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[μ-Bis(tri­methyl­silyl)amido]bis­­[μ-N,N-di­methyl-N′,N′′-bis­­(tri­methyl­silyl)guanidinato]-triangulo-tricopper(I)

aSchool of Life Science and Technology, Shanxi University, Taiyuan 030006, People's Republic of China, and bInstitute of Applied Chemistry, Shanxi University, Taiyuan 030006, People's Republic of China
*Correspondence e-mail: mszhou@sxu.edu.cn

(Received 9 March 2009; accepted 10 March 2009; online 14 March 2009)

The title compound, [Cu3(C6H18NSi2)(C9H24N3Si2)2], is a trinuclear CuI complex. A crystallographic twofold axis passes through one CuI atom and the N atom of the bis­(trimethyl­silyl)amide ligand that bridges between the other two CuI atoms. The Cu—Cu bonds bridged by the guanadinate ligands [2.7913 (9) Å] are slightly longer than the Cu—Cu bond bridged by the bis­(trimethyl­silyl)amide ligand [2.6405 (11) Å].

Related literature

For background literature concerning the coordination chemistry of guanidinates, see: Chandra et al. (1970[Chandra, G., Jenkins, A. D., Lappert, M. F. & Srivastava, R. C. (1970). J. Chem. Soc. A, pp. 2550-2558.]); Barker & Kilner (1994[Barker, J. & Kilner, M. (1994). Coord. Chem. Rev. 133, 219-300.]); Edelmann (1994[Edelmann, F. T. (1994). Coord. Chem. Rev. 137, 403-481.]); Bailey & Pace (2001[Bailey, P. J. & Pace, S. (2001). Coord. Chem. Rev. 214, 91-141.]); Zhou et al. (2007[Zhou, M.-S., Tong, H.-B., Wei, X.-H. & Liu, D.-S. (2007). J. Organomet. Chem. 692, 5195-5202.]).

[Scheme 1]

Experimental

Crystal data
  • [Cu3(C6H18NSi2)(C9H24N3Si2)2]

  • Mr = 812.00

  • Monoclinic, C 2/c

  • a = 16.445 (3) Å

  • b = 18.653 (4) Å

  • c = 14.046 (3) Å

  • β = 96.943 (3)°

  • V = 4277.1 (15) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 1.67 mm−1

  • T = 213 K

  • 0.30 × 0.20 × 0.20 mm

Data collection
  • Siemens SMART CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1997[Sheldrick, G. M. (1997). SADABS. University of Göttingen, Germany.]) Tmin = 0.622, Tmax = 0.717

  • 8714 measured reflections

  • 3773 independent reflections

  • 3394 reflections with I > 2σ(I)

  • Rint = 0.033

Refinement
  • R[F2 > 2σ(F2)] = 0.056

  • wR(F2) = 0.118

  • S = 1.26

  • 3773 reflections

  • 193 parameters

  • H-atom parameters constrained

  • Δρmax = 0.57 e Å−3

  • Δρmin = −0.46 e Å−3

Data collection: SMART (Siemens, 1996[Siemens (1996). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Siemens, 1996[Siemens (1996). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Since the first guanidinato complex was reported by Lapper and coworkers (Chandra et al., 1970), the coordination chemistry of guanidinates has been well explored for main group metals as well as transition metals (Bailey & Pace, 2001; Barker & Kilner, 1994; 1994; Edelmann, 1994). The trigonal-planar CN3 unit provides easy accessibillity and the possibility of substituent variation, which allows for tuning of the steric and electronic properties of the ligands. Recently, we reported a series of early transition metal guanidinates and their applications in the polymerization of ethylene (Zhou et al., 2007). Here we describe the synthesis and crystal structure of a new copper(I) guanidinato complex.

The molecular structure is illustrated in Fig. 1. In the trinuclear copper compound, each CuI atom coordinates to the other two CuI atoms and two N from the ligands. Atoms Cu1, Cu2, Cu1i and N4 are exactly co-planar with a crystallographic 2-fold rotation axis passing through Cu2 and N4. The bond lengths Cu1—Cu2 and Cu1i—Cu2 are therefore identical, whereas the bond length Cu1—Cu1i is slightly shorter (Table 1). The Cu1—N1 and Cu2—N3 bond lengths are 1.875 (3) and 1.885 (3) Å, respectively. In the guanidinato ligand, the bond lengths C1—N1, C1—N2 and C1—N3 are 1.329 (5), 1.386 (5) and 1.341 (5) Å, respectively. The bond angle N1—C1—N3 is 122.8 (3)°. The dihedral angle between N1/C1/N3 and Cu1/Cu2/N3 is 31.8° and that between Cu1/Cu2/Cu1i and Cu1/Cu2/N3 is 42.0°.

Related literature top

For background literature concerning the coordination chemistry of guanidinates, see: Chandra et al. (1970); Barker & Kilner (1994); Edelmann (1994); Bailey & Pace (2001); Zhou et al. (2007).

Experimental top

(CH3)2NCN (0.22 ml, 2.76 mmol) was added to a solution of LiN(SiMe3)2 (0.46 g, 2.76 mmol) in THF (30 ml) at -78°C. The resulting mixture was warmed to room temperature and stirred for 2 h. CuCl (0.27 g,2.76 mmol) was the added at -78°C and the mixture was warmed to again to room temperature and stirred for 24 h. The volatiles were removed in vacuo and the residue was extracted with dichloromethane then filtered. The filtrate was concentrated to give colorless crystals (0.14 g, 19%). M.p.: 398–400 K. 1H NMR (CDCl3):δ 0.10–0.43 (m, 54H, SiMe3), 2.86 (m, 12H, N(CH3)2). 13C NMR (CDCl3): δ 1.74~7.44 (SiMe3), 42.16 (N(CH3)2), 172.8 (NCN).

Refinement top

H atoms of the methyl groups were placed geometrically with C—H = 0.97 Å and allowed to ride during subsequent refinement with Uiso(H) = 1.5Ueq(C).

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure showing displacement ellipsoids at 50% probability. H atoms are omitted. Symmetry code: (i) -x, y, 3/2 - z.
[µ-Bis(trimethylsilyl)amido]bis[µ-N,N-dimethyl- N',N''-bis(trimethylsilyl)guanidinato]-triangulo- tricopper(I) top
Crystal data top
[Cu3(C6H18NSi2)(C9H24N3Si2)2]F(000) = 1720
Mr = 812.00Dx = 1.261 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 3322 reflections
a = 16.445 (3) Åθ = 2.3–27.5°
b = 18.653 (4) ŵ = 1.67 mm1
c = 14.046 (3) ÅT = 213 K
β = 96.943 (3)°Block, colourless
V = 4277.1 (15) Å30.30 × 0.20 × 0.20 mm
Z = 4
Data collection top
Siemens SMART CCD
diffractometer
3773 independent reflections
Radiation source: fine-focus sealed tube3394 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
ω scansθmax = 25.0°, θmin = 1.7°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1997)
h = 1916
Tmin = 0.622, Tmax = 0.717k = 2122
8714 measured reflectionsl = 1615
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)] = 0.056Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.118H-atom parameters constrained
S = 1.26 w = 1/[σ2(Fo2) + (0.0417P)2 + 4.1466P]
where P = (Fo2 + 2Fc2)/3
3773 reflections(Δ/σ)max < 0.001
193 parametersΔρmax = 0.57 e Å3
0 restraintsΔρmin = 0.46 e Å3
Crystal data top
[Cu3(C6H18NSi2)(C9H24N3Si2)2]V = 4277.1 (15) Å3
Mr = 812.00Z = 4
Monoclinic, C2/cMo Kα radiation
a = 16.445 (3) ŵ = 1.67 mm1
b = 18.653 (4) ÅT = 213 K
c = 14.046 (3) Å0.30 × 0.20 × 0.20 mm
β = 96.943 (3)°
Data collection top
Siemens SMART CCD
diffractometer
3773 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1997)
3394 reflections with I > 2σ(I)
Tmin = 0.622, Tmax = 0.717Rint = 0.033
8714 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0560 restraints
wR(F2) = 0.118H-atom parameters constrained
S = 1.26Δρmax = 0.57 e Å3
3773 reflectionsΔρmin = 0.46 e Å3
193 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
Cu10.00565 (3)0.28899 (3)0.65704 (4)0.03181 (17)
Cu20.00000.15714 (4)0.75000.0297 (2)
N10.0253 (2)0.22736 (18)0.5568 (2)0.0335 (8)
N20.1160 (3)0.1407 (2)0.5116 (3)0.0489 (11)
N30.0812 (2)0.14177 (18)0.6683 (3)0.0327 (8)
N40.00000.3629 (2)0.75000.0331 (12)
Si10.03059 (9)0.24764 (8)0.44721 (9)0.0484 (4)
Si20.16644 (8)0.10002 (7)0.73019 (10)0.0384 (3)
Si30.09487 (9)0.40530 (7)0.75808 (11)0.0444 (4)
C10.0727 (3)0.1708 (2)0.5803 (3)0.0326 (10)
C20.1565 (4)0.1842 (3)0.4465 (4)0.0711 (18)
H2A0.12950.17800.38170.107*
H2B0.21340.16970.44930.107*
H2C0.15380.23420.46480.107*
C30.1235 (4)0.0641 (3)0.5000 (4)0.077 (2)
H3A0.08990.03970.54190.116*
H3B0.18030.05010.51630.116*
H3C0.10550.05120.43390.116*
C40.0495 (4)0.1674 (4)0.3693 (4)0.085 (2)
H4A0.00180.15120.34900.127*
H4B0.08750.17960.31330.127*
H4C0.07260.12940.40480.127*
C50.0166 (4)0.3231 (4)0.3864 (5)0.087 (2)
H5A0.03220.36090.43250.131*
H5B0.02260.34170.33520.131*
H5C0.06480.30600.35980.131*
C60.1333 (3)0.2798 (4)0.4694 (4)0.0747 (19)
H6A0.16330.24070.49460.112*
H6B0.16290.29660.40970.112*
H6C0.12730.31870.51550.112*
C70.2640 (3)0.1337 (3)0.6908 (4)0.0577 (15)
H7A0.26680.11960.62480.087*
H7B0.31020.11330.73150.087*
H7C0.26580.18550.69570.087*
C80.1675 (3)0.1227 (3)0.8591 (4)0.0543 (14)
H8A0.17330.17420.86750.081*
H8B0.21310.09870.89620.081*
H8C0.11650.10720.88090.081*
C90.1591 (4)0.0000 (2)0.7255 (4)0.0586 (15)
H9A0.10340.01460.73210.088*
H9B0.19620.02050.77740.088*
H9C0.17380.01690.66460.088*
C100.1033 (4)0.4625 (3)0.6504 (5)0.085 (2)
H10A0.06600.50270.65040.128*
H10B0.08940.43430.59270.128*
H10C0.15900.48010.65230.128*
C110.1138 (4)0.4635 (3)0.8661 (5)0.080 (2)
H11A0.09900.43790.92160.120*
H11B0.08080.50670.85640.120*
H11C0.17130.47650.87670.120*
C120.1783 (3)0.3378 (3)0.7637 (4)0.0574 (15)
H12A0.23090.36200.77080.086*
H12B0.17250.30970.70520.086*
H12C0.17510.30640.81820.086*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0350 (3)0.0301 (3)0.0309 (3)0.0019 (2)0.0064 (2)0.0008 (2)
Cu20.0272 (4)0.0326 (4)0.0308 (4)0.0000.0095 (3)0.000
N10.037 (2)0.040 (2)0.0247 (19)0.0004 (18)0.0059 (15)0.0007 (16)
N20.058 (3)0.053 (3)0.040 (2)0.002 (2)0.025 (2)0.0066 (19)
N30.032 (2)0.0316 (19)0.037 (2)0.0019 (16)0.0125 (16)0.0031 (16)
N40.035 (3)0.031 (3)0.035 (3)0.0000.007 (2)0.000
Si10.0512 (9)0.0670 (10)0.0269 (7)0.0083 (7)0.0038 (6)0.0050 (6)
Si20.0318 (7)0.0326 (7)0.0523 (8)0.0043 (6)0.0111 (6)0.0007 (6)
Si30.0451 (8)0.0317 (7)0.0583 (9)0.0068 (6)0.0139 (7)0.0011 (6)
C10.032 (3)0.039 (3)0.029 (2)0.008 (2)0.0146 (19)0.0080 (19)
C20.065 (4)0.104 (5)0.051 (4)0.006 (4)0.033 (3)0.002 (3)
C30.106 (5)0.069 (4)0.060 (4)0.018 (4)0.024 (4)0.023 (3)
C40.082 (5)0.118 (6)0.052 (4)0.026 (4)0.003 (3)0.024 (4)
C50.092 (5)0.107 (5)0.062 (4)0.017 (4)0.005 (4)0.042 (4)
C60.061 (4)0.107 (5)0.054 (4)0.014 (4)0.004 (3)0.017 (3)
C70.035 (3)0.056 (3)0.085 (4)0.002 (3)0.020 (3)0.007 (3)
C80.048 (3)0.053 (3)0.059 (3)0.007 (3)0.003 (3)0.004 (3)
C90.063 (4)0.038 (3)0.077 (4)0.007 (3)0.019 (3)0.005 (3)
C100.074 (5)0.074 (4)0.109 (6)0.022 (4)0.017 (4)0.041 (4)
C110.074 (4)0.064 (4)0.105 (5)0.029 (3)0.021 (4)0.042 (4)
C120.041 (3)0.046 (3)0.086 (4)0.008 (2)0.013 (3)0.010 (3)
Geometric parameters (Å, º) top
Cu1—Cu1i2.6405 (11)C3—H3B0.970
Cu1—Cu22.7913 (9)C3—H3C0.970
Cu2—Cu1i2.7912 (9)C4—H4A0.970
Cu1—N11.875 (3)C4—H4B0.970
Cu1—N41.908 (3)C4—H4C0.970
Cu2—N31.885 (3)C5—H5A0.970
Cu2—N3i1.885 (3)C5—H5B0.970
N1—C11.329 (5)C5—H5C0.970
N1—Si11.737 (4)C6—H6A0.970
N2—C11.386 (5)C6—H6B0.970
N2—C31.444 (6)C6—H6C0.970
N2—C21.445 (6)C7—H7A0.970
N3—C11.341 (5)C7—H7B0.970
N3—Si21.742 (4)C7—H7C0.970
N4—Si31.741 (3)C8—H8A0.970
N4—Si3i1.741 (3)C8—H8B0.970
N4—Cu1i1.909 (3)C8—H8C0.970
Si1—C61.853 (6)C9—H9A0.970
Si1—C41.859 (6)C9—H9B0.970
Si1—C51.865 (6)C9—H9C0.970
Si2—C81.858 (5)C10—H10A0.970
Si2—C71.868 (5)C10—H10B0.970
Si2—C91.871 (5)C10—H10C0.970
Si3—C121.856 (5)C11—H11A0.970
Si3—C111.862 (6)C11—H11B0.970
Si3—C101.870 (6)C11—H11C0.970
C2—H2A0.970C12—H12A0.970
C2—H2B0.970C12—H12B0.970
C2—H2C0.970C12—H12C0.970
C3—H3A0.970
N1—Cu1—N4169.49 (13)N2—C3—H3C109.5
N1—Cu1—Cu1i141.39 (11)H3A—C3—H3C109.5
N4—Cu1—Cu1i46.23 (10)H3B—C3—H3C109.5
N1—Cu1—Cu280.18 (11)Si1—C4—H4A109.5
N4—Cu1—Cu2108.00 (10)Si1—C4—H4B109.5
Cu1i—Cu1—Cu261.768 (14)H4A—C4—H4B109.5
N3—Cu2—N3i162.5 (2)Si1—C4—H4C109.5
N3—Cu2—Cu1i119.01 (11)H4A—C4—H4C109.5
N3i—Cu2—Cu1i77.47 (10)H4B—C4—H4C109.5
N3—Cu2—Cu177.47 (10)Si1—C5—H5A109.5
N3i—Cu2—Cu1119.02 (11)Si1—C5—H5B109.5
Cu1i—Cu2—Cu156.46 (3)H5A—C5—H5B109.5
C1—N1—Si1128.6 (3)Si1—C5—H5C109.5
C1—N1—Cu1116.7 (3)H5A—C5—H5C109.5
Si1—N1—Cu1114.3 (2)H5B—C5—H5C109.5
C1—N2—C3122.5 (4)Si1—C6—H6A109.5
C1—N2—C2121.9 (4)Si1—C6—H6B109.5
C3—N2—C2115.6 (4)H6A—C6—H6B109.5
C1—N3—Si2129.0 (3)Si1—C6—H6C109.5
C1—N3—Cu2119.8 (3)H6A—C6—H6C109.5
Si2—N3—Cu2110.53 (19)H6B—C6—H6C109.5
Si3—N4—Si3i125.9 (3)Si2—C7—H7A109.5
Si3—N4—Cu1104.80 (7)Si2—C7—H7B109.5
Si3i—N4—Cu1113.64 (8)H7A—C7—H7B109.5
Si3—N4—Cu1i113.64 (8)Si2—C7—H7C109.5
Si3i—N4—Cu1i104.80 (7)H7A—C7—H7C109.5
Cu1—N4—Cu1i87.5 (2)H7B—C7—H7C109.5
N1—Si1—C6108.5 (2)Si2—C8—H8A109.5
N1—Si1—C4112.3 (3)Si2—C8—H8B109.5
C6—Si1—C4105.6 (3)H8A—C8—H8B109.5
N1—Si1—C5111.4 (3)Si2—C8—H8C109.5
C6—Si1—C5105.7 (3)H8A—C8—H8C109.5
C4—Si1—C5112.8 (3)H8B—C8—H8C109.5
N3—Si2—C8107.3 (2)Si2—C9—H9A109.5
N3—Si2—C7111.7 (2)Si2—C9—H9B109.5
C8—Si2—C7107.8 (3)H9A—C9—H9B109.5
N3—Si2—C9112.6 (2)Si2—C9—H9C109.5
C8—Si2—C9104.8 (2)H9A—C9—H9C109.5
C7—Si2—C9112.3 (2)H9B—C9—H9C109.5
N4—Si3—C12110.3 (2)Si3—C10—H10A109.5
N4—Si3—C11112.2 (2)Si3—C10—H10B109.5
C12—Si3—C11108.1 (3)H10A—C10—H10B109.5
N4—Si3—C10111.1 (2)Si3—C10—H10C109.5
C12—Si3—C10107.1 (3)H10A—C10—H10C109.5
C11—Si3—C10107.7 (3)H10B—C10—H10C109.5
N1—C1—N3122.8 (3)Si3—C11—H11A109.5
N1—C1—N2119.0 (4)Si3—C11—H11B109.5
N3—C1—N2118.2 (4)H11A—C11—H11B109.5
N2—C2—H2A109.5Si3—C11—H11C109.5
N2—C2—H2B109.5H11A—C11—H11C109.5
H2A—C2—H2B109.5H11B—C11—H11C109.5
N2—C2—H2C109.5Si3—C12—H12A109.5
H2A—C2—H2C109.5Si3—C12—H12B109.5
H2B—C2—H2C109.5H12A—C12—H12B109.5
N2—C3—H3A109.5Si3—C12—H12C109.5
N2—C3—H3B109.5H12A—C12—H12C109.5
H3A—C3—H3B109.5H12B—C12—H12C109.5
Symmetry code: (i) x, y, z+3/2.

Experimental details

Crystal data
Chemical formula[Cu3(C6H18NSi2)(C9H24N3Si2)2]
Mr812.00
Crystal system, space groupMonoclinic, C2/c
Temperature (K)213
a, b, c (Å)16.445 (3), 18.653 (4), 14.046 (3)
β (°) 96.943 (3)
V3)4277.1 (15)
Z4
Radiation typeMo Kα
µ (mm1)1.67
Crystal size (mm)0.30 × 0.20 × 0.20
Data collection
DiffractometerSiemens SMART CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1997)
Tmin, Tmax0.622, 0.717
No. of measured, independent and
observed [I > 2σ(I)] reflections
8714, 3773, 3394
Rint0.033
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.118, 1.26
No. of reflections3773
No. of parameters193
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.57, 0.46

Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997).

 

Acknowledgements

The authors thank the Natural Science Foundation of China (grant No. 20672070; M. Zhou), the Natural Science Foundation of Shanxi (grant No. 2007011020) and the Foundation for Returned Overseas Chinese Scholars of Shanxi Province (2006; M. Zhou).

References

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