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

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.

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Diverse protein assembly driven by metal and chelating amino acids with selectivity and tunability

Nature Communications ◽

10.1038/s41467-019-13491-w ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 10

Author(s):

Minwoo Yang ◽

Woon Ju Song

Keyword(s):

Amino Acids ◽

Self Assembly ◽

Protein Structures ◽

Functional Materials ◽

Building Blocks ◽

Unnatural Amino Acid ◽

Metal Coordination ◽

Specific Chemical ◽

Natural Building ◽

Kinetics Of

AbstractProteins are versatile natural building blocks with highly complex and multifunctional architectures, and self-assembled protein structures have been created by the introduction of covalent, noncovalent, or metal-coordination bonding. Here, we report the robust, selective, and reversible metal coordination properties of unnatural chelating amino acids as the sufficient and dominant driving force for diverse protein self-assembly. Bipyridine-alanine is genetically incorporated into a D3 homohexamer. Depending on the position of the unnatural amino acid, 1-directional, crystalline and noncrystalline 2-directional, combinatory, and hierarchical architectures are effectively created upon the addition of metal ions. The length and shape of the structures is tunable by altering conditions related to thermodynamics and kinetics of metal-coordination and subsequent reactions. The crystalline 1-directional and 2-directional biomaterials retain their native enzymatic activities with increased thermal stability, suggesting that introducing chelating ligands provides a specific chemical basis to synthesize diverse protein-based functional materials while retaining their native structures and functions.

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Tetra- and Octalactam Macrocycles and Catenanes with Exocyclic Metal Coordination Sites: Versatile Building Blocks for Supramolecular Chemistry

Chemistry - A European Journal ◽

10.1002/chem.200390153 ◽

2003 ◽

Vol 9 (6) ◽

pp. 1332-1347 ◽

Cited By ~ 39

Author(s):

Xi-you Li ◽

Jens Illigen ◽

Martin Nieger ◽

Steffen Michel ◽

Christoph A. Schalley

Keyword(s):

Supramolecular Chemistry ◽

Building Blocks ◽

Metal Coordination ◽

Coordination Sites

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

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314093322 ◽

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.

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

Chemical Communications ◽

10.1039/b504998a ◽

2005 ◽

pp. 4068 ◽

Cited By ~ 41

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

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2,2′-Biphospholes: Building Blocks for Tuning the HOMO-LUMO Gap of π-Systems Using Covalent Bonding and Metal Coordination

Angewandte Chemie ◽

10.1002/ange.201105924 ◽

2011 ◽

Vol 124 (1) ◽

pp. 218-221 ◽

Cited By ~ 17

Author(s):

Hui Chen ◽

Wylliam Delaunay ◽

Liujian Yu ◽

Damien Joly ◽

Zuoyong Wang ◽

...

Keyword(s):

Building Blocks ◽

Covalent Bonding ◽

Metal Coordination ◽

Homo Lumo

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

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768101014963 ◽

2001 ◽

Vol 57 (6) ◽

pp. 859-865 ◽

Cited By ~ 46

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.

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