Bis[μ-N-(diethyl­amino-κN)dimethyl­silylanilido-κ2N:N]bis­[chlorido­cobalt(II)]

Chen, J.

doi:10.1107/S1600536811054602

metal-organic compounds

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Volume 68| Part 1| January 2012| Page m81

doi:10.1107/S1600536811054602

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Bis[μ-N-(diethylamino-κN)dimethylsilylanilido-κ²N:N]bis[chloridocobalt(II)]

Juan Chen ^a ^*

^aDepartment of Chemistry, Taiyuan Teachers College, Taiyuan 030031, People's Republic of China
^*Correspondence e-mail: sdbai@sxu.edu.cn

(Received 26 November 2011; accepted 19 December 2011; online 23 December 2011)

In the title binuclear Co^II complex, [Co₂(C₁₂H₂₁N₂Si)₂Cl₂], an inversion center is located at the mid-point between the two Co atoms in the dimeric molecule. The bidentate N-silylated anilide ligand coordinates the Co^II atom in an N,N′-chelating mode and provides the anilide N atom as a bridge to link two Co^II atoms. The two ends of the N—Si—N chelating unit exhibit different affinities for the metal atom. The Co—N_anilide bond is 2.031 (6) Å and Co—N_amino bond is 2.214 (6) Å. The four-coordinate Co atom presents a distorted tetrahedral geometry, while the dimeric aggregation exhibits a (CoN)₂ rhombus core with 1.998 (6) Å as the shortest sides and shows a ladder structure composed of Co, N and Si atoms.

Related literature

For related reviews of metal amides, see: Holm et al. (1996 ); Kempe (2000 ). For catalytic applications of related N-silylated analido group 4 metal compounds towards olefin polymerization, see: Gibson et al. (1998 ); Hill & Hitchcock (2002 ); Yuan et al. (2010 ). For related organometallic compounds supported by analogous analido ligands, see: Schumann et al. (2000 ); Chen (2008 , 2009 ). For related cobalt amides, see: Murray & Power (1984 ); Hope et al. (1985 ).

Experimental

Crystal data

[Co₂(C₁₂H₂₁N₂Si)₂Cl₂]
M_r = 631.56
Orthorhombic, P c c n
a = 12.180 (1) Å
b = 15.6753 (13) Å
c = 16.0235 (13) Å
V = 3059.3 (4) Å³
Z = 4
Mo Kα radiation
μ = 1.36 mm⁻¹
T = 293 K
0.20 × 0.15 × 0.10 mm

Data collection

Bruker SMART area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.773, T_max = 0.876
16361 measured reflections
2885 independent reflections
1795 reflections with I > 2σ(I)
R_int = 0.093

Refinement

R[F² > 2σ(F²)] = 0.072
wR(F²) = 0.227
S = 1.17
2885 reflections
154 parameters
48 restraints
H-atom parameters constrained
Δρ_max = 1.97 e Å⁻³
Δρ_min = −0.51 e Å⁻³

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.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811054602/jj2112sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811054602/jj2112Isup2.hkl

checkCIF report

Comment top

Metal amides are important substitutes for cyclopentadienyl derivatives and are found to have valuable applications in various industrial and biological processes (Holm et al., 1996; Kempe, 2000). Group 4 metal amides supported with N-silylated anilido ligands are active catalysts for olefin polymerization reactions (Gibson et al., 1998; Hill & Hitchcock, 2002). Recently, a class of monoionic N-silylated anilido ligands bearing a pendant amino group were the subject of focus presuming that the empty d-orbitals on silicon would interact with the lone-pair electrons on the p-orbital of nitrogen center through a d—pπ interaction throughout the N—Si—N motif. Analogous compounds with different metals including Zn (Schumann et al., 2000), Zr (Chen, 2009) and Fe (Chen, 2008) have been synthesized. In addition, a group of zirconium amides with a similar ligand were reported showing good performance in ethylene polymerization reactions (Yuan et al., 2010). In view of the importance of these compounds, the synthesis and crystal structure of a new cobalt(II) anilido complex, (I), is reported.

The title compound, [Co(C₁₂H₂₁N₂Si)Cl]₂, is a binuclear Co^II complex with an inversion center located at the mid-point between two Co atoms in the dimeric molecule (Fig. 1). Each Co(II) atom is bound to three nitrogen atoms and one chlorine atom, resulting in a distorted tetrahedral geomety at the metal center. The bidentate N-silylated anilide ligand coordinates a metal center in an N,N'-chelating mode and provides the anilido nitrogen as a bridge to link the two Co atoms. The two ends of the N—Si—N chelating unit exhibit different affinities for the metal center. The Co—Co distance is 2.5682 (19) Å, which is similar to 2.583 (1) Å in [Co{N(SiMe₃)₂}₂]₂ and 2.566 (3) Å in [Co(NPh₂)₂]₂ (Murray & Power, 1984; Hope et al., 1985). The N—Si—N angle is constrained to be 98.8 (3)°. The Co—N_anilido bond is 2.031 (2) Å and Co—N_amino bond is 2.214 (6) Å. The four-coordinate Co atom presents a distorted tetrahedral geometry while the dimeric aggregation exhibits a (CoN)₂ rhombus core with 2.0 Å sides and shows a ladder structure composed of Co, N and Si atoms.

Related literature top

For related reviews of metal amides, see: Holm et al. (1996); Kempe (2000). For catalytic applications of related N-silylated analido group 4 metal compounds towards olefin polymerization, see: Gibson et al. (1998); Hill & Hitchcock (2002); Yuan et al. (2010). For related organometallic compounds supported by analogous analido ligands, see: Schumann et al. (2000); Chen (2008, 2009). For related cobalt amides, see: Murray & Power (1984); Hope et al. (1985).

Experimental top

The title compound was prepared by a one-pot reaction of LiBuⁿ, N-[(diethylamino)dimethylsilyl]aniline and CoCl₂ as follows: A solution of LiBuⁿ (1.6 M, 1.75 ml, 2.8 mmol) in hexane was slowly added into a solution of N-[(diethylamino)dimethylsilyl]aniline (0.62 g, 2.8 mmol) in Et₂O (20 ml) at 273 K by syringe. The mixture was stirred at room temperature for two hours and then added to a stirring suspension of CoCl₂ (0.37 g, 2.8 mmol) in Et₂O (20 ml) at 273 K. The resulting mixture was stirred at room temperature for 8 h. Then all the volatiles were removed under vacuum. The residue was extracted with toluene (25 ml). The filtrate was concentrated and suitable green single-crystals of the title compound were obtained by recrystallization in toluene. (yield 0.25 g, 28%). Anal. Calc. for C₂₄H₄₂Cl₂Co₂N₄Si₂: C, 45.64; H, 6.70; N, 8.87%. Found: C, 45.48; H, 6.65; N, 9.05%.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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 (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. An inversion center is located at the mid-point between two Co atoms in the dimeric molecule. H atoms have been omitted for clarity.

Bis[µ-N-(diethylamino-κN)dimethylsilylanilido- κ²N:N]bis[chloridocobalt(II)] top

Crystal data top

[Co₂(C₁₂H₂₁N₂Si)₂Cl₂]	F(000) = 1320
M_r = 631.56	D_x = 1.371 Mg m⁻³
Orthorhombic, Pccn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ab 2ac	Cell parameters from 3365 reflections
a = 12.180 (1) Å	θ = 2.3–26.3°
b = 15.6753 (13) Å	µ = 1.36 mm⁻¹
c = 16.0235 (13) Å	T = 293 K
V = 3059.3 (4) Å³	Block, green
Z = 4	0.20 × 0.15 × 0.10 mm

Data collection top

Bruker SMART area-detector diffractometer	2885 independent reflections
Radiation source: fine-focus sealed tube	1795 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.093
Detector resolution: 7.9 pixels mm^-1	θ_max = 25.6°, θ_min = 2.1°
ϕ and ω scan	h = −14→14
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −17→19
T_min = 0.773, T_max = 0.876	l = −13→19
16361 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.072	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.227	H-atom parameters constrained
S = 1.17	w = 1/[σ²(F_o²) + (0.0945P)² + 13.3754P] where P = (F_o² + 2F_c²)/3
2885 reflections	(Δ/σ)_max < 0.001
154 parameters	Δρ_max = 1.97 e Å⁻³
48 restraints	Δρ_min = −0.51 e Å⁻³

Crystal data top

[Co₂(C₁₂H₂₁N₂Si)₂Cl₂]	V = 3059.3 (4) Å³
M_r = 631.56	Z = 4
Orthorhombic, Pccn	Mo Kα radiation
a = 12.180 (1) Å	µ = 1.36 mm⁻¹
b = 15.6753 (13) Å	T = 293 K
c = 16.0235 (13) Å	0.20 × 0.15 × 0.10 mm

Data collection top

Bruker SMART area-detector diffractometer	2885 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1795 reflections with I > 2σ(I)
T_min = 0.773, T_max = 0.876	R_int = 0.093
16361 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.072	48 restraints
wR(F²) = 0.227	H-atom parameters constrained
S = 1.17	w = 1/[σ²(F_o²) + (0.0945P)² + 13.3754P] where P = (F_o² + 2F_c²)/3
2885 reflections	Δρ_max = 1.97 e Å⁻³
154 parameters	Δρ_min = −0.51 e Å⁻³

Special details top

Experimental. MS (EI, 70 eV): m/z 632 [M]⁺.

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

	x	y	z	U_iso*/U_eq
Co1	0.55911 (8)	0.48017 (6)	0.43654 (6)	0.0307 (3)
Si1	0.37762 (17)	0.55954 (13)	0.36970 (13)	0.0356 (5)
Cl1	0.71974 (18)	0.48946 (17)	0.37397 (16)	0.0617 (7)
N1	0.4612 (5)	0.5831 (4)	0.4563 (4)	0.0328 (14)
N2	0.4195 (5)	0.4511 (4)	0.3528 (4)	0.0303 (13)
C1	0.4863 (7)	0.6714 (5)	0.4684 (6)	0.0472 (14)
C2	0.5770 (8)	0.7089 (5)	0.4330 (6)	0.0534 (14)
H2A	0.6230	0.6770	0.3988	0.064*
C3	0.6006 (9)	0.7956 (6)	0.4482 (6)	0.0601 (15)
H3A	0.6627	0.8207	0.4250	0.072*
C4	0.5322 (9)	0.8417 (6)	0.4969 (6)	0.0620 (15)
H4A	0.5474	0.8991	0.5059	0.074*
C5	0.4443 (8)	0.8075 (6)	0.5320 (7)	0.0607 (15)
H5A	0.3997	0.8408	0.5660	0.073*
C6	0.4175 (8)	0.7207 (5)	0.5182 (6)	0.0536 (14)
H6A	0.3549	0.6971	0.5420	0.064*
C7	0.2306 (8)	0.5722 (7)	0.3939 (8)	0.079 (4)
H7A	0.1963	0.6064	0.3516	0.119*
H7B	0.2226	0.5996	0.4472	0.119*
H7C	0.1962	0.5171	0.3957	0.119*
C8	0.4136 (10)	0.6277 (6)	0.2788 (6)	0.073 (3)
H8A	0.3484	0.6541	0.2573	0.109*
H8B	0.4465	0.5932	0.2361	0.109*
H8C	0.4646	0.6710	0.2960	0.109*
C9	0.4621 (7)	0.4311 (5)	0.2680 (5)	0.0456 (18)
H9A	0.5153	0.4742	0.2523	0.055*
H9B	0.4019	0.4338	0.2285	0.055*
C10	0.5154 (8)	0.3447 (6)	0.2621 (6)	0.057 (2)
H10A	0.5407	0.3355	0.2060	0.085*
H10B	0.4629	0.3014	0.2765	0.085*
H10C	0.5765	0.3420	0.2998	0.085*
C11	0.3406 (7)	0.3856 (5)	0.3839 (5)	0.0468 (19)
H11A	0.3119	0.4042	0.4374	0.056*
H11B	0.3800	0.3326	0.3930	0.056*
C12	0.2441 (8)	0.3683 (6)	0.3251 (6)	0.056 (2)
H12A	0.1971	0.3257	0.3492	0.083*
H12B	0.2714	0.3483	0.2724	0.083*
H12C	0.2032	0.4200	0.3169	0.083*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.0344 (5)	0.0272 (5)	0.0305 (6)	0.0036 (4)	0.0043 (4)	0.0027 (4)
Si1	0.0450 (12)	0.0250 (11)	0.0369 (12)	0.0043 (9)	−0.0108 (10)	0.0007 (9)
Cl1	0.0470 (12)	0.0727 (17)	0.0655 (15)	0.0029 (11)	0.0246 (11)	0.0051 (12)
N1	0.040 (3)	0.023 (3)	0.036 (4)	0.005 (2)	−0.006 (3)	0.001 (2)
N2	0.045 (3)	0.018 (3)	0.028 (3)	0.000 (2)	−0.004 (3)	−0.002 (2)
C1	0.064 (3)	0.024 (3)	0.053 (3)	0.001 (2)	−0.020 (3)	0.003 (2)
C2	0.069 (3)	0.030 (3)	0.061 (3)	−0.004 (2)	−0.019 (3)	0.006 (2)
C3	0.077 (3)	0.035 (3)	0.068 (3)	−0.006 (3)	−0.022 (3)	0.007 (3)
C4	0.082 (3)	0.035 (3)	0.069 (3)	−0.001 (3)	−0.025 (3)	0.002 (2)
C5	0.081 (3)	0.036 (3)	0.066 (3)	0.007 (3)	−0.022 (3)	−0.003 (2)
C6	0.072 (3)	0.030 (3)	0.059 (3)	0.005 (2)	−0.020 (3)	−0.001 (2)
C7	0.058 (6)	0.079 (8)	0.100 (9)	0.027 (6)	−0.024 (6)	−0.027 (7)
C8	0.139 (10)	0.036 (5)	0.042 (5)	−0.014 (6)	−0.035 (6)	0.010 (4)
C9	0.060 (5)	0.043 (4)	0.034 (4)	−0.003 (4)	0.005 (3)	0.001 (3)
C10	0.074 (5)	0.051 (5)	0.046 (4)	0.004 (4)	0.007 (4)	−0.011 (4)
C11	0.056 (4)	0.036 (4)	0.048 (4)	−0.008 (3)	−0.012 (4)	0.006 (3)
C12	0.062 (4)	0.043 (4)	0.062 (5)	−0.014 (4)	−0.017 (4)	0.007 (4)

Geometric parameters (Å, º) top

Co1—N1ⁱ	1.998 (6)	C5—C6	1.416 (12)
Co1—N1	2.031 (6)	C5—H5A	0.9300
Co1—Cl1	2.203 (2)	C6—H6A	0.9300
Co1—N2	2.214 (6)	C7—H7A	0.9600
Co1—Co1ⁱ	2.5682 (19)	C7—H7B	0.9600
Co1—Si1	2.754 (2)	C7—H7C	0.9600
Si1—N1	1.760 (6)	C8—H8A	0.9600
Si1—N2	1.795 (6)	C8—H8B	0.9600
Si1—C7	1.843 (10)	C8—H8C	0.9600
Si1—C8	1.859 (9)	C9—C10	1.505 (12)
N1—C1	1.431 (9)	C9—H9A	0.9700
N1—Co1ⁱ	1.998 (6)	C9—H9B	0.9700
N2—C9	1.487 (10)	C10—H10A	0.9600
N2—C11	1.492 (10)	C10—H10B	0.9600
C1—C2	1.375 (13)	C10—H10C	0.9600
C1—C6	1.391 (13)	C11—C12	1.531 (11)
C2—C3	1.410 (12)	C11—H11A	0.9700
C2—H2A	0.9300	C11—H11B	0.9700
C3—C4	1.351 (14)	C12—H12A	0.9600
C3—H3A	0.9300	C12—H12B	0.9600
C4—C5	1.323 (14)	C12—H12C	0.9600
C4—H4A	0.9300

N1ⁱ—Co1—N1	100.8 (2)	C5—C4—C3	121.9 (10)
N1ⁱ—Co1—Cl1	122.26 (18)	C5—C4—H4A	119.1
N1—Co1—Cl1	122.67 (19)	C3—C4—H4A	119.1
N1ⁱ—Co1—N2	108.9 (2)	C4—C5—C6	120.6 (10)
N1—Co1—N2	78.9 (2)	C4—C5—H5A	119.7
Cl1—Co1—N2	114.83 (18)	C6—C5—H5A	119.7
N1ⁱ—Co1—Co1ⁱ	50.96 (17)	C1—C6—C5	119.0 (9)
N1—Co1—Co1ⁱ	49.84 (17)	C1—C6—H6A	120.5
Cl1—Co1—Co1ⁱ	147.37 (10)	C5—C6—H6A	120.5
N2—Co1—Co1ⁱ	95.69 (16)	Si1—C7—H7A	109.5
N1ⁱ—Co1—Si1	117.33 (18)	Si1—C7—H7B	109.5
N1—Co1—Si1	39.67 (17)	H7A—C7—H7B	109.5
Cl1—Co1—Si1	120.40 (9)	Si1—C7—H7C	109.5
N2—Co1—Si1	40.57 (15)	H7A—C7—H7C	109.5
Co1ⁱ—Co1—Si1	75.44 (6)	H7B—C7—H7C	109.5
N1—Si1—N2	98.8 (3)	Si1—C8—H8A	109.5
N1—Si1—C7	111.9 (4)	Si1—C8—H8B	109.5
N2—Si1—C7	114.2 (4)	H8A—C8—H8B	109.5
N1—Si1—C8	111.2 (4)	Si1—C8—H8C	109.5
N2—Si1—C8	111.0 (4)	H8A—C8—H8C	109.5
C7—Si1—C8	109.4 (6)	H8B—C8—H8C	109.5
N1—Si1—Co1	47.44 (19)	N2—C9—C10	113.5 (7)
N2—Si1—Co1	53.33 (19)	N2—C9—H9A	108.9
C7—Si1—Co1	138.3 (4)	C10—C9—H9A	108.9
C8—Si1—Co1	112.0 (4)	N2—C9—H9B	108.9
C1—N1—Si1	115.7 (5)	C10—C9—H9B	108.9
C1—N1—Co1ⁱ	112.9 (5)	H9A—C9—H9B	107.7
Si1—N1—Co1ⁱ	120.1 (3)	C9—C10—H10A	109.5
C1—N1—Co1	131.6 (5)	C9—C10—H10B	109.5
Si1—N1—Co1	92.9 (3)	H10A—C10—H10B	109.5
Co1ⁱ—N1—Co1	79.2 (2)	C9—C10—H10C	109.5
C9—N2—C11	112.6 (6)	H10A—C10—H10C	109.5
C9—N2—Si1	115.9 (5)	H10B—C10—H10C	109.5
C11—N2—Si1	114.7 (5)	N2—C11—C12	114.2 (7)
C9—N2—Co1	109.2 (5)	N2—C11—H11A	108.7
C11—N2—Co1	115.7 (4)	C12—C11—H11A	108.7
Si1—N2—Co1	86.1 (2)	N2—C11—H11B	108.7
C2—C1—C6	118.9 (8)	C12—C11—H11B	108.7
C2—C1—N1	122.0 (8)	H11A—C11—H11B	107.6
C6—C1—N1	119.2 (8)	C11—C12—H12A	109.5
C1—C2—C3	120.4 (10)	C11—C12—H12B	109.5
C1—C2—H2A	119.8	H12A—C12—H12B	109.5
C3—C2—H2A	119.8	C11—C12—H12C	109.5
C4—C3—C2	119.3 (10)	H12A—C12—H12C	109.5
C4—C3—H3A	120.4	H12B—C12—H12C	109.5
C2—C3—H3A	120.4

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	[Co₂(C₁₂H₂₁N₂Si)₂Cl₂]
M_r	631.56
Crystal system, space group	Orthorhombic, Pccn
Temperature (K)	293
a, b, c (Å)	12.180 (1), 15.6753 (13), 16.0235 (13)
V (Å³)	3059.3 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	1.36
Crystal size (mm)	0.20 × 0.15 × 0.10

Data collection
Diffractometer	Bruker SMART area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.773, 0.876
No. of measured, independent and observed [I > 2σ(I)] reflections	16361, 2885, 1795
R_int	0.093
(sin θ/λ)_max (Å⁻¹)	0.608

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.072, 0.227, 1.17
No. of reflections	2885
No. of parameters	154
No. of restraints	48
H-atom treatment	H-atom parameters constrained
	w = 1/[σ²(F_o²) + (0.0945P)² + 13.3754P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	1.97, −0.51

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL/PC (Sheldrick, 2008).

Acknowledgements

This work was sponsored by the Natural Science Foundation of China (20702029) and the Natural Science Foundation of Shanxi Province (2008011024).

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