23A0.40830.42900.51450.071*
C240.47270 (17)0.34019 (14)0.57119 (10)0.0410 (5)
H24A0.45350.29940.54120.049*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Si10.0250 (2)0.0252 (2)0.0230 (2)0.00224 (18)0.00372 (18)0.00254 (18)
Si20.0258 (3)0.0269 (2)0.0213 (2)0.00168 (19)0.00308 (18)0.00178 (18)
O10.0313 (7)0.0380 (7)0.0284 (6)0.0055 (6)0.0064 (5)0.0020 (6)
N10.0297 (8)0.0287 (8)0.0260 (7)0.0041 (6)0.0004 (6)0.0057 (6)
C10.0293 (9)0.0260 (8)0.0254 (8)0.0021 (7)0.0009 (7)0.0058 (7)
C20.0334 (11)0.0624 (14)0.0353 (11)0.0068 (10)0.0012 (9)0.0122 (10)
C30.0423 (12)0.0627 (15)0.0356 (11)0.0032 (11)0.0053 (9)0.0159 (10)
C40.0353 (11)0.0478 (12)0.0404 (11)0.0012 (9)0.0074 (9)0.0009 (10)
C50.0268 (10)0.0570 (14)0.0595 (14)0.0025 (10)0.0014 (10)0.0140 (12)
C60.0333 (10)0.0390 (11)0.0449 (12)0.0033 (9)0.0038 (9)0.0096 (9)
C70.0272 (9)0.0271 (9)0.0307 (9)0.0005 (7)0.0005 (7)0.0023 (7)
C80.0443 (12)0.0326 (10)0.0455 (12)0.0048 (9)0.0114 (9)0.0010 (9)
C90.0555 (15)0.0413 (12)0.0544 (14)0.0116 (11)0.0062 (11)0.0125 (11)
C100.0524 (14)0.0262 (10)0.0674 (16)0.0051 (9)0.0129 (12)0.0027 (10)
C110.0611 (15)0.0301 (11)0.0521 (13)0.0066 (10)0.0070 (11)0.0091 (10)
C120.0493 (12)0.0333 (10)0.0340 (10)0.0054 (9)0.0003 (9)0.0042 (8)
C130.0335 (10)0.0305 (9)0.0232 (8)0.0009 (7)0.0058 (7)0.0036 (7)
C140.0483 (13)0.0445 (12)0.0328 (10)0.0049 (10)0.0081 (9)0.0050 (9)
C150.0738 (18)0.0509 (14)0.0413 (12)0.0061 (13)0.0116 (12)0.0146 (11)
C160.0748 (18)0.0516 (14)0.0393 (12)0.0140 (13)0.0235 (12)0.0043 (11)
C170.0447 (13)0.0709 (17)0.0494 (14)0.0074 (12)0.0219 (11)0.0007 (12)
C180.0358 (11)0.0563 (14)0.0393 (11)0.0031 (10)0.0110 (9)0.0057 (10)
C190.0295 (9)0.0315 (9)0.0315 (9)0.0007 (7)0.0073 (7)0.0071 (8)
C200.0683 (17)0.0350 (12)0.0507 (13)0.0018 (11)0.0019 (12)0.0010 (10)
C210.113 (3)0.0323 (13)0.081 (2)0.0055 (15)0.0110 (19)0.0008 (13)
C220.094 (2)0.0425 (15)0.086 (2)0.0219 (15)0.0350 (19)0.0248 (15)
C230.0513 (14)0.0715 (18)0.0562 (15)0.0179 (13)0.0186 (12)0.0386 (14)
C240.0368 (11)0.0514 (13)0.0355 (11)0.0043 (9)0.0075 (9)0.0163 (9)
Geometric parameters (Å, º) top
Si1—O11.6338 (14)C10—C111.372 (4)
Si1—N11.7099 (15)C10—H10A0.9500
Si1—C71.8571 (19)C11—C121.381 (3)
Si1—C11.8630 (19)C11—H11A0.9500
Si2—O11.6302 (14)C12—H12A0.9500
Si2—N1i1.7098 (15)C13—C181.383 (3)
Si2—C131.8643 (19)C13—C141.390 (3)
Si2—C191.869 (2)C14—C151.392 (3)
N1—Si2i1.7098 (15)C14—H14A0.9500
N1—H1A0.8800C15—C161.386 (4)
C1—C61.390 (3)C15—H15A0.9500
C1—C21.393 (3)C16—C171.363 (4)
C2—C31.385 (3)C16—H16A0.9500
C2—H2A0.9500C17—C181.394 (3)
C3—C41.367 (3)C17—H17A0.9500
C3—H3A0.9500C18—H18A0.9500
C4—C51.369 (3)C19—C201.386 (3)
C4—H4A0.9500C19—C241.403 (3)
C5—C61.391 (3)C20—C211.388 (3)
C5—H5A0.9500C20—H20A0.9500
C6—H6A0.9500C21—C221.372 (4)
C7—C81.395 (3)C21—H21A0.9500
C7—C121.397 (3)C22—C231.373 (4)
C8—C91.390 (3)C22—H22A0.9500
C8—H8A0.9500C23—C241.390 (3)
C9—C101.381 (4)C23—H23A0.9500
C9—H9A0.9500C24—H24A0.9500
O1—Si1—N1112.01 (8)C11—C10—H10A120.0
O1—Si1—C7106.91 (8)C9—C10—H10A120.0
N1—Si1—C7111.40 (8)C10—C11—C12120.2 (2)
O1—Si1—C1107.65 (8)C10—C11—H11A119.9
N1—Si1—C1106.60 (8)C12—C11—H11A119.9
C7—Si1—C1112.27 (8)C11—C12—C7121.3 (2)
O1—Si2—N1i109.90 (7)C11—C12—H12A119.4
O1—Si2—C13105.76 (8)C7—C12—H12A119.4
N1i—Si2—C13111.95 (8)C18—C13—C14117.47 (18)
O1—Si2—C19111.49 (8)C18—C13—Si2119.63 (15)
N1i—Si2—C19107.92 (8)C14—C13—Si2122.87 (15)
C13—Si2—C19109.86 (8)C13—C14—C15121.1 (2)
Si2—O1—Si1148.79 (9)C13—C14—H14A119.4
Si2i—N1—Si1132.87 (10)C15—C14—H14A119.4
Si2i—N1—H1A113.6C16—C15—C14120.0 (2)
Si1—N1—H1A113.6C16—C15—H15A120.0
C6—C1—C2116.67 (18)C14—C15—H15A120.0
C6—C1—Si1121.53 (15)C17—C16—C15119.6 (2)
C2—C1—Si1121.61 (15)C17—C16—H16A120.2
C3—C2—C1121.7 (2)C15—C16—H16A120.2
C3—C2—H2A119.2C16—C17—C18120.2 (2)
C1—C2—H2A119.2C16—C17—H17A119.9
C4—C3—C2120.4 (2)C18—C17—H17A119.9
C4—C3—H3A119.8C13—C18—C17121.6 (2)
C2—C3—H3A119.8C13—C18—H18A119.2
C3—C4—C5119.4 (2)C17—C18—H18A119.2
C3—C4—H4A120.3C20—C19—C24117.0 (2)
C5—C4—H4A120.3C20—C19—Si2122.97 (16)
C4—C5—C6120.4 (2)C24—C19—Si2120.04 (16)
C4—C5—H5A119.8C19—C20—C21121.6 (2)
C6—C5—H5A119.8C19—C20—H20A119.2
C1—C6—C5121.4 (2)C21—C20—H20A119.2
C1—C6—H6A119.3C22—C21—C20120.2 (3)
C5—C6—H6A119.3C22—C21—H21A119.9
C8—C7—C12117.66 (18)C20—C21—H21A119.9
C8—C7—Si1122.53 (15)C21—C22—C23119.9 (2)
C12—C7—Si1119.81 (15)C21—C22—H22A120.0
C9—C8—C7120.8 (2)C23—C22—H22A120.0
C9—C8—H8A119.6C22—C23—C24120.0 (2)
C7—C8—H8A119.6C22—C23—H23A120.0
C10—C9—C8120.1 (2)C24—C23—H23A120.0
C10—C9—H9A120.0C23—C24—C19121.2 (2)
C8—C9—H9A120.0C23—C24—H24A119.4
C11—C10—C9120.0 (2)C19—C24—H24A119.4
N1i—Si2—O1—Si155.8 (2)C9—C10—C11—C121.5 (4)
C13—Si2—O1—Si1176.78 (17)C10—C11—C12—C70.9 (3)
C19—Si2—O1—Si163.8 (2)C8—C7—C12—C110.2 (3)
N1—Si1—O1—Si27.6 (2)Si1—C7—C12—C11179.88 (17)
C7—Si1—O1—Si2129.94 (18)O1—Si2—C13—C18162.77 (16)
C1—Si1—O1—Si2109.24 (18)N1i—Si2—C13—C1843.10 (19)
O1—Si1—N1—Si2i66.15 (15)C19—Si2—C13—C1876.79 (18)
C7—Si1—N1—Si2i53.55 (15)O1—Si2—C13—C1418.92 (19)
C1—Si1—N1—Si2i176.34 (12)N1i—Si2—C13—C14138.60 (17)
O1—Si1—C1—C6164.56 (16)C19—Si2—C13—C14101.52 (18)
N1—Si1—C1—C675.08 (18)C18—C13—C14—C151.1 (3)
C7—Si1—C1—C647.16 (18)Si2—C13—C14—C15179.47 (18)
O1—Si1—C1—C220.62 (19)C13—C14—C15—C160.8 (4)
N1—Si1—C1—C299.73 (18)C14—C15—C16—C172.2 (4)
C7—Si1—C1—C2138.02 (17)C15—C16—C17—C181.6 (4)
C6—C1—C2—C30.8 (3)C14—C13—C18—C171.7 (3)
Si1—C1—C2—C3174.23 (19)Si2—C13—C18—C17179.86 (19)
C1—C2—C3—C41.3 (4)C16—C17—C18—C130.4 (4)
C2—C3—C4—C50.7 (4)O1—Si2—C19—C20107.10 (19)
C3—C4—C5—C60.2 (4)N1i—Si2—C19—C2013.7 (2)
C2—C1—C6—C50.1 (3)C13—Si2—C19—C20135.99 (19)
Si1—C1—C6—C5175.18 (18)O1—Si2—C19—C2471.58 (17)
C4—C5—C6—C10.6 (4)N1i—Si2—C19—C24167.65 (15)
O1—Si1—C7—C8153.74 (16)C13—Si2—C19—C2445.33 (18)
N1—Si1—C7—C831.06 (19)C24—C19—C20—C210.6 (4)
C1—Si1—C7—C888.42 (18)Si2—C19—C20—C21179.4 (2)
O1—Si1—C7—C1226.55 (18)C19—C20—C21—C222.0 (5)
N1—Si1—C7—C12149.23 (15)C20—C21—C22—C231.9 (5)
C1—Si1—C7—C1291.29 (17)C21—C22—C23—C240.6 (4)
C12—C7—C8—C90.5 (3)C22—C23—C24—C190.8 (4)
Si1—C7—C8—C9179.76 (18)C20—C19—C24—C230.7 (3)
C7—C8—C9—C100.1 (4)Si2—C19—C24—C23178.04 (17)
C8—C9—C10—C111.2 (4)
Symmetry code: (i) x+1, y, z+3/2.

Experimental details

Crystal data
Chemical formulaC48H42N2O2Si4
Mr791.20
Crystal system, space groupMonoclinic, C2/c
Temperature (K)173
a, b, c (Å)12.1188 (18), 17.016 (3), 20.621 (3)
β (°) 93.216 (3)
V3)4245.8 (11)
Z4
Radiation typeMo Kα
µ (mm1)0.18
Crystal size (mm)0.35 × 0.35 × 0.05
Data collection
DiffractometerRigaku MM007-HF CCD (Saturn 724+)
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2007)
Tmin, Tmax0.939, 0.991
No. of measured, independent and
observed [I > 2σ(I)] reflections
14029, 4833, 4411
Rint0.039
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.052, 0.120, 1.10
No. of reflections4833
No. of parameters253
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.39, 0.30

Computer programs: CrystalClear (Rigaku, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

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

References

First citationRigaku (2007). CrystalClear. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationVoronkov, M. G., Varezhkin, Yu. M., Zhinkin, D. Ya., Morgunova, M. M., Gurkova, S. N., Gusev, A. I. & Alekseev, N. V. (1977). Dokl. Akad. Nauk SSSR, 237, 102–104.  CAS Google Scholar

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Volume 67| Part 5| May 2011| Page o1233
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