Archan Dey and Gautam R. Desiraju*
School of Chemistry, University of Hyderabad, Hyderabad 500 046,
India. E-mail: gautam_desiraju@yahoo.com
Notes and references
{ The uncertainties in these values are estimated by comparison with values
obtained with GAUSSIAN (B3LYP/6-31G(d,p). Typically, for 4-(4-
methoxyphenoxy)-N,N-dimethylaniline, the dipole moment is 3.648 D
with the AM1 approximation and 3.867 D with GAUSSIAN. Again, for
1-(trifluoroacetyl)imidazole, the dipole moment is 0.909 D (AM1) and
0.404 D (GAUSSIAN).
§ We selected the first and last non-metal atom containing compounds in
200 randomly selected pages from the Aldrich catalogue.
b502516h/ for crystallographic data in CIF or other electronic format.
Fig. 3 Cartoon depiction of alignment of local dipoles arising from the
electron withdrawing substituents in centrosymmetric diphenyl ethers.
Four possibilities are indicated: (a) 4-(4-methoxyphenoxy)nitrobenzene;
(b) 4-(4-methylphenoxy)benzonitrile; (c) 4-(4-nitrophenoxy)phenol and;
(d) 4-amino-49-cyanodiphenyl ether. Crystallization in space group P21/c is
especially common for such compounds.
1 (a) Non-linear optical properties of organic and molecular crystals, ed.
J. Zyss and D. S. Chemla, Academic, New York, 1987, vols. 1 and 2; (b)
G. R. Desiraju, Crystal Engineering. The Design of Organic Solids,
Elsevier, Amsterdam, 1989, pp. 225–259.
2 J. K. Whitesell, R. E. Davis, L. L. Saunders, R. J. Wilson and
J. P. Feagins, J. Am. Chem. Soc., 1991, 113, 3267.
3 For selected references, see: (a) C. P. Brock, W. B. Schweizer and
J. D. Dunitz, J. Am. Chem. Soc., 1991, 113, 9811; (b) G. P. Dado,
J. M. Desper, S. K. Holmgren, C. J. Rito and S. H. Gellman, J. Am.
Chem. Soc., 1992, 114, 4834; (c) M. L. Peterson, J. T. Strnad,
T. P. Markotan, C. A. Morales, D. V. Scaltrito and S. W. Staley, J. Org.
Chem., 1999, 64, 9067; (d) L. Yu, G. A. Stephenson, C. A. Mitchell,
C. A. Bunnell, S. V. Snorek, J. J. Bowyer, T. B. Borchardt, J. G. Stowell
and S. R. Byrn, J. Am. Chem. Soc., 2000, 122, 585; (e) A. Ka´lma´n,
L. Fa´bia´n, G. Argay, G. Berna´th and Z. Gyarmati, J. Am. Chem. Soc.,
2003, 125, 34; (f) Z. Dominguez, T. A. V. Khuong, H. Dang,
C. N. Sanrame, J. E. Nunez and M. A. Garcia-Garibay, J. Am. Chem.
Soc., 2003, 125, 8830.
4 (a) J. Zyss, D. S. Chemla and J. F. Nicoud, J. Chem. Phys., 1981, 74,
4800; (b) M. Sigelle and R. Hierle, J. Appl. Phys., 1981, 52, 4199; (c)
M. Sigelle, J. Zyss and R. Hierle, J. Non-Cryst. Solids, 1982, 47,
287.
5 V. R. Thalladi, S. Brasselet, D. Bla¨ser, R. Boese, J. Zyss, A. Nangia and
G. R. Desiraju, Chem. Commun., 1997, 1841.
6 F. H. Allen and R. Taylor, Chem. Soc. Rev., 2004, 33, 463.
7 G. R. Desiraju, J. D. Dunitz, A. Nangia, J. A. R. P. Sarma and E. Zass,
Helv. Chim. Acta, 2000, 83, 1.
8 J. W. Yao, J. C. Cole, E. Pidcock, F. H. Allen, J. A. K.
Howard and W. D. S. Motherwell, Acta Crystallogr., Sect. B, 2002,
58, 640.
geometry would be robust and well sustained in the final crystal
packing.
This study shows that some matters relating to crystal packing
may not be resolved easily with a purely statistical CSD type
approach. Crystallisation is too complex an issue and many factors
are in play in determining stable packing modes.13 Accordingly, it
would be simplistic to expect that questions of the type ‘‘will a high
dipole moment lead to a centrosymmetric space group?’’ could be
resolved one way or another with CSD searches. Secondly, general
solutions to complex problems are often not available and the only
working approach is to sacrifice generality for precision. In crystal
engineering, this is done by selecting a subset of compounds rather
than aiming for global correlations. In this particular case, the
family selected is a good prototype for dipolar NLO materials and,
in all probability, the correlation found here will apply to other
polarizable systems. Finally, high throughput crystallography can
and should be used in crystal engineering wherever possible
because it can provide a route to the solution of otherwise difficult
and subtle problems. We conclude that there is a strong tendency
towards centrosymmetry for conjugated or aromatic molecules
with large dipole moments.
We thank the CSIR for the award of an SRF to AD, and the
DST (IRPHA) for the CCD diffractometer. The University of
Hyderabad is supported by UGC under the UPE programme. We
thank R. Banerjee, D. Das and L. S. Reddy for assistance with
X-ray data collection and Dr. C. Broder (Durham) and Dr. R. K.
R. Jetti (Essen) for four of the data sets. We thank Prof. R. E.
Davis for making available some of the data from his earlier study.
9 A. Dey and G. R. Desiraju, CrystEngComm, 2004, 6, 642.
10 A. R. Choudhury, K. Islam, M. T. Kirchner, G. Mehta and T. N.
Guru Row, J. Am Chem. Soc., 2004, 126, 12274.
11 I. Bensenmann, M. Gdaniec and T. Polonski, New J. Chem., 2002, 26,
448.
12 C. P. Brock and J. D. Dunitz, Chem. Mater., 1994, 6, 1118.
13 G. R. Desiraju, Curr. Sci., 2005, 88, 374.
2488 | Chem. Commun., 2005, 2486–2488
This journal is ß The Royal Society of Chemistry 2005