organic compounds
Bis[4-(diphenylmethyleneamino)phenyl]methanone
aDEP Facultad de Ciencias Químicas, UANL, Guerrero y Progreso S/N, Col. Treviño, 64570 Monterrey, NL, Mexico, bLaboratorio de Síntesis de Complejos, Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, AP 1067, 72001 Puebla, Pue., Mexico, and cDepartamento de Ingeniería Química, Universidad Politécnica de Tlaxcala, Calle 21, no. 611, Col. La Loma Xicohténcatl, Tlaxcala, Tlax., Mexico
*Correspondence e-mail: sylvain_bernes@Hotmail.com
The title molecule, C39H28N2O, is a well known dendron used in the synthesis of phenylazomethine dendrimers. The central benzophenone core is twisted, as expected, due to hindrance between H atoms: the dihedral angle between core benzene rings is 54.49 (5)°, identical to that of the stable polymorph of benzophenone (56°). For the same reason, phenyl groups substituting imine C atoms make a large dihedral angle, although similar for each imine: 71.83 (6) and 67.64 (5)°. The six aromatic rings in the molecule thus seem to be quite randomly oriented, and such an arrangement is not favorable for efficient stacking interactions in the crystal. The same behaviour is observed in the vast majority of diphenylimino-containing organics. The low triclinic crystal symmetry may be a consequence of these features.
Related literature
For the use of the title molecule in the synthesis of dendritic systems, see: Higuchi et al. (2001); Takanashi et al. (2004); Yamamoto & Higuchi (2004). For the structure of benzophenone, see: Fleischer et al. (1968); Kutzke et al. (2000). For related structures including the diphenylimino fragment, see: Appel et al. (1985); Buhmann et al. (1993). For geometrical analysis using the Cambridge Structural Database, see: Bruno et al. (2002).
Experimental
Crystal data
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Data collection: XSCANS (Siemens, 1996); cell XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 .
Supporting information
https://doi.org/10.1107/S1600536810016375/fl2303sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810016375/fl2303Isup2.hkl
A modified procedure for improved synthesis of the title compound was used. The Higuchi's route (Higuchi et al., 2001; see compound 'dendron G2' in this paper) consists of the condensation between benzophenone and 4,4'-diaminobenzophenone in presence of DABCO (1,4-diazabicyclo[2.2.2]octane) and TiCl4, in chlorobenzene. In the original synthesis, the mixture was heated at 398 K for 24 h to afford dendron G2 in 48% yield. In place of thermal activation, we performed a microwave-assisted synthesis in a monomode MIC-1 oven (Tekno-lab, S.A.) with maximum power output of 600 W. Irradiation was applied for 20 min., affording the title compound with an enhanced yield of 65% after silica gel
(ethyl acetate:hexane = 1:5). Single crystals were obtained by slow evaporation of the at 298 K.All H atoms were placed in idealized positions and refined as riding to their carrier C atoms, with bond lengths fixed to 0.93 Å. Isotropic displacement parameters were calculated as Uiso(H) = 1.2Ueq(carrier C atom).
The title benzophenone derivative has been widely employed as a dendron in the synthesis of phenylazomethine dendrimers (DPAs), mostly in the group of Yamamoto at the Keio University (Higuchi et al., 2001; Takanashi et al., 2004; Yamamoto & Higuchi, 2004). This group and others reported on the preparation of a vast array of supramolecular entities with interesting properties. We became interested in preparing this dendron by using microwave heating, given that it is becoming an important method in laboratories worldwide: it is an environment-friendly technique for the efficient syntheses of organic molecules. The main advantages of microwave-assisted organic synthesis are shorter reaction times, minimum waste and generally higher yields, operational simplicity as well as reduction of thermal degradative byproducts along with cleaner work-up. As expected, better yields were obtained and we realized that, surprisingly, the
had not been reported so far.The molecule (Fig. 1) crystallizes in the low symmetry 1. The imine bond lengths, 1.2813 (18) and 1.2784 (19) Å, are as expected, however, N atoms significantly deviate from trigonality. Large C═N—C angles are observed, 127.61 (12) and 123.09 (13)°, probably because of the steric repulsion between the central benzophenone benzene rings and the diphenylmethylene groups. The central benzophenone displays a twisted conformation, the dihedral angle between benzene rings being 54.49 (5)°. This value is indeed close to that reported for benzophenone, 56° (orthorhombic phase, Fleischer et al., 1968) or 64° (metastable monoclinic phase, Kutzke et al., 2000). This conformation avoids any intramolecular H···H contacts. In the same way, diphenyl groups bonded to imine C atoms are twisted, by 71.83 (6)° (diphenyl group at C9) and 67.64 (5)° (diphenyl group at C29). These angles are common for diphenylimino-containing organics (range of angles retrieved from the CSD : 57 to 90°; CSD, version 5.31 with all updates; Bruno et al., 2002).
PAs a whole, the six rings in the molecule seem to be randomly oriented. This chaotic arrangement is consistent with the low crystal symmetry, and does not favor π···π or C—H···π interactions in the For example, the shortest intermolecular separation between centroids of two rings is 4.45 Å. The calculated packing index is indeed low for this polyphenyl molecule, 0.672. A search in the CSD for organic molecules containing the Ph2C═N fragment shows that more densely packed crystals in this class of compounds are scarce. For 151 hits, only two structures present symmetry-related diphenylimino groups with phenyl rings separated by less than 3.9 Å (Appel et al., 1985; Buhmann et al., 1993).
For the use of the title molecule in the synthesis of dendritic systems, see: Higuchi et al. (2001); Takanashi et al. (2004); Yamamoto & Higuchi (2004). For the structure of benzophenone, see: Fleischer et al. (1968); Kutzke et al. (2000). For related structures including the diphenylimino fragment, see: Appel et al. (1985); Buhmann et al. (1993). For geometrical analysis using the Cambridge Structural Database, see: Bruno et al. (2002).
Data collection: XSCANS (Siemens, 1996); cell
XSCANS (Siemens, 1996); data reduction: XSCANS (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. Molecular structure of the title compound, with 50% probability level displacement ellipsoids for non-H atoms. |
C39H28N2O | Z = 2 |
Mr = 540.63 | F(000) = 568 |
Triclinic, P1 | Dx = 1.245 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 11.1723 (10) Å | Cell parameters from 82 reflections |
b = 11.3487 (13) Å | θ = 4.6–12.5° |
c = 13.2331 (15) Å | µ = 0.08 mm−1 |
α = 103.121 (9)° | T = 296 K |
β = 105.170 (8)° | Prism, yellow |
γ = 108.746 (8)° | 0.55 × 0.28 × 0.24 mm |
V = 1441.9 (3) Å3 |
Bruker P4 diffractometer | Rint = 0.018 |
Radiation source: fine-focus sealed tube | θmax = 26.4°, θmin = 2.0° |
Graphite monochromator | h = −13→2 |
2θ/ω scans | k = −13→13 |
6892 measured reflections | l = −16→16 |
5865 independent reflections | 3 standard reflections every 97 reflections |
4471 reflections with I > 2σ(I) | intensity decay: 1% |
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)] = 0.042 | H-atom parameters constrained |
wR(F2) = 0.113 | w = 1/[σ2(Fo2) + (0.0461P)2 + 0.275P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max < 0.001 |
5865 reflections | Δρmax = 0.19 e Å−3 |
380 parameters | Δρmin = −0.14 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 constraints | Extinction coefficient: 0.0198 (18) |
Primary atom site location: structure-invariant direct methods |
C39H28N2O | γ = 108.746 (8)° |
Mr = 540.63 | V = 1441.9 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 11.1723 (10) Å | Mo Kα radiation |
b = 11.3487 (13) Å | µ = 0.08 mm−1 |
c = 13.2331 (15) Å | T = 296 K |
α = 103.121 (9)° | 0.55 × 0.28 × 0.24 mm |
β = 105.170 (8)° |
Bruker P4 diffractometer | Rint = 0.018 |
6892 measured reflections | 3 standard reflections every 97 reflections |
5865 independent reflections | intensity decay: 1% |
4471 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.113 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.19 e Å−3 |
5865 reflections | Δρmin = −0.14 e Å−3 |
380 parameters |
x | y | z | Uiso*/Ueq | ||
C1 | 0.81457 (15) | 0.23158 (15) | 0.66331 (12) | 0.0425 (3) | |
O1 | 0.92972 (12) | 0.26828 (14) | 0.66240 (11) | 0.0658 (4) | |
C2 | 0.70743 (14) | 0.24601 (14) | 0.57791 (12) | 0.0383 (3) | |
C3 | 0.72166 (15) | 0.24315 (15) | 0.47594 (12) | 0.0425 (3) | |
H3A | 0.7902 | 0.2224 | 0.4599 | 0.051* | |
C4 | 0.63532 (15) | 0.27069 (15) | 0.39873 (12) | 0.0407 (3) | |
H4A | 0.6459 | 0.2673 | 0.3309 | 0.049* | |
C5 | 0.53212 (14) | 0.30355 (13) | 0.42020 (11) | 0.0373 (3) | |
C6 | 0.51690 (15) | 0.30587 (15) | 0.52197 (12) | 0.0424 (3) | |
H6A | 0.4486 | 0.3270 | 0.5381 | 0.051* | |
C7 | 0.60322 (15) | 0.27683 (15) | 0.59917 (12) | 0.0416 (3) | |
H7A | 0.5914 | 0.2779 | 0.6663 | 0.050* | |
N8 | 0.46589 (12) | 0.34758 (12) | 0.33981 (10) | 0.0419 (3) | |
C9 | 0.34487 (14) | 0.34189 (13) | 0.31471 (11) | 0.0374 (3) | |
C10 | 0.30371 (14) | 0.40362 (14) | 0.23057 (12) | 0.0395 (3) | |
C11 | 0.39664 (17) | 0.46820 (17) | 0.18792 (13) | 0.0505 (4) | |
H11A | 0.4834 | 0.4696 | 0.2098 | 0.061* | |
C12 | 0.3613 (2) | 0.5302 (2) | 0.11344 (15) | 0.0614 (5) | |
H12A | 0.4245 | 0.5732 | 0.0858 | 0.074* | |
C13 | 0.23276 (19) | 0.52870 (18) | 0.07989 (14) | 0.0585 (4) | |
H13A | 0.2094 | 0.5712 | 0.0304 | 0.070* | |
C14 | 0.14043 (18) | 0.46438 (19) | 0.11986 (15) | 0.0614 (5) | |
H14A | 0.0534 | 0.4622 | 0.0968 | 0.074* | |
C15 | 0.17516 (16) | 0.40203 (17) | 0.19474 (14) | 0.0536 (4) | |
H15A | 0.1109 | 0.3585 | 0.2212 | 0.064* | |
C16 | 0.24182 (14) | 0.27839 (14) | 0.36114 (11) | 0.0372 (3) | |
C17 | 0.20701 (16) | 0.35573 (16) | 0.43619 (13) | 0.0473 (4) | |
H17A | 0.2458 | 0.4474 | 0.4564 | 0.057* | |
C18 | 0.11442 (17) | 0.29636 (18) | 0.48108 (13) | 0.0529 (4) | |
H18A | 0.0925 | 0.3485 | 0.5321 | 0.064* | |
C19 | 0.05504 (17) | 0.16072 (18) | 0.45026 (14) | 0.0547 (4) | |
H19A | −0.0065 | 0.1214 | 0.4808 | 0.066* | |
C20 | 0.08672 (18) | 0.08337 (17) | 0.37436 (16) | 0.0575 (4) | |
H20A | 0.0454 | −0.0083 | 0.3527 | 0.069* | |
C21 | 0.18011 (16) | 0.14185 (15) | 0.33012 (14) | 0.0477 (4) | |
H21A | 0.2015 | 0.0890 | 0.2792 | 0.057* | |
C22 | 0.78337 (15) | 0.17280 (14) | 0.74811 (12) | 0.0404 (3) | |
C23 | 0.89013 (16) | 0.20074 (16) | 0.84510 (13) | 0.0475 (4) | |
H23A | 0.9765 | 0.2609 | 0.8578 | 0.057* | |
C24 | 0.87042 (17) | 0.14101 (16) | 0.92269 (13) | 0.0513 (4) | |
H24A | 0.9428 | 0.1621 | 0.9875 | 0.062* | |
C25 | 0.74229 (16) | 0.04910 (14) | 0.90414 (12) | 0.0436 (3) | |
C26 | 0.63567 (16) | 0.02012 (16) | 0.80788 (13) | 0.0465 (4) | |
H26A | 0.5500 | −0.0420 | 0.7944 | 0.056* | |
C27 | 0.65529 (16) | 0.08267 (15) | 0.73147 (12) | 0.0448 (3) | |
H27A | 0.5820 | 0.0642 | 0.6683 | 0.054* | |
N28 | 0.72437 (15) | −0.02708 (13) | 0.97419 (11) | 0.0495 (3) | |
C29 | 0.73136 (14) | 0.02098 (14) | 1.07383 (12) | 0.0391 (3) | |
C30 | 0.72464 (14) | −0.06736 (14) | 1.14219 (12) | 0.0409 (3) | |
C31 | 0.7430 (2) | −0.18335 (17) | 1.10693 (15) | 0.0584 (4) | |
H31A | 0.7576 | −0.2060 | 1.0405 | 0.070* | |
C32 | 0.7397 (2) | −0.2648 (2) | 1.17030 (18) | 0.0717 (6) | |
H32A | 0.7527 | −0.3419 | 1.1465 | 0.086* | |
C33 | 0.7174 (2) | −0.23299 (19) | 1.26838 (16) | 0.0657 (5) | |
H33A | 0.7156 | −0.2883 | 1.3107 | 0.079* | |
C34 | 0.69800 (19) | −0.11972 (19) | 1.30364 (15) | 0.0598 (5) | |
H34A | 0.6823 | −0.0985 | 1.3697 | 0.072* | |
C35 | 0.70164 (16) | −0.03645 (16) | 1.24098 (13) | 0.0487 (4) | |
H35A | 0.6886 | 0.0404 | 1.2654 | 0.058* | |
C36 | 0.74461 (14) | 0.15897 (14) | 1.12429 (12) | 0.0386 (3) | |
C37 | 0.85587 (15) | 0.24739 (15) | 1.21870 (13) | 0.0452 (3) | |
H37A | 0.9195 | 0.2189 | 1.2534 | 0.054* | |
C38 | 0.8732 (2) | 0.37737 (17) | 1.26174 (15) | 0.0577 (4) | |
H38A | 0.9499 | 0.4367 | 1.3232 | 0.069* | |
C39 | 0.7766 (2) | 0.41837 (19) | 1.21333 (17) | 0.0657 (5) | |
H39A | 0.7879 | 0.5056 | 1.2423 | 0.079* | |
C40 | 0.6634 (2) | 0.3310 (2) | 1.12217 (16) | 0.0655 (5) | |
H40A | 0.5973 | 0.3588 | 1.0911 | 0.079* | |
C41 | 0.64726 (18) | 0.20148 (18) | 1.07617 (14) | 0.0513 (4) | |
H41A | 0.5716 | 0.1434 | 1.0134 | 0.062* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0422 (8) | 0.0497 (9) | 0.0425 (8) | 0.0226 (7) | 0.0182 (6) | 0.0192 (7) |
O1 | 0.0458 (7) | 0.1042 (10) | 0.0667 (8) | 0.0347 (7) | 0.0264 (6) | 0.0504 (8) |
C2 | 0.0402 (7) | 0.0395 (7) | 0.0392 (7) | 0.0174 (6) | 0.0164 (6) | 0.0164 (6) |
C3 | 0.0430 (8) | 0.0527 (9) | 0.0414 (8) | 0.0253 (7) | 0.0209 (7) | 0.0179 (7) |
C4 | 0.0414 (8) | 0.0510 (8) | 0.0347 (7) | 0.0192 (7) | 0.0181 (6) | 0.0177 (6) |
C5 | 0.0350 (7) | 0.0376 (7) | 0.0397 (7) | 0.0130 (6) | 0.0138 (6) | 0.0161 (6) |
C6 | 0.0424 (8) | 0.0517 (8) | 0.0437 (8) | 0.0243 (7) | 0.0220 (7) | 0.0200 (7) |
C7 | 0.0468 (8) | 0.0499 (8) | 0.0364 (7) | 0.0229 (7) | 0.0201 (6) | 0.0186 (6) |
N8 | 0.0394 (7) | 0.0496 (7) | 0.0434 (7) | 0.0193 (6) | 0.0172 (5) | 0.0232 (6) |
C9 | 0.0381 (7) | 0.0367 (7) | 0.0374 (7) | 0.0149 (6) | 0.0144 (6) | 0.0123 (6) |
C10 | 0.0392 (8) | 0.0399 (8) | 0.0383 (7) | 0.0154 (6) | 0.0130 (6) | 0.0137 (6) |
C11 | 0.0499 (9) | 0.0678 (11) | 0.0520 (9) | 0.0316 (8) | 0.0268 (8) | 0.0320 (8) |
C12 | 0.0657 (11) | 0.0802 (13) | 0.0621 (11) | 0.0352 (10) | 0.0355 (9) | 0.0438 (10) |
C13 | 0.0653 (11) | 0.0697 (11) | 0.0510 (9) | 0.0329 (9) | 0.0185 (8) | 0.0343 (9) |
C14 | 0.0475 (9) | 0.0747 (12) | 0.0651 (11) | 0.0275 (9) | 0.0112 (8) | 0.0360 (10) |
C15 | 0.0381 (8) | 0.0637 (10) | 0.0615 (10) | 0.0174 (8) | 0.0157 (7) | 0.0329 (9) |
C16 | 0.0337 (7) | 0.0412 (7) | 0.0382 (7) | 0.0161 (6) | 0.0121 (6) | 0.0160 (6) |
C17 | 0.0423 (8) | 0.0450 (8) | 0.0481 (8) | 0.0151 (7) | 0.0154 (7) | 0.0089 (7) |
C18 | 0.0487 (9) | 0.0704 (11) | 0.0422 (8) | 0.0269 (8) | 0.0210 (7) | 0.0142 (8) |
C19 | 0.0466 (9) | 0.0738 (12) | 0.0572 (10) | 0.0240 (8) | 0.0268 (8) | 0.0376 (9) |
C20 | 0.0563 (10) | 0.0488 (9) | 0.0772 (12) | 0.0199 (8) | 0.0311 (9) | 0.0328 (9) |
C21 | 0.0514 (9) | 0.0426 (8) | 0.0591 (9) | 0.0223 (7) | 0.0282 (8) | 0.0205 (7) |
C22 | 0.0453 (8) | 0.0446 (8) | 0.0380 (7) | 0.0234 (7) | 0.0167 (6) | 0.0168 (6) |
C23 | 0.0447 (8) | 0.0502 (9) | 0.0439 (8) | 0.0159 (7) | 0.0120 (7) | 0.0189 (7) |
C24 | 0.0524 (9) | 0.0550 (9) | 0.0376 (8) | 0.0181 (8) | 0.0059 (7) | 0.0176 (7) |
C25 | 0.0571 (9) | 0.0407 (8) | 0.0372 (7) | 0.0219 (7) | 0.0195 (7) | 0.0147 (6) |
C26 | 0.0461 (8) | 0.0487 (9) | 0.0441 (8) | 0.0167 (7) | 0.0170 (7) | 0.0176 (7) |
C27 | 0.0437 (8) | 0.0519 (9) | 0.0389 (7) | 0.0208 (7) | 0.0119 (6) | 0.0173 (7) |
N28 | 0.0639 (9) | 0.0438 (7) | 0.0414 (7) | 0.0212 (6) | 0.0180 (6) | 0.0181 (6) |
C29 | 0.0350 (7) | 0.0417 (8) | 0.0405 (8) | 0.0147 (6) | 0.0114 (6) | 0.0180 (6) |
C30 | 0.0374 (7) | 0.0428 (8) | 0.0423 (8) | 0.0152 (6) | 0.0111 (6) | 0.0194 (6) |
C31 | 0.0796 (12) | 0.0550 (10) | 0.0570 (10) | 0.0361 (9) | 0.0311 (9) | 0.0284 (8) |
C32 | 0.0982 (16) | 0.0598 (11) | 0.0783 (13) | 0.0440 (11) | 0.0347 (12) | 0.0407 (10) |
C33 | 0.0734 (12) | 0.0606 (11) | 0.0667 (12) | 0.0231 (10) | 0.0186 (10) | 0.0418 (10) |
C34 | 0.0614 (11) | 0.0696 (12) | 0.0512 (9) | 0.0185 (9) | 0.0243 (8) | 0.0328 (9) |
C35 | 0.0497 (9) | 0.0516 (9) | 0.0509 (9) | 0.0203 (7) | 0.0217 (7) | 0.0246 (7) |
C36 | 0.0397 (7) | 0.0448 (8) | 0.0427 (7) | 0.0204 (6) | 0.0213 (6) | 0.0230 (6) |
C37 | 0.0415 (8) | 0.0470 (8) | 0.0523 (9) | 0.0195 (7) | 0.0203 (7) | 0.0201 (7) |
C38 | 0.0665 (11) | 0.0458 (9) | 0.0624 (10) | 0.0193 (8) | 0.0317 (9) | 0.0165 (8) |
C39 | 0.1079 (16) | 0.0549 (10) | 0.0672 (12) | 0.0482 (11) | 0.0528 (12) | 0.0327 (9) |
C40 | 0.0996 (15) | 0.0870 (14) | 0.0656 (12) | 0.0726 (13) | 0.0506 (12) | 0.0506 (11) |
C41 | 0.0556 (10) | 0.0696 (11) | 0.0486 (9) | 0.0373 (9) | 0.0239 (8) | 0.0322 (8) |
C1—O1 | 1.2225 (18) | C21—H21A | 0.9300 |
C1—C22 | 1.490 (2) | C22—C27 | 1.391 (2) |
C1—C2 | 1.496 (2) | C22—C23 | 1.393 (2) |
C2—C7 | 1.395 (2) | C23—C24 | 1.379 (2) |
C2—C3 | 1.394 (2) | C23—H23A | 0.9300 |
C3—C4 | 1.377 (2) | C24—C25 | 1.392 (2) |
C3—H3A | 0.9300 | C24—H24A | 0.9300 |
C4—C5 | 1.396 (2) | C25—C26 | 1.383 (2) |
C4—H4A | 0.9300 | C25—N28 | 1.4130 (19) |
C5—C6 | 1.3964 (19) | C26—C27 | 1.384 (2) |
C5—N8 | 1.4127 (18) | C26—H26A | 0.9300 |
C6—C7 | 1.387 (2) | C27—H27A | 0.9300 |
C6—H6A | 0.9300 | N28—C29 | 1.2784 (19) |
C7—H7A | 0.9300 | C29—C30 | 1.4926 (19) |
N8—C9 | 1.2813 (18) | C29—C36 | 1.498 (2) |
C9—C10 | 1.4950 (19) | C30—C35 | 1.387 (2) |
C9—C16 | 1.5033 (19) | C30—C31 | 1.392 (2) |
C10—C15 | 1.382 (2) | C31—C32 | 1.380 (2) |
C10—C11 | 1.393 (2) | C31—H31A | 0.9300 |
C11—C12 | 1.383 (2) | C32—C33 | 1.375 (3) |
C11—H11A | 0.9300 | C32—H32A | 0.9300 |
C12—C13 | 1.381 (3) | C33—C34 | 1.370 (3) |
C12—H12A | 0.9300 | C33—H33A | 0.9300 |
C13—C14 | 1.361 (2) | C34—C35 | 1.390 (2) |
C13—H13A | 0.9300 | C34—H34A | 0.9300 |
C14—C15 | 1.388 (2) | C35—H35A | 0.9300 |
C14—H14A | 0.9300 | C36—C37 | 1.389 (2) |
C15—H15A | 0.9300 | C36—C41 | 1.391 (2) |
C16—C21 | 1.386 (2) | C37—C38 | 1.384 (2) |
C16—C17 | 1.391 (2) | C37—H37A | 0.9300 |
C17—C18 | 1.390 (2) | C38—C39 | 1.373 (3) |
C17—H17A | 0.9300 | C38—H38A | 0.9300 |
C18—C19 | 1.376 (2) | C39—C40 | 1.375 (3) |
C18—H18A | 0.9300 | C39—H39A | 0.9300 |
C19—C20 | 1.375 (2) | C40—C41 | 1.389 (3) |
C19—H19A | 0.9300 | C40—H40A | 0.9300 |
C20—C21 | 1.387 (2) | C41—H41A | 0.9300 |
C20—H20A | 0.9300 | ||
O1—C1—C22 | 119.75 (13) | C20—C21—H21A | 119.7 |
O1—C1—C2 | 118.82 (13) | C27—C22—C23 | 118.10 (13) |
C22—C1—C2 | 121.43 (13) | C27—C22—C1 | 123.37 (13) |
C7—C2—C3 | 118.23 (13) | C23—C22—C1 | 118.30 (14) |
C7—C2—C1 | 123.51 (13) | C24—C23—C22 | 121.35 (15) |
C3—C2—C1 | 117.86 (13) | C24—C23—H23A | 119.3 |
C4—C3—C2 | 120.68 (13) | C22—C23—H23A | 119.3 |
C4—C3—H3A | 119.7 | C23—C24—C25 | 120.03 (14) |
C2—C3—H3A | 119.7 | C23—C24—H24A | 120.0 |
C3—C4—C5 | 121.35 (13) | C25—C24—H24A | 120.0 |
C3—C4—H4A | 119.3 | C26—C25—C24 | 119.11 (14) |
C5—C4—H4A | 119.3 | C26—C25—N28 | 119.71 (14) |
C4—C5—C6 | 118.22 (13) | C24—C25—N28 | 120.61 (14) |
C4—C5—N8 | 114.03 (12) | C25—C26—C27 | 120.64 (15) |
C6—C5—N8 | 127.22 (13) | C25—C26—H26A | 119.7 |
C7—C6—C5 | 120.31 (13) | C27—C26—H26A | 119.7 |
C7—C6—H6A | 119.8 | C26—C27—C22 | 120.73 (14) |
C5—C6—H6A | 119.8 | C26—C27—H27A | 119.6 |
C6—C7—C2 | 121.20 (13) | C22—C27—H27A | 119.6 |
C6—C7—H7A | 119.4 | C29—N28—C25 | 123.09 (13) |
C2—C7—H7A | 119.4 | N28—C29—C30 | 117.26 (13) |
C9—N8—C5 | 127.61 (12) | N28—C29—C36 | 123.77 (13) |
N8—C9—C10 | 116.13 (13) | C30—C29—C36 | 118.97 (12) |
N8—C9—C16 | 126.07 (13) | C35—C30—C31 | 118.81 (14) |
C10—C9—C16 | 117.80 (12) | C35—C30—C29 | 121.70 (14) |
C15—C10—C11 | 117.84 (14) | C31—C30—C29 | 119.49 (14) |
C15—C10—C9 | 121.89 (13) | C32—C31—C30 | 120.19 (17) |
C11—C10—C9 | 120.25 (13) | C32—C31—H31A | 119.9 |
C12—C11—C10 | 120.72 (15) | C30—C31—H31A | 119.9 |
C12—C11—H11A | 119.6 | C33—C32—C31 | 120.56 (18) |
C10—C11—H11A | 119.6 | C33—C32—H32A | 119.7 |
C13—C12—C11 | 120.39 (16) | C31—C32—H32A | 119.7 |
C13—C12—H12A | 119.8 | C34—C33—C32 | 119.89 (16) |
C11—C12—H12A | 119.8 | C34—C33—H33A | 120.1 |
C14—C13—C12 | 119.44 (15) | C32—C33—H33A | 120.1 |
C14—C13—H13A | 120.3 | C33—C34—C35 | 120.21 (17) |
C12—C13—H13A | 120.3 | C33—C34—H34A | 119.9 |
C13—C14—C15 | 120.52 (16) | C35—C34—H34A | 119.9 |
C13—C14—H14A | 119.7 | C30—C35—C34 | 120.34 (16) |
C15—C14—H14A | 119.7 | C30—C35—H35A | 119.8 |
C10—C15—C14 | 121.07 (15) | C34—C35—H35A | 119.8 |
C10—C15—H15A | 119.5 | C37—C36—C41 | 118.92 (14) |
C14—C15—H15A | 119.5 | C37—C36—C29 | 120.45 (13) |
C21—C16—C17 | 118.85 (14) | C41—C36—C29 | 120.62 (14) |
C21—C16—C9 | 120.62 (13) | C38—C37—C36 | 120.79 (15) |
C17—C16—C9 | 120.53 (13) | C38—C37—H37A | 119.6 |
C16—C17—C18 | 120.17 (15) | C36—C37—H37A | 119.6 |
C16—C17—H17A | 119.9 | C39—C38—C37 | 119.74 (18) |
C18—C17—H17A | 119.9 | C39—C38—H38A | 120.1 |
C19—C18—C17 | 120.25 (15) | C37—C38—H38A | 120.1 |
C19—C18—H18A | 119.9 | C38—C39—C40 | 120.28 (17) |
C17—C18—H18A | 119.9 | C38—C39—H39A | 119.9 |
C20—C19—C18 | 119.98 (15) | C40—C39—H39A | 119.9 |
C20—C19—H19A | 120.0 | C39—C40—C41 | 120.41 (17) |
C18—C19—H19A | 120.0 | C39—C40—H40A | 119.8 |
C19—C20—C21 | 120.12 (16) | C41—C40—H40A | 119.8 |
C19—C20—H20A | 119.9 | C40—C41—C36 | 119.79 (17) |
C21—C20—H20A | 119.9 | C40—C41—H41A | 120.1 |
C16—C21—C20 | 120.60 (15) | C36—C41—H41A | 120.1 |
C16—C21—H21A | 119.7 | ||
O1—C1—C2—C7 | −144.52 (16) | O1—C1—C22—C27 | −152.96 (16) |
C22—C1—C2—C7 | 36.0 (2) | C2—C1—C22—C27 | 26.6 (2) |
O1—C1—C2—C3 | 28.0 (2) | O1—C1—C22—C23 | 21.4 (2) |
C22—C1—C2—C3 | −151.51 (14) | C2—C1—C22—C23 | −159.09 (14) |
C7—C2—C3—C4 | 0.3 (2) | C27—C22—C23—C24 | 0.2 (2) |
C1—C2—C3—C4 | −172.64 (14) | C1—C22—C23—C24 | −174.49 (14) |
C2—C3—C4—C5 | 0.7 (2) | C22—C23—C24—C25 | 1.0 (3) |
C3—C4—C5—C6 | −1.0 (2) | C23—C24—C25—C26 | −0.7 (2) |
C3—C4—C5—N8 | 171.19 (13) | C23—C24—C25—N28 | 170.63 (14) |
C4—C5—C6—C7 | 0.4 (2) | C24—C25—C26—C27 | −0.8 (2) |
N8—C5—C6—C7 | −170.67 (14) | N28—C25—C26—C27 | −172.23 (14) |
C5—C6—C7—C2 | 0.6 (2) | C25—C26—C27—C22 | 2.0 (2) |
C3—C2—C7—C6 | −0.9 (2) | C23—C22—C27—C26 | −1.7 (2) |
C1—C2—C7—C6 | 171.58 (14) | C1—C22—C27—C26 | 172.67 (14) |
C4—C5—N8—C9 | 154.35 (15) | C26—C25—N28—C29 | −115.96 (18) |
C6—C5—N8—C9 | −34.3 (2) | C24—C25—N28—C29 | 72.8 (2) |
C5—N8—C9—C10 | 176.47 (13) | C25—N28—C29—C30 | −173.82 (14) |
C5—N8—C9—C16 | −4.1 (2) | C25—N28—C29—C36 | 6.7 (2) |
N8—C9—C10—C15 | 178.78 (15) | N28—C29—C30—C35 | −165.71 (15) |
C16—C9—C10—C15 | −0.7 (2) | C36—C29—C30—C35 | 13.8 (2) |
N8—C9—C10—C11 | −3.0 (2) | N28—C29—C30—C31 | 14.9 (2) |
C16—C9—C10—C11 | 177.57 (14) | C36—C29—C30—C31 | −165.62 (15) |
C15—C10—C11—C12 | 1.0 (2) | C35—C30—C31—C32 | −0.7 (3) |
C9—C10—C11—C12 | −177.38 (15) | C29—C30—C31—C32 | 178.75 (17) |
C10—C11—C12—C13 | −0.2 (3) | C30—C31—C32—C33 | 0.4 (3) |
C11—C12—C13—C14 | −0.7 (3) | C31—C32—C33—C34 | 0.2 (3) |
C12—C13—C14—C15 | 0.7 (3) | C32—C33—C34—C35 | −0.4 (3) |
C11—C10—C15—C14 | −0.9 (3) | C31—C30—C35—C34 | 0.4 (2) |
C9—C10—C15—C14 | 177.43 (16) | C29—C30—C35—C34 | −179.01 (15) |
C13—C14—C15—C10 | 0.0 (3) | C33—C34—C35—C30 | 0.1 (3) |
N8—C9—C16—C21 | −72.1 (2) | N28—C29—C36—C37 | −120.14 (17) |
C10—C9—C16—C21 | 107.31 (16) | C30—C29—C36—C37 | 60.38 (18) |
N8—C9—C16—C17 | 107.75 (18) | N28—C29—C36—C41 | 58.6 (2) |
C10—C9—C16—C17 | −72.83 (18) | C30—C29—C36—C41 | −120.93 (15) |
C21—C16—C17—C18 | 1.6 (2) | C41—C36—C37—C38 | −2.8 (2) |
C9—C16—C17—C18 | −178.23 (14) | C29—C36—C37—C38 | 175.92 (14) |
C16—C17—C18—C19 | −1.0 (2) | C36—C37—C38—C39 | 2.6 (2) |
C17—C18—C19—C20 | −0.3 (3) | C37—C38—C39—C40 | −0.3 (3) |
C18—C19—C20—C21 | 1.0 (3) | C38—C39—C40—C41 | −1.8 (3) |
C17—C16—C21—C20 | −0.9 (2) | C39—C40—C41—C36 | 1.6 (3) |
C9—C16—C21—C20 | 178.93 (15) | C37—C36—C41—C40 | 0.7 (2) |
C19—C20—C21—C16 | −0.4 (3) | C29—C36—C41—C40 | −178.01 (14) |
Experimental details
Crystal data | |
Chemical formula | C39H28N2O |
Mr | 540.63 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 11.1723 (10), 11.3487 (13), 13.2331 (15) |
α, β, γ (°) | 103.121 (9), 105.170 (8), 108.746 (8) |
V (Å3) | 1441.9 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.55 × 0.28 × 0.24 |
Data collection | |
Diffractometer | Bruker P4 |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6892, 5865, 4471 |
Rint | 0.018 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.113, 1.03 |
No. of reflections | 5865 |
No. of parameters | 380 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.19, −0.14 |
Computer programs: XSCANS (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2008).
Acknowledgements
Partial support from VIEP-UAP (GUPJ-NAT08-G) is acknowledged.
References
Appel, R., Knoch, F. & Zimmermann, R. (1985). Chem. Ber. 118, 814–824. CrossRef CAS Web of Science Google Scholar
Bruno, I. J., Cole, J. C., Edgington, P. R., Kessler, M., Macrae, C. F., McCabe, P., Pearson, J. & Taylor, R. (2002). Acta Cryst. B58, 389–397. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Buhmann, M., Würthwein, E.-U. & Möller, M. H. (1993). Chem. Ber. 126, 957–967. CrossRef Web of Science Google Scholar
Fleischer, E. B., Sung, N. & Hawkinson, S. (1968). J. Phys. Chem. 72, 4311–4312. CSD CrossRef CAS Web of Science Google Scholar
Higuchi, M., Shiki, S., Ariga, K. & Yamamoto, K. (2001). J. Am. Chem. Soc. 123, 4414–4420. Web of Science CSD CrossRef PubMed CAS Google Scholar
Kutzke, H., Klapper, H., Hammond, R. B. & Roberts, K. J. (2000). Acta Cryst. B56, 486–496. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Siemens (1996). XSCANS. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar
Takanashi, K., Chiba, H., Higuchi, M. & Yamamoto, K. (2004). Org. Lett. 6, 1709–1712. Web of Science CrossRef PubMed CAS Google Scholar
Yamamoto, K. & Higuchi, M. (2004). Pure Appl. Chem. 76, 1399–1408. Web of Science CrossRef CAS Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The title benzophenone derivative has been widely employed as a dendron in the synthesis of phenylazomethine dendrimers (DPAs), mostly in the group of Yamamoto at the Keio University (Higuchi et al., 2001; Takanashi et al., 2004; Yamamoto & Higuchi, 2004). This group and others reported on the preparation of a vast array of supramolecular entities with interesting properties. We became interested in preparing this dendron by using microwave heating, given that it is becoming an important method in laboratories worldwide: it is an environment-friendly technique for the efficient syntheses of organic molecules. The main advantages of microwave-assisted organic synthesis are shorter reaction times, minimum waste and generally higher yields, operational simplicity as well as reduction of thermal degradative byproducts along with cleaner work-up. As expected, better yields were obtained and we realized that, surprisingly, the crystal structure had not been reported so far.
The molecule (Fig. 1) crystallizes in the low symmetry space group P1. The imine bond lengths, 1.2813 (18) and 1.2784 (19) Å, are as expected, however, N atoms significantly deviate from trigonality. Large C═N—C angles are observed, 127.61 (12) and 123.09 (13)°, probably because of the steric repulsion between the central benzophenone benzene rings and the diphenylmethylene groups. The central benzophenone displays a twisted conformation, the dihedral angle between benzene rings being 54.49 (5)°. This value is indeed close to that reported for benzophenone, 56° (orthorhombic phase, Fleischer et al., 1968) or 64° (metastable monoclinic phase, Kutzke et al., 2000). This conformation avoids any intramolecular H···H contacts. In the same way, diphenyl groups bonded to imine C atoms are twisted, by 71.83 (6)° (diphenyl group at C9) and 67.64 (5)° (diphenyl group at C29). These angles are common for diphenylimino-containing organics (range of angles retrieved from the CSD : 57 to 90°; CSD, version 5.31 with all updates; Bruno et al., 2002).
As a whole, the six rings in the molecule seem to be randomly oriented. This chaotic arrangement is consistent with the low crystal symmetry, and does not favor π···π or C—H···π interactions in the crystal structure. For example, the shortest intermolecular separation between centroids of two rings is 4.45 Å. The calculated packing index is indeed low for this polyphenyl molecule, 0.672. A search in the CSD for organic molecules containing the Ph2C═N fragment shows that more densely packed crystals in this class of compounds are scarce. For 151 hits, only two structures present symmetry-related diphenylimino groups with phenyl rings separated by less than 3.9 Å (Appel et al., 1985; Buhmann et al., 1993).