(How) does 1,3,5-triethylbenzene scaffolding work? Analyzing the abilities of 1,3,5-triethylbenzene- and 1,3,5-trimethylbenzene-based scaffolds to preorganize the binding elements of supramolecular hosts and to improve binding of targets

• Xing Wang and
• Fraser Hof

Beilstein J. Org. Chem. 2012, 8, 1–10, doi:10.3762/bjoc.8.1

• -triethylbenzene- and 1,3,5-trimethylbenzene-derived hosts in the solid state. One must always be cautious in interpreting crystallographic data on molecular conformations, as it is subject to crystal packing influences, which are not present in solution. However, those artifacts are diminished in surveys that

Structural conditions required for the bridge lithiation and substitution of a basic calix[4]arene

• Conrad Fischer,
• Wilhelm Seichter and
• Edwin Weber

Beilstein J. Org. Chem. 2011, 7, 1602–1608, doi:10.3762/bjoc.7.188

• and crystal packing illustration of mixed ether 12. Acknowledgements The authors are grateful for generous financial support to this work from the German Federal Ministry of Economics and Technology (BMWi) under grant No. 16IN0218 'ChemoChips'.

NMR studies of anion-induced conformational changes in diindolylureas and diindolylthioureas

• Damjan Makuc,
• Jennifer R. Hiscock,
• Mark E. Light,
• Philip A. Gale and
• Janez Plavec

Beilstein J. Org. Chem. 2011, 7, 1205–1214, doi:10.3762/bjoc.7.140

• dictated by other forces, such as crystal packing. These observations are in agreement with minute 1H chemical shift changes and the weak stability constant of 1 for the binding of chloride anions. Considerable changes in the NOE enhancements were observed upon addition of acetate anions to 1. The

Synthesis and crystallographic analysis of meso-2,3-difluoro-1,4-butanediol and meso-1,4-dibenzyloxy-2,3-difluorobutane

• Bruno Linclau,
• Leo Leung,
• Jean Nonnenmacher and
• Graham Tizzard

Beilstein J. Org. Chem. 2010, 6, No. 62, doi:10.3762/bjoc.6.62

• ); HRMS (EI+) for C6H12O79BrSi (M-tBu)+: Calcd 206.9835; Measured 206.9841. Vicinal difluoride containing building blocks. Molecular overlay of both conformers of 7. Crystal packing of 7 viewed along the b axis. Short contacts (see text) are shown in light blue. Crystal structure of 3. Crystal packing of

Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions

• Tilman Lechel,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, No. 42, doi:10.3762/bjoc.6.42

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• adopt a conformation with a cavity size large enough to include a peptidic substrate, the X-ray structure obtained for antiparallel receptor 1 shows the collapse of the designed cavity. Although crystal packing may contribute to this conformational change to some degree, the solid-state structure of 1

The subtle balance of weak supramolecular interactions: The hierarchy of halogen and hydrogen bonds in haloanilinium and halopyridinium salts

• Kari Raatikainen,
• Massimo Cametti and
• Kari Rissanen

Beilstein J. Org. Chem. 2010, 6, No. 4, doi:10.3762/bjoc.6.4

• atoms (3.79 Å) [17][44], definitely weaker than in the classical PFC-I···N systems [11][12][13][14][15][16]. The crystal packing reveals a pattern of complementary donor and acceptor sites for three N+–H···Cl− hydrogen bonds, which in addition to one I···Cl− mentioned above, creates a distorted

• different crystal architecture. The strong charge-assisted hydrogen bonding clearly overrules the weaker halogen bonding and is the major cause for the crystal packing. Halogen and hydrogen bonding in 4-IPhNH3Br (5) Exchanging the chlorine counter anion for bromine was expected to give weaker halogen bond

• hydrogen bonds. The layers are perpendicular to the crystallographic c axis and the spacing between the layers is about 13 Å. Aromatic moieties are segregated between these layers, thus the overall crystal packing (Figure 4b) is very similar to the haloanilinium halides (Figure 1 and Figure 3

The efficient synthesis of dibenzo[d,d′]benzo[1,2-b:4,3-b′]dithiophene and cyclopenta[1,2-b:4,3-b′]bis(benzo[d]thiophen)-6-one

• Zhihua Wang,
• Sheng Zhu,
• Jianwu Shi and
• Hua Wang

Beilstein J. Org. Chem. 2009, 5, No. 55, doi:10.3762/bjoc.5.55

• °. Using the middle benzene ring as a reference, the inner (C(5), C(6), C(7), C(12), C(13), and C(18)) helix increases by 1.46 Å and turns in-plane by 237.0° [22][23]. The crystal packing structure of 1 (Figure 3) is based on π-stacking along the a-axis in which the plane-to-plane distance is ca. 3.857 Å

• , wR2 = 0.0846. Chemical structures of 1 and 2. Molecular structure and conformation of 1. Crystal packing structure of 1. UV–vis spectra of 1 and 2 in chloroform ([C] = 1 × 10−5 M). Synthetic route to 1 and 2. Reagents and conditions: (a) (i) n-BuLi (2.3 equiv), Et2O, reflux; (ii) −78 °C, DMF (4.0

A convenient method for preparing rigid-core ionic liquid crystals

• Julien Fouchet,
• Laurent Douce,
• Benoît Heinrich,
• Richard Welter and
• Alain Louati

Beilstein J. Org. Chem. 2009, 5, No. 51, doi:10.3762/bjoc.5.51

• interactions is given in Figure 1 (the interactions also being listed in Table 1). The alkyloxy chains are quite parallel, as is clear from the crystal packing given in Figure 2, with segregation between the rigid part (including iodine atoms) and the alkyloxy chains (≈20 Å, see Figure 2). The length of the

A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions

• Marc Debeaux,
• Kai Brandhorst,
• Peter G. Jones,
• Henning Hopf,
• Jörg Grunenberg,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2009, 5, No. 31, doi:10.3762/bjoc.5.31

• . Ellipsoid representation (50% level) of compound 7 in the crystal. Packing diagram of compound 7 viewed parallel to b; hydrogen bonds C-H···O are indicated by dashed lines. Ellipsoid representation (50% level) of compound 11 in the crystal. Packing diagram of compound 11 viewed perpendicular to the bc plane

A simple route for renewable nano- sized arjunolic and asiatic acids and self- assembly of arjuna- bromolactone

• Braja G. Bag,
• Partha P. Dey,
• Shaishab K. Dinda,
• William S. Sheldrick and
• Iris M. Oppel

Beilstein J. Org. Chem. 2008, 4, No. 24, doi:10.3762/bjoc.4.24

• arjuna-bromolactone 3. The length of the molecule (3O•••30C) is 1.26 nm. Crystal packing diagram of arjuna-bromolactone 3. A network of hydrogen bridges leading to the formation of a one-dimensional helix is observed. (a) (i) Br2/AcOH, (ii) CH2N2, (iii) separation by crystallization, (b) Zn/AcOH/RT (c

Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines

• Sihui Long,
• Venkatraj Muthusamy,
• Peter G. Willis,
• Sean Parkin and
• Arthur Cammers

Beilstein J. Org. Chem. 2008, 4, No. 23, doi:10.3762/bjoc.4.23

• nuances inherent in crystal packing engender boundless diversity in the arrangements of hydrogen bonded organic solid states. Due to its relative strength and its directional nature, the hydrogen bond has drawn much attention as a structural element in the design of crystalline phases [1][2][3][4][5]. The

• phase [23]; although, exceptions have been noted [24]. Musing about this issue, Brock and Dunitz state, “Inversion centers are especially favorable for crystal packing because they diminish like-like interactions and are uniquely compatible with translation.” [25] Symmetry is a powerful component in

Shape- persistent macrocycle with intraannular alkyl groups: some structural limits of discotic liquid crystals with an inverted structure

• Sigurd Höger,
• Jill Weber,
• Andreas Leppert and
• Volker Enkelmann

Beilstein J. Org. Chem. 2008, 4, No. 1, doi:10.1186/1860-5397-4-1

• ). The remaining portions of the alkyl chains are located above and below the rigid phenyl acetylene backbone of the rings which is in both cases relatively flat. Although the crystal packing shows that the alkyl chains are sandwiched between the macrocycles, there exist still some close contacts between

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

• David O'Hagan,
• Henry S. Rzepa,
• Martin Schüler and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2006, 2, No. 19, doi:10.1186/1860-5397-2-19

• structure is shown in Figure 5. In the X-ray crystal structure of erythro-19 both of the carboxylic acid carbonyl oxygens adopt a syn periplanar conformation with respect to the C-F bonds. In the crystal packing, the carboxylate groups of two neighbouring molecules are hydrogen bonded and this clearly

• [29][30]. X-ray structure of erythro-22. Crystal packing of erythro-22 clearly indicating intermolecular hydrogen bonding. X-ray structure of threo-22. The conformations of erythro- and threo- 23 are very different as a consequence of each conformation preserving a vicinal fluorine gauche relationship

Hydrogen bonding patterns in the cocrystals of 5-nitrouracil with several donor and acceptor molecules

• Reji Thomas,
• R. Srinivasa Gopalan,
• G. U. Kulkarni and
• C. N. R. Rao

Beilstein J. Org. Chem. 2005, 1, No. 15, doi:10.1186/1860-5397-1-15

• . Introduction Crystalline molecular solids exhibit properties- chemical reactivity, electrical, optical or magnetic – unique to their crystal structure. This justifies the growing interest in designing and preparing molecular crystals with desired properties and understanding crystal packing, which are clearly