Synthesen mit anionischen Templaten

Vilar, Ramón

doi:10.1002/ange.200200551

Cited by 60 publications

(15 citation statements)

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“…[1][2][3][4][5][6][7][8][9][10][11][12] Recently, we developed the concept of Vernier templating-the use of noncommensurate combinations of templates and building blocks to direct the formation of cyclic oligomers, such that the number of binding sites in the product is the lowest common multiple of the numbers of sites in the template and the starting material. [1][2][3][4][5][6][7][8][9][10][11][12] Recently, we developed the concept of Vernier templating-the use of noncommensurate combinations of templates and building blocks to direct the formation of cyclic oligomers, such that the number of binding sites in the product is the lowest common multiple of the numbers of sites in the template and the starting material.…”

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confidence: 99%

Two Vernier‐Templated Routes to a 24‐Porphyrin Nanoring

Kondratuk¹,

Perdigão²,

O’Sullivan³

et al. 2012

Angew Chem Int Ed

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Dedicated to Professor Fraser Stoddart on the occasion of his 70th birthdayIngenious new template-directed strategies make it possible to synthesize an increasingly wide range of molecular architectures, which would otherwise be inaccessible. [1][2][3][4][5][6][7][8][9][10][11][12] Recently, we developed the concept of Vernier templating-the use of noncommensurate combinations of templates and building blocks to direct the formation of cyclic oligomers, such that the number of binding sites in the product is the lowest common multiple of the numbers of sites in the template and the starting material. [12d] This principle allows a small template to direct the formation of a much larger macrocycle. Previously, we illustrated this idea with the synthesis of a 12-porphyrin nanoring, c-P12, from a linear zinc porphyrin tetramer, l-P4, and a hexapyridyl template, T6.Here we report the synthesis of a 24-porphyrin ring, c-P24, by two Vernier-templated routes: a) coupling the linear porphyrin octamer l-P8 in the presence of hexapyridyl template T6, and b) coupling the linear porphyrin hexamer l-P6 in the presence of the octapyridyl template T8 (Scheme 1). The 24porphyrin nanoring can be prepared in yields of up to 25 %. It has a diameter of 10 nm, as confirmed by scanning tunneling microscopy (STM), and a molecular weight of 26 kDa, thus placing it in the size range of a typical protein. This flexible macrocycle can be locked into a planar p-conjugated conformation by the cooperative self-assembly of a 2:24 doublestrand complex with the linear diamine ligand 1,4diazabicyclo[2.2.2]octane (DABCO).The representation of the two routes to c-P24 in Scheme 1 overlooks the fact that complexes such as (l-P8) 3 ·(T6) 4 and c-P24·(T6) 4 have many possible isomers, as illustrated in Figure 1. However, the formation of these isomeric intermediates should not detract from the efficiency of the Vernier-templated synthesis, because removal of the template will convert all these isomers into the same c-P24 open ring (except for knotted structures, for example, Figure 1 d [13] ).Palladium-catalyzed oxidative coupling of the linear porphyrin octamer l-P8 [12a] in the presence of the hexapyridyl template T6 [12b,c] gave the expected product c-P24, together with the 16-porphyrin ring c-P16 [14] and linear polymers, all as complexes with T6. The polymeric by-products were removed Scheme 1. a) Vernier-templated synthesis of the nanoring c-P24. Reagents: 1) [PdCl 2 (PPh 3 ) 2 ], CuI, benzoquinone, iPr 2 NH; 2) pyridine. b) Structures of T6, T8, and c-P24; Ar = 3,5-bis(octyloxy)phenyl. Figure 1. Four examples of possible isomers of c-P24·(T6) 4 . [13]

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Two Vernier‐Templated Routes to a 24‐Porphyrin Nanoring

Kondratuk¹,

Perdigão²,

O’Sullivan³

et al. 2012

Angew Chem Int Ed

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“…Many inorganic polyatomic anions have been utilized in the construction of finite assemblies, and the size and shape of the directing anions dictate the geometry and connectivity of the final structures. [2][3][4] Recently, we developed a facile template approach for the synthesis of high-nuclearity silver(I) alkynyl clusters, [5] and a variety of silver clusters have been isolated with spherical chloride, triangular carbonate, and tetrahedral chromate templates. [5,6] Considering that polyoxometalates (POMs) are large oxo anions of group 6 or 5 elements and have good affinity to silver ions, [7][8][9][10] we attempted to incorporate POMs into silver alkynyl systems.…”

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confidence: 99%

A Giant Silver Alkynyl Cage with Sixty Silver(I) Ions Clustered around Polyoxometalate Templates

2010

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Chemical templates play an important role in the formation of complex systems containing multiple components which have well-defined finite structures of large size, sometimes on the nanoscale. [1] Compared with the widely studied templation by cations and neutral compounds, anion templation has been much less developed in synthetic chemistry. However, it has been increasingly recognized that anionic templates are very useful in preparing metalla-assemblies. Many inorganic polyatomic anions have been utilized in the construction of finite assemblies, and the size and shape of the directing anions dictate the geometry and connectivity of the final structures. [2][3][4] Recently, we developed a facile template approach for the synthesis of high-nuclearity silver(I) alkynyl clusters, [5] and a variety of silver clusters have been isolated with spherical chloride, triangular carbonate, and tetrahedral chromate templates. [5,6] Considering that polyoxometalates (POMs) are large oxo anions of group 6 or 5 elements and have good affinity to silver ions, [7][8][9][10] we attempted to incorporate POMs into silver alkynyl systems. The advantages of employing a clusterlike POM anion as template lie not only in increasing the nuclearity of silver clusters but also in introducing new redox centers that can profoundly affect the physical properties of the cluster.We expected that it would be difficult to obtain structural information on the products, because of the insolubility of silver polyoxometalates. Fortunately, we found that the solvothermal method worked well in our silver alkynyl/ POM system, and giant silver cluster [Ag 60 (Mo 6 O 22 ) 2 (tBuC C) 38 ](CF 3 SO 3 ) 6 (1), which is the largest silver alkynyl cluster so far, was isolated by using the POM templating strategy under solvothermal conditions. Surprisingly, incorporation of polyoxomolybdate stabilizes the silver cluster and makes it insensitive to light. Furthermore, cyclovoltammetric studies revealed that electronic communication exists between POM core and Ag 60 shell. Herein we report the synthesis, structure, and redox behavior of this novel POM-templated silver cluster.The reaction of tBuCCAg with AgCF 3 SO 3 in methanol in the presence of (NH 4 ) 6 Mo 7 O 24 led to the formation of a white solid, which was then solvothermally treated to give 1 as colorless crystals in moderate yield. A similar procedure with AgBF 4 in place of AgCF 3 SO 3 gave a compound isostructural to 1.The composition of 1 is supported by elemental analysis. An IR band at 2013 cm À1 confirmed the presence of the CC group in 1; the band at 823 cm À1 is assigned to the MoÀO vibration; and the bands at 1159 and 1046 cm À1 are due to the triflate anion. The structure of 1 was established by singlecrystal X-ray structure analysis, [11] which revealed that the cationic part of 1 is a giant cluster consisting of 60 silver atoms peripherally bridged by 38 alkynyl ligands with double templation by two in-situ-generated Mo 6 O 22 8À anions. The bulk of the sample was confirmed to be uniform by...

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“…Metal-directed self-assembly has in recent years become a powerful tool for the construction of systems containing cavities which possess intrinsic physical and chemical properties that are promising for the creation of new materials and new metal-based drugs [1][2][3][4][5][6][7][8][9][10]. More recently, non-covalent weak molecular forces capable of connecting these metallic subunits into looser and more intriguing supramolecular infrastructures (such as hydrogen bonds, van der Waals forces, non-bonded contacts, and pi-pi interactions) have been widely investigated in structural and material chemistry, biology, and the pharmaceutical sciences [11][12][13][14][15][16].…”

Section: B S T R a C Tmentioning

confidence: 99%