Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680101683X/cf6094sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S160053680101683X/cf6094Isup2.hkl |
CCDC reference: 176005
Key indicators
- Single-crystal X-ray study
- T = 298 K
- Mean (C-C) = 0.006 Å
- R factor = 0.068
- wR factor = 0.167
- Data-to-parameter ratio = 12.6
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
Alert Level B:
PLAT_360 Alert B Short C(sp3)-C(sp3) Bond C(18) - C(19) = 1.24 Ang.
Author response: C(18) and C(19) are carbon atom of the solvent 1,4-dioxane. |
Alert Level C:
REFLT_03 From the CIF: _diffrn_reflns_theta_max 25.03 From the CIF: _reflns_number_total 2746 TEST2: Reflns within _diffrn_reflns_theta_max Count of symmetry unique reflns 3011 Completeness (_total/calc) 91.20% Alert C: < 95% complete
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
1 Alert Level C = Please check
trans-1-(4-Methoxyphenyl)-2-[2-(5-phenyl-1,3,4-oxadiazolyl)]ethene (PDE) was synthesized by condensing 4-methoxybenzaledhyde and 2-methyl-5-phenyl-1,3,4-oxadiazole in DMF with KOH catalysis at 348 K; m.p. 403–404 K. UV (1,4-dioxane): λmax 338 (logε 4.58) nm; IR (KBr): 3056 (w), 1640 (m), 1606 (versus), 1528 (versus), 1246 (versus), 1176 (versus), 1012 (m), 960 (m) cm-1; 1H NMR (CDCl3): δ 8.14–8.08 (4H, m), 7.60–7.47 (12H, m), 6.96–6.89 (6H, m), 4.10 (4H, t), 2.00 (4H, m) p.p.m. 1.0 g PDE was dissolved in 200 ml acetonitrile and irradiated with a 300 W medium-pressure mercury lamp for 70 h. Then 200 ml of water was added, the precipitate was filtered and recrystallized from ethanol to give 123 mg t-DPC; m.p. 504–505 K. λmax 255 (logε 4.58) nm; IR (KBr): 3037 (w), 2958 (w), 1612 (s), 1563 (s), 1515 (versus), 1251 (versus), 1181 (s), 1037 (s), 829 (s), 775 (s) cm-1; 1H NMR (CDCl3): δ 7.81 (4H, d), 7.47 (6H, m), 7.26 (4H, d), 6.77 (4H, d), 4.89 (2H, t), 4.80 (2H, d), 3.66 (6H, s) p.p.m. 13C NMR (CDCl3): δ 165.65, 165.40, 159.19, 131.77, 129.37, 129.11, 128.60, 126.96, 123.97, 114.36, 55.39, 43.70, 39.93 p.p.m. A single-crystal of t-DPOE was grown in 1,4-dioxane by slow evaporation of the solvent.
Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT and SHELXTL (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
C34H28N4O4·C4H8O2 | Z = 1 |
Mr = 644.71 | F(000) = 340 |
Triclinic, P1 | Dx = 1.257 Mg m−3 |
a = 5.995 (2) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 10.242 (4) Å | Cell parameters from 2713 reflections |
c = 14.292 (5) Å | θ = 2.6–21.3° |
α = 93.370 (6)° | µ = 0.09 mm−1 |
β = 90.595 (6)° | T = 298 K |
γ = 103.557 (6)° | Plate, colorless |
V = 851.4 (5) Å3 | 0.30 × 0.25 × 0.20 mm |
CCD area-detector diffractometer | 1195 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.043 |
Graphite monochromator | θmax = 25.0°, θmin = 1.4° |
ϕ and ω scans | h = −7→6 |
3275 measured reflections | k = −12→7 |
2746 independent reflections | l = −16→16 |
Refinement on F2 | H-atom parameters constrained |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.065P)2] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.068 | (Δ/σ)max = 0.003 |
wR(F2) = 0.167 | Δρmax = 0.16 e Å−3 |
S = 0.97 | Δρmin = −0.19 e Å−3 |
2746 reflections | Extinction correction: SHELXL97 |
218 parameters | Extinction coefficient: 0.023 (4) |
0 restraints |
C34H28N4O4·C4H8O2 | γ = 103.557 (6)° |
Mr = 644.71 | V = 851.4 (5) Å3 |
Triclinic, P1 | Z = 1 |
a = 5.995 (2) Å | Mo Kα radiation |
b = 10.242 (4) Å | µ = 0.09 mm−1 |
c = 14.292 (5) Å | T = 298 K |
α = 93.370 (6)° | 0.30 × 0.25 × 0.20 mm |
β = 90.595 (6)° |
CCD area-detector diffractometer | 1195 reflections with I > 2σ(I) |
3275 measured reflections | Rint = 0.043 |
2746 independent reflections |
R[F2 > 2σ(F2)] = 0.068 | 0 restraints |
wR(F2) = 0.167 | H-atom parameters constrained |
S = 0.97 | Δρmax = 0.16 e Å−3 |
2746 reflections | Δρmin = −0.19 e Å−3 |
218 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 | −0.3133 (12) | −0.1523 (6) | −0.0055 (3) | 0.160 (3) | |
H1A | −0.4122 | −0.1540 | −0.0590 | 0.240* | |
H1B | −0.3095 | −0.2427 | 0.0074 | 0.240* | |
H1C | −0.1611 | −0.1025 | −0.0182 | 0.240* | |
O2 | 0.3104 (3) | 0.3051 (2) | 0.57005 (15) | 0.0545 (7) | |
O1 | −0.3966 (6) | −0.0904 (3) | 0.0726 (2) | 0.1250 (12) | |
C2 | −0.2768 (8) | −0.0801 (4) | 0.1579 (3) | 0.0773 (12) | |
C3 | −0.0896 (8) | −0.1309 (4) | 0.1727 (3) | 0.0834 (13) | |
H3A | −0.0353 | −0.1785 | 0.1241 | 0.100* | |
C4 | 0.0216 (6) | −0.1115 (3) | 0.2611 (3) | 0.0646 (10) | |
H4A | 0.1524 | −0.1437 | 0.2703 | 0.078* | |
C5 | −0.0618 (5) | −0.0454 (3) | 0.3341 (2) | 0.0485 (9) | |
C6 | −0.2565 (6) | 0.0027 (3) | 0.3178 (2) | 0.0591 (10) | |
H6A | −0.3149 | 0.0479 | 0.3665 | 0.071* | |
C7 | −0.3649 (6) | −0.0159 (4) | 0.2303 (3) | 0.0699 (11) | |
H7A | −0.4968 | 0.0151 | 0.2207 | 0.084* | |
C8 | 0.0598 (5) | −0.0253 (3) | 0.4283 (2) | 0.0487 (9) | |
H8A | 0.2160 | −0.0380 | 0.4219 | 0.058* | |
C9 | 0.0628 (5) | 0.1072 (3) | 0.4897 (2) | 0.0494 (9) | |
H9A | −0.0388 | 0.1573 | 0.4617 | 0.059* | |
C10 | 0.2916 (6) | 0.1959 (3) | 0.5100 (2) | 0.0490 (9) | |
N1 | 0.4888 (5) | 0.1817 (3) | 0.4801 (2) | 0.0648 (9) | |
N2 | 0.6531 (5) | 0.2931 (3) | 0.5227 (2) | 0.0658 (9) | |
C11 | 0.5393 (5) | 0.3593 (3) | 0.5743 (2) | 0.0519 (9) | |
C12 | 0.6285 (6) | 0.4813 (3) | 0.6347 (2) | 0.0509 (9) | |
C13 | 0.8570 (6) | 0.5469 (3) | 0.6323 (2) | 0.0627 (10) | |
H13A | 0.9538 | 0.5126 | 0.5923 | 0.075* | |
C14 | 0.9436 (7) | 0.6617 (4) | 0.6876 (3) | 0.0728 (12) | |
H14A | 1.0983 | 0.7045 | 0.6852 | 0.087* | |
C15 | 0.8032 (7) | 0.7132 (4) | 0.7462 (3) | 0.0820 (13) | |
H15A | 0.8627 | 0.7910 | 0.7839 | 0.098* | |
C16 | 0.5771 (7) | 0.6517 (4) | 0.7498 (3) | 0.0885 (13) | |
H16A | 0.4817 | 0.6883 | 0.7891 | 0.106* | |
C17 | 0.4878 (6) | 0.5334 (3) | 0.6945 (3) | 0.0736 (12) | |
H17A | 0.3337 | 0.4900 | 0.6980 | 0.088* | |
C18 | −0.2010 (15) | −0.4902 (10) | 0.0342 (10) | 0.213 (4) | |
H18A | −0.1529 | −0.3928 | 0.0360 | 0.256* | |
H18B | −0.3574 | −0.5175 | 0.0552 | 0.256* | |
O3 | −0.169 (2) | −0.5559 (10) | −0.0619 (9) | 0.310 (4) | |
C19 | −0.067 (2) | −0.5407 (16) | 0.0782 (9) | 0.345 (11) | |
H19A | −0.0709 | −0.6315 | 0.0534 | 0.414* | |
H19B | −0.1013 | −0.5423 | 0.1444 | 0.414* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.253 (8) | 0.162 (5) | 0.064 (3) | 0.059 (5) | −0.014 (4) | −0.034 (3) |
O2 | 0.0482 (14) | 0.0503 (13) | 0.0627 (15) | 0.0118 (11) | −0.0036 (12) | −0.0158 (11) |
O1 | 0.177 (3) | 0.138 (3) | 0.065 (2) | 0.057 (2) | −0.040 (2) | −0.0237 (18) |
C2 | 0.097 (3) | 0.076 (3) | 0.055 (3) | 0.016 (3) | −0.005 (3) | −0.005 (2) |
C3 | 0.109 (3) | 0.081 (3) | 0.060 (3) | 0.031 (3) | 0.014 (3) | −0.029 (2) |
C4 | 0.065 (2) | 0.065 (2) | 0.064 (2) | 0.0220 (19) | 0.009 (2) | −0.0160 (19) |
C5 | 0.0404 (18) | 0.0499 (19) | 0.052 (2) | 0.0073 (16) | 0.0089 (17) | −0.0145 (16) |
C6 | 0.055 (2) | 0.058 (2) | 0.056 (2) | 0.0000 (18) | −0.0041 (18) | −0.0105 (18) |
C7 | 0.063 (2) | 0.071 (2) | 0.073 (3) | 0.013 (2) | −0.008 (2) | −0.006 (2) |
C8 | 0.0391 (17) | 0.0459 (18) | 0.059 (2) | 0.0093 (15) | −0.0001 (17) | −0.0128 (16) |
C9 | 0.0440 (18) | 0.0449 (19) | 0.060 (2) | 0.0152 (16) | −0.0033 (17) | −0.0127 (17) |
C10 | 0.058 (2) | 0.0398 (18) | 0.049 (2) | 0.0145 (18) | −0.0043 (18) | −0.0124 (15) |
N1 | 0.0535 (18) | 0.0584 (18) | 0.078 (2) | 0.0099 (15) | −0.0012 (17) | −0.0216 (15) |
N2 | 0.0526 (18) | 0.0586 (18) | 0.079 (2) | 0.0053 (16) | −0.0009 (17) | −0.0197 (17) |
C11 | 0.044 (2) | 0.046 (2) | 0.060 (2) | 0.0011 (17) | −0.0057 (18) | −0.0050 (18) |
C12 | 0.057 (2) | 0.0431 (19) | 0.051 (2) | 0.0087 (17) | −0.0093 (18) | −0.0032 (16) |
C13 | 0.055 (2) | 0.055 (2) | 0.069 (2) | −0.0010 (18) | −0.0097 (18) | −0.0109 (18) |
C14 | 0.069 (3) | 0.064 (3) | 0.075 (3) | −0.003 (2) | −0.009 (2) | −0.008 (2) |
C15 | 0.085 (3) | 0.063 (3) | 0.083 (3) | −0.009 (2) | −0.032 (3) | −0.012 (2) |
C16 | 0.083 (3) | 0.080 (3) | 0.095 (3) | 0.018 (2) | −0.008 (3) | −0.043 (2) |
C17 | 0.057 (2) | 0.068 (2) | 0.088 (3) | 0.007 (2) | −0.005 (2) | −0.032 (2) |
C18 | 0.153 (7) | 0.241 (9) | 0.294 (12) | 0.125 (7) | 0.101 (9) | 0.081 (10) |
O3 | 0.316 (12) | 0.348 (10) | 0.268 (9) | 0.103 (9) | −0.044 (9) | −0.057 (8) |
C19 | 0.194 (9) | 0.56 (2) | 0.375 (17) | 0.195 (12) | 0.155 (10) | 0.386 (18) |
C1—O1 | 1.405 (5) | C10—N1 | 1.298 (4) |
O2—C10 | 1.352 (3) | N1—N2 | 1.422 (3) |
O2—C11 | 1.354 (3) | N2—C11 | 1.281 (4) |
O1—C2 | 1.394 (5) | C11—C12 | 1.463 (4) |
C2—C3 | 1.363 (5) | C12—C17 | 1.379 (4) |
C2—C7 | 1.369 (5) | C12—C13 | 1.379 (4) |
C3—C4 | 1.404 (5) | C13—C14 | 1.368 (5) |
C4—C5 | 1.373 (4) | C14—C15 | 1.364 (5) |
C5—C6 | 1.391 (4) | C15—C16 | 1.357 (5) |
C5—C8 | 1.504 (4) | C16—C17 | 1.398 (5) |
C6—C7 | 1.387 (4) | C18—C19 | 1.240 (9) |
C8—C9 | 1.569 (4) | C18—O3 | 1.527 (10) |
C8—C9i | 1.569 (4) | O3—C19ii | 1.552 (12) |
C9—C10 | 1.472 (4) | C19—O3ii | 1.552 (12) |
C9—C8i | 1.569 (4) | ||
C10—O2—C11 | 102.9 (3) | N1—C10—C9 | 128.5 (3) |
C2—O1—C1 | 118.0 (4) | O2—C10—C9 | 118.8 (3) |
C3—C2—C7 | 120.3 (4) | C10—N1—N2 | 105.3 (3) |
C3—C2—O1 | 125.0 (4) | C11—N2—N1 | 105.9 (3) |
C7—C2—O1 | 114.7 (4) | N2—C11—O2 | 113.1 (3) |
C2—C3—C4 | 120.1 (4) | N2—C11—C12 | 127.7 (3) |
C5—C4—C3 | 120.4 (4) | O2—C11—C12 | 119.1 (3) |
C4—C5—C6 | 118.4 (3) | C17—C12—C13 | 118.6 (3) |
C4—C5—C8 | 119.6 (3) | C17—C12—C11 | 121.2 (3) |
C6—C5—C8 | 122.0 (3) | C13—C12—C11 | 120.1 (4) |
C7—C6—C5 | 121.1 (3) | C14—C13—C12 | 121.1 (4) |
C2—C7—C6 | 119.7 (4) | C15—C14—C13 | 120.0 (4) |
C5—C8—C9 | 118.3 (3) | C16—C15—C14 | 120.4 (4) |
C5—C8—C9i | 117.8 (2) | C15—C16—C17 | 120.0 (4) |
C9—C8—C9i | 88.4 (2) | C12—C17—C16 | 119.9 (3) |
C10—C9—C8 | 115.4 (3) | C19—C18—O3 | 96.6 (10) |
C10—C9—C8i | 117.5 (3) | C18—O3—C19ii | 94.7 (9) |
C8—C9—C8i | 91.6 (2) | C18—C19—O3ii | 102.4 (8) |
N1—C10—O2 | 112.7 (3) |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x, −y−1, −z. |
Experimental details
Crystal data | |
Chemical formula | C34H28N4O4·C4H8O2 |
Mr | 644.71 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 298 |
a, b, c (Å) | 5.995 (2), 10.242 (4), 14.292 (5) |
α, β, γ (°) | 93.370 (6), 90.595 (6), 103.557 (6) |
V (Å3) | 851.4 (5) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.30 × 0.25 × 0.20 |
Data collection | |
Diffractometer | CCD area-detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3275, 2746, 1195 |
Rint | 0.043 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.068, 0.167, 0.97 |
No. of reflections | 2746 |
No. of parameters | 218 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.16, −0.19 |
Computer programs: SMART (Bruker, 1998), SMART, SAINT and SHELXTL (Bruker, 1998), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL.
C1—O1 | 1.405 (5) | C8—C9i | 1.569 (4) |
O2—C10 | 1.352 (3) | C9—C10 | 1.472 (4) |
O2—C11 | 1.354 (3) | C10—N1 | 1.298 (4) |
O1—C2 | 1.394 (5) | N1—N2 | 1.422 (3) |
C5—C8 | 1.504 (4) | N2—C11 | 1.281 (4) |
C8—C9 | 1.569 (4) | C11—C12 | 1.463 (4) |
C10—O2—C11 | 102.9 (3) | C8—C9—C8i | 91.6 (2) |
C2—O1—C1 | 118.0 (4) | N1—C10—O2 | 112.7 (3) |
C3—C2—O1 | 125.0 (4) | C10—N1—N2 | 105.3 (3) |
C7—C2—O1 | 114.7 (4) | C11—N2—N1 | 105.9 (3) |
C9—C8—C9i | 88.4 (2) | N2—C11—O2 | 113.1 (3) |
Symmetry code: (i) −x, −y, −z+1. |
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The cyclobutane rings for most tetraarylcyclobutanes have a puckered conformation, such as in r-1,c-2,t-3,t-4–1,3-bis[2-(4-R-phenyl)]-2,4-di-(4-pyridyl)cyclobutane (R = Cl, CH3, C6H5). The average dihedral angles of the cyclobutane ring are 19.2, 24.6 and 16.4°, respectively, in the three structures (Busetti et al., 1980; Zhang et al., 1998; Zhang, Zhang et al., 2000). However, it is very interesting that some tetraoxazolyl-substituted cyclobutanes have planar four-membered rings, as found in r-1,c-2,t-3,t-4-tetrakis[2-(5-phenyl-oxazolyl)]cyclobutane (Zhang et al., 1996), r-1,c-2,t-3,t-4-tetrakis[2-benzoxazolyl]cyclobutane (Zhang, Li et al., 2000) and r-1,c-2,t-3,t-4-tetrakis[2-(6,7-dimethylbenzoxazolyl)]cyclobutane (Kao et al., 1989). This interesting phenomenon prompted us to generate a new heteroaryl-substituted cyclobutane in order to study the effect of the substitutent on the conformation of the cyclobutane ring. We report here for the first time that a diphenyl-diphenyloxadiazolyl-substituted cyclobutane (t-DPC) has a planar conformation.
The X-ray diffraction results clearly show that there are one t-DPC molecule and one 1,4-dioxane molecule in the unit cell and the molecules are exactly centrosymmetric, demonstrating that head-to-tail photodimerization process has occurred. The cyclobutane ring of t-DPC is planar, just as in tetraoxazolylcyclobutanes. It appears that the substituents in these compounds, lacking an α-H atom, have a relatively small steric requirement, allowing a planar four-membered ring.
The two independent pairs of C—C bonds of the cyclobutane ring are equal in length [1.569 (4) Å] and are longer than a normal C—C single bond. However, this elongation is common for cyclobutanes. The bond angles C8—C9—C8i and C9—C8—C9i are 91.6 (2) and 88.4 (2)° respectively, so that the cyclobutane ring is almost a square. The dihedral angle between the phenyloxadiazolyl plane and the 4-methoxyphenyl plane situated on the same side of the cyclobutane ring is 50.4 (3)°, intermediate between parallel and perpendicular.
For the five bonds in the oxadiazolyl ring, the C—O single bonds are shorter than that (1.365 Å) of 2,5-di(4-pyridyl)-1,3,4-oxadiazole (DPO), but the N—N single bond is much longer than that (1.409 Å) of DPO (Stockhause et al., 2001).
The bond angle C1—O1—C2 is 118.0 (4)°, which is quite large compared with that of common aliphatic ethers, and atoms C1 and O1 are almost coplanar with the benzene ring plane [the torsion angles C1—O2—C2—C3 and C1—O2—C2—C3 are -3(4) and 179 (8)°, respectively], which means that O1 is an sp2 hybridized atom and there exists a n-π conjugation between O1 and the benzene ring. Because of the non-bonding repulsion between the methyl group and H3a (on C3), the bond angle C3—C2—O1 is increased to 125.0 (4)°, whereas the C7—C2—O1 angle is reduced to 114.7 (4)°.