Chemical Topology: Complex Molecular Knots, Links, and Entanglements

Forgan, Ross S.; Sauvage, Jean Pierre; Stoddart, J. Fraser

doi:10.1021/cr200034u

Cited by 807 publications

(599 citation statements)

References 309 publications

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“…There have been previous examples of stimuli-responsive molecular cages (41,61) and baskets (45)(46)(47)(48)(49)(50)(51)(52)62) for targeted delivery; however, most of the systems lack the spontaneous spectral or other kinds of responses to facilitate instant signal detection. In contrast, the guest release and capture processes of the current molecular rectangles are capable of being probed by UV-vis absorption and emission titration studies.…”

Section: Resultsmentioning

confidence: 99%

Multiaddressable molecular rectangles with reversible host–guest interactions: Modulation of pH-controlled guest release and capture

Chan

Lam

Tanaka

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

122

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A series of multiaddressable platinum(II) molecular rectangles with different rigidities and cavity sizes has been synthesized by endcapping the U-shaped diplatinum(II) terpyridine moiety with various bisalkynyl ligands. The studies of the host-guest association with various square planar platinum(II), palladium(II), and gold(III) complexes and the related low-dimensional gold(I) complexes, most of which are potential anticancer therapeutics, have been performed. Excellent guest confinement and selectivity of the rectangular architecture have been shown. Introduction of pH-responsive functionalities to the ligand backbone generates multifunctional molecular rectangles that exhibit reversible guest release and capture on the addition of acids and bases, indicating their potential in controlled therapeutics delivery on pH modulation. The reversible host-guest interactions are found to be strongly perturbed by metal-metal and π-π interactions and to a certain extent, electrostatic interactions, giving rise to various spectroscopic changes depending on the nature of the guest molecules. Their binding mode and thermodynamic parameters have been determined by 2D NMR and van't Hoff analysis and supported by computational study. noncovalent interactions | platinum complex | luminescence T he study of metal-metal interactions has drawn enormous attention since the past two decades because of the intriguing spectroscopic and photophysical properties arising from the close proximity of the metal centers (1, 2). Square planar d 8 platinum(II) complexes with coordination unsaturation are one of the important classes of metal complexes that have been extensively explored because of their capability to exhibit metalmetal interactions and display rich photophysical properties (3-26). Platinum(II) terpyridine complexes have been found to exhibit rich polymorphism in the solid state (16)(17)(18)(19)(20) owing to their square planar coordination geometry, which permits facile access to Pt(II)···Pt(II) interactions as well as π-π interactions between the chromophores. It was not until 2001 that the first successful synthesis of platinum(II) terpyridine alkynyl complexes, which possess enhanced solubility and luminescence compared with the chloro counterpart, was reported (16). Additional efforts have been devoted to the use of the system to respond to external stimuli, such as variation in solvent composition (17, 18), pH (19, 20), temperature (21, 22), addition of ionic (24-26), and polymeric species (27,28), in which spectral changes induced by strong Pt(II)···Pt(II) and π−π interactions have been displayed.In the past few decades, enormous efforts have been devoted to the construction of molecular architectures by fusing the organic framework to the transition metal centers through selfassembly processes (29-57). There has been continuous interest in the construction of stimuli-responsive metallosupramolecular architectures with diverse sizes, shapes, and symmetries to rationalize the criteria for molecular recognition and impa...

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Section: Resultsmentioning

confidence: 99%

Multiaddressable molecular rectangles with reversible host–guest interactions: Modulation of pH-controlled guest release and capture

Chan

Lam

Tanaka

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

122

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“…[25] Other groups have also been interested in chemical topology.I mpressive topologies at the molecular level have been reported by the research teams of Stoddart, Leigh, and Siegel, just to cite afew. [26][27][28] …”

Section: Chemical Topologymentioning

confidence: 99%

From Chemical Topology to Molecular Machines (Nobel Lecture)

2017

Self Cite

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To a large extent, the field of “molecular machines” started after several groups were able to prepare, reasonably easily, interlocking ring compounds (named catenanes for compounds consisting of interlocking rings and rotaxanes for rings threaded by molecular filaments or axes). Important families of molecular machines not belonging to the interlocking world were also designed, prepared, and studied but, for most of them, their elaboration was more recent than that of catenanes or rotaxanes. Since the creation of interlocking ring molecules is so important in relation to the molecular machinery area, we will start with this aspect of our work. The second part will naturally be devoted to the dynamic properties of such systems and to the compounds for which motions can be directed in a controlled manner from the outside, that is, molecular machines. We will restrict our discussion to a very limited number of examples which we consider as particularly representative of the field.

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“…The interaction between mathematical topology, in particular topological graph theory, and the investigation of chemical structures is a rich area ( [1][2][3][4][5][6][7] and the references therein). Topological graph theory studies embeddings of graphs in 3-space.…”

Section: Introductionmentioning

confidence: 99%