Intramolecular π-Stacking Interaction in a Rigid Molecular Hinge Substituted with 1-(Pyrenylethynyl) Units

Nandy, Ritesh; Subramoni, Mahadevan; Varghese, Babu; Sankararaman, S.

doi:10.1021/jo062173y

Cited by 98 publications

(62 citation statements)

References 36 publications

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“…It is hence reasonable to assume that the shielding of the hydrogen atoms borne by the fluorene units, in 2 a , results from their face‐to‐face geometry and not from their different indenofluorenyl central core. Indeed, transannular π–π interactions are usually accompanied by high field shifts in 1 H NMR spectra9, 32–35 and have been observed in different systems such as for example acridylnaphthalene,32 paracyclophane,35 polyfluorene,9, 34 thiophene derivatives15 and tetrapyrenyl compounds 36. The t Bu‐substituted derivatives 1 b and 2 b rigorously present the same behavior as that reported above for 1 a and 2 a (Table S2).…”

Section: Resultssupporting

confidence: 75%

Violet‐to‐Blue Tunable Emission of Aryl‐Substituted Dispirofluorene–Indenofluorene Isomers by Conformationally‐Controllable Intramolecular Excimer Formation

Thirion

Poriel

Métivier

et al. 2011

Chemistry A European J

114

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Two series of DiSpiroFluorene-IndenoFluorene (DSF-IF) positional isomers, namely dispiro[2,7-diarylfluorene-9',6,9'',12-indeno[1,2-b]fluorenes], (1,2-b)-DSF-IFs 1 and dispiro[2,7-diarylfluorene-9',6,9'',12-indeno[2,1-a]fluorenes], (2,1-a)-DSF-IFs 2 have been synthesized. These violet-to-blue fluorescent emitters possess a 3π-2spiro architecture, which combines via two spiro links two different indenofluorene cores, that is, (1,2-b)-IF or (2,1-a)-IF and 2,7-substituted-diaryl-fluorene units. Due to their different geometric profiles, the two families of positional isomers present drastically different properties. The marked difference observed between the properties of (1,2-b)-DSF-IF (1) and (2,1-a)-DSF-IF (2) is discussed in terms of intramolecular π-π interactions occurring in (2,1-a)-DSF-IF (2) leading to conformationally-controllable intramolecular excimer formation. Indeed, the original geometry of the (2,1-a)-DSF-IF (2) family, with face-to-face "aryl-fluorene-aryl" moieties, leads to remarkable excimer emission through intramolecular π-π interactions in the excited state. Furthermore, the emission wavelengths can be gradually modulated by the control of the steric hindrance between the adjacent substituted phenyl rings. Thus, through a comparative and detailed study of the (1)H NMR, electrochemical and photophysical properties of DSF-IFs 1 and 2, we have evidenced the intramolecular π-π interactions occurring between the two "aryl-fluorene-aryl" moieties in the ground state and in the excited state. These properties have been finally correlated to the spectacular conformational change modeled by density functional theory (DFT) calculations. Indeed, the two "aryl-fluorene-aryl" moieties switch from a staggered conformation in the ground state to an eclipsed conformation in the first excited state.

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Section: Resultssupporting

confidence: 75%

Violet‐to‐Blue Tunable Emission of Aryl‐Substituted Dispirofluorene–Indenofluorene Isomers by Conformationally‐Controllable Intramolecular Excimer Formation

Thirion

Poriel

Métivier

et al. 2011

Chemistry A European J

114

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“…Upon increasing the temperature of a solution of 3, the aromatic resonances shifted towards higher field, which-as has been discussed previously for other aromatic systems-is consistent with p-p interactions being disrupted as the temperature is increased. [14] A similar effect was observed when the 1 H NMR spectra were recorded at various concentrations: upon decreasing the concentration, a high field shift of the aromatic resonances was observed, consistent with the expected reduction in p-p interactions at lower concentrations. This shows that complex 3 displays p-p interactions in DMSO solution, which is generally a good indication of a complexs potential to interact via p-p stacking with DNA.…”

supporting

confidence: 69%

A Cyclometallated Platinum Complex as a Selective Optical Switch for Quadruplex DNA

Suntharalingam

Łęczkowska

Furrer

et al. 2012

Chemistry A European J

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Hits the spot: A cyclometalled platinum(II) complex with a substituted phenanthroline ligand is reported. The complex has high in vitro affinity for quadruplex DNA and upon binding its emission is switched on. The complex can be easily delivered to the cell by using a metallo-cage as a carrier (see illustration). By means of confocal microscopy, it is shown that the complex is released inside the cell, penetrates the nucleus and localises in the nucleoli.

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“…These upfield shits indicate that both pyrene units in compounds 1 and 2 would be closely located, because it is well-established that π-stacking interactions between aromatic rings result in shielding of the protons due to the anisotropy of the ring current effect. 28,29 Furthermore, all pyrene protons in compound 2 were remarkably shifted to a higher magnetic field than those in compound 1. These results and fluorescence spectra described above reasonably indicate that the pyrene units in compound 2 would be located more closely than that in compound 1. .…”

Section: Issn 1551-7012mentioning

confidence: 98%

Effective Na+ fluorescent sensing by new podand-type receptor connecting two pyrene units and diphenyl ether

Nishimura¹,

Takemura²,

Arai³

2009

Arkivoc

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A new podand-type receptor for Na + detection has been synthesized by connecting two 1-pyrenecarbonylmethyl groups with two hydroxy groups of 2,2'-dihydroxydiphenyl ether. With the addition of Na + in the range of 20-200 µM, the increasing monomer emission (423 nm) and the decreasing excimer emission (524 nm) of pyrene were observed. In contrast with the receptor, the fluorescence spectra of the corresponding compound obtained from 2,2'-dihydroxydiphenylmethane are only slightly affected by the addition of Na + .

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Intramolecular π-Stacking Interaction in a Rigid Molecular Hinge Substituted with 1-(Pyrenylethynyl) Units

Cited by 98 publications

References 36 publications

Violet‐to‐Blue Tunable Emission of Aryl‐Substituted Dispirofluorene–Indenofluorene Isomers by Conformationally‐Controllable Intramolecular Excimer Formation

Violet‐to‐Blue Tunable Emission of Aryl‐Substituted Dispirofluorene–Indenofluorene Isomers by Conformationally‐Controllable Intramolecular Excimer Formation

A Cyclometallated Platinum Complex as a Selective Optical Switch for Quadruplex DNA

Effective Na+ fluorescent sensing by new podand-type receptor connecting two pyrene units and diphenyl ether

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