Association constants of organic charge-transfer complexes derived from optical and from nuclear magnetic resonance chemical shift measurements; the presence of termolecular complexes

Dodson, Bryan J.; Foster, R.; Bright, A.; Foreman, M. I.; Gorton, J. E.

doi:10.1039/j29710001283

Cited by 34 publications

(24 citation statements)

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“…To take the experimental artefacts of nonspecific complex formation, [24] such as nonlinearity [25] or self-aggregation, [26] into account, the validity of the Lambert-Beer law, that is, a linear dependence of absorbance from the solute's concentration, was tested for pure solutions of host 7 in the appropriate concentration regime within a first set of experiments. Surprisingly .…”

Section: Host-guest Complex Formationmentioning

confidence: 99%

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Bredenkötter

Grzywa

Alaghemandi

et al. 2014

Chemistry A European J

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The synthesis of a stereochemically pure concave tribenzotriquinacene receptor (7) for C60 fullerene, possessing C3 point group symmetry, by threefold condensation of C2 -symmetric 1,2-diketone synthons (5) and a hexaaminotribenzotriquinacene core (6) is described. The chiral diketone was synthesized in a five-step reaction sequence starting from C2h -symmetric 2,6-di-tert-butylanthracene. The highly diastereo-discriminating Diels-Alder reaction of 2,6-di-tert-butylanthracene with fumaric acid di(-)menthyl ester, catalyzed by aluminium chloride, is the relevant stereochemistry introducing step. The structure of the fullerene receptor was verified by (1)H and (13)C NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. VCD and ECD spectra were recorded, which were corroborated by ab initio DFT calculations, establishing the chiral nature of 7 with about 99.7 % ee, based on the ee (99.9 %) of the chiral synthon (1). The absolute configuration of 7 could thus be established as all-S [(2S,7S,16S,21S,30S,35S)-(7)]. Spectroscopic titration experiments reveal that the host forms 1:1 complexes with either pure fullerene (C60) or fullerene derivatives, such as rotor 1'-(4-nitrophenyl)-3'-(4-N,N-dimethylaminophenyl)-pyrazolino[4',5':1,2][60]fullerene (R). The complex stability constants of the complexes dissolved in CHCl3/CS2 (1:1 vol. %) are K([C60 ⊂7]) = 319(±156) M(-1) and K([R⊂7]) = 110(±50) M(-1). With molecular dynamics simulations using a first-principles parameterized force field the asymmetry of the rotational potential for [R⊂7] was shown, demonstrating the potential suitability of receptor 7 to act as a stator in a unidirectionally operating nanoratchet.

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Section: Host-guest Complex Formationmentioning

confidence: 99%

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Bredenkötter

Grzywa

Alaghemandi

et al. 2014

Chemistry A European J

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“…In addition, the Job's plots were symmetrical on either side s f the maxima. This suggests an absence of termolecular complexes (12). While this does not rule out the possibility of the formation of higher compiexes in these systems, it does mean, that over the range of experimental concentrations used in the present study, the 1 : 1 complex clearly predominates.…”

Section: Introductionmentioning

confidence: 65%

A Study of the Donor Properties of the Phenoxachalcogenines.: I. Tetracyanoethylene and Chloranil as Acceptors

Heller¹,

Zingaro²,

Meyers³

1974

Can. J. Chem.

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Can. J. Chem. 52.3814 (1 974).The phenoxachalcogenines have been studied as donors toward tetracyanoethylene (TCNE) as the acceptor. It was found that the thermodynamic values for the interactions show no significant trends when the chalcogenine atom is varied from Te to Se to S to 0. For the four 1 : 1 complexes studied, the following average values for the thermodynamic properties here obtained at 20 ' C (the total range for each quantity is given in parentheses):

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“…While we do not have the data, we can make an estimate from data in the literature. In cases where both 1:l and 1:2 molecular complexes have been shown to exist and their values have been determined, K2 is usually less than K1 (15). In addition it would be expected that due to saturation, the effect of substituents on K2 would be smaller.…”

Section: Resultsmentioning

confidence: 99%

Influence of alkene structure on the formation constants of alkene–ICl molecular complexes

Sçhmid¹,

Gordon²

1986

Can. J. Chem.

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The experimentally determined rate law for the addition of IC1 to 22 alkenes in CC14 at 25OC under conditions of (alkene)o > > (ICl)o is -d(ICl)/dt = k,,,(alkene)o(~~1)3/{l + C2(alkene)o} 3. The constant C2 is shown to be equal to K,,, which is a measure of the formation constant or constants of the molecular complexes in this system. Under the experimental conditions used, C2 is a good approximation of the formation constant of the 1:l alkene-IC1 molecular complex. Thus the values of C2 obtained allow an estimate of the effect of alkene structure on the formation constant of the first molecular complex involved in this addition reaction. The contribution of the effect of substituents on C2 is estimated to be approximately 24% of the overall change in rate due to change in the alkene structure. GEORGE H. SCHMID et JAMES W. GORDON. Can. J . Chem. 64, 2171 (1986) Operant dans le CC14, a 25°C et dans des conditions ou la ( a l~e n e )~ >> (ICl)o, on a dCterminC expkrimentalement que la loi de vitese pour l'addition du ICl sur 22 alcknes est dCfinie par 1'Cquation -d(ICl)/dt = k,,,(al~kne)~(1C1)~/{1 + ~~( a l c k n e )~}~. On dCmontre que la constante C2 est Cgale a K,,, qui est une mesure de la constante de formation ou des constantes des complexes molCculaires impliquCs dans ce systeme. Dans les conditions experimentales utilisCes, C2 est une bonne approximation de la constante de formation du complexe molCculaire 1 : 1 alcene/ICl. Les valeurs de C2 obtenues permettent donc dlCvaluer I'effet de la structure de l'alckne sur la constante de formation du premier complexe molCculaire impliquC dans cette reaction d'addition. On a Cvalut que la contribution de l'effet des substituants sur Cz est Cgale a environ 24% du changcmcnt global dans la vitesse du a un changement dans la structure de l'alcene.[Traduit par la revue]There is ample evidence in the literature (1-3) that molecular complexes or charge transfer complexes (CTC) as they are also called are involved on the reaction pathway prior to the rate determining step in electrophilic additions of bromine, chlorine, and iodine monochloride to alkenes. These complexes are defined according to Mulliken as o-T CTC (4).The existence of one or more complexes prior to the rate determining step introduces a complication in the interpretation of linear free energy relationships in electrophilic additions of bromine to alkenes because a change in alkene structure affects not only the rate determining step but also the value of the formation constant of the CTC. Thus the value of p obtained from such rate data is the sum of p for the formation of the complex or complexes and p for the rate determining step.Based upon data from CTC formed between ketones and bromine, it was concluded that the effect of structure on the formation constants of the CTC is much smaller than the kinetic substituent effect. Consequently, it was assumed that p for the formation constant of the CTC is negligible as compared to p for the rate determining step (5). While values of formation constants ...

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Association constants of organic charge-transfer complexes derived from optical and from nuclear magnetic resonance chemical shift measurements; the presence of termolecular complexes

Cited by 34 publications

References 0 publications

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

A Study of the Donor Properties of the Phenoxachalcogenines.: I. Tetracyanoethylene and Chloranil as Acceptors

Influence of alkene structure on the formation constants of alkene–ICl molecular complexes

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Association constants of organic charge-transfer complexes derived from optical and from nuclear magnetic resonance chemical shift measurements; the presence of termolecular complexes

Cited by 34 publications

References 0 publications

Tribenzotriquinacene Receptors for C60 Fullerene Rotors: Towards C3 Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Tribenzotriquinacene Receptors for C60 Fullerene Rotors: Towards C3 Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

A Study of the Donor Properties of the Phenoxachalcogenines.: I. Tetracyanoethylene and Chloranil as Acceptors

Influence of alkene structure on the formation constants of alkene–ICl molecular complexes

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Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets

Tribenzotriquinacene Receptors for C₆₀ Fullerene Rotors: Towards C₃ Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets