A New Functional Bis(<i>m</i>-phenylene)-32-crown-10-Based Cryptand Host for Paraquats

Pederson, Adam M.-P.; Vetor, Ryan C.; Rouser, Mason A.; Huang, Feihe; Slebodnick, Carla; Schoonover, Daniel V.; Gibson, Harry W.

doi:10.1021/jo8006368

Cited by 41 publications

(11 citation statements)

References 39 publications

(11 reference statements)

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“…Through analysis of CPK models and crystal structures, host molecules have been advanced to highly evolved crown‐based pyridyl cryptands, for example 5 and 6 . However, little improvement has been offered in way of the paraquat guest, the standard being dimethyl paraquat as the PF 6 salt ( 7 ) which displays reasonable association constants with various crown ethers[2–5] and analogous cryptands [4] …”

Section: Introductionmentioning

confidence: 99%

Improved complexation of paraquats with crown ether‐based pyridyl cryptands

Price

Slebodnick

Gibson

2017

Heteroatom Chemistry

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The commonly used paraquat guest N,N′‐dimethyl‐4,4′‐bipyridinium bis(hexafluorophosphate) (7) was targeted for structural alterations to improve the binding constants with crown ethers and cryptands. The association constant was improved by one order of magnitude (to Ka = 1.00 × 106 mol L−1) with the dibenzo‐30‐crown‐10 pyridyl cryptand host 5 by changing the N‐methyl groups to benzyl and the counterions from PF6 to TFSI, that is, 11. Moreover, through addition of a p‐bromobenzyloxy moiety on the 4‐position of the pyridyl ring of cryptand 18, an association constant of Ka = 5.35 × 106 mol L−1 was achieved with paraquat 11.

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Section: Introductionmentioning

confidence: 99%

Improved complexation of paraquats with crown ether‐based pyridyl cryptands

Price

Slebodnick

Gibson

2017

Heteroatom Chemistry

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“…In order to improve complexation with paraquat derivatives, we introduced cryptands that have proved to be much better hosts than simple crown ethers [14][15][16][17][18]. Most of these reported cryptand/paraquat complexes are only pseudorotaxane-like because paraquat is not long enough to extend outside of the cavities of cryptands [14][15][16][17][18]. Here we report a "true" cryptand/paraquat [2]pseudorotaxane in which the paraquat derivative guest is long enough to extend from the cavity of the host.…”

Section: Introductionmentioning

confidence: 93%

“…Crown ethers [7][8][9][10][11][12][13], cryptands [14][15][16][17][18], cyclodextrins [19][20][21][22], cucurbit[n]urils [23][24][25], and calix[n]arenes [26,27] have been universally used as hosts to fabricate various supramolecular assemblies, which have great potential in molecular devices, chemosensors, and nano materials. Paraquat ( Figure 1) and its derivatives (N,N′-dialkyl-4,4′-bipyridinium salts) are common guests in the field of pseudorotaxanes and rotaxanes [28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

“…They have been widely used to construct numerous host-guest complexes with bis(p-phenylene)-34-crown-10 (BPP34C10, 3) derivatives and bis(m-phenylene)-32-crown-10 derivatives (BMP32C10) [28][29][30][31]. In order to improve complexation with paraquat derivatives, we introduced cryptands that have proved to be much better hosts than simple crown ethers [14][15][16][17][18]. Most of these reported cryptand/paraquat complexes are only pseudorotaxane-like because paraquat is not long enough to extend outside of the cavities of cryptands [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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A new cryptand/paraquat [2]pseudorotaxane

Zheng

Huang

et al. 2010

Sci. China Chem.

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A new cryptand/paraquat [2]pseudorotaxane and its crown ether analog were synthesized and characterized by proton NMR, mass spectrometry, and single crystal X-ray analysis. The Job plots based on proton NMR data demonstrated that both the complex between cryptand 1 and paraquat derivative 2a and the complex between bis(p-phenylene)-34-crown-10 (3) and paraquat derivative 2b have 1:1 stoichiometry in solution. The apparent association constants (K a,exp ) of 1·2a and 3·2b calculated for 1:1 complexes were 1.4 ( 0.2)  10 4 and 4.7 ( 0.5)  10 2 M 1 , respectively. X-ray analysis showed that 1·2a is stabilized by ten hydrogen bonds and face-to-face -stacking interactions in the solid state, while 3·2b is stabilized by four hydrogen bonds and face-to-face -stacking interactions. As well as in the X-ray structure of 1·2c, a water molecule acts as a hydrogen bridge between the -pyridinium protons of 2a and the ether oxygen atoms of 1 in 1·2a. The successful preparation of 1·2a demonstrated that the tert-butyl group is not big enough to be a stopper for rotaxanes based on 1. host-guest system, self-assembly, pseudorotaxane, cryptand, paraquat

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“…Work in the crown ether area illustrates this progress. The crown ether hosts provided modest binding strengths ( K a = 10 2 to 10 3 mol −1 ) with cationic guests, eg, secondary ammonium and bipyridinium salts,[2] but these were supplanted by the higher binding ( K a ≥ 10 5 mol −1 with bipyridinium guests) cryptand hosts [3]. Over time, highly efficient syntheses have been developed for the crown ethers[1g],[3d],[4] and the derived cryptands [3h]…”

Section: Introductionmentioning

confidence: 99%

“Reverse” pyridyl cryptands as hosts for viologens

Pederson

Price

Schoonover

et al. 2018

Heteroatom Chemistry

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Two new cryptands, 2 and 4, were prepared from bis(m‐phenylene)‐32‐crown‐10 (BMP32) 5,5'‐diacid chloride and dibenzo‐30‐crown‐10 (DB30) 4,4'‐diacid chloride, respectively, by reaction with pyridine‐2,6‐dimethanol. The resultant cryptands 2 and 4 have the ester moieties reversed from the previously reported isomers, 1 and 3. These “reverse” cryptands display lower association constants with viologen derivatives than the original cryptands; this is rationalized by the conjugation of the ester moieties with the aromatic rings, which reduces their electron‐donating properties and offsets the increased basicity of the pyridyl nitrogen atoms. The crystal structure of the BMP32‐based cryptand 2 indeed confirms the coplanarity of the ester and aromatic moieties and indicates that, as a result, the available cavity is quite small and that the pyridyl nitrogen atom points away from the cavity.

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A New Functional Bis(m-phenylene)-32-crown-10-Based Cryptand Host for Paraquats

Cited by 41 publications

References 39 publications

Improved complexation of paraquats with crown ether‐based pyridyl cryptands

Improved complexation of paraquats with crown ether‐based pyridyl cryptands

A new cryptand/paraquat [2]pseudorotaxane

“Reverse” pyridyl cryptands as hosts for viologens

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