Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113017496/qs3027sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113017496/qs3027Isup2.hkl | |
MDL mol file https://doi.org/10.1107/S0108270113017496/qs3027Isup3.mol | |
Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270113017496/qs3027Isup4.cml |
CCDC reference: 964813
The large departure of the bond angles in three-membered cyclopropane rings from tetrahedral angles and the resulting strain energy are of great theoretical interest. The research described in this paper is an attempt to extend the theoretical and quantitative information on the molecular structures and electron-density distributions of cyclopropane molecules available through combining X-ray crystallography and quantum mechanical calculations of a substituted cyclopropane. In their development of invarioms, Birger Dittrich and co-workers have defined a procedure by which Gaussian wavefunctions are used to project theoretical electron densities onto the multipole model (Dittrich et al., 2005). In this method, theoretical structure factors are generated by the program Tonto (Jayatilaka & Grimwood, 2003) from the Gaussian wavefunction and then least-squares refinements give the populations of the multipoles. We have determined the nature of the electron density in the cyclopropropane ring in the title compound, (I), by this method and observed the effects of substitution on the covalent bonding between these C atoms.
Crystal data, data collection and structure refinement details are summarized in Table 1.
A mixture of trans-β-methylstyrene (2.5 mmol) and AgOTf (0.05 mmol) was weighed into a 25 ml one-necked round-bottomed flask covered with aluminium foil to exclude light. The mixture was dissolved with dichloromethane (2 ml) and stirred at room temperature under an atmosphere of argon. Methyl phenyldiazoacetate (0.5 mmol) in dichloromethane (8 ml) was then added to the solution via syringe pump over a period of 3 h. After addition, the mixture was stirred for an additional 1 h and then concentrated in vacuo. Purification by silica-gel chromatography (using 20:1 v/v hexane–Et2O as the solvent system) gave the product in 64% yield (86 mg) as colorless crystals. 1H NMR (600 MHz, δ, p.p.m.): 7.11–7.7.13 (m, 2H), 6.76–7.05 (m, 6H), 7.02–7.06 (m, 2H), 3.65 (s, 3H), 3.08 (d, 1H, J = 7.8 Hz), 2.25 (dq, 1H, J = 7.2 and 6.0 Hz), 1.47 (d, 3H, J = 6.0 Hz); 13C NMR (100 MHz, δ, p.p.m.): 172.3, 137.0, 136.4, 131.3, 127.9, 127.8, 127.6, 126.9, 126.0, 52.3, 42.4, 37.7, 27.3, 12.9. The spectroscopic data are consistent with the previously reported results (Thompson & Davies, 2007).
The program InvariomTool (Hübschle et al., 2007) was used to prepare the master and input files for a multipole refinement with the XDLSM program of the XD2006 suite (Volkov et al., 2006). Nonspherical scattering factors were obtained from theoretical calculations of (I) by following a procedure developed by Dittrich et al. (2006). Density functional theory (DFT) calculations were carried out using the B3LYP method in the GAUSSIAN09 suite of programs (Frisch et al., 2009). A Dunning–Huzinaga full double-zeta basis set with 3df and 3dp polarization functions was used (Dunning & Hay, 1977). Calculations were carried out using 1164 basis functions. The wavefunction was calculated for the nuclear configuration geometry from the crystal structure. Electron densities were derived by evaluating the Gaussian orbitals using the programs AIMAII (Keith, 2012) and Tonto (Jayatilaka & Grimwood, 2003). An artificial crystal of (I) (space group P1), with a cubic cell edge of 30 Å and the molecule centered at the position (1/4, 1/4, 1/4), was constructed. Structure factors for this crystal were generated by Tonto up to a resolution of sinθ /λ = 1.15 Å-1. Thermal smearing was ignored and the contributions of the core electrons were included in structure-factor calculations. Least-squares refinements of the multipole populations parameters with these structure factors, and the fixed geometry from the crystal structure, yielded a multipole model suitable for reproducing the electron density in the molecule. This method provides a means of calculating the atomic electron densities without having to partition individual atoms into pseudo-atoms. These multipole parameters, together with orientation and symmetry of the local atomic coordinate system, were transferred to the input files for a refinement with the XDLSM program of the XD2006 suite. Full matrix least-squares refinements on F2 using complete multipole expansions were carried out with the program XDLSM using statistical weights. Only reflections with intensities I > 3σ(I) were included in the refinement. In the final cycles, all atom positions were refined freely. Positional and displacement (anisotropic for non-H atoms) parameters, but not multipoles, were refined. However, a hexadecapolar level of the multipole expansion was used for all atoms. The introduction of the multipole model improved R(F) from 0.043 to 0.030, while using the same weighting scheme {w = 1/[s2(Fo2)]} as with the spherical atom refinement, and improved the goodness-of-fit value from 2.819 to 1.597.
The molecular structure of (I) (Fig. 1) can be derived from that of cyclopropane by replacing two H atoms on C2 by a methyl formate group and a phenyl ring, one H atom on C3 with a methyl group, and one H atom on C4 with a phenyl ring. The conformation of this compound is of interest. The phenyl rings across the C—C bond give rise to 1,3-steric repulsion, which favors a staggered arrangement in an unbridged C—C bond. The steric repulsion between these groups might influence the electron density in the bond and is likely to have an effect on the geometry of the molecule. The electronic interaction between the substituents and the ring is also of interest. Methyl, phenyl and methyl formate groups might be expected to withdraw electron density and weaken the C—C bonds.
A large number of basis functions for atoms with a large number of electrons are needed to yield accurate results. This compound has 142 electrons, of which 71 are designated β electrons. Calculations were carried out using 1164 basis functions. The nuclear geometry from the crystal structure was used for the wavefunction calculations. Subsequent X-ray refinements with the new scattering factors yielded a geometry-optimized structure. Topological analysis of the resulting densities in the cyclopropane C—C bonds, using AIMAII (Keith, 2012), was carried out and the values compared with those derived from X-ray refinements using scattering factors derived from the quantum mechanical calculations. This is useful for testing how well the calculated electron densities are projected onto multipole crystal structure refinements and whether the XD2006 (Volkov et al., 2006) densities represent the theoretical densities faithfully. The results are presented in Table 2. There is a correlation between the densities with some differences, but the match seems to be acceptable.
The C—C bonds are expected to be weakened by strain. The characteristic C—C bond length in cyclopropane is 1.50 Å, shorter than the normal C—C bond length of 1.54 Å (Cambridge Structural Database, Version 5.34; Allen, 2002). The three C atoms in a symmetrically substituted cyclopropane form the geometry of an equilateral triangle (see, for example, Hartman & Hirshfeld, 1966). In cyclopropane (I), the ring does not have C3 symmetry but has two normal C—C bonds [1.5421 (4) and 1.5338 (4) Å] and one short bond [1.5019 (4) Å; Table 3]. The shortest C—C bond occurs between the hydrido-substituted C atoms distal to the formate group, while the longest bonds are to the C atom bonded to methyl formate. The basicity of the CO2 group is expected to reduce the electron density in the two C—C bonds attached to this C atom, lengthening these two bonds (and shortening the distal bond). This effect is reflected in the atomic charges and electron densities at the bond-critical points (Table 2). The shortest bond occurs where the phenyl and methyl substituents are trans, for which repulsion between these 1,4-bonded atoms will be less. The molecular graph is shown in Fig. 2. Bond-critical points were located between the nuclei. Another two bond-critical points were located that are not normally associated with chemical bonds. The distance between atoms H6 and C12 is only 2.709 (7) Å and a (3,-1) critical point exists between them. The second (3,-1) critical point is associated with a weak intramolecular hydrogen bond (C11—H11A··· O2; Table 4). The existence of a (3,-1) critical point is insufficient evidence for chemical bonding between these two atoms (Haaland et al. (2004), but it does show that electron density is accumulating preferentially along this direction, thereby stabilizing this short contact.
A difference electron-density map in the plane of the cyclopropane ring is shown in Fig. 3. It is evident from this plot that there is an accumulation of charge over the entire cyclopropane triangle area and beyond the C—C bonds. Critical points (CP), due to C—C bonding, are displaced by 0.031–0.041 Å from the C—C internuclear axes. The electron density at the critical points for the C—C bonds, calculated by XD2006, are in the range 1.48–1.61 e Å-3. The largest peak, and the shortest bond path, occur between atoms C3 and C4. The smallest bond-path angle (63.85°) corresponds to the internuclear angle C4—C2—C3 and the longest C—C bonds. These distances indicate that the carboxylate group withdraws some of the valence density from these bonds, thereby lengthening them and decreasing the angles between them. These bond-path angles are greater than the bond angles, but still substantially smaller than the tetrahedral angle normally associated with C—C bonds.
The electron density is at a minimum near the center of the plane of the three C atoms and this point is a (3,+1) critical point of the electron density. The electron density in this ring critical point is very large (0.190 e Å-3), even though this point is the local minimum of the electron density. The bond ellipticities give a measure of how much electron density accumulates normal to the direction of the bond. Single bonds in linear alkanes typically have ellipticities close to 0. The bond ellipticities in these three C—C bonds are very large, even considerably larger than those found in ethylene and aromatic systems (Bader, 1983).
The bonding electron density has a flattened form in the plane of the ring, perpendicular to the bond paths. The small bond angles force the electron density to flatten out, away from the bond-path angles and towards the center of the ring [Original text not clear - please check].
Cyclopropyl groups resemble π-systems (Bader, 1983), and the total charge distribution on this fragment of (I) makes it suitable for conjugation with the carboxyl group and the neighboring phenyl rings.
These results show a cyclopropane group with an asymmetric and highly flattened bonding charge density. Lengthening of the C2—C4 and C2—C3 bonds and shortening of the C3—C4 bond, due to the withdrawal of electron density by the carboxylate group, is reflected by the electron densities at the bond-critical points. The spread out density is likely to have been enhanced by the proximity of the two phenyl rings and the carboxylate group.
Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: XD2006 (Volkov et al., 2006); molecular graphics: XD2006 (Volkov et al., 2006), OLEX2 (Dolomanov et al., 2009) and AIMAII (Keith, 2012); software used to prepare material for publication: XD2006 (Volkov et al., 2006).
C18H18O2 | F(000) = 568 |
Mr = 266.32 | Dx = 1.231 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 16.9049 (7) Å | Cell parameters from 9516 reflections |
b = 7.4168 (3) Å | θ = 2.5–44.4° |
c = 11.7545 (5) Å | µ = 0.08 mm−1 |
β = 102.869 (2)° | T = 173 K |
V = 1436.76 (10) Å3 | Plate, colourless |
Z = 4 | 0.74 × 0.54 × 0.26 mm |
Bruker APEXII area-detector diffractometer | 9819 reflections with I > 3σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.038 |
Graphite monochromator | θmax = 44.9° |
Absorption correction: empirical (using intensity measurements) (SADABS; Bruker, 2008) | h = −33→32 |
Tmin = 0.829, Tmax = 1.000 | k = 0→14 |
52859 measured reflections | l = 0→23 |
11659 independent reflections |
Refinement on F | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.030 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.027 | All H-atom parameters refined |
S = 1.60 | w1 = 1/[s2(Fo)] |
9819 reflections | (Δ/σ)max = 0.001 |
199 parameters | Δρmax = 0.18 e Å−3 |
0 restraints | Δρmin = −0.34 e Å−3 |
C18H18O2 | V = 1436.76 (10) Å3 |
Mr = 266.32 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 16.9049 (7) Å | µ = 0.08 mm−1 |
b = 7.4168 (3) Å | T = 173 K |
c = 11.7545 (5) Å | 0.74 × 0.54 × 0.26 mm |
β = 102.869 (2)° |
Bruker APEXII area-detector diffractometer | 11659 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Bruker, 2008) | 9819 reflections with I > 3σ(I) |
Tmin = 0.829, Tmax = 1.000 | Rint = 0.038 |
52859 measured reflections |
R[F2 > 2σ(F2)] = 0.030 | 0 restraints |
wR(F2) = 0.027 | All H-atom parameters refined |
S = 1.60 | Δρmax = 0.18 e Å−3 |
9819 reflections | Δρmin = −0.34 e Å−3 |
199 parameters |
Experimental. Absorption correction: SADABS2008/1 (Bruker, 2008) was used for absorption correction. Rint was 0.0669 before and 0.0526 after correction. The ratio of minimum to maximum transmission is 0.8289. The λ/2 correction factor is 0.0015. |
Refinement. An invariom refinement was performed initially (Dittrich, Acta Cryst. A62, 217). Improved multipole populations parameters were obtained from theoretical calculations of the title compound. This is similar to the Invariom approach, except that the multipole populations parameters were obtained from theoretical calculations of the title compound without geometry optimization. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.09722 (3) | 0.44089 (6) | 0.63043 (5) | 0.018 | |
O2 | 0.11751 (3) | 0.68409 (7) | 0.74652 (5) | 0.021 | |
C3 | 0.18684 (2) | 0.83592 (4) | 0.54491 (3) | 0.013 | |
C12 | 0.227930 (15) | 0.49634 (3) | 0.53796 (2) | 0.010 | |
C4 | 0.252358 (19) | 0.80448 (4) | 0.65247 (3) | 0.012 | |
C13 | 0.289726 (15) | 0.38543 (3) | 0.59957 (2) | 0.013 | |
C6 | 0.371088 (15) | 0.77696 (3) | 0.55323 (2) | 0.013 | |
C2 | 0.196225 (18) | 0.64740 (4) | 0.59992 (3) | 0.011 | |
C17 | 0.196782 (15) | 0.46292 (3) | 0.41957 (2) | 0.012 | |
C14 | 0.319322 (16) | 0.24176 (3) | 0.54485 (3) | 0.015 | |
C5 | 0.340212 (16) | 0.81407 (3) | 0.65204 (3) | 0.011 | |
C10 | 0.394014 (16) | 0.87593 (3) | 0.75275 (2) | 0.014 | |
C7 | 0.453071 (16) | 0.80206 (4) | 0.55524 (3) | 0.016 | |
C15 | 0.286497 (17) | 0.20686 (3) | 0.42726 (3) | 0.015 | |
C1 | 0.134438 (19) | 0.59621 (4) | 0.66799 (3) | 0.013 | |
C16 | 0.225779 (17) | 0.31828 (3) | 0.36434 (3) | 0.014 | |
C9 | 0.476275 (16) | 0.90094 (4) | 0.75516 (3) | 0.017 | |
C11 | 0.11671 (2) | 0.96115 (5) | 0.54654 (4) | 0.019 | |
C8 | 0.505856 (17) | 0.86423 (4) | 0.65620 (3) | 0.019 | |
C18 | 0.03444 (3) | 0.38624 (7) | 0.68833 (5) | 0.025 | |
H4 | 0.2400 (7) | 0.8482 (9) | 0.7281 (7) | 0.0124 (18) | |
H3 | 0.2070 (4) | 0.8390 (15) | 0.4698 (7) | 0.0107 (17) | |
H17 | 0.1551 (4) | 0.5418 (8) | 0.3754 (6) | 0.0197 (14) | |
H13 | 0.3125 (4) | 0.4125 (9) | 0.6818 (6) | 0.0221 (14) | |
H10 | 0.3727 (4) | 0.9060 (8) | 0.8215 (6) | 0.0207 (14) | |
H6 | 0.3338 (4) | 0.7359 (7) | 0.4811 (6) | 0.0176 (13) | |
H16 | 0.2035 (4) | 0.2960 (9) | 0.2817 (6) | 0.0227 (14) | |
H7 | 0.4737 (5) | 0.7777 (8) | 0.4851 (6) | 0.0251 (15) | |
H15 | 0.3062 (4) | 0.1028 (8) | 0.3884 (6) | 0.0198 (14) | |
H14 | 0.3634 (4) | 0.1675 (9) | 0.5896 (6) | 0.0235 (15) | |
H11A | 0.1015 (8) | 0.9544 (12) | 0.6185 (9) | 0.025 (2) | |
H11B | 0.0711 (7) | 0.9360 (12) | 0.4827 (10) | 0.031 (2) | |
H9 | 0.5129 (4) | 0.9458 (8) | 0.8258 (6) | 0.0245 (15) | |
H8 | 0.5633 (4) | 0.8827 (9) | 0.6571 (7) | 0.0300 (16) | |
H11C | 0.1340 (6) | 1.0826 (12) | 0.5366 (9) | 0.026 (2) | |
H18A | −0.0070 (8) | 0.4770 (17) | 0.6773 (10) | 0.040 (3) | |
H18B | 0.0140 (9) | 0.2774 (16) | 0.6524 (9) | 0.039 (3) | |
H18C | 0.0564 (7) | 0.3654 (17) | 0.7690 (9) | 0.031 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.01517 (14) | 0.01622 (14) | 0.0256 (2) | −0.00675 (13) | 0.01098 (14) | −0.00731 (14) |
O2 | 0.02093 (17) | 0.02196 (17) | 0.0244 (2) | −0.00799 (15) | 0.01469 (17) | −0.01087 (17) |
C3 | 0.01117 (11) | 0.01068 (11) | 0.01603 (14) | 0.00145 (9) | 0.00289 (10) | −0.00090 (10) |
C12 | 0.00941 (9) | 0.00909 (9) | 0.01096 (11) | 0.00042 (7) | 0.00218 (7) | −0.00046 (8) |
C4 | 0.01002 (11) | 0.01128 (10) | 0.01386 (13) | −0.00154 (9) | 0.00344 (9) | −0.00281 (10) |
C13 | 0.01336 (9) | 0.01111 (9) | 0.01243 (11) | 0.00199 (7) | 0.00122 (7) | 0.00122 (7) |
C6 | 0.01123 (9) | 0.01398 (9) | 0.01443 (11) | −0.00182 (7) | 0.00425 (8) | −0.00174 (8) |
C2 | 0.00962 (10) | 0.01000 (10) | 0.01293 (13) | −0.00078 (9) | 0.00351 (9) | −0.00181 (9) |
C17 | 0.01186 (9) | 0.01182 (9) | 0.01154 (10) | 0.00162 (7) | 0.00116 (7) | −0.00130 (7) |
C14 | 0.01505 (10) | 0.01051 (9) | 0.01817 (13) | 0.00339 (8) | 0.00359 (8) | 0.00195 (8) |
C5 | 0.00996 (9) | 0.01014 (9) | 0.01256 (11) | −0.00149 (7) | 0.00265 (8) | −0.00063 (8) |
C10 | 0.01226 (9) | 0.01498 (10) | 0.01309 (11) | −0.00241 (8) | 0.00133 (8) | −0.00034 (8) |
C7 | 0.01216 (10) | 0.01882 (11) | 0.01943 (13) | −0.00262 (8) | 0.00652 (9) | −0.00151 (9) |
C15 | 0.01678 (10) | 0.01093 (9) | 0.01809 (12) | 0.00210 (8) | 0.00700 (9) | −0.00104 (8) |
C1 | 0.01043 (11) | 0.01299 (11) | 0.01549 (14) | −0.00227 (9) | 0.00521 (10) | −0.00355 (11) |
C16 | 0.01678 (10) | 0.01322 (9) | 0.01308 (11) | 0.00126 (8) | 0.00373 (8) | −0.00237 (8) |
C9 | 0.01196 (10) | 0.02016 (11) | 0.01755 (13) | −0.00344 (8) | 0.00006 (8) | −0.00038 (9) |
C11 | 0.01412 (13) | 0.01497 (13) | 0.0263 (2) | 0.00465 (11) | 0.00306 (13) | −0.00258 (13) |
C8 | 0.01084 (10) | 0.02260 (12) | 0.02239 (14) | −0.00371 (9) | 0.00378 (9) | −0.00076 (10) |
C18 | 0.01967 (16) | 0.02324 (17) | 0.0377 (3) | −0.00933 (15) | 0.01721 (18) | −0.00786 (18) |
C2—C3 | 1.5338 (4) | C14—C15 | 1.3941 (5) |
C3—C4 | 1.5019 (5) | C14—H14 | 0.980 (7) |
C4—C2 | 1.5421 (4) | C5—C10 | 1.3999 (4) |
C2—C1 | 1.4992 (4) | C10—C9 | 1.3970 (4) |
O1—C1 | 1.3395 (5) | C10—H10 | 0.981 (6) |
O2—C1 | 1.2150 (5) | C7—C8 | 1.3948 (4) |
C3—C11 | 1.5096 (5) | C7—H7 | 0.980 (7) |
C3—H3 | 1.015 (8) | C15—C16 | 1.3948 (4) |
C12—C13 | 1.3984 (4) | C15—H15 | 0.991 (6) |
C12—C2 | 1.4989 (4) | C16—H16 | 0.974 (7) |
C12—C17 | 1.3961 (4) | C9—C8 | 1.3915 (5) |
C4—C5 | 1.4880 (4) | C9—H9 | 0.977 (7) |
C4—H4 | 1.011 (8) | C11—H11A | 0.939 (9) |
C13—C14 | 1.3939 (4) | C11—H11B | 0.966 (10) |
C13—H13 | 0.978 (7) | C11—H11C | 0.962 (9) |
C6—C5 | 1.4026 (4) | C8—H8 | 0.979 (7) |
C6—C7 | 1.3933 (4) | C18—H18A | 0.960 (11) |
C6—H6 | 0.985 (6) | C18—H18B | 0.940 (11) |
C17—C16 | 1.3980 (4) | C18—H18C | 0.951 (10) |
C17—H17 | 0.973 (6) | ||
C2—C4—C3 | 60.50 (2) | C3—C2—C12 | 119.41 (3) |
C3—C2—C4 | 58.46 (2) | C3—C2—C1 | 115.91 (3) |
C4—C3—C2 | 61.05 (2) | C12—C2—C1 | 115.92 (3) |
C4—C3—C11 | 121.26 (3) | C12—C17—C16 | 120.39 (2) |
C4—C3—H3 | 114.1 (5) | C13—C14—C15 | 119.67 (2) |
C2—C3—C11 | 124.29 (3) | C4—C5—C6 | 123.32 (3) |
C2—C3—H3 | 111.3 (6) | C4—C5—C10 | 118.28 (3) |
C11—C3—H3 | 114.4 (6) | C6—C5—C10 | 118.24 (2) |
C13—C12—C2 | 119.66 (3) | C5—C10—C9 | 121.13 (3) |
C13—C12—C17 | 118.96 (2) | C6—C7—C8 | 120.27 (3) |
C2—C12—C17 | 121.39 (2) | C6—C7—H7 | 120.0 (5) |
C3—C4—C5 | 122.63 (3) | C14—C15—C16 | 119.94 (2) |
C3—C4—H4 | 115.6 (6) | C1—O1—C18 | 115.32 (5) |
C5—C4—H4 | 112.9 (6) | O1—C1—O2 | 122.61 (4) |
C12—C13—C14 | 120.95 (3) | O1—C1—C2 | 111.95 (3) |
C12—C13—H13 | 118.4 (4) | O2—C1—C2 | 125.42 (4) |
C14—C13—H13 | 120.7 (4) | C17—C16—C15 | 120.07 (3) |
C5—C6—C7 | 120.79 (3) | C10—C9—C8 | 119.90 (3) |
C5—C6—H6 | 119.2 (4) | C7—C8—C9 | 119.67 (2) |
C7—C6—H6 | 120.0 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···O2 | 1.01 (1) | 2.45 (1) | 2.8877 (6) | 105 (1) |
C11—H11A···O2 | 0.94 (1) | 2.49 (1) | 3.1200 (7) | 125 (1) |
C17—H17···O2i | 0.97 (1) | 2.53 (1) | 3.4020 (6) | 149 (1) |
Symmetry code: (i) x, −y+3/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C18H18O2 |
Mr | 266.32 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 16.9049 (7), 7.4168 (3), 11.7545 (5) |
β (°) | 102.869 (2) |
V (Å3) | 1436.76 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.74 × 0.54 × 0.26 |
Data collection | |
Diffractometer | Bruker APEXII area-detector diffractometer |
Absorption correction | Empirical (using intensity measurements) (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.829, 1.000 |
No. of measured, independent and observed [I > 3σ(I)] reflections | 52859, 11659, 9819 |
Rint | 0.038 |
(sin θ/λ)max (Å−1) | 0.993 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.027, 1.60 |
No. of reflections | 9819 |
No. of parameters | 199 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.18, −0.34 |
Computer programs: APEX2 (Bruker, 2011), SAINT (Bruker, 2009), SHELXS97 (Sheldrick, 2008), XD2006 (Volkov et al., 2006), OLEX2 (Dolomanov et al., 2009) and AIMAII (Keith, 2012).
Property | X-ray refinement | Gaussian wavefunction |
C2—C3 | ||
Bond length (Å) | 1.5338 (4) | 1.5348 |
ρ(r) (e- Å-3) | 1.48 | 1.54 |
Bond path (Å) | 1.538 | 1.537 |
Bond path angle (°) C4—C2—C3 | 67.69 | 67.27 |
Ellipticity, ε | 0.609 | 0.529 |
Δ2ρ(r) (e- Å-5) | -4.589 | -2.875 |
λ1 | -10.157 | -10.679 |
λ2 | -6.31 | -6.99 |
λ3 | 11.88 | 7.39 |
C3—C4 | ||
Bond distance (Å) | 1.5019 (4) | 1.5016 |
ρ(r) (e- Å-3) | 1.62 | 1.67 |
Bond path (Å) | 1.506 | 1.504 |
Bond path angle (°) C2—C3—C4 | 67.69 | 67.27 |
Ellipticity, ε | 0.609 | 0.529 |
Δ2ρ(r) (e- Å-5) | -4.589 | -2.875 |
λ1 | -10.157 | -10.679 |
λ2 | -6.31 | -6.99 |
λ3 | 11.88 | 7.39 |
C4—C2 | ||
Bond distance (Å) | 1.5421 (4) | 1.54233 |
ρ(r) (e- Å-3) | 1.46 | 1.51 |
Bond path (Å) | 1.545 | 1.544 |
Bond path angle (°) C3—C4—C2 | 63.85 | 63.38 |
Ellipticity, ε | 0.67 | 0.57 |
Δ2ρ(r) (e- Å-5) | -3.94 | -2.74 |
λ1 | -9.96 | -10.53 |
λ2 | -5.95 | -6.69 |
λ3 | 11.97 | 7.43 |
C2—C3 | 1.5338 (4) | C14—C15 | 1.3941 (5) |
C3—C4 | 1.5019 (5) | C14—H14 | 0.980 (7) |
C4—C2 | 1.5421 (4) | C5—C10 | 1.3999 (4) |
C2—C1 | 1.4992 (4) | C10—C9 | 1.3970 (4) |
O1—C1 | 1.3395 (5) | C10—H10 | 0.981 (6) |
O2—C1 | 1.2150 (5) | C7—C8 | 1.3948 (4) |
C3—C11 | 1.5096 (5) | C7—H7 | 0.980 (7) |
C3—H3 | 1.015 (8) | C15—C16 | 1.3948 (4) |
C12—C13 | 1.3984 (4) | C15—H15 | 0.991 (6) |
C12—C2 | 1.4989 (4) | C16—H16 | 0.974 (7) |
C12—C17 | 1.3961 (4) | C9—C8 | 1.3915 (5) |
C4—C5 | 1.4880 (4) | C9—H9 | 0.977 (7) |
C4—H4 | 1.011 (8) | C11—H11A | 0.939 (9) |
C13—C14 | 1.3939 (4) | C11—H11B | 0.966 (10) |
C13—H13 | 0.978 (7) | C11—H11C | 0.962 (9) |
C6—C5 | 1.4026 (4) | C8—H8 | 0.979 (7) |
C6—C7 | 1.3933 (4) | C18—H18A | 0.960 (11) |
C6—H6 | 0.985 (6) | C18—H18B | 0.940 (11) |
C17—C16 | 1.3980 (4) | C18—H18C | 0.951 (10) |
C17—H17 | 0.973 (6) | ||
C2—C4—C3 | 60.50 (2) | C3—C2—C12 | 119.41 (3) |
C3—C2—C4 | 58.46 (2) | C3—C2—C1 | 115.91 (3) |
C4—C3—C2 | 61.05 (2) | C12—C2—C1 | 115.92 (3) |
C4—C3—C11 | 121.26 (3) | C12—C17—C16 | 120.39 (2) |
C4—C3—H3 | 114.1 (5) | C13—C14—C15 | 119.67 (2) |
C2—C3—C11 | 124.29 (3) | C4—C5—C6 | 123.32 (3) |
C2—C3—H3 | 111.3 (6) | C4—C5—C10 | 118.28 (3) |
C11—C3—H3 | 114.4 (6) | C6—C5—C10 | 118.24 (2) |
C13—C12—C2 | 119.66 (3) | C5—C10—C9 | 121.13 (3) |
C13—C12—C17 | 118.96 (2) | C6—C7—C8 | 120.27 (3) |
C2—C12—C17 | 121.39 (2) | C6—C7—H7 | 120.0 (5) |
C3—C4—C5 | 122.63 (3) | C14—C15—C16 | 119.94 (2) |
C3—C4—H4 | 115.6 (6) | C1—O1—C18 | 115.32 (5) |
C5—C4—H4 | 112.9 (6) | O1—C1—O2 | 122.61 (4) |
C12—C13—C14 | 120.95 (3) | O1—C1—C2 | 111.95 (3) |
C12—C13—H13 | 118.4 (4) | O2—C1—C2 | 125.42 (4) |
C14—C13—H13 | 120.7 (4) | C17—C16—C15 | 120.07 (3) |
C5—C6—C7 | 120.79 (3) | C10—C9—C8 | 119.90 (3) |
C5—C6—H6 | 119.2 (4) | C7—C8—C9 | 119.67 (2) |
C7—C6—H6 | 120.0 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···O2 | 1.011 (9) | 2.453 (11) | 2.8877 (6) | 105.2 (6) |
C11—H11A···O2 | 0.939 (11) | 2.485 (9) | 3.1200 (7) | 125.0 (8) |
C17—H17···O2i | 0.972 (7) | 2.530 (6) | 3.4020 (6) | 149.2 (5) |
Symmetry code: (i) x, −y+3/2, z−1/2. |