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The title compound, [(η2-C16H8)Co2(CO)6], (I), has been prepared by treatment of 5,6,11,12-tetrade­hydro­dibenzo­[a,e]cyclo­octene, (II), with dicobalt octa­carbonyl. Although one acetyl­ene in (II) remains intact upon treatment with Co2(CO)8, the other is coordinated to Co2(CO)6, exhibiting a C[triple bond]C bond lengthened to 1.356 (2) Å and a C[triple bond]C—C bond angle contracted to 147.53 (16)°.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802021062/ob6184sup1.cif
Contains datablocks General, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536802021062/ob6184Isup2.hkl
Contains datablock I

CCDC reference: 202300

Key indicators

  • Single-crystal X-ray study
  • T = 93 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.031
  • wR factor = 0.090
  • Data-to-parameter ratio = 14.7

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
ABSTM_02 Alert C The ratio of expected to reported Tmax/Tmin(RR') is < 0.90 Tmin and Tmax reported: 0.471 0.694 Tmin' and Tmax expected: 0.568 0.694 RR' = 0.829 Please check that your absorption correction is appropriate. PLAT_320 Alert C Check Hybridisation of C(9) in Main Residue ? PLAT_320 Alert C Check Hybridisation of C(10) in Main Residue ?
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
3 Alert Level C = Please check

Comment top

It has been recognized that 5,6,11,12-tetradehydrodibenzo[a,e]cyclooctene, (II), C16H8, has the most strained acetylenes (Destro et al., 1975). Although these triple bonds are quite reactive because of their great strain energy, only one example of a plutinum complex on the triple bonds has been reported so far (Shimada et al., 1997). We have advanced a new methodology for access to various acetylenes and succeeded in preparing a Co2(CO)6 complex of an acetylenic cyclophane (Orita et al., 2002). We have been intrigued by the structural features of Co2(CO)6 complexes of the most strained acetylene 5,6,11,12-tetradehydrodibenzo[a,e]cyclooctene, (II), and have carried out an investigation of the title compound, (I).

By X-ray analysis of the starting cyclophane (II), it has been revealed that the triple bonds adopt a bond length of 1.195 (2) Å and a bond angle of 155.3 (1)° (Destro et al., 1975). Coordination of the Co2(CO)6 moiety on the acetylene of (I) makes the C1—C2 bond length lengthen to 1.356 (2) Å and the bond angle C1—C2—C3 contract to 147.53 (16)°. In sharp contrast to these, the corresponding length and angle of the other side in (I) remain unchanged, exhibiting the same bond length [1.196 (2) Å] and angle [155.98 (18)°] as observed in (II). Interestingly, the lengths of the C1—C2, C2—C3 and C1—C16 bonds are almost the same as in the (η2-PhC CPh)-Co2(CO)6 complex (Gregson et al., 1983). The bond angle C1—C2—C3 [147.53 (16)°] is somewhat larger than the corresponding angle [140.2 (9)°] in diphenylacetylene-Co2(CO)6. Two cobalt atoms Co1 and Co2 are located at the same distance from C1 and C2, but unsymmetrically folded out of the plane involving the eight-membered ring [Co1—C1—C2—C3 = 154.1 (4)° and Co2—C1—C2—C3 = -122.5 (4)°].

Experimental top

To a flame-dried flask were added (II) (100.1 mg, 0.5 mmol) and Co2(CO)8 (512.9 mg, 0.5 mmol) and CH2Cl2 (10 ml), and the mixture was stirred for 12 h at room temperature in the dark. After evaporation, hexane was added to the residual black solid and filtered through a thin layer of silica gel. After evaporation of the filtrate, dark purple crystals of (I) were obtained in 50–60% yield.

Refinement top

The H atoms were located from difference density maps and refined isotropically with restraints, C—H 0.968 (3)–1.079 (3) Å.

Structure description top

It has been recognized that 5,6,11,12-tetradehydrodibenzo[a,e]cyclooctene, (II), C16H8, has the most strained acetylenes (Destro et al., 1975). Although these triple bonds are quite reactive because of their great strain energy, only one example of a plutinum complex on the triple bonds has been reported so far (Shimada et al., 1997). We have advanced a new methodology for access to various acetylenes and succeeded in preparing a Co2(CO)6 complex of an acetylenic cyclophane (Orita et al., 2002). We have been intrigued by the structural features of Co2(CO)6 complexes of the most strained acetylene 5,6,11,12-tetradehydrodibenzo[a,e]cyclooctene, (II), and have carried out an investigation of the title compound, (I).

By X-ray analysis of the starting cyclophane (II), it has been revealed that the triple bonds adopt a bond length of 1.195 (2) Å and a bond angle of 155.3 (1)° (Destro et al., 1975). Coordination of the Co2(CO)6 moiety on the acetylene of (I) makes the C1—C2 bond length lengthen to 1.356 (2) Å and the bond angle C1—C2—C3 contract to 147.53 (16)°. In sharp contrast to these, the corresponding length and angle of the other side in (I) remain unchanged, exhibiting the same bond length [1.196 (2) Å] and angle [155.98 (18)°] as observed in (II). Interestingly, the lengths of the C1—C2, C2—C3 and C1—C16 bonds are almost the same as in the (η2-PhC CPh)-Co2(CO)6 complex (Gregson et al., 1983). The bond angle C1—C2—C3 [147.53 (16)°] is somewhat larger than the corresponding angle [140.2 (9)°] in diphenylacetylene-Co2(CO)6. Two cobalt atoms Co1 and Co2 are located at the same distance from C1 and C2, but unsymmetrically folded out of the plane involving the eight-membered ring [Co1—C1—C2—C3 = 154.1 (4)° and Co2—C1—C2—C3 = -122.5 (4)°].

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO; data reduction: TEXSAN (Rigaku, 1999); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: CrystalStructure (Molecular Structure Corporation/Rigaku Corporation, 2001).

Figures top
[Figure 1] Fig. 1. View of (I). Displacement ellipsoids are drawn at the 50% probability level.
Hexacarbonyldicobalt(0) complex of "Magazine-rack" molecule, [(η2-C32H20)Co2(CO)6] top
Crystal data top
[Co2(C16H8)(CO)6]F(000) = 968.0
Mr = 486.17Dx = 1.742 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.7107 Å
a = 16.2876 (8) ÅCell parameters from 8782 reflections
b = 7.4552 (4) Åθ = 4.0–27.5°
c = 17.1415 (5) ŵ = 1.83 mm1
β = 117.075 (3)°T = 93 K
V = 1853.34 (15) Å3Cubic, black
Z = 40.30 × 0.30 × 0.20 mm
Data collection top
Rigaku RAXIS-IV
diffractometer
3763 reflections with F2 > 2σ(F2)
Detector resolution: 10.00 pixels mm-1Rint = 0.037
ω scansθmax = 27.5°
Absorption correction: multi-scan
(Higashi, 1995)
h = 2121
Tmin = 0.471, Tmax = 0.694k = 99
14932 measured reflectionsl = 2121
4379 independent reflections
Refinement top
Refinement on F2All H-atom parameters refined
R[F2 > 2σ(F2)] = 0.031 w = 1/[0.002Fo2 + 1.000σ2(Fo)]/(4Fo2)
wR(F2) = 0.090(Δ/σ)max < 0.001
S = 0.99Δρmax = 0.59 e Å3
4090 reflectionsΔρmin = 0.90 e Å3
279 parameters
Crystal data top
[Co2(C16H8)(CO)6]V = 1853.34 (15) Å3
Mr = 486.17Z = 4
Monoclinic, P21/cMo Kα radiation
a = 16.2876 (8) ŵ = 1.83 mm1
b = 7.4552 (4) ÅT = 93 K
c = 17.1415 (5) Å0.30 × 0.30 × 0.20 mm
β = 117.075 (3)°
Data collection top
Rigaku RAXIS-IV
diffractometer
4379 independent reflections
Absorption correction: multi-scan
(Higashi, 1995)
3763 reflections with F2 > 2σ(F2)
Tmin = 0.471, Tmax = 0.694Rint = 0.037
14932 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.031279 parameters
wR(F2) = 0.090All H-atom parameters refined
S = 0.99Δρmax = 0.59 e Å3
4090 reflectionsΔρmin = 0.90 e Å3
Special details top

Refinement. Refinement using reflections with F2 > -10.0 σ(F2). The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2.0 σ(F2) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Co10.38094 (2)0.17146 (3)0.28606 (1)0.01106 (7)
Co20.26158 (2)0.35769 (3)0.17228 (1)0.01072 (7)
O20.4392 (1)0.4646 (2)0.41524 (9)0.0329 (4)
O40.3628 (1)0.4352 (2)0.06964 (9)0.0255 (4)
O50.06619 (9)0.3703 (2)0.04409 (9)0.0220 (3)
O10.4323 (1)0.1258 (2)0.41238 (9)0.0247 (4)
O60.2603 (1)0.6809 (2)0.27254 (9)0.0250 (4)
O30.5318 (1)0.1777 (2)0.23545 (9)0.0252 (4)
C130.0564 (1)0.1268 (3)0.3466 (1)0.0164 (4)
C210.1428 (1)0.3695 (2)0.0920 (1)0.0152 (4)
C200.3230 (1)0.4129 (3)0.1085 (1)0.0165 (4)
C80.1662 (1)0.1107 (2)0.0582 (1)0.0130 (4)
C100.0846 (1)0.0361 (3)0.1521 (1)0.0152 (4)
C10.2469 (1)0.1542 (2)0.2383 (1)0.0116 (4)
C20.2736 (1)0.0918 (2)0.1791 (1)0.0113 (4)
C190.4738 (1)0.1737 (2)0.2548 (1)0.0160 (4)
C90.1057 (1)0.0845 (3)0.0972 (1)0.0150 (4)
C70.1446 (1)0.2097 (3)0.0181 (1)0.0166 (4)
C110.0975 (1)0.0473 (2)0.2323 (1)0.0134 (4)
C150.2018 (1)0.2259 (2)0.3560 (1)0.0148 (4)
C140.1388 (1)0.2193 (3)0.3901 (1)0.0162 (4)
C50.2963 (1)0.1492 (2)0.0041 (1)0.0180 (4)
C180.4177 (1)0.3489 (3)0.3670 (1)0.0193 (4)
C120.0349 (1)0.0417 (3)0.2675 (1)0.0160 (4)
C170.4127 (1)0.0156 (3)0.3617 (1)0.0160 (4)
C220.2628 (1)0.5587 (3)0.2340 (1)0.0163 (4)
C40.3178 (1)0.0486 (3)0.0712 (1)0.0156 (4)
C160.1823 (1)0.1403 (2)0.2763 (1)0.0120 (4)
C30.2536 (1)0.0267 (2)0.1038 (1)0.0125 (4)
C60.2098 (1)0.2296 (3)0.0489 (1)0.0186 (4)
H10.3759 (1)0.0145 (3)0.1015 (1)0.020 (1)*
H20.3342 (1)0.1761 (2)0.0376 (1)0.024 (1)*
H30.1951 (1)0.2961 (3)0.1023 (1)0.024 (1)*
H40.0783 (1)0.2749 (3)0.0496 (1)0.021 (1)*
H50.0218 (1)0.0267 (3)0.2361 (1)0.020 (1)*
H60.0133 (1)0.1271 (3)0.3774 (1)0.022 (1)*
H70.1524 (1)0.2889 (3)0.4422 (1)0.021 (1)*
H80.2589 (1)0.2967 (2)0.3870 (1)0.018 (1)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co10.0072 (1)0.0128 (1)0.0118 (1)0.00002 (8)0.0032 (1)0.00026 (8)
Co20.0078 (1)0.0120 (1)0.0118 (1)0.00017 (8)0.0040 (1)0.00012 (7)
O20.0311 (8)0.0277 (8)0.0236 (7)0.0039 (7)0.0019 (6)0.0111 (6)
O40.0192 (7)0.0349 (8)0.0274 (7)0.0008 (6)0.0150 (6)0.0073 (6)
O50.0110 (7)0.0286 (8)0.0222 (6)0.0025 (5)0.0040 (5)0.0040 (5)
O10.0238 (8)0.0236 (7)0.0245 (7)0.0008 (6)0.0091 (6)0.0066 (6)
O60.0272 (8)0.0195 (7)0.0243 (7)0.0030 (6)0.0082 (6)0.0046 (6)
O30.0159 (7)0.0336 (9)0.0305 (7)0.0027 (6)0.0144 (6)0.0059 (6)
C130.0163 (9)0.0187 (9)0.0187 (8)0.0030 (7)0.0119 (7)0.0021 (7)
C210.0162 (9)0.0163 (9)0.0156 (8)0.0017 (7)0.0095 (7)0.0010 (6)
C200.0128 (8)0.0159 (8)0.0166 (7)0.0011 (7)0.0029 (6)0.0028 (6)
C80.0124 (8)0.0130 (8)0.0154 (7)0.0011 (6)0.0080 (6)0.0000 (6)
C100.0092 (8)0.0204 (9)0.0160 (7)0.0046 (7)0.0059 (6)0.0028 (7)
C10.0082 (8)0.0127 (8)0.0127 (7)0.0002 (6)0.0036 (6)0.0010 (5)
C20.0072 (7)0.0131 (8)0.0124 (7)0.0013 (6)0.0032 (6)0.0001 (6)
C190.0117 (8)0.0157 (9)0.0170 (8)0.0010 (6)0.0035 (6)0.0027 (6)
C90.0103 (8)0.0176 (9)0.0154 (7)0.0044 (7)0.0045 (6)0.0024 (6)
C70.0172 (9)0.0179 (9)0.0159 (8)0.0042 (7)0.0085 (6)0.0032 (6)
C110.0109 (8)0.0144 (8)0.0159 (7)0.0001 (6)0.0069 (6)0.0001 (6)
C150.0150 (8)0.0159 (8)0.0141 (7)0.0003 (7)0.0071 (6)0.0015 (6)
C140.0204 (9)0.0160 (9)0.0153 (7)0.0014 (7)0.0107 (7)0.0002 (6)
C50.022 (1)0.0184 (9)0.0191 (8)0.0009 (7)0.0140 (7)0.0013 (6)
C180.0133 (9)0.022 (1)0.0171 (8)0.0028 (7)0.0017 (7)0.0012 (7)
C120.0128 (8)0.0185 (9)0.0188 (8)0.0010 (7)0.0091 (6)0.0011 (7)
C170.0109 (8)0.0195 (9)0.0169 (7)0.0012 (7)0.0056 (6)0.0025 (7)
C220.0117 (8)0.0195 (9)0.0144 (7)0.0004 (7)0.0030 (6)0.0018 (6)
C40.0125 (8)0.0175 (8)0.0191 (7)0.0008 (7)0.0090 (6)0.0010 (6)
C160.0115 (8)0.0132 (8)0.0119 (7)0.0012 (6)0.0059 (6)0.0013 (6)
C30.0120 (8)0.0119 (8)0.0144 (7)0.0006 (6)0.0067 (6)0.0001 (6)
C60.0240 (9)0.0177 (9)0.0180 (8)0.0022 (7)0.0131 (7)0.0034 (7)
Geometric parameters (Å, º) top
Co1—Co22.4616 (3)C13—C121.390 (2)
Co1—C11.9564 (17)C13—H61.053 (4)
Co1—C21.9626 (16)C8—C71.401 (2)
C1—C21.356 (2)C8—C31.420 (2)
C2—C31.474 (2)C10—C111.434 (2)
C8—C91.434 (2)C1—C161.471 (2)
C9—C101.196 (2)C7—C61.391 (2)
Co1—C191.8196 (19)C7—H41.079 (3)
Co1—C181.8101 (19)C11—C121.401 (2)
Co1—C171.8122 (18)C11—C161.417 (2)
Co2—C211.7942 (19)C15—C141.394 (2)
Co2—C201.8331 (18)C15—C161.408 (2)
Co2—C11.9719 (16)C15—H80.989 (3)
Co2—C21.9903 (18)C14—H70.968 (3)
Co2—C221.8297 (18)C5—C41.392 (2)
O2—C181.135 (2)C5—C61.396 (3)
O4—C201.133 (2)C5—H21.036 (3)
O5—C211.140 (2)C12—H50.975 (3)
O1—C171.131 (2)C4—C31.400 (2)
O6—C221.136 (2)C4—H10.970 (3)
O3—C191.135 (2)C6—H30.970 (3)
C13—C141.386 (3)
C1—C2—C3147.53 (16)Co1—C1—C270.0 (1)
C2—C3—C8120.83 (14)Co2—C1—C270.7 (1)
C3—C8—C9114.39 (14)Co1—C1—C16134.95 (12)
C8—C9—C10155.98 (18)Co2—C1—C16127.31 (12)
Co2—Co1—C151.48 (5)C2—C1—C16147.67 (16)
Co2—Co1—C251.99 (5)Co1—C2—Co277.03 (6)
C1—Co1—C240.49 (6)Co1—C2—C169.5 (1)
Co2—Co1—C19102.93 (6)Co2—C2—C169.3 (1)
C1—Co1—C19142.76 (7)Co1—C2—C3138.38 (12)
C2—Co1—C19103.51 (7)Co2—C2—C3124.67 (11)
Co2—Co1—C1893.52 (6)Co1—C19—O3178.97 (16)
C1—Co1—C18106.57 (8)C8—C7—C6119.97 (16)
C2—Co1—C18141.27 (8)C8—C7—H4118.2 (1)
C19—Co1—C18100.97 (9)C6—C7—H4121.76 (11)
Co2—Co1—C17150.05 (6)C10—C11—C12125.57 (15)
C1—Co1—C1798.60 (7)C10—C11—C16113.79 (14)
C2—Co1—C17106.17 (7)C12—C11—C16120.64 (14)
C19—Co1—C17102.29 (8)C14—C15—C16120.47 (16)
C18—Co1—C1797.28 (8)C14—C15—H8119.1 (1)
Co1—Co2—C21145.29 (6)C16—C15—H8120.4 (1)
Co1—Co2—C2098.65 (5)C13—C14—C15120.63 (15)
C21—Co2—C20102.85 (7)C13—C14—H7121.5 (1)
Co1—Co2—C150.92 (5)C15—C14—H7117.7 (1)
C21—Co2—C196.17 (7)C4—C5—C6120.37 (16)
C20—Co2—C1139.19 (8)C4—C5—H2130.96 (11)
Co1—Co2—C250.98 (4)C6—C5—H2108.6 (1)
C21—Co2—C297.86 (7)Co1—C18—O2177.44 (16)
C20—Co2—C2101.11 (7)C13—C12—C11119.78 (16)
C1—Co2—C240.02 (6)C13—C12—H5122.18 (11)
Co1—Co2—C22101.95 (5)C11—C12—H5118.0 (1)
C21—Co2—C2297.31 (8)Co1—C17—O1176.04 (16)
C20—Co2—C22107.23 (8)Co2—C22—O6177.16 (17)
C1—Co2—C22105.67 (7)C5—C4—C3120.95 (16)
C2—Co2—C22143.79 (7)C5—C4—H1122.04 (11)
C14—C13—C12120.26 (16)C3—C4—H1116.9 (1)
C14—C13—H6115.6 (1)C1—C16—C11121.30 (14)
C12—C13—H6124.09 (11)C1—C16—C15120.44 (15)
Co2—C21—O5175.95 (16)C11—C16—C15118.21 (15)
Co2—C20—O4175.37 (17)C8—C3—C4118.17 (14)
C9—C8—C7125.03 (16)C2—C3—C4120.83 (15)
C7—C8—C3120.59 (15)C7—C6—C5119.95 (16)
C9—C10—C11156.41 (18)C7—C6—H3120.6 (1)
Co1—C1—Co277.60 (6)C5—C6—H3119.4 (1)
C1—C2—C3—C811.0 (6)Co1—C1—C2—C3154.1 (4)
C3—C8—C9—C107.2 (7)Co2—C1—C2—C3122.5 (4)
C16—C1—C2—C37.9 (7)Co1—C1—C16—C1533.3 (3)
C8—C9—C10—C113.0 (10)Co2—C1—C16—C1579.0 (2)

Experimental details

Crystal data
Chemical formula[Co2(C16H8)(CO)6]
Mr486.17
Crystal system, space groupMonoclinic, P21/c
Temperature (K)93
a, b, c (Å)16.2876 (8), 7.4552 (4), 17.1415 (5)
β (°) 117.075 (3)
V3)1853.34 (15)
Z4
Radiation typeMo Kα
µ (mm1)1.83
Crystal size (mm)0.30 × 0.30 × 0.20
Data collection
DiffractometerRigaku RAXIS-IV
Absorption correctionMulti-scan
(Higashi, 1995)
Tmin, Tmax0.471, 0.694
No. of measured, independent and
observed [F2 > 2σ(F2)] reflections
14932, 4379, 3763
Rint0.037
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.090, 0.99
No. of reflections4090
No. of parameters279
No. of restraints?
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.59, 0.90

Computer programs: PROCESS-AUTO (Rigaku, 1998), PROCESS-AUTO, TEXSAN (Rigaku, 1999), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), CrystalStructure (Molecular Structure Corporation/Rigaku Corporation, 2001).

Selected geometric parameters (Å, º) top
Co1—Co22.4616 (3)Co2—C201.8331 (18)
Co1—C11.9564 (17)Co2—C11.9719 (16)
Co1—C21.9626 (16)Co2—C21.9903 (18)
C1—C21.356 (2)Co2—C221.8297 (18)
C2—C31.474 (2)O2—C181.135 (2)
C8—C91.434 (2)O1—C171.131 (2)
C9—C101.196 (2)O3—C191.135 (2)
Co1—C191.8196 (19)C8—C31.420 (2)
Co1—C181.8101 (19)C10—C111.434 (2)
Co1—C171.8122 (18)C1—C161.471 (2)
Co2—C211.7942 (19)C11—C161.417 (2)
C1—C2—C3147.53 (16)Co2—C1—C270.7 (1)
C2—C3—C8120.83 (14)Co1—C1—C16134.95 (12)
C3—C8—C9114.39 (14)Co2—C1—C16127.31 (12)
C8—C9—C10155.98 (18)C2—C1—C16147.67 (16)
Co1—Co2—C150.92 (5)C10—C11—C16113.79 (14)
C7—C8—C3120.59 (15)C1—C16—C11121.30 (14)
C9—C10—C11156.41 (18)C8—C3—C4118.17 (14)
Co1—C1—C270.0 (1)
C1—C2—C3—C811.0 (6)Co1—C1—C2—C3154.1 (4)
C3—C8—C9—C107.2 (7)Co2—C1—C2—C3122.5 (4)
C16—C1—C2—C37.9 (7)Co1—C1—C16—C1533.3 (3)
C8—C9—C10—C113.0 (10)Co2—C1—C16—C1579.0 (2)
 

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