Transition Metal‐Incorporating Catenanes

Fujita, Makoto

doi:10.1002/9783527613724.ch04

Cited by 6 publications

(2 citation statements)

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“…The modified concepts were combined with the concepts of proligands and promolecules 87 so as to develop Fujita's proligand method. An alternative formulation of Fujita's proligand method was demonstrated 88 in terms of the sphericity concept introduced directly by the concept of mandalas. 69,71 From one point of view, Fujita's proligand method is regarded as an extension of Fujita's USCI approach by taking account of the concept of cycle indices due to Pólya's theorem.…”

Section: Fujita's Proligand Method;mentioning

confidence: 99%

Numbers of Alkanes and Monosubstituted Alkanes. A Long-Standing Interdisciplinary Problem over 130 Years

Fujita¹

2009

Bulletin of the Chemical Society of Japan

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Enumeration of alkanes and monosubstituted alkanes with given carbon contents has been investigated by chemists and mathematicians over 130 years and solved recently by the present author in agreement with stereochemical and mathematical requirements. In the present account, the advances of the methodologies for solving the problem are discussed from an interdisciplinary point of view between chemistry and mathematics. Historical backgrounds of the interdisciplinary problem are introduced by emphasizing three epochs, i.e., the first epoch marked by Cayley, a mathematician (the 1870s), the second epoch by Pólya, a mathematician (the 1930s), and the third epoch by Fujita, an organic chemist (the first decade of this century). Among them, the accomplishments of the second epoch and those of the third epoch are compared in detail, where graphs (trees, rooted trees, or planted trees) and three-dimensional (3D) objects as mathematical terms are correlated to constitutions (two-dimensional structures) and 3D structures as chemical terms.After an introduction to terminology on isomerism and stereoisomerism, alkanes and monosubstituted alkanes are enumerated as graphs or constitutional isomers by Pólya's theorem, while they are alternatively enumerated as 3D objects or 3D-structural isomers by Fujita's proligand method. The present account of the long-standing problem would provide readers with a hint or a motivation for pursuing a concrete route to "the Heavens of Fujita," which have caricatured stereochemical and mathematical barriers lying in wait for them.

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Section: Fujita's Proligand Method;mentioning

confidence: 99%

Numbers of Alkanes and Monosubstituted Alkanes. A Long-Standing Interdisciplinary Problem over 130 Years

Fujita¹

2009

Bulletin of the Chemical Society of Japan

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“…Quantitative self-assembly of a coordination [2]catenane has been described by Fujita with Pd 2+ and Pt 2+ , 12 showing that simple rings and [2]catenane are in equilibrium, which can be influenced by the concentration of the participating species. The mechanism to obtain such a [2]catenane is proposed as a reversible ring formation and reopening processes during which interpenetration can occur.…”

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confidence: 99%

The First Two-Dimensional Polycatenane: A New Type of Robust Network Obtained by Ag-Connected One-Dimensional Polycatenanes

Sague

Fromm

2006

Crystal Growth & Design

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ABSTRACT:The two-dimensional structure described here is the first example of a coordination polymer structure consisting of onedimensional polycatenanes fused via silver ions. It can be derived from simple rings consisting of two silver ions and two ligand molecules.In the past decade, metal-organic frameworks (MOFs) have turned out to be a fascinating pool for structure design, synthesis, and applications in numerous fields such as catalysis, magnetism, luminescence, or gas storage. 1 By judicious choice of the building units, (i) the ligand concerning rigidity, form, and donor functions and (ii) the metal ion with its capacity to accept coordination by a given number of ligands, low-dimensional frameworks can be designed and constructed. 2 However, polymorphism and supramolecular isomerism occur more frequently the more flexible both building blocks are. 3 Porous frameworks with large empty spaces are a big challenge as interpenetration can occur. 4 We are interested in using a flexible system with a metal ion such as Ag + and a multitopic ligand Ln (n ) 1, 2 ...) (Scheme 1) with N-and O-donor atoms to synthesize adaptable MOFs, which are able to link a second metal ion type. With the shorter ligand L1, n ) 1, a number of one-dimensional (1D) structural motifs could be characterized, 5-7 whereas with L2, a zero-dimensional metallacycle with two Ag + ions and two L2 molecules, as well as a 1D helix, could be reported. 8 Whereas with this ligand type Ln and Ag + , only coordination numbers of two for Ag + with respect to the nitrogen atoms of Ln were reported so far; 6-9 we now report a new type of network derived from the polycatenation of a 1D chain of fused metallacycles in which Ag + has a coordination number of four with respect to L2. The obtained structure is an unprecedented example of linked polycatenane chains to give a very robust two-dimensional (2D) network of high density.Results and Discussion. The reaction of L2 with AgClO 4 in the ratio 1:1 yields the 2:2 metallacycle or a 1D helix as a supramolecular isomer. 8 With AgPF 6 , exo-linked 2:2 metallacycles of the composition [Ag(L2)] 2 (PF 6 ) 2 ‚THF (1) (THF ) tetrahydrofuran) are obtained. The ratio L2/Ag + of 2:1 yields, after a long reaction time of over two months, a very dense and highly catenated structure of composition [Ag(L2) 2 ](PF 6 ) (2) representing a missing link in polycatenation motifs.1 crystallizes in the triclinic space group P1 h (No. 2), 15 with one molecule per unit cell. Two ligands L2 adopt a U-shape and coordinate to two metal ions to yield a cyclic structure, with Ag-N distances of 2.136(4) and 2.143(4) Å, and an N1-Ag-N2 angle of 169.31(19)° (Figure 1). The two PF 6 -anions bridge two silver ions belonging to the same ring; the Ag-F bonds are weak with distances of 2.960(7) and 3.092(5) Å. Because of this arrangement, the Ag-Ag distance within the ring is rather long at 5.213(13) Å, and π-stacking within the ring is thus excluded with pyridine rings offset from each other by 5.1218 Å.The rings in 1 are arranged parallel...

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N⋅⋅⋅Br Halogen Bonding: One‐Dimensional Infinite Chains through the Self‐Assembly of Dibromotetrafluorobenzenes with Dipyridyl Derivatives

Santis

Forni

Liantonio

et al. 2003

Chemistry A European J

140

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The N.Br halogen bonding drives the self-assembly of 1,4-dibromotetrafluorobenzene (1 a) and its 1,3 or 1,2 analogues (1 b,c, respectively) with dipyridyl derivatives 2 a,b. The isomeric supramolecular architectures 3 a-f are obtained as cocrystals that are stable in the air at room temperature. The solid-state features of these 1D infinite chains 3 have been fully characterized by single-crystal X-ray, Raman, and IR analyses. The occurrence of N.Br halogen bonding in solution has been detected with (19)F NMR spectroscopy. The N.Br halogen bonding is highly selective and directional and the geometry of the single strands of noncovalent copolymers 3 is programmed by the geometry of halogen-bonding donor and acceptor sites on the starting modules. The composition and topology of the instructed networks can be predicted with great accuracy. Experiments of competitive cocrystal formation established the strength of the N.Br interaction relative to other halogen bondings and the ability of different modules 1 to be involved in site-selective supramolecular syntheses.

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Transition Metal‐Incorporating Catenanes

Cited by 6 publications

References 46 publications

Numbers of Alkanes and Monosubstituted Alkanes. A Long-Standing Interdisciplinary Problem over 130 Years

Numbers of Alkanes and Monosubstituted Alkanes. A Long-Standing Interdisciplinary Problem over 130 Years

The First Two-Dimensional Polycatenane: A New Type of Robust Network Obtained by Ag-Connected One-Dimensional Polycatenanes

N⋅⋅⋅Br Halogen Bonding: One‐Dimensional Infinite Chains through the Self‐Assembly of Dibromotetrafluorobenzenes with Dipyridyl Derivatives

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