Resorcinarene-based cavitands as building blocks for crystal engineering

CrystEngComm ◽  
2016 ◽  
Vol 18 (31) ◽  
pp. 5788-5802 ◽  
Author(s):  
R. Pinalli ◽  
E. Dalcanale ◽  
F. Ugozzoli ◽  
C. Massera
Keyword(s):  
Crystal Engineering ◽  
Building Blocks

Hierarchy of Supramolecular Arrangements and Building Blocks: Inverted Paradigm of Crystal Engineering in the Unprecedented Metal Coordination of Methylene Blue

2017 ◽  
Vol 56 (6) ◽  
pp. 3512-3516 ◽  
Author(s):  
Stefano Canossa ◽  
Alessia Bacchi ◽  
Claudia Graiff ◽  
Paolo Pelagatti ◽  
Giovanni Predieri ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Crystal Engineering ◽  
Building Blocks ◽  
Metal Coordination ◽  
Supramolecular Arrangements

A threefold interpenetrated two-dimensional zinc(II) supramolecular architecture based on 3-nitrobenzoic acid and 4,4′-bipyridine

2016 ◽  
Vol 72 (2) ◽  
pp. 128-132 ◽  
Author(s):  
Long Tang ◽  
Ji-Jiang Wang ◽  
Feng Fu ◽  
Sheng-Wen Wang ◽  
Qi-Rui Liu
Keyword(s):  
Coordination Polymers ◽  
Crystal Engineering ◽  
Critical Factor ◽  
Building Blocks ◽  
Zigzag Chain ◽  
Great Success ◽  
Supramolecular Architecture ◽  
Two Dimensional ◽  
Hydrothermal Conditions ◽  
Nitrobenzoic Acid

With regard to crystal engineering, building block or modular assembly methodologies have shown great success in the design and construction of metal–organic coordination polymers. The critical factor for the construction of coordination polymers is the rational choice of the organic building blocks and the metal centre. The reaction of Zn(OAc)2·2H2O (OAc is acetate) with 3-nitrobenzoic acid (HNBA) and 4,4′-bipyridine (4,4′-bipy) under hydrothermal conditions produced a two-dimensional zinc(II) supramolecular architecture,catena-poly[[bis(3-nitrobenzoato-κ2O,O′)zinc(II)]-μ-4,4′-bipyridine-κ2N:N′], [Zn(C7H4NO4)2(C10H8N2)]nor [Zn(NBA)2(4,4′-bipy)]n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction analysis. The ZnIIions are connected by the 4,4′-bipy ligands to form a one-dimensional zigzag chain and the chains are decorated with anionic NBA ligands which interact further through aromatic π–π stacking interactions, expanding the structure into a threefold interpenetrated two-dimensional supramolecular architecture. The solid-state fluorescence analysis indicates a slight blue shift compared with pure 4,4′-bipyridine and HNBA.

scholarly journals Towards computer-guided tuning of the crystal packing of porous organic cages

2014 ◽  
Vol 70 (a1) ◽  
pp. C667-C667
Author(s):  
Angeles Pulido ◽  
Ming Liu ◽  
Paul Reiss ◽  
Anna Slater ◽  
Sam Chong ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Engineering ◽  
Molecular Sieves ◽  
Structure Prediction ◽  
Crystal Packing ◽  
Aromatic Aldehydes ◽  
Lattice Energy ◽  
Building Blocks ◽  
Molecular Assembly ◽  
Computational Techniques

Among microporous materials, there has been an increasing recent interest in porous organic cage (POC) crystals, which can display permanent intrinsic (molecular) and extrinsic (crystal network) porosity. These materials can be used as molecular sieves for gas separation and potential applications as enzyme mimics have been suggested since they exhibit structural response toward guest molecules[1]. Small structural modifications of the initial building blocks of the porous organic molecules can lead to quite different molecular assembly[1]. Moreover, the crystal packing of POCs is based on weak molecular interactions and is less predictable that other porous materials such as MOFs or zeolites.[2] In this contribution, we show that computational techniques -molecular conformational searches and crystal structure prediction- can be successfully used to understand POC crystal packing preferences. Computational results will be presented for a series of closely related tetrahedral imine- and amine-linked porous molecules, formed by [4+6] condensation of aromatic aldehydes and cyclohexyl linked diamines. While the basic cage is known to have one strongly preferred crystal structure, the presence of small alkyl groups on the POC modifies its crystal packing preferences, leading to extensive polymorphism. Calculations were able to successfully identify these trends as well as to predict the structures obtained experimentally, demonstrating the potential for computational pre-screening in the design of POCs within targeted crystal structures. Moreover, the need of accurate molecular (ab initio calculations) and crystal (based on atom-atom potential lattice energy minimization) modelling for computer-guided crystal engineering will be discussed.

Directional control of π-stacked building blocks for crystal engineering: the 1,8-naphthalimide synthon

2005 ◽  
pp. 4068 ◽  
Author(s):  
Daniel L. Reger ◽  
J. Derek Elgin ◽  
Radu F. Semeniuc ◽  
Perry J. Pellechia ◽  
Mark D. Smith
Keyword(s):  
Crystal Engineering ◽  
Building Blocks ◽  
Directional Control

Associations of squaric acid and its anions as multiform building blocks of hydrogen-bonded molecular crystals

2001 ◽  
Vol 57 (6) ◽  
pp. 859-865 ◽  
Author(s):  
Gastone Gilli ◽  
Valerio Bertolasi ◽  
Paola Gilli ◽  
Valeria Ferretti
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Engineering ◽  
Negative Charge ◽  
Three Dimensional ◽  
Molecular Crystals ◽  
Building Blocks ◽  
Squaric Acid ◽  
Orthosilicic Acid ◽  
Molecular Plane ◽  
Dimensional Crystal

Squaric acid, H2C4O4 (H2SQ), is a completely flat diprotic acid that can crystallize as such, as well as in three different anionic forms, i.e. H2SQ·HSQ−, HSQ− and SQ2−. Its interest for crystal engineering studies arises from three notable factors: (i) its ability of donating and accepting hydrogen bonds strictly confined to the molecular plane; (ii) the remarkable strength of the O—H...O bonds it may form with itself which are either of resonance-assisted (RAHB) or negative-charge-assisted [(−)CAHB] types; (iii) the ease with which it may donate a proton to an aromatic base which, in turn, back-links to the anion by strong low-barrier N—H+...O1/2− charge-assisted hydrogen bonds. Analysis of all the structures so far known shows that, while H2SQ can only crystallize in an extended RAHB-linked planar arrangement and SQ2− tends to behave much as a monomeric dianion, the monoanion HSQ− displays a number of different supramolecular patterns that are classifiable as β-chains, α-chains, α-dimers and α-tetramers. Partial protonation of these motifs leads to H2SQ·HSQ− anions whose supramolecular patterns include ribbons of dimerized β-chains and chains of emiprotonated α-dimers. The topological similarities between the three-dimensional crystal chemistry of orthosilicic acid, H4SiO4, and the two-dimensional one of squaric acid, H2C4O4, are finally stressed.

scholarly journals Making crystals with a purpose; a journey in crystal engineering at the University of Bologna

IUCrJ ◽  
2017 ◽  
Vol 4 (4) ◽  
pp. 369-379 ◽  
Author(s):  
Dario Braga ◽  
Fabrizia Grepioni ◽  
Lucia Maini ◽  
Simone d'Agostino
Keyword(s):  
Charge Distribution ◽  
Functional Groups ◽  
Crystal Engineering ◽  
Building Blocks ◽  
Mixed Crystals ◽  
The Other ◽  
Molecular Building Blocks ◽  
The One ◽  
The University ◽  
Conceptual Relationship

The conceptual relationship between crystal reactivity, stability and metastability, solubility and morphology on the one hand and shape, charge distribution, chirality and distribution of functional groups over the molecular surfaces on the other hand is discussed,viaa number of examples coming from three decades of research in the field of crystal engineering at the University of Bologna. The bottom-up preparation of mixed crystals, co-crystals and photoreactive materials starting from molecular building blocks across the borders of organic, organometallic and metalorganic chemistry is recounted.

scholarly journals Design of Mechanically Flexible Organic Crystals: A Crystal Engineering Approach

2014 ◽  
Vol 70 (a1) ◽  
pp. C648-C648
Author(s):  
Gamidi Krishna ◽  
Ramesh Devarapalli ◽  
Garima Lal ◽  
C. Reddy
Keyword(s):  
Crystal Structures ◽  
Organic Solar Cells ◽  
Crystal Engineering ◽  
Rational Design ◽  
Organic Materials ◽  
Building Blocks ◽  
Design Strategy ◽  
High Plasticity ◽  
Simple Strategy ◽  
Slip Planes

Utilization of organic single crystal materials is increasing day by day owing to their promising applications in organic light emitting diodes [1], organic solar cells, mechanochromic luminescence [2] and tablatability [3] of APIs etc. These desirable functions, especially mechanical properties, can be achieved by imparting soft nature in organic materials, however unfortunately there is no simple strategy to attain this. Till date all the findings are serendipitous discoveries, so a rational design strategy is necessary to accomplish such soft mechanical behavior in molecular crystals. Here we propose a design strategy to attain plastically deformable organic materials by introducing slip planes in the crystal structures. The high plasticity can be achieved by introducing hydrophobic groups, such as t-Bu, -OMe, -Me and multiple –Cl (or) –Br groups on -Ar building blocks, for example on naphthalene diimide (NDI), which leads to the formation of slip planes in the crystal structures (as shown in attached figure), hence facilitate the plastic (irreversible) bending [2].

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