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

More documents

Recommendations

Info

Functional Organic Zeolite Analogues 147 2.5 Modes of Guest Binding The percent volume occupied by host or guest provides a measure of the porosity of a network. In this respect, many of the networks such as 11 (Fig. 1), 23 (Fig. 7), 30 (Fig. 9), 38 (Fig. 10), 42 (Fig. 11), and 45 (Fig. 12) are highly porous, i.e. ≥ 50% of the total volume of the adduct is occupied by the guest or only ≥ 50% of that is occupied by the host framework. Some of the guest-binding channels have a cross-section as wide as 10 Å. For comparison, typical pore sizes of zeolites (molecular sieves 4 A, 5 A, and 13X) fall in the range 4–13 Å and void volumes are generally < 50% [63]. For the stoichiometry, selectivity, mobility and catalysis it is of crucial importance if there is host-guest interaction. In many cases of multiple hydrogen bonds such as those between carboxyl groups (1 and 2 in Fig 1), pyridones (3 in Fig. 1),or 2,4-diaminotriazines (38 in Fig. 10),all or most of the hydrogen-bonding capacity is consumed to build a robust network. In most metal-organic solids whose crystal structures have been determined, the metal centres are coordinatively saturated [58, 64]; there is no guest-metal interaction expected unless guest/ligand exchange occurs. In the absence of strong host-guest (metalguest) interaction, guest (solvent) molecules included in a large cavity or channel are, not surprisingly, highly disordered. Thus, it is remarkable that two-thirds by volume of what is definitely a crystal (adduct 11 ◊ x(C 6H 5NO 2) (x ≥ 7.7) is essentially a liquid [35]. It is also likely that the host-guest stoichiometry is primarily controlled on a size basis. Host 35 (Fig. 10), for example, forms such adducts as 35 ◊ 5(dioxane), 35 ◊ 10(CH 3CN), 35 ◊ 10(HCO 2H) and 35 ◊ 21(H 2O) [54]. The simple hydrogen bond between OH groups is coordinatively unsaturated. Two or one such free protons (O-H◊◊◊O-H) capable of hydrogen-bonding fixation of a polar guest are available for the diresorcinol or monoresorcinol host 29 or 32 (Fig. 9), respectively. This gives a 1:2 29:guest or 1:1 32:guest stoichiometry for various polar guests having different sizes [52, 53]. In fact, when crystallized from ethyl acetete, host 29 only affords a 1:2 adduct. On the other hand, when crystallized from a mixture of ethyl acetate and benzene, the host gives rise to a ternary adduct 29 ◊ 2(ester) ◊ 2(benzene) [50]. Thus the stoichiometry of the polar host-guest interaction is very strict and the void space still available is better filled with a hydrocarbon guest. The formation of such a ternary adduct containing polar and nonpolar guests simultaneously bound in a cavity provides a basis of its application as a solid catalyst to the bimolecular Diels-Alder reactions [65]. An analogous diresorcinol derivative of Zn II -porphyrin (39) generates a similar 2D net 40 (Fig. 11), having cavities much wider than those (30 in Fig. 9) of the anthracene host 29. The porphyrin host forms adduct 39 ◊ 4THF [55]. Two molecules of the guest are hydrogen-bonded to the host as above,while the remaining two are coordinated to the central Zn II ions. Cooperation of coordination and hydrogen bonding would be a potential tool for assembling different types of guests in a cavity. The host-guest hydrogen bonding can also be applied to achieve a particular alignment of host and guest components. Quinones as strong electron-acceptors
148 Y. Aoyama are intriguing guests. Duroquinone, for example, can be inserted into the narrow cavities in the pseudo 2D net of anthracene-monoresorcinol host (34 in Fig. 9), thereby generating a system of closely packed alternating anthracene-quinone (A-Q) columns (64 in Fig. 15) [53]. Use of a less bulky guest such as ethyl acetate induces a dimeric lattice pattern 65, which exclusively emits excimer fluorescence from the face-to-face dimeric anthracene units [53]. Segregated anthracene (A) and anthraquinone (Q) columns (66) are found in the charge-transfer molecular crystals of adduct 29◊2 (anthraquinone) [66]. This is also the case for the 1:1 complex of the diresorcinol derivative of anthracene (29) and the dipyrimidine derivative of anthraquinone (67) as a specific hydrogen-bond donor and an acceptor, respectively [66]. 2.6 Selectivities and Pore Size Control 64 65 66 67 Fig. 15. Formation of various columns in host-guest adducts; A, Q, G represent anthracene ring, quinone moiety, and guest species, respectively Selectivity is a particularly important aspect of inclusion phenomena.Although a number of highly enantioselective [67, 68], regioselective [44] or functional group-selective [69] solid-state complexations are known, it is not easy to understand fully the origin of such a selectivity. Even when host-guest complexation is primarily driven by a particular interaction such as hydrogen bonding, the actual affinity of a guest markedly depends on how other binding forces, especially the cavity packing, cooperate with the essential host-guest interaction. Detailed studies [52, 53] on the selectivities of hosts 29 and 32 (Fig. 9) reveal that the hydrogen bonded network is somehow adjustable to smaller guests but
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 and 100:
90 A. Nangia · G.R. Desiraju b c F
Page 101 and 102:
92 A. Nangia · G.R. Desiraju all a
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: 146 Y. Aoyama clusion compounds (se
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 205 and 206:
Crystalline Polymorphism of Organic
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?