1,2-Bis(dicyclo­hexyl­phosphino)-1,2-di­carba-closo-dodeca­borane

The title compound, C₂₆H₅₄B₁₀P₂, was obtained by the reaction of 1,2-carborane, n-butyl­lithium and dicyclo­hexyl­chloro­phosphine in diethyl ether. The mol­ecule lies on a crystallographic twofold rotation axis through the mid-point of the C-C bond of the carborane. The P atoms of the dicyclo­hexyl­phosphine groups are bonded to the two C atoms in the 1,2-dicarbaborane cage with a unique P-C distance of 1.894 (3) Å.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.063
• wR factor = 0.197
• Data-to-parameter ratio = 15.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       3.20
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.24 Ratio
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for        C11
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C9
PLAT320_ALERT_2_C Check Hybridisation of  C1     in Main Residue .          ?
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5
PLAT367_ALERT_2_C Long?  C(sp?)-C(sp?) Bond  C1     -   C1_a   ...       1.69 Ang.
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.13 Ratio

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   9 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   6 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The structure of 1,2-(PPh₂)-1,2-C₂B₁₀H₁₀ (Zhang et al., 2006) has recently been reported and was synthesized by the method of Alexander & Schroeder (1963). In addition, 1,2-(PⁱPr₂)₂-1,2-C₂B₁₀H₁₀ was synthesized and characterized by Kivekäs et al. (1995). Since then, many complexes containing the above two lignads have been reported. We are interested in phosphine derivatives of 1,2-dicarba-closo-dodecaborane. In this paper, we report the structure of 1,2-bis(dicyclohexylphosphino)-1,2-dicarba-closo-dodecaborane.

As shown in Fig. 1, the molecular structure of the title compound has crystallographic twofold rotation symmetry. The P atom of dicyclohexylphosphine group is bonded to C1. The P—C1 distance is 1.894 (3) Å, which is agreement well with the corresponding distance 1.894 (3) Å in 1,2-(PⁱPr₂)₂-1,2-C₂B₁₀H₁₀ and 1.885 Å in 1,2-(PPh₂)-1,2-C₂B₁₀H₁₀. The P—C1—C1ⁱ angle [symmetry code (i): 1 - x, y, 1/2 - z] in 1,2-(PCycl₂)-1,2-C₂B₁₀H₁₀ is 113.48 (5)°. The corresponding angles in 1,2-(PPh₂)-1,2-C₂B₁₀H₁₀ (Zhang et al., 2006) and 1,2-(PⁱPr₂)₂-1,2-C₂B₁₀H₁₀ (Kivekäs et al., 1995) are 116.6 (2),111.07 (19)° and 112.9 (2),112.3 (1)° respectively. The two phosphorus and two cage C atoms are almost coplanar with the torsion angle 10.9 (4)°, which is samller than that of 12.1 (2)° for 1,2-(PⁱPr₂)₂-1,2-C₂B₁₀H₁₀ (Kivekäs et al., 1995), and almost equal to that of 10.6 (3)° for 1,2-(PPh₂)-1,2-C₂B₁₀H₁₀ (Zhang et al., 2006).

Related literature

For synthesis see: Alexander & Schroeder (1963) and for related structures see: Zhang et al. (2006); Kivekäs et al. (1995).

S2. Experimental

The title compound was synthesizd according to the literature method (Alexander & Schroeder, 1963). But in our synthesis diphenylchorophosphine was substituted with dicyclohexylchorophosphine. A white solid was dissolved in dichloromethane, and crystals suitable for X-ray diffraction were obtained after partial evaporation (65.2%, m.p. 528–529 K). FTIR (KBr) v (cm-l): 2928,2850 (C–H); 2643,2622,2599,2555 (B–H).

S3. Refinement

All H atoms were placed geometrically and treated as riding on their parent atoms, with B—H 1.10, C—H 0.97 (methylene) C—H 0.98 Å (hypomethyl), with U_iso(H) = 1.2U_eq(B,C).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. The molecular structure with atom labels and 40% probability displacement ellipsoids for non-H atoms.

1,2-Bis(dicyclohexylphosphino)-1,2-dicarba-closo-dodecaborane

Crystal data

C26H54B10P2	F(000) = 1160
Mr = 536.73	Dx = 1.109 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1912 reflections
a = 21.507 (2) Å	θ = 2.3–26.8°
b = 10.0350 (14) Å	µ = 0.15 mm^−1
c = 15.2976 (18) Å	T = 298 K
β = 103.196 (2)°	Block, colorless
V = 3214.4 (7) Å^3	0.58 × 0.57 × 0.46 mm
Z = 4

Data collection

Bruker SMART CCD diffractometer	2743 independent reflections
Radiation source: fine-focus sealed tube	1814 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.081
φ and ω scans	θmax = 25.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −25→19
Tmin = 0.917, Tmax = 0.934	k = −11→10
6226 measured reflections	l = −17→18

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.063	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.197	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.095P)^2 + 4.2002P] where P = (Fo^2 + 2Fc^2)/3
2743 reflections	(Δ/σ)max < 0.001
172 parameters	Δρmax = 0.84 e Å^−3
1 restraint	Δρmin = −0.26 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
P1	0.42512 (4)	0.27894 (9)	0.24958 (6)	0.0338 (3)
B1	0.43839 (18)	0.5863 (4)	0.2987 (3)	0.0430 (10)
H1	0.3976	0.5852	0.3308	0.052*
B2	0.42621 (18)	0.5876 (4)	0.1819 (3)	0.0449 (10)
H2	0.3780	0.5879	0.1379	0.054*
B3	0.49093 (16)	0.4982 (4)	0.1542 (3)	0.0369 (9)
H3	0.4852	0.4392	0.0923	0.044*
B4	0.4907 (2)	0.6734 (4)	0.1540 (3)	0.0507 (11)
H4	0.4848	0.7297	0.0909	0.061*
B5	0.4581 (2)	0.7292 (4)	0.2444 (3)	0.0533 (12)
H5	0.4310	0.8228	0.2410	0.064*
C1	0.45992 (3)	0.4513 (3)	0.2439 (2)	0.0322 (7)
C2	0.34879 (14)	0.3209 (4)	0.2810 (2)	0.0376 (8)
H2A	0.3332	0.4063	0.2534	0.045*
C3	0.29691 (16)	0.2158 (4)	0.2520 (2)	0.0491 (10)
H3A	0.2880	0.2056	0.1872	0.059*
H3B	0.3121	0.1308	0.2788	0.059*
C4	0.23611 (17)	0.2539 (5)	0.2798 (3)	0.0585 (12)
H4A	0.2048	0.1837	0.2621	0.070*
H4B	0.2189	0.3346	0.2485	0.070*
C5	0.24694 (19)	0.2765 (5)	0.3802 (3)	0.0596 (11)
H5A	0.2079	0.3091	0.3943	0.071*
H5B	0.2581	0.1928	0.4116	0.071*
C6	0.30009 (18)	0.3768 (4)	0.4113 (3)	0.0579 (11)
H6A	0.3089	0.3847	0.4762	0.070*
H6B	0.2866	0.4634	0.3858	0.070*
C7	0.36042 (16)	0.3344 (4)	0.3831 (2)	0.0469 (9)
H7A	0.3750	0.2497	0.4110	0.056*
H7B	0.3937	0.3998	0.4040	0.056*
C8	0.40569 (16)	0.2213 (4)	0.1319 (2)	0.0411 (8)
H8	0.4456	0.2351	0.1124	0.049*
C9	0.35584 (16)	0.2903 (4)	0.0595 (2)	0.0421 (9)
H9A	0.3146	0.2842	0.0749	0.050*
H9B	0.3667	0.3839	0.0579	0.050*
C10	0.3510 (3)	0.2312 (5)	−0.0312 (3)	0.0753 (14)
H10A	0.3147	0.2705	−0.0727	0.090*
H10B	0.3891	0.2541	−0.0518	0.090*
C11	0.3436 (3)	0.0868 (6)	−0.0332 (3)	0.104 (2)
H11A	0.3444	0.0544	−0.0927	0.124*
H11B	0.3024	0.0642	−0.0216	0.124*
C12	0.3957 (3)	0.0175 (5)	0.0354 (3)	0.0798 (15)
H12A	0.4366	0.0311	0.0203	0.096*
H12B	0.3873	−0.0775	0.0346	0.096*
C13	0.3979 (2)	0.0735 (4)	0.1297 (3)	0.0677 (12)
H13A	0.3588	0.0504	0.1475	0.081*
H13B	0.4333	0.0333	0.1725	0.081*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0271 (4)	0.0393 (5)	0.0346 (5)	−0.0027 (3)	0.0062 (3)	0.0053 (4)
B1	0.0341 (19)	0.043 (2)	0.055 (3)	0.0033 (16)	0.0179 (17)	−0.006 (2)
B2	0.0306 (19)	0.047 (2)	0.059 (3)	0.0054 (17)	0.0147 (17)	0.013 (2)
B3	0.0304 (17)	0.043 (2)	0.040 (2)	0.0035 (16)	0.0118 (15)	0.0096 (17)
B4	0.045 (2)	0.041 (2)	0.070 (3)	0.0025 (19)	0.022 (2)	0.015 (2)
B5	0.046 (2)	0.040 (2)	0.079 (4)	0.0055 (19)	0.026 (2)	0.001 (2)
C1	0.0214 (15)	0.0375 (18)	0.0391 (19)	−0.0004 (13)	0.0103 (12)	0.0026 (14)
C2	0.0266 (15)	0.052 (2)	0.0353 (19)	−0.0063 (14)	0.0096 (13)	0.0050 (16)
C3	0.0410 (19)	0.069 (3)	0.040 (2)	−0.0186 (18)	0.0134 (15)	0.0007 (18)
C4	0.0346 (19)	0.093 (3)	0.051 (3)	−0.0203 (19)	0.0150 (17)	−0.003 (2)
C5	0.048 (2)	0.081 (3)	0.058 (3)	−0.015 (2)	0.0298 (18)	−0.003 (2)
C6	0.059 (2)	0.075 (3)	0.046 (2)	−0.016 (2)	0.0254 (18)	−0.008 (2)
C7	0.0398 (18)	0.062 (2)	0.038 (2)	−0.0123 (17)	0.0089 (15)	0.0043 (18)
C8	0.0354 (17)	0.048 (2)	0.040 (2)	0.0072 (15)	0.0083 (14)	0.0042 (16)
C9	0.0398 (18)	0.049 (2)	0.036 (2)	−0.0035 (16)	0.0053 (14)	0.0078 (16)
C10	0.091 (3)	0.082 (3)	0.047 (3)	0.007 (3)	0.003 (2)	−0.003 (2)
C11	0.157 (6)	0.081 (4)	0.055 (3)	−0.005 (4)	−0.013 (3)	−0.018 (3)
C12	0.111 (4)	0.056 (3)	0.066 (3)	0.007 (3)	0.007 (3)	−0.015 (2)
C13	0.076 (3)	0.054 (3)	0.071 (3)	−0.004 (2)	0.012 (2)	−0.003 (2)

Geometric parameters (Å, º)

P1—C8	1.845 (4)	C3—C4	1.514 (5)
P1—C2	1.861 (3)	C3—H3A	0.9700
P1—C1	1.894 (3)	C3—H3B	0.9700
B1—C1	1.712 (5)	C4—C5	1.517 (6)
B1—B2	1.747 (6)	C4—H4A	0.9700
B1—B5	1.757 (6)	C4—H4B	0.9700
B1—B4^i	1.762 (6)	C5—C6	1.516 (5)
B1—B3^i	1.764 (5)	C5—H5A	0.9700
B1—H1	1.1000	C5—H5B	0.9700
B2—C1	1.727 (5)	C6—C7	1.519 (5)
B2—B5	1.762 (6)	C6—H6A	0.9700
B2—B4	1.766 (6)	C6—H6B	0.9700
B2—B3	1.786 (5)	C7—H7A	0.9700
B2—H2	1.1000	C7—H7B	0.9700
B3—C1	1.722 (5)	C8—C13	1.493 (6)
B3—C1^i	1.737 (5)	C8—C9	1.521 (5)
B3—B4	1.758 (6)	C8—H8	0.9800
B3—B1^i	1.764 (5)	C9—C10	1.491 (6)
B3—H3	1.1000	C9—H9A	0.9700
B4—B1^i	1.762 (6)	C9—H9B	0.9700
B4—B5^i	1.778 (7)	C10—C11	1.458 (7)
B4—B5	1.779 (7)	C10—H10A	0.9700
B4—H4	1.1000	C10—H10B	0.9700
B5—B5^i	1.771 (8)	C11—C12	1.517 (7)
B5—B4^i	1.778 (7)	C11—H11A	0.9700
B5—H5	1.1000	C11—H11B	0.9700
C1—C1^i	1.6911 (10)	C12—C13	1.539 (6)
C1—B3^i	1.737 (5)	C12—H12A	0.9700
C2—C3	1.526 (5)	C12—H12B	0.9700
C2—C7	1.530 (5)	C13—H13A	0.9700
C2—H2A	0.9800	C13—H13B	0.9700
C8—P1—C2	107.84 (15)	B3—C1—B2	62.4 (2)
C8—P1—C1	104.18 (15)	C1^i—C1—B3^i	60.30 (19)
C2—P1—C1	100.73 (13)	B1—C1—B3^i	61.5 (2)
C1—B1—B2	59.9 (2)	B3—C1—B3^i	112.0 (2)
C1—B1—B5	107.0 (3)	B2—C1—B3^i	111.8 (3)
B2—B1—B5	60.4 (2)	C1^i—C1—P1	113.48 (5)
C1—B1—B4^i	106.8 (2)	B1—C1—P1	123.10 (18)
B2—B1—B4^i	109.3 (3)	B3—C1—P1	121.0 (2)
B5—B1—B4^i	60.7 (3)	B2—C1—P1	128.88 (17)
C1—B1—B3^i	59.93 (19)	B3^i—C1—P1	111.8 (2)
B2—B1—B3^i	109.6 (3)	C3—C2—C7	107.3 (3)
B5—B1—B3^i	108.9 (3)	C3—C2—P1	113.4 (3)
B4^i—B1—B3^i	59.8 (2)	C7—C2—P1	109.6 (2)
C1—B1—H1	122.9	C3—C2—H2A	108.8
B2—B1—H1	120.6	C7—C2—H2A	108.8
B5—B1—H1	121.5	P1—C2—H2A	108.8
B4^i—B1—H1	121.7	C4—C3—C2	111.4 (3)
B3^i—B1—H1	121.0	C4—C3—H3A	109.4
C1—B2—B1	59.1 (2)	C2—C3—H3A	109.4
C1—B2—B5	106.1 (3)	C4—C3—H3B	109.4
B1—B2—B5	60.1 (2)	C2—C3—H3B	109.4
C1—B2—B4	105.3 (2)	H3A—C3—H3B	108.0
B1—B2—B4	108.0 (3)	C3—C4—C5	112.3 (3)
B5—B2—B4	60.5 (3)	C3—C4—H4A	109.1
C1—B2—B3	58.67 (19)	C5—C4—H4A	109.1
B1—B2—B3	107.2 (3)	C3—C4—H4B	109.1
B5—B2—B3	107.8 (3)	C5—C4—H4B	109.1
B4—B2—B3	59.3 (2)	H4A—C4—H4B	107.9
C1—B2—H2	123.9	C6—C5—C4	110.4 (3)
B1—B2—H2	121.7	C6—C5—H5A	109.6
B5—B2—H2	121.7	C4—C5—H5A	109.6
B4—B2—H2	122.3	C6—C5—H5B	109.6
B3—B2—H2	122.3	C4—C5—H5B	109.6
C1—B3—C1^i	58.54 (13)	H5A—C5—H5B	108.1
C1—B3—B4	105.9 (3)	C5—C6—C7	110.9 (3)
C1^i—B3—B4	105.9 (3)	C5—C6—H6A	109.5
C1—B3—B1^i	105.4 (3)	C7—C6—H6A	109.5
C1^i—B3—B1^i	58.6 (2)	C5—C6—H6B	109.5
B4—B3—B1^i	60.1 (2)	C7—C6—H6B	109.5
C1—B3—B2	59.0 (2)	H6A—C6—H6B	108.1
C1^i—B3—B2	105.7 (3)	C6—C7—C2	111.3 (3)
B4—B3—B2	59.8 (2)	C6—C7—H7A	109.4
B1^i—B3—B2	107.3 (3)	C2—C7—H7A	109.4
C1—B3—H3	123.5	C6—C7—H7B	109.4
C1^i—B3—H3	123.5	C2—C7—H7B	109.4
B4—B3—H3	122.4	H7A—C7—H7B	108.0
B1^i—B3—H3	122.5	C13—C8—C9	112.3 (3)
B2—B3—H3	122.3	C13—C8—P1	109.4 (3)
B3—B4—B1^i	60.1 (2)	C9—C8—P1	122.2 (3)
B3—B4—B2	60.9 (2)	C13—C8—H8	103.6
B1^i—B4—B2	108.2 (3)	C9—C8—H8	103.6
B3—B4—B5^i	108.2 (3)	P1—C8—H8	103.6
B1^i—B4—B5^i	59.5 (2)	C10—C9—C8	112.7 (3)
B2—B4—B5^i	107.8 (3)	C10—C9—H9A	109.1
B3—B4—B5	108.3 (3)	C8—C9—H9A	109.1
B1^i—B4—B5	107.1 (3)	C10—C9—H9B	109.1
B2—B4—B5	59.6 (3)	C8—C9—H9B	109.1
B5^i—B4—B5	59.7 (3)	H9A—C9—H9B	107.8
B3—B4—H4	121.1	C11—C10—C9	113.5 (4)
B1^i—B4—H4	122.1	C11—C10—H10A	108.9
B2—B4—H4	121.5	C9—C10—H10A	108.9
B5^i—B4—H4	122.0	C11—C10—H10B	108.9
B5—B4—H4	122.2	C9—C10—H10B	108.9
B1—B5—B2	59.5 (2)	H10A—C10—H10B	107.7
B1—B5—B5^i	107.7 (3)	C10—C11—C12	112.5 (4)
B2—B5—B5^i	108.3 (3)	C10—C11—H11A	109.1
B1—B5—B4^i	59.8 (2)	C12—C11—H11A	109.1
B2—B5—B4^i	107.9 (3)	C10—C11—H11B	109.1
B5^i—B5—B4^i	60.2 (3)	C12—C11—H11B	109.1
B1—B5—B4	106.9 (3)	H11A—C11—H11B	107.8
B2—B5—B4	59.8 (2)	C11—C12—C13	110.0 (4)
B5^i—B5—B4	60.1 (3)	C11—C12—H12A	109.7
B4^i—B5—B4	107.8 (3)	C13—C12—H12A	109.7
B1—B5—H5	122.4	C11—C12—H12B	109.7
B2—B5—H5	121.7	C13—C12—H12B	109.7
B5^i—B5—H5	121.4	H12A—C12—H12B	108.2
B4^i—B5—H5	121.7	C8—C13—C12	111.3 (4)
B4—B5—H5	122.1	C8—C13—H13A	109.4
C1^i—C1—B1	109.19 (19)	C12—C13—H13A	109.4
C1^i—C1—B3	61.16 (19)	C8—C13—H13B	109.4
B1—C1—B3	111.8 (3)	C12—C13—H13B	109.4
C1^i—C1—B2	110.50 (19)	H13A—C13—H13B	108.0
B1—C1—B2	61.0 (2)

Symmetry code: (i) −x+1, y, −z+1/2.