Ligand and Metal Control of Self‐Assembly in Supramolecular Chemistry

Saalfrank, Rolf W.; Demleitner, Bernhard

doi:10.1002/9780470511510.ch1

Cited by 41 publications

(17 citation statements)

References 225 publications

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“…The designed self-organization of well-defined supramolecular architectures from their components rests on the storage of the required molecular information in the covalent framework of the components and its processing at the supramolecular level through specific interactional algorithms. , A further step toward systems of increasing complexity consists of the implementation of constitutional dynamic chemistry (CDC) and its adaptive features for the design of chemical learning systems that are not just programmed beforehand for a given process but can be trained toward the acquisition of a given function, such as remembering an agent to which it had been subjected. Training and learning involve progressive adaptation of a system, in effect a constitutional dynamic library (CDL), subjected to repetitive application of a physical stimulus or of a chemical effector, thus building up an adapted state and retaining it .…”

Section: Introductionmentioning

confidence: 99%

Training a Constitutional Dynamic Network for Effector Recognition: Storage, Recall, and Erasing of Information

2016

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Constitutional dynamic libraries (CDLs) of hydrazones, acylhydrazones, and imines undergo reorganization and adaptation in response to chemical effectors (herein metal cations) via component exchange and selection. Such CDLs can be subjected to training by exposition to given effectors and keep memory of the information stored by interaction with a specific metal ion. The long-term storage of the acquired information into the set of constituents of the system allows for fast recognition on subsequent contacts with the same effector(s). Dynamic networks of constituents were designed to adapt orthogonally to different metal cations by up- and down-regulation of specific constituents in the final distribution. The memory may be erased by component exchange between the constituents so as to regenerate the initial (statistical) distribution. The libraries described represent constitutional dynamic systems capable of acting as information storage molecular devices, in which the presence of components linked by reversible covalent bonds in slow exchange and bearing adequate coordination sites allows for the adaptation to different metal ions by constitutional variation. The system thus performs information storage, recall, and erase processes.

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Section: Introductionmentioning

confidence: 99%

Training a Constitutional Dynamic Network for Effector Recognition: Storage, Recall, and Erasing of Information

2016

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“…The self-assembly of large metal–organic coordination architectures is a fascinating, intricate process whereby the intrinsic structural characteristics of multitopic ligand molecules, in sync with the coordination preference of metals, lead to complex assemblies via multiple ligand–metal coordinate bond formation . Depending on the geometric placement of the donor atoms and on the flexibility of the ligand, the resulting coordination architecture can either assume a discrete often highly symmetric structure (such as polygons and polyhedra) or extend into a 1D, 2D, or 3D framework .…”

Section: Introdutionmentioning

confidence: 99%

From Ordinary to Extraordinary: Insights into the Formation Mechanism and pH-Dependent Assembly/Disassembly of Nanojars

Ahmed

Mezei

2016

Inorg. Chem.

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Nanojars are large (2 nm wide) anion-incarcerating coordination complexes of the composition [anion⊂{Cu(μ-OH)(μ-pz)}n] (n = 27-36), formed by the self-assembly of simple Cu(2+), HO(-), and pyrazolate (pz(-) = C3H3N2(-)) ions in the presence of certain anions with large hydration energy (e.g., CO3(2-), SO4(2-), PO4(3-), HPO4(2-)). Nanojars display spectacular chemical properties, such as unparalleled anion binding strength and, as shown herein, extraordinary resistance to extreme alkalinities (10 M NaOH). To shed light on the mechanism of the self-assembly process leading to these distinctive constructs, we employed an array of complementary techniques including mass spectrometry, pH titration, UV-vis and NMR spectroscopies, chemical synthesis, and single-crystal X-ray diffraction. In the reaction of Cu(NO3)2, pyrazole, NaOH, and Na2CO3 in tetrahydrofuran (THF), the first major intermediate is a trinuclear copper pyrazolate complex, [Cu3(μ3-OH)(μ-pz)3(NO3)2(H2O)], which was separately isolated and characterized. As the THF-insoluble NaOH slowly reacts, the nitrate ions are gradually precipitated out as NaNO3 and replaced by hydroxide ions. The resulting species, [Cu3(μ3-OH)(μ-pz)3(OH)x(NO3)3-x](-) (x = 1-3), have unstable terminal Cu-OH groups and react with each other to yield OH-bridged units, such as [Cu3(μ3-OH)(μ-pz)3(NO3)2]2(μ-OH) and then [{Cu3(μ3-OH)(μ-pz)3(μ-OH)2}x(NaNO3)y(Na2CO3)z] oligomers. The Cu3(OH)3(pz)3 repeating units of these oligomers have the same composition as the [Cu(OH)(pz)]n (n = 3x) nanojars and rearrange to the final products, Na2[CO3⊂{Cu(μ-OH)(μ-pz)}n] (n = 27, 29, 31), while eliminating the last amounts of NaNO3. pH titration, UV-vis monitoring, and chemical synthesis also confirm the formation of the trinuclear intermediate, followed by its clean transformation to nanojars. While displaying an unusual stability to high pH, nanojars are sensitive to acids stronger than water, a property exploitable for the recovery of the incarcerated anion. On lowering the pH, nanojars first break down to trinuclear complexes and finally to copper ions and pyrazole. This process is fully reversible, and nanojars are reassembled as pH is increased.

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“…A particular symmetrical class comprises the so-called ferric wheels with 6, 8, 10, 12 and even 18 iron(III) ions [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Recently, we reported the template-mediated self-assembly of sixand eight-membered iron coronates {Na , [Fe 6 (L 1 ) 6 [47]. As in 1 and 2, the m 2 -O donors of the methyldiethanolamine ligands in 3a are structure determining.…”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Coordination Networks of Ferric Wheels, their Surface-supported Supramolecular Architectures and STM/STS Imaging

Ako

Maid

Sperner

et al. 2005

Supramolecular Chemistry

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Six-membered ferric wheels [Fe 6 Cl 6 (L 2 ) 6 ] were generated from the corresponding N-alkylsubstituted 19 (3e)}, calcium hydride and iron(III) chloride. Compound 3d was characterized by X-ray crystal structure analysis. The lipophilic tails of 3d interdigitate to create strands that, by lateral van der Waals interactions, pack to form 2D layers. The stacking of these sheets creates the final 3D architecture of the crystal. An elementary structure formation process of complex molecule 3d on highly oriented pyrolytic graphite (HOPG) was studied. Using scanning tunneling microscopy (STM) under ambient conditions, we succeeded in combining high-resolution topography mapping with simultaneous current -voltage characteristics (scanning tunneling spectroscopy, STS) measurements on single molecules deposited on HOPG surfaces. One of the most interesting results is that the location of the individual metal ions in their organic matrix is directly addressable by STS.

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Ligand and Metal Control of Self‐Assembly in Supramolecular Chemistry

Cited by 41 publications

References 225 publications

Training a Constitutional Dynamic Network for Effector Recognition: Storage, Recall, and Erasing of Information

Training a Constitutional Dynamic Network for Effector Recognition: Storage, Recall, and Erasing of Information

From Ordinary to Extraordinary: Insights into the Formation Mechanism and pH-Dependent Assembly/Disassembly of Nanojars

Metal–Organic Coordination Networks of Ferric Wheels, their Surface-supported Supramolecular Architectures and STM/STS Imaging

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