Ionization energies of organic compounds by equilibrium measurements

Lias, Sharon G.; Ausloos, P.

doi:10.1021/ja00487a009

Cited by 57 publications

(34 citation statements)

References 2 publications

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“…lowest electronic state of the molecule. This is rigorously equal to the difference in the enthalpies of formation of RHf' and RH at OK. For most aromatic compounds the heat capacities of the molecule and the corresponding radical cation are effectively the same, so that AJC, dT is negligible and AH3,, x -I P ( a d i a b a t i~)~~ (30).…”

Section: Figmentioning

confidence: 99%

“…AG34c is calculable because AHof(~+,,, AHof(~),,, SoH+(,,), AG,,, is assumed to be equal to AH3,, because and SOH-(,,) are well known (25,31); AG34a can AS,,, has been shown to be negligible (29,30 tion and shows a difference in symmetry compared to benzene. Thus there will be a change in rotational entropy on forming the From Fig.…”

Section: Figmentioning

confidence: 99%

“…Whenever possible, experimentally determined A G O f (~t ) E can be (25,31)' In the absence thermochemical quantities have been used.g In the of changes in entropy and heat capacity of RH on ionization eq. [76] can be assumed (29,30). For personal use only.…”

Section: Applications and Conclusionmentioning

confidence: 99%

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Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pK_a of radical cations based on thermochemical calculations

Nicholas¹,

Arnold²

1982

Can. J. Chem.

190

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A. MARTIN DE P. NICHOLAS and DONALD R. ARNOLD. Can. J. Chem. 60, 2165Chem. 60, (1982. Three methods for estimating the pKa of a radical cation using thermochemical cycles are discussed. These methods enable the calculations of the pK, of radical cations which have not been determined experimentally. Radical cation acids are classified according to the nature of their respective conjugate bases. The application of these methods is illustrated for a o-acid (the benzene radical cation) and n-acid (the toluene radical cation). The potential of these methods to estimate relative and absolute solvation energies is also discussed. The use of thermochemical cycles in estimating standard oxidation potentials of organic compounds is outlined.Calculations show that the toluene radical cation is an extremely strong acid and the benzene radical cation a moderately strong acid in acetonitrile solution. Difficulties in directly determining the pK, value of aromatic hydrocarbon radical cations are also discussed.A. MARTIN DE P. NICHOLAS et DONALD R. ARNOLD. Can. J. Chem. 60, 2165Chem. 60, (1982. On discute de trois methodes d'evaluation du pKa d'un cation radicalaire en utilisant les cycles thermochimiques. Ces methodes permettent de calculer le pKa des cations radicalaires que l'on ne peut pas diterminer experimentalement. Les cations radicalaires acides sont classes selon la nature de leurs bases conjuguCes respectives. On illustre I'application de ces methodes dans le cas d'un acide o (le cation radicalaire du benzene) et dans le cas d'un acide n (le cation radicalaire du toluene). On discute egalement du potentiel de ces methodes en ce qui a trait B I'Cvaluation des Cnergies de solvatation relatives et absolues. On souligne I'utilisation des cycles thermochimiques dans I'Cvaluation des potentiels standard d'oxydation des composCs organiques.Les calculs indiquent que le cation radicalaire du toluene est un acide extrkmement fort et que le cation radicalaire du benzene est un acide moyennement fort en solution dans I'acetonitrile. On discute egalement des difficultCs rencontrees lors de la determination directe de la valeur du pKa des cations radicalaires des hydrocarbures aromatiques.[Traduit par le journal]

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Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

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Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pK_a of radical cations based on thermochemical calculations

Nicholas¹,

Arnold²

1982

Can. J. Chem.

190

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“…The single positive charge of the chromophore in its ground state electron configuration is compensated by the anion. On the contrary, exciting a cyanine and transferring an electron to an acceptor in an OPV device creates formally a doubly positively charged molecule for a short period, a highly unfavourable state for the cyanine chromophore when considering the standard ionisation potential approach for molecules ,. Additionally, typical exciton radii in organic materials are smaller than the unit cell volume .…”

Section: Introductionmentioning

confidence: 99%

“…On the contrary, exciting a cyanine and transferring an electron to an acceptor in an OPV device creates formally a doubly positively charged molecule for a short period, a highly unfavourable state for the cyanine chromophore when considering the standard ionisation potential approach for molecules. [34,35] Additionally, typical exciton radii in organic materials are smaller than the unit cell volume. [36] Therefore in conventional organic semiconductors [36,37] and especially salts, [31] where strong Coulomb forces are dominant, excitons are trapped in low energy excited states and are prone to non-radiative recombination.…”

Section: Introductionmentioning

confidence: 99%

Superweak Coordinating Anion as Superstrong Enhancer of Cyanine Organic Semiconductor Properties

et al. 2018

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The superweak tetrakis(nonafluoro‐tert‐butoxy)aluminate coordinating anion was employed to introduce pseudo‐gas‐phase conditions to the 2‐[5‐(1,3‐dihydro‐1,3,3‐trimethyl‐2H‐indol‐2‐ylidene)‐1,3‐pentadien‐1‐yl]‐1,3,3‐trimethyl‐3H‐indolium chromophore. The resulting formation of a photoactive organic–inorganic hybrid salt has led to a highly stabilized excited state of the organic chromophore mainly due to the minimized lattice energy and Coulomb interactions. These highly beneficial features caused by the well dispersed negative charge of the anion have led to an enhanced neat spin‐casted film fluorescence intensity, prolonged fluorescence lifetime, smooth thin film surfaces and a record power photovoltaic efficiency of 3.8 % when compared to organic salts of this particular chromophore containing anions with localised negative charge. Clear evidence is given that a superweak coordinating anion is an emerging key parameter in cyanine dye photochemistry. This approach can be seen as a general guideline to prepare highly efficient ionic dyes for organic semiconductor applications.

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Mathematical transformations of recurrent relations for different types of homologues

Зенкевич

2016

Journal of Chemometrics

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Most of discrete properties A of individual organic compounds belonging to single-row homologous seriescan be approximated with first order linear recurrent relations A(n + 1) = aA(n) + b. The important chemical property of recurrences is the equality of coefficients a and b for various homologous series of similar topology (with the same homologous differences at the constancy of the number of rows). The values of coefficients a and b for single-and multi-rows series even with the same structural fragments X = Y are different.The algorithm of the mutual recalculating of the coefficients of recurrent relations for single-and multi-rows homologous series is proposed and considered. It allows evaluating different physicochemical properties of insufficiently characterized unsymmetrical organic compounds with different alkyl substituents, like C 2 H 5 NHC 3 H 7 , (CH 3 ) 2 B(C 2 H 5 ), (CF 3 )N(C 2 F 5 ) 2 , etc., using the data for better characterized "symmetrical" homologues (illustrated by examples).

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Ionization energies of organic compounds by equilibrium measurements

Cited by 57 publications

References 2 publications

Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pK_a of radical cations based on thermochemical calculations

Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pK_a of radical cations based on thermochemical calculations

Superweak Coordinating Anion as Superstrong Enhancer of Cyanine Organic Semiconductor Properties

Mathematical transformations of recurrent relations for different types of homologues

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Ionization energies of organic compounds by equilibrium measurements

Cited by 57 publications

References 2 publications

Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pKa of radical cations based on thermochemical calculations

Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pKa of radical cations based on thermochemical calculations

Superweak Coordinating Anion as Superstrong Enhancer of Cyanine Organic Semiconductor Properties

Mathematical transformations of recurrent relations for different types of homologues

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Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pK_a of radical cations based on thermochemical calculations

Thermochemical parameters for organic radicals and radical ions. Part 1. The estimation of the pK_a of radical cations based on thermochemical calculations