Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270105006426/fg1824sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270105006426/fg1824Isup2.hkl |
CCDC reference: 269051
Compound (I) was synthesized from 4-tert-butyl-2,6-dimethylphenylacetylene and oxalyl chloride following the procedure outlined in Faust et al. (1997) [m.p. 437 K (decomposition)]. Spectroscopic analysis: IR (Medium?, ν, cm-1): 2953, 2176, 1664, 1107; 1H NMR (500 MHz, CDCl3, δ, p.p.m.): 7.05 (4H, s, CH), 2.47 (12H, s, CH3), 1.28 (18H, s, CH3); 13C NMR (125.7 MHz, CDCl3, δ, p.p.m.): 173.31, 155.28, 143.79, 124.46, 116.32, 93.74, 80.99, 34.93, 30.98, 21.24; APCI-MS: 427 (33) [M+H]+; 399 (70) [M—CO+H]+; 213 (100) [M/2]+. Single crystals of (I) suitable for X-ray diffraction studies were obtained by slow evaporation from acetonitrile.
H atoms were placed in geometric positions and treated as riding, with C—H distances in the range 0.94–0.97 Å and with Uiso(H) = 1.2Ueq(C). Please check added text.
The title compound is a newly synthesized member of the diacetylenic 1,2-diones, a class of compounds first introduced in 1996 (Faust & Weber, 1996; Faust et al., 1997). The two typifying interconnected ynone moieties of this molecular structure give rise to a rich chemistry that we have explored to form, inter alia, metal-chelating diazabutadienes (Faust, Göbelt & Weber, 1999; Faust, Göbelt et al., 1999), alkyne-substituted N-heterocyclic carbenes (Faust & Göbelt, 2000) and acetylenic phthalocyanines (Faust, 2001). Despite these successful developments, two questions remain about the electronic aspects of these compounds. Firstly, the kinetic stability of dialkynyl diones appears to rely largely on the size of the terminal alkyne substituents. Whereas bulky triisoproylsilyl groups lend excellent stability to the hexadiynedione core, smaller terminal substituents, such as alkyls or the trimethylsilyl group, are insufficient to protect the reactive ynone system from nucleophilic attack (Faust et al., 1997). Similarly, aryl termini shield the reactive core of the molecule most effectively when, as in the case discussed here, they possess sizeable 2,6-substituents flanking the alkyne subunit. The second question concerns the effective conjugation path of the hexa-1,5-diyne-3,4-dione framework. We have speculated that, similar to the related 2,3-dialkynyldiazabutadienes (Faust et al., 1999 Which?), a valid description of dialkynyl diones is that of two interconnected but largely electronically independent bis(ynone) units, rather than that of a species fully delocalized along the hexadiynedione core. The present solid-state study is the first on this class of compounds and was undertaken to shed some light on these matters.
The title compound, (I), with the atomic numbering, is shown in Fig. 1. The molecule crystallizes in the triclinic space group P1 with one molecule in the asymmetric unit. Inspection of Fig. 1 reveals an extended conformation of the molecule with a formal s-trans geometry [torsion angle O2—C4—C3—O1 175.2 (2) °] around the 1,2-dione subunit. The maximum deviation of the atoms from a plane through C2/C3/C4/C5/O1/O2 is only 0.062 (1) Å For which atom?. The phenyl ring system around C7 is almost perfectly coplanar with the dione unit, as the plane through C1/C2/C3/C7/C8/C12/O1 forms an angle of only 4.2 (1)° with that of the dione substructure. On the other hand, the phenyl ring system around C19 (i.e. a plane through C4/C5/C6/C19/C20/C24) is twisted by about 20.3 (1)° from the plane of the dione moiety.
In terms of π electronic delocalization, it appears that, in the crystal, the electronic interaction between one phenyl group and the ynone portion of the molecule is maximized, whereas that of the other is slightly diminished. The distance between the two carbonyl atoms C3—C4 is 1.535 (2) Å (Table 1), suggesting a rather long Csp2—Csp2 single bond through which little electron density is transmitted. While most other structural parameters within this part of the molecule are within the normal range (Allen et al., 1987), the C—C—C angles around the carbonyl C atoms [i.e. C2—C3—C4 116.7 (1)° and C3—C4—C5 114.5 (1)°] are significantly compressed.
The methyl groups on the 2,6-positions on the aryl rings protrude into the space segment above and below the C1≡C2 (and C5≡C6) triple bonds, a structural feature that helps to explain the increased stability of this system towards nucleophilic attack, particularly in solution, where there is free rotation around the C7—C1 (and C6—C19) single bonds. There are no close intramolecular contacts between the methyl H atoms and the carbonyl O atoms.
An inspection of the packing arrangement (Fig. 2) of compound (I) in the crystal reveals that the tert-butyl groups of one molecule reside in the space above the dione subunits of adjacent molecules. In conjunction with the findings above, this might indicate that the planarity of the dione substructure is dictated by the space requirements of the bulky alkyl group, rather than by intramolecular electronic interactions such as π delocalization. The crystal packing forces are enhanced by very weak intermolecular hydrogen bonds between methyl H atoms and the carbonyl O atoms. The relevant distances are depicted as dashed lines in Fig. 2, with details given in Table 2. In this way, chains of centrosymmetric rings develop along [101]. The alkyl substitution of the aryl rings prevents intermolecular π–π stacking interactions.
Data collection: X-AREA (Stoe, 2004); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: Please provide missing details.
C30H34O2 | Z = 2 |
Mr = 426.57 | F(000) = 460 |
Triclinic, P1 | Dx = 1.145 Mg m−3 |
Hall symbol: -P 1 | Melting point: 437 K |
a = 9.3933 (11) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 11.4531 (14) Å | Cell parameters from 11904 reflections |
c = 11.9823 (13) Å | θ = 1.8–25.6° |
α = 93.289 (9)° | µ = 0.07 mm−1 |
β = 105.303 (9)° | T = 213 K |
γ = 93.674 (10)° | Block, yellow |
V = 1237.1 (3) Å3 | 0.58 × 0.32 × 0.31 mm |
Stoe IPDS 2 diffractometer | 4296 independent reflections |
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus | 3130 reflections with I > 2σ(I) |
Plane graphite monochromator | Rint = 0.055 |
Detector resolution: 6.67 pixels mm-1 | θmax = 25.0°, θmin = 1.8° |
rotation scans | h = −11→11 |
Absorption correction: integration X-RED (Stoe, 2004) | k = −13→13 |
Tmin = 0.974, Tmax = 0.991 | l = −13→14 |
15963 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.039 | H-atom parameters constrained |
wR(F2) = 0.107 | w = 1/[σ2(Fo2) + (0.0663P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.00 | (Δ/σ)max < 0.001 |
4296 reflections | Δρmax = 0.18 e Å−3 |
300 parameters | Δρmin = −0.20 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.023 (4) |
C30H34O2 | γ = 93.674 (10)° |
Mr = 426.57 | V = 1237.1 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 9.3933 (11) Å | Mo Kα radiation |
b = 11.4531 (14) Å | µ = 0.07 mm−1 |
c = 11.9823 (13) Å | T = 213 K |
α = 93.289 (9)° | 0.58 × 0.32 × 0.31 mm |
β = 105.303 (9)° |
Stoe IPDS 2 diffractometer | 4296 independent reflections |
Absorption correction: integration X-RED (Stoe, 2004) | 3130 reflections with I > 2σ(I) |
Tmin = 0.974, Tmax = 0.991 | Rint = 0.055 |
15963 measured reflections |
R[F2 > 2σ(F2)] = 0.039 | 0 restraints |
wR(F2) = 0.107 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.18 e Å−3 |
4296 reflections | Δρmin = −0.20 e Å−3 |
300 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 1.01527 (16) | 0.29304 (13) | 0.97660 (14) | 0.0385 (4) | |
C2 | 0.92104 (17) | 0.35511 (13) | 0.93211 (15) | 0.0417 (4) | |
C3 | 0.79814 (16) | 0.42133 (13) | 0.88130 (14) | 0.0395 (4) | |
C4 | 0.82169 (16) | 0.50726 (13) | 0.79288 (14) | 0.0381 (4) | |
C5 | 0.69143 (16) | 0.56197 (13) | 0.73571 (15) | 0.0408 (4) | |
C6 | 0.57402 (16) | 0.59718 (12) | 0.68861 (14) | 0.0380 (4) | |
C7 | 1.12465 (15) | 0.21929 (12) | 1.03434 (13) | 0.0341 (3) | |
C8 | 1.26782 (16) | 0.22913 (12) | 1.01846 (13) | 0.0342 (3) | |
C9 | 1.37194 (15) | 0.15815 (12) | 1.07939 (13) | 0.0337 (3) | |
H9 | 1.4682 | 0.1644 | 1.0697 | 0.040* | |
C10 | 1.33885 (15) | 0.07865 (12) | 1.15380 (13) | 0.0324 (3) | |
C11 | 1.19492 (15) | 0.07044 (13) | 1.16644 (13) | 0.0363 (3) | |
H11 | 1.1707 | 0.0166 | 1.2162 | 0.044* | |
C12 | 1.08671 (15) | 0.13850 (13) | 1.10840 (13) | 0.0363 (3) | |
C13 | 1.30931 (17) | 0.31482 (14) | 0.93975 (15) | 0.0440 (4) | |
H13A | 1.3261 | 0.3932 | 0.9785 | 0.053* | |
H13B | 1.2296 | 0.3132 | 0.8690 | 0.053* | |
H13C | 1.3990 | 0.2934 | 0.9209 | 0.053* | |
C14 | 1.45266 (15) | −0.00149 (12) | 1.21979 (13) | 0.0349 (3) | |
C15 | 1.60622 (16) | 0.02569 (14) | 1.20256 (16) | 0.0463 (4) | |
H15A | 1.6401 | 0.1069 | 1.2289 | 0.056* | |
H15B | 1.6016 | 0.0128 | 1.1209 | 0.056* | |
H15C | 1.6747 | −0.0253 | 1.2469 | 0.056* | |
C16 | 1.39901 (17) | −0.12889 (13) | 1.17445 (15) | 0.0415 (4) | |
H16A | 1.3888 | −0.1380 | 1.0917 | 0.050* | |
H16B | 1.3039 | −0.1486 | 1.1891 | 0.050* | |
H16C | 1.4704 | −0.1807 | 1.2139 | 0.050* | |
C17 | 1.46431 (18) | 0.01323 (14) | 1.34964 (14) | 0.0452 (4) | |
H17A | 1.3680 | −0.0062 | 1.3622 | 0.054* | |
H17B | 1.4979 | 0.0939 | 1.3786 | 0.054* | |
H17C | 1.5345 | −0.0387 | 1.3905 | 0.054* | |
C18 | 0.93255 (17) | 0.12525 (16) | 1.12358 (16) | 0.0476 (4) | |
H18A | 0.8639 | 0.0932 | 1.0512 | 0.057* | |
H18B | 0.9041 | 0.2014 | 1.1455 | 0.057* | |
H18C | 0.9303 | 0.0727 | 1.1839 | 0.057* | |
C19 | 0.43427 (15) | 0.63724 (11) | 0.63012 (14) | 0.0347 (3) | |
C20 | 0.31617 (15) | 0.63061 (12) | 0.68204 (13) | 0.0349 (3) | |
C21 | 0.18203 (15) | 0.66959 (12) | 0.62232 (13) | 0.0341 (3) | |
H21 | 0.1023 | 0.6649 | 0.6560 | 0.041* | |
C22 | 0.16117 (14) | 0.71543 (11) | 0.51427 (13) | 0.0315 (3) | |
C23 | 0.27989 (15) | 0.71885 (12) | 0.46446 (14) | 0.0341 (3) | |
H23 | 0.2672 | 0.7479 | 0.3910 | 0.041* | |
C24 | 0.41663 (15) | 0.68043 (12) | 0.52039 (14) | 0.0355 (3) | |
C25 | 0.33359 (17) | 0.58291 (14) | 0.79879 (15) | 0.0460 (4) | |
H25A | 0.3879 | 0.6417 | 0.8591 | 0.055* | |
H25B | 0.3875 | 0.5131 | 0.8026 | 0.055* | |
H25C | 0.2366 | 0.5631 | 0.8100 | 0.055* | |
C26 | 0.00963 (15) | 0.75651 (12) | 0.45258 (13) | 0.0343 (3) | |
C27 | −0.09986 (16) | 0.64772 (14) | 0.41172 (15) | 0.0440 (4) | |
H27C | −0.1957 | 0.6716 | 0.3706 | 0.053* | |
H27B | −0.1094 | 0.6068 | 0.4784 | 0.053* | |
H27A | −0.0637 | 0.5959 | 0.3603 | 0.053* | |
C28 | −0.04462 (17) | 0.83650 (14) | 0.53718 (15) | 0.0431 (4) | |
H28A | 0.0300 | 0.9007 | 0.5697 | 0.052* | |
H28B | −0.0623 | 0.7917 | 0.5992 | 0.052* | |
H28C | −0.1359 | 0.8677 | 0.4961 | 0.052* | |
C29 | 0.01637 (17) | 0.82469 (15) | 0.34774 (15) | 0.0452 (4) | |
H29A | 0.0442 | 0.7738 | 0.2908 | 0.054* | |
H29B | 0.0892 | 0.8915 | 0.3725 | 0.054* | |
H29C | −0.0800 | 0.8520 | 0.3135 | 0.054* | |
C30 | 0.54216 (16) | 0.68559 (14) | 0.46463 (16) | 0.0437 (4) | |
H30A | 0.5831 | 0.6099 | 0.4659 | 0.052* | |
H30B | 0.6185 | 0.7450 | 0.5070 | 0.052* | |
H30C | 0.5061 | 0.7052 | 0.3849 | 0.052* | |
O1 | 0.68026 (12) | 0.41040 (10) | 0.90492 (11) | 0.0527 (3) | |
O2 | 0.94217 (11) | 0.52403 (10) | 0.77459 (11) | 0.0493 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0407 (8) | 0.0387 (8) | 0.0337 (9) | 0.0092 (6) | 0.0046 (6) | 0.0010 (6) |
C2 | 0.0416 (8) | 0.0408 (8) | 0.0409 (10) | 0.0111 (7) | 0.0059 (7) | 0.0034 (7) |
C3 | 0.0363 (8) | 0.0385 (8) | 0.0417 (10) | 0.0094 (6) | 0.0059 (7) | 0.0017 (7) |
C4 | 0.0350 (8) | 0.0395 (8) | 0.0377 (9) | 0.0099 (6) | 0.0054 (6) | −0.0001 (7) |
C5 | 0.0374 (8) | 0.0398 (8) | 0.0439 (10) | 0.0088 (6) | 0.0067 (7) | 0.0061 (7) |
C6 | 0.0368 (8) | 0.0317 (7) | 0.0434 (10) | 0.0045 (6) | 0.0061 (7) | 0.0051 (6) |
C7 | 0.0369 (8) | 0.0344 (7) | 0.0291 (8) | 0.0100 (6) | 0.0038 (6) | 0.0016 (6) |
C8 | 0.0392 (8) | 0.0319 (7) | 0.0307 (9) | 0.0060 (6) | 0.0071 (6) | 0.0032 (6) |
C9 | 0.0326 (7) | 0.0341 (7) | 0.0346 (9) | 0.0059 (6) | 0.0087 (6) | 0.0042 (6) |
C10 | 0.0352 (7) | 0.0317 (7) | 0.0294 (8) | 0.0055 (6) | 0.0062 (6) | 0.0027 (6) |
C11 | 0.0379 (8) | 0.0403 (8) | 0.0324 (9) | 0.0067 (6) | 0.0100 (6) | 0.0099 (6) |
C12 | 0.0358 (7) | 0.0411 (8) | 0.0316 (9) | 0.0080 (6) | 0.0078 (6) | 0.0013 (6) |
C13 | 0.0461 (9) | 0.0431 (8) | 0.0442 (10) | 0.0095 (7) | 0.0111 (7) | 0.0146 (7) |
C14 | 0.0361 (7) | 0.0342 (7) | 0.0330 (9) | 0.0077 (6) | 0.0047 (6) | 0.0073 (6) |
C15 | 0.0366 (8) | 0.0469 (9) | 0.0538 (11) | 0.0123 (7) | 0.0053 (7) | 0.0125 (8) |
C16 | 0.0456 (9) | 0.0367 (8) | 0.0406 (10) | 0.0105 (6) | 0.0062 (7) | 0.0061 (7) |
C17 | 0.0517 (9) | 0.0440 (9) | 0.0357 (10) | 0.0126 (7) | 0.0021 (7) | 0.0064 (7) |
C18 | 0.0379 (8) | 0.0639 (10) | 0.0440 (11) | 0.0125 (7) | 0.0132 (7) | 0.0095 (8) |
C19 | 0.0316 (7) | 0.0275 (7) | 0.0423 (10) | 0.0049 (5) | 0.0038 (6) | 0.0063 (6) |
C20 | 0.0355 (7) | 0.0283 (7) | 0.0379 (9) | 0.0011 (5) | 0.0042 (6) | 0.0063 (6) |
C21 | 0.0322 (7) | 0.0316 (7) | 0.0388 (9) | 0.0024 (6) | 0.0097 (6) | 0.0052 (6) |
C22 | 0.0302 (7) | 0.0267 (7) | 0.0355 (9) | 0.0038 (5) | 0.0049 (6) | 0.0031 (6) |
C23 | 0.0331 (7) | 0.0324 (7) | 0.0374 (9) | 0.0061 (5) | 0.0083 (6) | 0.0082 (6) |
C24 | 0.0321 (7) | 0.0288 (7) | 0.0451 (10) | 0.0050 (5) | 0.0082 (6) | 0.0058 (6) |
C25 | 0.0428 (8) | 0.0478 (9) | 0.0441 (10) | 0.0022 (7) | 0.0039 (7) | 0.0163 (7) |
C26 | 0.0299 (7) | 0.0362 (7) | 0.0362 (9) | 0.0089 (6) | 0.0061 (6) | 0.0045 (6) |
C27 | 0.0313 (7) | 0.0472 (9) | 0.0507 (11) | 0.0058 (6) | 0.0066 (7) | −0.0017 (7) |
C28 | 0.0414 (8) | 0.0432 (8) | 0.0454 (10) | 0.0149 (6) | 0.0104 (7) | 0.0035 (7) |
C29 | 0.0386 (8) | 0.0543 (9) | 0.0434 (10) | 0.0170 (7) | 0.0072 (7) | 0.0134 (8) |
C30 | 0.0350 (8) | 0.0454 (9) | 0.0539 (11) | 0.0107 (6) | 0.0141 (7) | 0.0116 (7) |
O1 | 0.0446 (7) | 0.0519 (7) | 0.0672 (9) | 0.0154 (5) | 0.0197 (6) | 0.0176 (6) |
O2 | 0.0372 (6) | 0.0623 (7) | 0.0520 (8) | 0.0146 (5) | 0.0139 (5) | 0.0126 (6) |
C1—C2 | 1.203 (2) | C17—H17C | 0.97 |
C1—C7 | 1.4321 (19) | C18—H18A | 0.97 |
C2—C3 | 1.440 (2) | C18—H18B | 0.97 |
C3—O1 | 1.2139 (18) | C18—H18C | 0.97 |
C3—C4 | 1.535 (2) | C19—C24 | 1.404 (2) |
C4—O2 | 1.2139 (18) | C19—C20 | 1.408 (2) |
C4—C5 | 1.437 (2) | C20—C21 | 1.390 (2) |
C5—C6 | 1.205 (2) | C20—C25 | 1.504 (2) |
C6—C19 | 1.4330 (19) | C21—C22 | 1.395 (2) |
C7—C8 | 1.406 (2) | C21—H21 | 0.94 |
C7—C12 | 1.410 (2) | C22—C23 | 1.396 (2) |
C8—C9 | 1.3941 (19) | C22—C26 | 1.5376 (18) |
C8—C13 | 1.502 (2) | C23—C24 | 1.3945 (19) |
C9—C10 | 1.387 (2) | C23—H23 | 0.94 |
C9—H9 | 0.94 | C24—C30 | 1.501 (2) |
C10—C11 | 1.397 (2) | C25—H25A | 0.97 |
C10—C14 | 1.5406 (18) | C25—H25B | 0.97 |
C11—C12 | 1.384 (2) | C25—H25C | 0.97 |
C11—H11 | 0.94 | C26—C29 | 1.530 (2) |
C12—C18 | 1.506 (2) | C26—C27 | 1.533 (2) |
C13—H13A | 0.97 | C26—C28 | 1.534 (2) |
C13—H13B | 0.97 | C27—H27C | 0.97 |
C13—H13C | 0.97 | C27—H27B | 0.97 |
C14—C15 | 1.526 (2) | C27—H27A | 0.97 |
C14—C17 | 1.529 (2) | C28—H28A | 0.97 |
C14—C16 | 1.532 (2) | C28—H28B | 0.97 |
C15—H15A | 0.97 | C28—H28C | 0.97 |
C15—H15B | 0.97 | C29—H29A | 0.97 |
C15—H15C | 0.97 | C29—H29B | 0.97 |
C16—H16A | 0.97 | C29—H29C | 0.97 |
C16—H16B | 0.97 | C30—H30A | 0.97 |
C16—H16C | 0.97 | C30—H30B | 0.97 |
C17—H17A | 0.97 | C30—H30C | 0.97 |
C17—H17B | 0.97 | ||
C2—C1—C7 | 177.24 (17) | C12—C18—H18B | 109.5 |
C1—C2—C3 | 174.50 (17) | H18A—C18—H18B | 109.5 |
O1—C3—C2 | 122.82 (15) | C12—C18—H18C | 109.5 |
O1—C3—C4 | 120.52 (13) | H18A—C18—H18C | 109.5 |
C2—C3—C4 | 116.65 (13) | H18B—C18—H18C | 109.5 |
O2—C4—C5 | 124.80 (15) | C24—C19—C20 | 121.01 (12) |
O2—C4—C3 | 120.69 (13) | C24—C19—C6 | 119.18 (13) |
C5—C4—C3 | 114.51 (13) | C20—C19—C6 | 119.80 (14) |
C6—C5—C4 | 173.22 (16) | C21—C20—C19 | 118.13 (14) |
C5—C6—C19 | 178.60 (18) | C21—C20—C25 | 120.55 (14) |
C8—C7—C12 | 120.92 (12) | C19—C20—C25 | 121.32 (13) |
C8—C7—C1 | 120.21 (13) | C20—C21—C22 | 122.53 (13) |
C12—C7—C1 | 118.86 (13) | C20—C21—H21 | 118.7 |
C9—C8—C7 | 118.14 (13) | C22—C21—H21 | 118.7 |
C9—C8—C13 | 120.52 (13) | C21—C22—C23 | 117.80 (12) |
C7—C8—C13 | 121.34 (12) | C21—C22—C26 | 119.89 (12) |
C10—C9—C8 | 122.45 (13) | C23—C22—C26 | 122.29 (13) |
C10—C9—H9 | 118.8 | C24—C23—C22 | 122.01 (14) |
C8—C9—H9 | 118.8 | C24—C23—H23 | 119.0 |
C9—C10—C11 | 117.78 (12) | C22—C23—H23 | 119.0 |
C9—C10—C14 | 122.69 (12) | C23—C24—C19 | 118.50 (13) |
C11—C10—C14 | 119.52 (12) | C23—C24—C30 | 120.69 (14) |
C12—C11—C10 | 122.49 (13) | C19—C24—C30 | 120.81 (13) |
C12—C11—H11 | 118.8 | C20—C25—H25A | 109.5 |
C10—C11—H11 | 118.8 | C20—C25—H25B | 109.5 |
C11—C12—C7 | 118.21 (13) | H25A—C25—H25B | 109.5 |
C11—C12—C18 | 120.53 (14) | C20—C25—H25C | 109.5 |
C7—C12—C18 | 121.27 (13) | H25A—C25—H25C | 109.5 |
C8—C13—H13A | 109.5 | H25B—C25—H25C | 109.5 |
C8—C13—H13B | 109.5 | C29—C26—C27 | 109.10 (13) |
H13A—C13—H13B | 109.5 | C29—C26—C28 | 108.23 (12) |
C8—C13—H13C | 109.5 | C27—C26—C28 | 109.55 (12) |
H13A—C13—H13C | 109.5 | C29—C26—C22 | 112.03 (12) |
H13B—C13—H13C | 109.5 | C27—C26—C22 | 108.11 (11) |
C15—C14—C17 | 108.51 (13) | C28—C26—C22 | 109.80 (12) |
C15—C14—C16 | 108.77 (13) | C26—C27—H27C | 109.5 |
C17—C14—C16 | 109.25 (13) | C26—C27—H27B | 109.5 |
C15—C14—C10 | 112.22 (12) | H27C—C27—H27B | 109.5 |
C17—C14—C10 | 109.84 (12) | C26—C27—H27A | 109.5 |
C16—C14—C10 | 108.20 (12) | H27C—C27—H27A | 109.5 |
C14—C15—H15A | 109.5 | H27B—C27—H27A | 109.5 |
C14—C15—H15B | 109.5 | C26—C28—H28A | 109.5 |
H15A—C15—H15B | 109.5 | C26—C28—H28B | 109.5 |
C14—C15—H15C | 109.5 | H28A—C28—H28B | 109.5 |
H15A—C15—H15C | 109.5 | C26—C28—H28C | 109.5 |
H15B—C15—H15C | 109.5 | H28A—C28—H28C | 109.5 |
C14—C16—H16A | 109.5 | H28B—C28—H28C | 109.5 |
C14—C16—H16B | 109.5 | C26—C29—H29A | 109.5 |
H16A—C16—H16B | 109.5 | C26—C29—H29B | 109.5 |
C14—C16—H16C | 109.5 | H29A—C29—H29B | 109.5 |
H16A—C16—H16C | 109.5 | C26—C29—H29C | 109.5 |
H16B—C16—H16C | 109.5 | H29A—C29—H29C | 109.5 |
C14—C17—H17A | 109.5 | H29B—C29—H29C | 109.5 |
C14—C17—H17B | 109.5 | C24—C30—H30A | 109.5 |
H17A—C17—H17B | 109.5 | C24—C30—H30B | 109.5 |
C14—C17—H17C | 109.5 | H30A—C30—H30B | 109.5 |
H17A—C17—H17C | 109.5 | C24—C30—H30C | 109.5 |
H17B—C17—H17C | 109.5 | H30A—C30—H30C | 109.5 |
C12—C18—H18A | 109.5 | H30B—C30—H30C | 109.5 |
O1—C3—C4—O2 | 175.22 (15) | C9—C10—C14—C16 | −114.48 (15) |
C2—C3—C4—O2 | −5.5 (2) | C11—C10—C14—C16 | 64.13 (18) |
O1—C3—C4—C5 | −5.5 (2) | C24—C19—C20—C21 | −0.9 (2) |
C2—C3—C4—C5 | 173.76 (14) | C6—C19—C20—C21 | −179.58 (13) |
C12—C7—C8—C9 | −1.0 (2) | C24—C19—C20—C25 | 179.14 (14) |
C1—C7—C8—C9 | 177.96 (14) | C6—C19—C20—C25 | 0.5 (2) |
C12—C7—C8—C13 | 179.96 (15) | C19—C20—C21—C22 | −0.5 (2) |
C1—C7—C8—C13 | −1.1 (2) | C25—C20—C21—C22 | 179.44 (14) |
C7—C8—C9—C10 | 0.3 (2) | C20—C21—C22—C23 | 1.6 (2) |
C13—C8—C9—C10 | 179.38 (14) | C20—C21—C22—C26 | 179.73 (13) |
C8—C9—C10—C11 | 0.3 (2) | C21—C22—C23—C24 | −1.3 (2) |
C8—C9—C10—C14 | 178.94 (14) | C26—C22—C23—C24 | −179.38 (13) |
C9—C10—C11—C12 | −0.3 (2) | C22—C23—C24—C19 | −0.1 (2) |
C14—C10—C11—C12 | −179.02 (14) | C22—C23—C24—C30 | −179.83 (14) |
C10—C11—C12—C7 | −0.3 (2) | C20—C19—C24—C23 | 1.2 (2) |
C10—C11—C12—C18 | 179.14 (14) | C6—C19—C24—C23 | 179.86 (13) |
C8—C7—C12—C11 | 1.0 (2) | C20—C19—C24—C30 | −179.05 (13) |
C1—C7—C12—C11 | −177.99 (14) | C6—C19—C24—C30 | −0.4 (2) |
C8—C7—C12—C18 | −178.45 (14) | C21—C22—C26—C29 | 169.16 (13) |
C1—C7—C12—C18 | 2.6 (2) | C23—C22—C26—C29 | −12.79 (19) |
C9—C10—C14—C15 | 5.5 (2) | C21—C22—C26—C27 | −70.59 (17) |
C11—C10—C14—C15 | −175.86 (14) | C23—C22—C26—C27 | 107.46 (15) |
C9—C10—C14—C17 | 126.34 (15) | C21—C22—C26—C28 | 48.87 (17) |
C11—C10—C14—C17 | −55.05 (18) | C23—C22—C26—C28 | −133.07 (14) |
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13A···O1i | 0.97 | 2.59 | 3.545 (2) | 168 |
C27—H27A···O2ii | 0.97 | 2.59 | 3.558 (2) | 173 |
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C30H34O2 |
Mr | 426.57 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 213 |
a, b, c (Å) | 9.3933 (11), 11.4531 (14), 11.9823 (13) |
α, β, γ (°) | 93.289 (9), 105.303 (9), 93.674 (10) |
V (Å3) | 1237.1 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.07 |
Crystal size (mm) | 0.58 × 0.32 × 0.31 |
Data collection | |
Diffractometer | Stoe IPDS 2 |
Absorption correction | Integration X-RED (Stoe, 2004) |
Tmin, Tmax | 0.974, 0.991 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15963, 4296, 3130 |
Rint | 0.055 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.107, 1.00 |
No. of reflections | 4296 |
No. of parameters | 300 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.18, −0.20 |
Computer programs: X-AREA (Stoe, 2004), X-AREA, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), Please provide missing details.
C1—C2 | 1.203 (2) | C4—C5 | 1.437 (2) |
C1—C7 | 1.4321 (19) | C5—C6 | 1.205 (2) |
C2—C3 | 1.440 (2) | C6—C19 | 1.4330 (19) |
C3—O1 | 1.2139 (18) | C8—C13 | 1.502 (2) |
C3—C4 | 1.535 (2) | C11—C12 | 1.384 (2) |
C4—O2 | 1.2139 (18) | ||
C1—C2—C3 | 174.50 (17) | C5—C4—C3 | 114.51 (13) |
C2—C3—C4 | 116.65 (13) | C6—C5—C4 | 173.22 (16) |
O1—C3—C4—O2 | 175.22 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13A···O1i | 0.97 | 2.59 | 3.545 (2) | 168 |
C27—H27A···O2ii | 0.97 | 2.59 | 3.558 (2) | 173 |
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) −x+1, −y+1, −z+1. |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
The title compound is a newly synthesized member of the diacetylenic 1,2-diones, a class of compounds first introduced in 1996 (Faust & Weber, 1996; Faust et al., 1997). The two typifying interconnected ynone moieties of this molecular structure give rise to a rich chemistry that we have explored to form, inter alia, metal-chelating diazabutadienes (Faust, Göbelt & Weber, 1999; Faust, Göbelt et al., 1999), alkyne-substituted N-heterocyclic carbenes (Faust & Göbelt, 2000) and acetylenic phthalocyanines (Faust, 2001). Despite these successful developments, two questions remain about the electronic aspects of these compounds. Firstly, the kinetic stability of dialkynyl diones appears to rely largely on the size of the terminal alkyne substituents. Whereas bulky triisoproylsilyl groups lend excellent stability to the hexadiynedione core, smaller terminal substituents, such as alkyls or the trimethylsilyl group, are insufficient to protect the reactive ynone system from nucleophilic attack (Faust et al., 1997). Similarly, aryl termini shield the reactive core of the molecule most effectively when, as in the case discussed here, they possess sizeable 2,6-substituents flanking the alkyne subunit. The second question concerns the effective conjugation path of the hexa-1,5-diyne-3,4-dione framework. We have speculated that, similar to the related 2,3-dialkynyldiazabutadienes (Faust et al., 1999 Which?), a valid description of dialkynyl diones is that of two interconnected but largely electronically independent bis(ynone) units, rather than that of a species fully delocalized along the hexadiynedione core. The present solid-state study is the first on this class of compounds and was undertaken to shed some light on these matters.
The title compound, (I), with the atomic numbering, is shown in Fig. 1. The molecule crystallizes in the triclinic space group P1 with one molecule in the asymmetric unit. Inspection of Fig. 1 reveals an extended conformation of the molecule with a formal s-trans geometry [torsion angle O2—C4—C3—O1 175.2 (2) °] around the 1,2-dione subunit. The maximum deviation of the atoms from a plane through C2/C3/C4/C5/O1/O2 is only 0.062 (1) Å For which atom?. The phenyl ring system around C7 is almost perfectly coplanar with the dione unit, as the plane through C1/C2/C3/C7/C8/C12/O1 forms an angle of only 4.2 (1)° with that of the dione substructure. On the other hand, the phenyl ring system around C19 (i.e. a plane through C4/C5/C6/C19/C20/C24) is twisted by about 20.3 (1)° from the plane of the dione moiety.
In terms of π electronic delocalization, it appears that, in the crystal, the electronic interaction between one phenyl group and the ynone portion of the molecule is maximized, whereas that of the other is slightly diminished. The distance between the two carbonyl atoms C3—C4 is 1.535 (2) Å (Table 1), suggesting a rather long Csp2—Csp2 single bond through which little electron density is transmitted. While most other structural parameters within this part of the molecule are within the normal range (Allen et al., 1987), the C—C—C angles around the carbonyl C atoms [i.e. C2—C3—C4 116.7 (1)° and C3—C4—C5 114.5 (1)°] are significantly compressed.
The methyl groups on the 2,6-positions on the aryl rings protrude into the space segment above and below the C1≡C2 (and C5≡C6) triple bonds, a structural feature that helps to explain the increased stability of this system towards nucleophilic attack, particularly in solution, where there is free rotation around the C7—C1 (and C6—C19) single bonds. There are no close intramolecular contacts between the methyl H atoms and the carbonyl O atoms.
An inspection of the packing arrangement (Fig. 2) of compound (I) in the crystal reveals that the tert-butyl groups of one molecule reside in the space above the dione subunits of adjacent molecules. In conjunction with the findings above, this might indicate that the planarity of the dione substructure is dictated by the space requirements of the bulky alkyl group, rather than by intramolecular electronic interactions such as π delocalization. The crystal packing forces are enhanced by very weak intermolecular hydrogen bonds between methyl H atoms and the carbonyl O atoms. The relevant distances are depicted as dashed lines in Fig. 2, with details given in Table 2. In this way, chains of centrosymmetric rings develop along [101]. The alkyl substitution of the aryl rings prevents intermolecular π–π stacking interactions.