198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

More documents

Recommendations

Info

Supramolecular Synthons and Pattern Recognition 91 certain functional group category, no dominant motif is adopted by the molecules. Such appears to be the case for acetylenic alcohols containing the fragment 63 [93]. Retrieval of data for sub-structure 63 from the CSD produced a list of 76 compounds. The hydrogen bonding networks of these molecules did not produce a single recurring pattern that can be associated with this sub-structure [94]. Rather, four different motifs could be identified (Scheme 13), with none being predominant. This is in contrast to the behaviour of simple monoalcohols that crystallise mainly in two type of O-H◊◊◊O aggregates – chains and rings [95]. There is significant structural interference in these acetylenic alcohols. Instead of the CC-H and OH groups associating in their isolated networks, complex patterns are formed wherein CC-H◊◊◊OH 65 and OH◊◊◊CC-H 66 hydrogen bonds are found in addition to the expected CC-H◊◊◊CC-H 67 and O-H◊◊◊O-H 64 hydrogen bonds. This may be due to the fact that the four different hydrogen bonding patterns between the two functional groups, O-H◊◊◊O 64, C-H◊◊◊O 65, O-H◊◊◊p 66, and C-H◊◊◊p 67 have comparable energies, steric requirements and topologies. At a certain level, the absence of patterns in groups of crystal structures is a manifestation of the fact that the molecular and crystal structures need not be related in obvious ways. After all, the geminal positioning of hydroxy and ethynyl groups in 63 is only a molecular structural feature. There is no need that 63 64 65 66 Scheme 13. Four common supramolecular synthons 64–67in 76 occurrences of the acetylenic alcohol fragment 63 67 68 69
92 A. Nangia · G.R. Desiraju all acetylenic alcohols should have related crystal structures. At yet another level, though, it is possible that the “absence” of patterns is only indicative of the fact that the crystal structures are being compared at an inappropriate frame of reference. If, for instance, the hydroxy and ethynyl groups were considered as being equivalent to Q-H, then the four patterns 64–67 reduce to Q-H◊◊◊Q interaction 68 and its repeating array 69. 11 Conclusions Patterns in crystals reflect recognition features of molecules and the recurring nature of these patterns reveals their robustness, which is a very desirable attribute in crystal engineering and design. Patterns of interactions are important not only in molecular crystals but also in the related biological areas of drug design and receptor-ligand binding. The concept of a supramolecular synthon places the geometrical notion of a pattern in a chemical context. More significantly, this concept lends itself to retrosynthetic analysis and to the identification of similar crystal structures that can be derived from dissimilar molecules. Supramolecular synthons are critical sub-structural units that contain the maximum of structural information encapsulated in patterns of the most economical size. A full three-dimensional structure contains all possible structural information for a given crystal but is too detailed to permit realistic comparisons with other crystal structures. Structural simplification is therefore necessary. The graph set notation of a crystal structure provides precise topological information but inherent in its definition is a drastic reduction in the chemical information underlying molecular recognition. The supramolecular synthon combines chemical and geometrical features and occupies a middle ground between the full crystal structure and its graph set notation. With these and similar ideas, it is hoped that the task of designing and building a crystal from smaller structural units will progress to a more reliable and manageable exercise. Acknowledgements. Financial assistance from the Department of Science and Technology (SP/S1/G19/94) and the Council of Scientific and Industrial Research (1/1431/96/EMR-II), Government of India is acknowledged. We thank Prof. G. Klebe for the originals of Figs. 3 and 4 and Dr. R.S. Rowland for making available a copy of the NIPMAT program. 12 References 1. Lehn J-M (1994) Perspectives in supramolecular chemistry: from the lock-and-key image to the information paradigm. In: Behr JP (ed) Perspectives in supramolecular chemistry, vol 1. The lock-and-key principle. The state of the art – 100 years on. Wiley, Chichester, p 307 2. Desiraju GR, Sharma CVK (1995) Crystal engineering and molecular recognition. Twin facets of supramolecular chemistry. In: Desiraju GR (ed) Perspectives in supramolecular chemistry, vol 2. The crystal as a supramolecular entity. Wiley, Chichester, p 31
Page 1 and 2:
198 Topics in Current Chemistry Edi
Page 3 and 4:
Design of Organic Solids Volume Edi
Page 5 and 6:
Volume Editors Prof. Dr. Edwin Webe
Page 7 and 8:
VIII preface tion at an amazing lev
Page 9 and 10:
Contents of Volume 196 Carbon Rich
Page 11 and 12:
2 J.P. Glusker 5 Interactions of Pl
Page 13 and 14:
4 J.P. Glusker Perturbations to the
Page 15 and 16:
6 J.P. Glusker 2.1 Sources of Cryst
Page 17 and 18:
8 J.P. Glusker other induced, will
Page 19 and 20:
10 J.P. Glusker The forces here hav
Page 21 and 22:
12 J.P. Glusker lographic structure
Page 23 and 24:
14 J.P. Glusker a c Fig. 6 a - c. D
Page 25 and 26:
16 J.P. Glusker hydrogen bond H◊
Page 27 and 28:
18 J.P. Glusker Fig. 9. Citric acid
Page 29 and 30:
20 J.P. Glusker peptide plane and a
Page 31 and 32:
22 J.P. Glusker 4.5 F◊◊◊H Int
Page 33 and 34:
24 J.P. Glusker rine-containing com
Page 35 and 36:
26 J.P. Glusker Fig. 17. The packin
Page 37 and 38:
28 J.P. Glusker bind to a metal ion
Page 39 and 40:
30 J.P. Glusker As for carboxylate
Page 41 and 42:
32 J.P. Glusker Fig. 24. The magnes
Page 43 and 44:
34 J.P. Glusker structures of magne
Page 45 and 46:
36 J.P. Glusker b a Fig. 28 a, b. A
Page 47 and 48:
38 J.P. Glusker Fig. 30. Complexati
Page 49 and 50: 40 J.P. Glusker 7.1 Descriptions of
Page 51 and 52: 42 J.P. Glusker Fig. 34. Glycine cr
Page 53 and 54: 44 J.P. Glusker bonding capabilitie
Page 55 and 56: 46 J.P. Glusker 2. Non-intercalativ
Page 57 and 58: 48 J.P. Glusker d Fig. 37 d. The ch
Page 59 and 60: 50 J.P. Glusker Fig. 39. Hydrogen-b
Page 61 and 62: 52 J.P. Glusker 72, 104], but other
Page 63 and 64: 54 J.P. Glusker 23. Cody V, Murray-
Page 65 and 66: 56 J.P. Glusker: Directional Aspect
Page 67 and 68: 58 A. Nangia · G.R. Desiraju 7 Sup
Page 69 and 70: 60 A. Nangia · G.R. Desiraju elect
Page 71 and 72: 62 A. Nangia · G.R. Desiraju 14 15
Page 73 and 74: 64 A. Nangia · G.R. Desiraju [23]
Page 75 and 76: 66 A. Nangia · G.R. Desiraju struc
Page 77 and 78: 68 A. Nangia · G.R. Desiraju Fig.
Page 79 and 80: 70 A. Nangia · G.R. Desiraju -NH 2
Page 81 and 82: 72 A. Nangia · G.R. Desiraju ingfu
Page 83 and 84: 74 A. Nangia · G.R. Desiraju and r
Page 85 and 86: 76 A. Nangia · G.R. Desiraju bonds
Page 87 and 88: 78 A. Nangia · G.R. Desiraju 2.86-
Page 89 and 90: 80 A. Nangia · G.R. Desiraju from
Page 91 and 92: 82 A. Nangia · G.R. Desiraju ted a
Page 93 and 94: 84 A. Nangia · G.R. Desiraju envir
Page 95 and 96: 86 A. Nangia · G.R. Desiraju PYRAZ
Page 97 and 98: 88 A. Nangia · G.R. Desiraju napht
Page 99: 90 A. Nangia · G.R. Desiraju b c F
Page 103 and 104: 94 A. Nangia · G.R. Desiraju 42. J
Page 105 and 106: Hydrogen-Bonded Ribbons, Tapes and
Page 139 and 140: 132 Y. Aoyama 4 Catalysis . . . . .
Page 141 and 142: 134 Y. Aoyama 2.2 Symmetry-Controll
Page 143 and 144: 136 Y. Aoyama A trigonal centre is
Page 145 and 146: 138 Y. Aoyama 18 19 Fig. 5. 2D net
Page 147 and 148: 140 Y. Aoyama 24 ded (O-H◊◊◊O
Page 149 and 150: 142 Y. Aoyama 2.4 Interaction-Suppo
Page 151 and 152:
144 Y. Aoyama In the presence of a
Page 153 and 154:
146 Y. Aoyama clusion compounds (se
Page 155 and 156:
148 Y. Aoyama are intriguing guests
Page 157 and 158:
150 Y. Aoyama The tuning or enginee
Page 159 and 160:
152 Y. Aoyama Fig. 16. Binding isot
Page 161 and 162:
154 Y. Aoyama The desorption of the
Page 163 and 164:
156 Y. Aoyama Fig. 17. Suggested me
Page 165 and 166:
158 Y. Aoyama 5 Concluding Remarks
Page 167 and 168:
160 Y. Aoyama 4. Hölderich W, Hess
Page 169 and 170:
Crystalline Polymorphism of Organic
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Author Index Volumes 151-198 Author
Page 217 and 218:
Author Index Volumes 151 - 198 2 1
Page 219 and 220:
Author Index Volumes 151 - 198 213
Page 221 and 222:
Page 223 and 224:
Author Index Volumes 151 - 198 2 ]
Page 225 and 226:
Page 227 and 228:
Springer and the environment At Spr
show all

198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

Create successful ePaper yourself

Delete template?

Save as template?