Monoclinic form of 1,2,4,5-tetra­cyclo­hexyl­benzene

Mague, J.T.; Linhardt, L.; Medina, I.; Sattler, D.J.; Fink, M.J.

doi:10.1107/S160053680706758X

organic compounds

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ISSN: 2056-9890

Volume 64| Part 2| February 2008| Page o375

doi:10.1107/S160053680706758X

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Monoclinic form of 1,2,4,5-tetracyclohexylbenzene

Joel T. Mague,^a ^* Lisa Linhardt,^a Iliana Medina,^a Daniel J. Sattler ^a and Mark J. Fink ^a

^aDepartment of Chemistry, Tulane University, New Orleans, LA 70118, USA
^*Correspondence e-mail: joelt@tulane.edu

(Received 13 December 2007; accepted 18 December 2007; online 4 January 2008)

The molecule of the title compound, C₃₀H₄₆, has a crystallographically imposed inversion center and the cyclohexyl groups are oriented with their methine H atoms pointing towards one another (H⋯H = 1.99 Å). The cyclohexyl groups adopt chair conformations. A significant C—H⋯π interaction assembles molecules into layers parallel to (100).

Related literature

For related structures, see: Mague et al. (2008a ,b ); Vilardo et al. (2000 ). For related literature, see: Koudelka et al. (1985 ); Saito et al. (2004 ); Schweiger et al. (2001 ).

Experimental

Crystal data

C₃₀H₄₆
M_r = 406.67
Monoclinic, P 2₁ /c
a = 10.3868 (7) Å
b = 10.1434 (7) Å
c = 11.5419 (8) Å
β = 93.314 (1)°
V = 1213.99 (14) Å³
Z = 2
Mo Kα radiation
μ = 0.06 mm⁻¹
T = 100 (2) K
0.24 × 0.21 × 0.11 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2002 ) T_min = 0.975, T_max = 0.993
10421 measured reflections
2805 independent reflections
2460 reflections with I > 2σ(I)
R_int = 0.019

Refinement

R[F² > 2σ(F²)] = 0.046
wR(F²) = 0.126
S = 1.04
2805 reflections
136 parameters
H-atom parameters constrained
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

Cg is the centroid of the aromatic ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6A⋯Cgⁱ	0.99	2.62	3.520 (2)	150
Symmetry code: (i) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2000 ); cell refinement: SAINT-Plus (Bruker 2004 ); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680706758X/gk2127sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053680706758X/gk2127Isup2.hkl

checkCIF report

Comment top

Poly(cyclohexyl)benzenes have been used in the synthesis of a variety of sterically bulky protecting groups (Koudelka et al., 1985); Saito et al., 2004; Vilardo et al., 2000; Schweiger et al., 2001). Crystallization of 1,2,4,5-tetracylohexylbenzene (C₃₀H₄₆) from hot methylcyclohexane forms colorless needle-shaped crystals together with a smaller quantity having a distinctly different block-shaped morphology. The latter is monoclinic with the molecule having crystallographically imposed centrosymmetry. The cyclohexyl rings adopt the chair conformation and are oriented with their methine hydrogen atoms pointed towards one another (H···H distance 1.99 Å). This contrasts with the structure of 1-bromo-2,4,6-tricyclohexylbenzene (Mague et al., 2008b) where the methine hydrogen atoms of the meta-disposed cyclohexyl groups point towards the intervening ring substituent. This is presumably to minimize intramolecular contacts between the ortho-disposed cyclohexyl rings. Indeed, there are very few close contacts involving these substituents, the shortest being H4···H10 (1.99 Å), H3···H5a (2.18 Å) and H3···H11a' (2.07 Å). The plane defined by the atoms C5, C6, C8, C9 ("seat" of the chair) is inclined to the plane of the aromatic ring by 79.0 (2)° while that for the other cyclohexyl ring (C11, C12, C14, C15) is inclined at an angle of only 61.7 (2)°. A significant C—H···π interaction occurs between C6—H6A and the center of gravity (Cg) of the aromatic ring in the molecule at 1 - x, 1/2 + y, 0.5 - z where the H—Cg distance is 2.62 Å and the C—H···Cg angle is 150°. This interaction forms layers of molecules parallel to (100) at approximately x = 0.5.

Related literature top

For related structures, see: Mague et al. (2008a,b); Vilardo et al. (2000). For related literature, see: Koudelka et al. (1985); Saito et al. (2004); Schweiger et al. (2001).

Experimental top

A mixture of chlorocyclohexane (125 ml, 1.05 mol) and benzene (9 ml, 0.1 mol) in a 250 ml 3-necked flask was cooled to -40° C and mechanically stirred while anhydrous AlCl₃ (6.6 g, 0.05 mol) was added in portions over a 20 min. period. The mixture was allowed to slowly warm to -15° C and the stirring continued for 2 h. The resulting yellow-orange mixture was quenched by pouring it over 800 g of ice and, after thawing, was filtered. The organic layer of the filtrate was separated off, washed several times with water and reduced to a small volume under reduced pressure. After standing for 1 week, a precipitate formed which was filtered off, washed with 10% aqueous HCl and collected by filtration to provide 16.0 g (40%) of white solid (M.p. 549–550 K, bulk sample). ¹H NMR (δ, CDCl₃): 1.4 (20H, br multiplet), 1.8 (20H, br multiplet),2.7 (4H, multiplet), 7.2 (2H, s). ¹³C NMR (δ, CDCl₃): 26.59, 27.56, 34.97, 123.25, 141.8.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT-Plus (Bruker 2004); data reduction: SAINT-Plus (Bruker 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker,2000); software used to prepare material for publication: SHELXTL (Bruker,2000).

Figures top

Fig. 1. Molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level and H-atoms are represented by spheres of arbitrary radius. Primed atoms are related to unprimed atoms by the symmetry operation 0.5 - x, -y, -z

1,2,4,5-tetracyclohexylbenzene top

Crystal data top

C₃₀H₄₆	F(000) = 452
M_r = 406.67	D_x = 1.113 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 6595 reflections
a = 10.3868 (7) Å	θ = 2.7–28.3°
b = 10.1434 (7) Å	µ = 0.06 mm⁻¹
c = 11.5419 (8) Å	T = 100 K
β = 93.314 (1)°	Block, colorless
V = 1213.99 (14) Å³	0.24 × 0.21 × 0.11 mm
Z = 2

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	2805 independent reflections
Radiation source: fine-focus sealed tube	2460 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.019
Detector resolution: 0 pixels mm^-1	θ_max = 27.6°, θ_min = 2.0°
ω scans	h = −13→13
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	k = −13→13
T_min = 0.975, T_max = 0.993	l = −14→14
10421 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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.126	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0727P)² + 0.3565P] where P = (F_o² + 2F_c²)/3
2805 reflections	(Δ/σ)_max < 0.001
136 parameters	Δρ_max = 0.39 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₃₀H₄₆	V = 1213.99 (14) Å³
M_r = 406.67	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.3868 (7) Å	µ = 0.06 mm⁻¹
b = 10.1434 (7) Å	T = 100 K
c = 11.5419 (8) Å	0.24 × 0.21 × 0.11 mm
β = 93.314 (1)°

Data collection top

Bruker SMART APEX CCD area-detector diffractometer	2805 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	2460 reflections with I > 2σ(I)
T_min = 0.975, T_max = 0.993	R_int = 0.019
10421 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.046	0 restraints
wR(F²) = 0.126	H-atom parameters constrained
S = 1.04	Δρ_max = 0.39 e Å⁻³
2805 reflections	Δρ_min = −0.21 e Å⁻³
136 parameters

Special details top

Experimental. The diffraction data were collected in three sets of 606 frames (ω scans, 0.3°/scan) at ϕ settings of 0, 120 and 240°.

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. H-atoms were placed in calculated positions (C—H = 0.95 - 0.98 Å) and included as riding contributions with isotropic displacement parameters 1.2 - 1.5 times those of the attached carbon atoms.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.62897 (10)	−0.01942 (10)	0.04453 (8)	0.0136 (2)
C2	0.57336 (10)	0.10675 (10)	0.04764 (9)	0.0144 (2)
C3	0.44681 (10)	0.12214 (10)	0.00191 (9)	0.0152 (2)
H3	0.4101	0.2079	0.0025	0.018*
C4	0.64402 (10)	0.22668 (10)	0.09843 (9)	0.0147 (2)
H4	0.7248	0.1947	0.1408	0.018*
C5	0.56481 (11)	0.30053 (11)	0.18625 (10)	0.0202 (2)
H5A	0.4827	0.3308	0.1472	0.024*
H5B	0.5438	0.2396	0.2494	0.024*
C6	0.63818 (11)	0.41900 (11)	0.23785 (10)	0.0207 (3)
H6A	0.5833	0.4663	0.2915	0.025*
H6B	0.7165	0.3882	0.2829	0.025*
C7	0.67666 (12)	0.51267 (11)	0.14301 (10)	0.0225 (3)
H7A	0.7280	0.5861	0.1783	0.027*
H7B	0.5981	0.5506	0.1034	0.027*
C8	0.75542 (11)	0.44235 (12)	0.05420 (10)	0.0228 (3)
H8A	0.8390	0.4141	0.0918	0.027*
H8B	0.7734	0.5043	−0.0092	0.027*
C9	0.68369 (11)	0.32171 (11)	0.00324 (9)	0.0185 (2)
H9A	0.7399	0.2747	−0.0495	0.022*
H9B	0.6057	0.3512	−0.0429	0.022*
C10	0.76656 (9)	−0.04649 (10)	0.09169 (9)	0.0142 (2)
H10	0.8166	0.0370	0.0840	0.017*
C11	0.83559 (10)	−0.15393 (11)	0.02505 (10)	0.0194 (2)
H11A	0.7864	−0.2374	0.0283	0.023*
H11B	0.8383	−0.1277	−0.0574	0.023*
C12	0.97328 (10)	−0.17627 (12)	0.07605 (10)	0.0225 (3)
H12A	1.0137	−0.2487	0.0335	0.027*
H12B	1.0249	−0.0954	0.0661	0.027*
C13	0.97401 (11)	−0.21099 (11)	0.20452 (11)	0.0223 (3)
H13A	1.0641	−0.2210	0.2361	0.027*
H13B	0.9293	−0.2961	0.2140	0.027*
C14	0.90724 (11)	−0.10416 (12)	0.27195 (10)	0.0211 (3)
H14A	0.9570	−0.0211	0.2689	0.025*
H14B	0.9049	−0.1309	0.3543	0.025*
C15	0.76953 (10)	−0.08069 (11)	0.22168 (9)	0.0176 (2)
H15A	0.7303	−0.0076	0.2643	0.021*
H15B	0.7174	−0.1609	0.2327	0.021*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0136 (5)	0.0149 (5)	0.0123 (4)	−0.0003 (4)	−0.0001 (4)	0.0019 (4)
C2	0.0159 (5)	0.0138 (5)	0.0134 (5)	−0.0014 (4)	−0.0002 (4)	0.0003 (4)
C3	0.0167 (5)	0.0126 (5)	0.0161 (5)	0.0017 (4)	−0.0004 (4)	0.0011 (4)
C4	0.0148 (5)	0.0121 (5)	0.0169 (5)	−0.0006 (4)	−0.0022 (4)	−0.0004 (4)
C5	0.0215 (5)	0.0203 (5)	0.0192 (5)	−0.0063 (4)	0.0045 (4)	−0.0042 (4)
C6	0.0224 (5)	0.0199 (5)	0.0198 (5)	−0.0033 (4)	0.0025 (4)	−0.0067 (4)
C7	0.0268 (6)	0.0135 (5)	0.0267 (6)	−0.0019 (4)	−0.0032 (5)	−0.0019 (4)
C8	0.0267 (6)	0.0217 (6)	0.0203 (5)	−0.0103 (5)	0.0022 (4)	0.0002 (4)
C9	0.0194 (5)	0.0192 (5)	0.0171 (5)	−0.0044 (4)	0.0017 (4)	−0.0018 (4)
C10	0.0127 (5)	0.0132 (5)	0.0164 (5)	0.0001 (4)	−0.0013 (4)	0.0004 (4)
C11	0.0153 (5)	0.0216 (5)	0.0208 (5)	0.0024 (4)	−0.0012 (4)	−0.0041 (4)
C12	0.0139 (5)	0.0243 (6)	0.0291 (6)	0.0034 (4)	0.0008 (4)	−0.0051 (5)
C13	0.0150 (5)	0.0189 (5)	0.0321 (6)	0.0022 (4)	−0.0052 (4)	0.0022 (5)
C14	0.0178 (5)	0.0249 (6)	0.0198 (5)	0.0013 (4)	−0.0045 (4)	0.0022 (4)
C15	0.0148 (5)	0.0209 (5)	0.0167 (5)	0.0023 (4)	−0.0011 (4)	0.0024 (4)

Geometric parameters (Å, º) top

C1—C3ⁱ	1.3941 (14)	C8—H8B	0.9900
C1—C2	1.4053 (14)	C9—H9A	0.9900
C1—C10	1.5245 (13)	C9—H9B	0.9900
C2—C3	1.3967 (14)	C10—C11	1.5353 (14)
C2—C4	1.5207 (14)	C10—C15	1.5384 (14)
C3—C1ⁱ	1.3941 (14)	C10—H10	1.0000
C3—H3	0.9500	C11—C12	1.5316 (14)
C4—C9	1.5357 (14)	C11—H11A	0.9900
C4—C5	1.5368 (14)	C11—H11B	0.9900
C4—H4	1.0000	C12—C13	1.5237 (17)
C5—C6	1.5255 (15)	C12—H12A	0.9900
C5—H5A	0.9900	C12—H12B	0.9900
C5—H5B	0.9900	C13—C14	1.5243 (16)
C6—C7	1.5203 (16)	C13—H13A	0.9900
C6—H6A	0.9900	C13—H13B	0.9900
C6—H6B	0.9900	C14—C15	1.5308 (14)
C7—C8	1.5250 (17)	C14—H14A	0.9900
C7—H7A	0.9900	C14—H14B	0.9900
C7—H7B	0.9900	C15—H15A	0.9900
C8—C9	1.5322 (15)	C15—H15B	0.9900
C8—H8A	0.9900

C3ⁱ—C1—C2	117.82 (9)	C4—C9—H9A	109.3
C3ⁱ—C1—C10	119.96 (9)	C8—C9—H9B	109.3
C2—C1—C10	122.21 (9)	C4—C9—H9B	109.3
C3—C2—C1	118.12 (9)	H9A—C9—H9B	107.9
C3—C2—C4	118.62 (9)	C1—C10—C11	113.85 (8)
C1—C2—C4	123.26 (9)	C1—C10—C15	110.75 (8)
C1ⁱ—C3—C2	124.04 (10)	C11—C10—C15	110.17 (9)
C1ⁱ—C3—H3	118.0	C1—C10—H10	107.3
C2—C3—H3	118.0	C11—C10—H10	107.3
C2—C4—C9	111.71 (8)	C15—C10—H10	107.3
C2—C4—C5	112.29 (8)	C12—C11—C10	111.42 (9)
C9—C4—C5	110.00 (9)	C12—C11—H11A	109.3
C2—C4—H4	107.5	C10—C11—H11A	109.3
C9—C4—H4	107.5	C12—C11—H11B	109.3
C5—C4—H4	107.5	C10—C11—H11B	109.3
C6—C5—C4	111.54 (9)	H11A—C11—H11B	108.0
C6—C5—H5A	109.3	C13—C12—C11	111.12 (9)
C4—C5—H5A	109.3	C13—C12—H12A	109.4
C6—C5—H5B	109.3	C11—C12—H12A	109.4
C4—C5—H5B	109.3	C13—C12—H12B	109.4
H5A—C5—H5B	108.0	C11—C12—H12B	109.4
C7—C6—C5	110.94 (9)	H12A—C12—H12B	108.0
C7—C6—H6A	109.5	C12—C13—C14	110.84 (9)
C5—C6—H6A	109.5	C12—C13—H13A	109.5
C7—C6—H6B	109.5	C14—C13—H13A	109.5
C5—C6—H6B	109.5	C12—C13—H13B	109.5
H6A—C6—H6B	108.0	C14—C13—H13B	109.5
C6—C7—C8	111.42 (9)	H13A—C13—H13B	108.1
C6—C7—H7A	109.3	C13—C14—C15	111.09 (9)
C8—C7—H7A	109.3	C13—C14—H14A	109.4
C6—C7—H7B	109.3	C15—C14—H14A	109.4
C8—C7—H7B	109.3	C13—C14—H14B	109.4
H7A—C7—H7B	108.0	C15—C14—H14B	109.4
C7—C8—C9	111.33 (9)	H14A—C14—H14B	108.0
C7—C8—H8A	109.4	C14—C15—C10	111.74 (9)
C9—C8—H8A	109.4	C14—C15—H15A	109.3
C7—C8—H8B	109.4	C10—C15—H15A	109.3
C9—C8—H8B	109.4	C14—C15—H15B	109.3
H8A—C8—H8B	108.0	C10—C15—H15B	109.3
C8—C9—C4	111.80 (9)	H15A—C15—H15B	107.9
C8—C9—H9A	109.3

C3ⁱ—C1—C2—C3	−1.33 (16)	C7—C8—C9—C4	−54.77 (12)
C10—C1—C2—C3	179.74 (9)	C2—C4—C9—C8	−179.76 (9)
C3ⁱ—C1—C2—C4	178.54 (9)	C5—C4—C9—C8	54.84 (12)
C10—C1—C2—C4	−0.39 (15)	C3ⁱ—C1—C10—C11	34.20 (13)
C1—C2—C3—C1ⁱ	1.42 (17)	C2—C1—C10—C11	−146.89 (10)
C4—C2—C3—C1ⁱ	−178.46 (9)	C3ⁱ—C1—C10—C15	−90.60 (11)
C3—C2—C4—C9	−73.47 (12)	C2—C1—C10—C15	88.31 (12)
C1—C2—C4—C9	106.67 (11)	C1—C10—C11—C12	179.78 (9)
C3—C2—C4—C5	50.66 (12)	C15—C10—C11—C12	−55.11 (12)
C1—C2—C4—C5	−129.21 (10)	C10—C11—C12—C13	56.53 (13)
C2—C4—C5—C6	178.97 (9)	C11—C12—C13—C14	−56.64 (13)
C9—C4—C5—C6	−55.96 (12)	C12—C13—C14—C15	56.22 (12)
C4—C5—C6—C7	56.89 (12)	C13—C14—C15—C10	−55.83 (12)
C5—C6—C7—C8	−56.00 (12)	C1—C10—C15—C14	−178.25 (9)
C6—C7—C8—C9	54.96 (12)	C11—C10—C15—C14	54.90 (12)

Symmetry code: (i) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6A···Cgⁱⁱ	0.99	2.62	3.520 (2)	150

Symmetry code: (ii) −x+1, y+1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₃₀H₄₆
M_r	406.67
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	10.3868 (7), 10.1434 (7), 11.5419 (8)
β (°)	93.314 (1)
V (Å³)	1213.99 (14)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.06
Crystal size (mm)	0.24 × 0.21 × 0.11

Data collection
Diffractometer	Bruker SMART APEX CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2002)
T_min, T_max	0.975, 0.993
No. of measured, independent and observed [I > 2σ(I)] reflections	10421, 2805, 2460
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.652

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.046, 0.126, 1.04
No. of reflections	2805
No. of parameters	136
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.39, −0.21

Computer programs: SMART (Bruker, 2000), SAINT-Plus (Bruker 2004), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker,2000).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6A···Cgⁱ	0.99	2.62	3.520 (2)	150

Symmetry code: (i) −x+1, y+1/2, −z+1/2.

Acknowledgements

We thank the Chemistry Department of Tulane University for support of the X-ray laboratory, and the Louisiana Board of Regents through the Louisiana Educational Quality Support Fund [grant LEQSF (2003–2003)-ENH-TR-67] for the purchase of the APEX diffractometer.

References

Bruker (2000). SMART (Version 5.625) and SHELXTL (Version 6.10). Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2004). SAINT-Plus. Version 7.03. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Koudelka, J., Saman, J. & Exner, O. (1985). Collect. Czech. Chem. Commun. 50, 208–214. CrossRef CAS Google Scholar
Mague, J. T., Linhardt, L., Medina, I. & Fink, M. J. (2008a). Acta Cryst. E64, o376. Web of Science CSD CrossRef IUCr Journals Google Scholar
Mague, J. T., Linhardt, L., Medina, I. & Fink, M. J. (2008b). Acta Cryst. E64, o335. Web of Science CSD CrossRef IUCr Journals Google Scholar
Saito, M., Tokitoh, N. & Okazaki, R. (2004). J. Am. Chem. Soc. 126, 15572–15582. Web of Science CrossRef PubMed CAS Google Scholar
Schweiger, S. W., Salberg, M. M., Pulvirenti, A. L., Freeman, E. E., Fanwick, P. E. & Rothwell, I. P. (2001). J. Chem. Soc. Dalton Trans. pp. 2020–2031. Web of Science CSD CrossRef Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2002). SADABS, Version 2.05. University of Göttingen, Germany. Google Scholar
Vilardo, J. S., Salberg, M. M., Parker, J. R., Fanwick, P. E. & Rothwell, I. P. (2000). Inorg. Chim. Acta, 299, 135–141. Web of Science CSD CrossRef CAS Google Scholar