Corrigenda

Radom, L.; Hehre, W. J.; Pople, J. A.; Carlson, G. L.; Fateley, W. G.; Anastassiou, A. G.; Griffith, R. C.

doi:10.1039/c39720000704

Cited by 13 publications

(15 citation statements)

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“…This trend was reasonably explained by a change in conjugation of the SH group with the aromatic nucleus. Such substituent induced changes in V2 are supported by STO-3G MO calculations (25) and are also found in analogous phenol derivatives (26).…”

Section: Conformational Properties Of 2-methoxythiophenolsupporting

confidence: 48%

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Comparison of the intramolecular hydrogen bonds and of the internal barrier to rotation the hydroxyl and sulfhydryl groups in 2-methoxyphenol and 2-methoxythiophenol

Schaefer¹,

Wildman²

1979

Can. J. Chem.

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. J. Chem. 57,450 (1979).The long-range spin-spin coupling constants involving the hydroxyl proton in 2-methoxyphenol are consistent with a potential function for rotation of the hydroxyl group derived from far infrared torsion data. The internally hydrogen bonded cis conformer is the only one detected by nmr. In contrast, the long-range couplings of the sulfhydryl group in 2-methoxythiophenol indicate that the trans conformer is favored over the cis conformer by a free energy difference of 0.2 f 0.2 kcal/mol. Furthermore, the barrier to internal rotation of the sulfhydryl group is much smaller than that of the hydroxyl group in these two compounds. It is suggested that the barrier in the thiophenol derivative is 2.7 f 0.6 kcal/mol, to be compared with a twofold component of 6 kcal/mol in the rotational potential function of the phenol analog.TED SCHAEFER et TIMOTHY A. WILDMAN. Can. J. Chem. 57,450 (1979).Les constantes de couplage spin-spin a longue distance impliquant le groupe hydroxyle du methoxy-2 phenol sont en accord avec une fonction de potentiel ttablie, pour la rotation du groupe hydroxyle, a partir de donnees de torsion provenant de I'infrarouge lointoin. En rmn, on ne detecte que la presence du conformere cis impliquk dans une liaison hydrogene interne. Par ailleurs, les constantes de couplage a longue distance impliquant le groupe sulfhydryle de methoxy-2 thiophknol indiquent que le conformere trans est plus favoris6 que le conformere cis; la difference d'inergie libre est de 0.2 f 2.0 kcal/mol. De plus, la barriere a la rotation interne du groupe sulfhydryle est beaucoup plus faible que celle du groupe hydroxyle dans ces deux composes. On suggkre que la barriere dans le derive thiophknol est 2.7 0.6 kcal/mol; on doit comparer cette valeur avec une composante binaire de 6 kcal/mol dans la fonction de potentiel de rotation de I'analogue oxygene.[Traduit par le journal]

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Section: Conformational Properties Of 2-methoxythiophenolsupporting

confidence: 48%

“…In the para derivatives the barrier decreases relative to the parent compounds by about 1 kcal/mol (25,26). In the ortho derivatives, the V2 component increases by about 2 kcal/mol relative to the parent compounds.…”

Section: Conformational Properties Of 2-methoxythiophenolmentioning

confidence: 96%

Comparison of the intramolecular hydrogen bonds and of the internal barrier to rotation the hydroxyl and sulfhydryl groups in 2-methoxyphenol and 2-methoxythiophenol

Schaefer¹,

Wildman²

1979

Can. J. Chem.

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“…It is then easy to obtain cis-trans ν Br OH = 94 cm −1 , which agrees with the experimental values ranging from 74 to 93 cm − 1 218, 224, 229 (Tables 1 and 5 of Reference 222). On the other hand, the calculated cis-trans E Br ortho = 12.9 kJ mol −1 (the experimental free energy difference in the vapour is 13.1 ± 14.6 kJ mol −1 224 ) implies that, first, the intramolecular hydrogen bond is slightly stronger with Br than with Cl, which surely contradicts the common order of the hydrogen bond acceptors 155,171,236,237 , and, second, the equilibrium constant k Br cis trans = 5.2 × 10 −3 < k Cl cis trans , although the experiments show the reverse trend 233,234 . Altogether, this was dubbed as an 'anomalous' order in the strength of the intramolecular hydrogen bond 223, 224, 229, 231, 238 -240 ; the 'state of affairs' was summarized by Sandorfy and coauthors 229 in their 1963 work: 'Nothing emerges from our work, however, to explain this order.…”

Section: A Intramolecular Hydrogen Bond In Ortho-halogenophenolsmentioning

confidence: 61%

“…Table 2 in Reference 236), which is completely opposite to that widely accepted for usual intermolecular hydrogen bonds 225,226 . Such variance was in fact a matter of numerous investigations in the past 155,236,237 . Here, we could offer an explanation 239 is clearly seen in Figure 12: due to a larger van der Waals radius, the Br atom slightly better accommodates the intramolecular bond, even 'overcoming the innate lower H-bonding tendency to Br' 240 than Cl which, in turn, does better than F. Such a conclusion is also supported by the inequalities in equation 7.…”

Section: A Intramolecular Hydrogen Bond In Ortho-halogenophenolsmentioning

confidence: 99%

General and Theoretical Aspects of Phenols

Nguyen

Kryachko

Vanquickenborne

2009

Patai's Chemistry of Functional Groups

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Introduction Molecular Structure and Bonding of Phenol Structures and Properties of Substituted Phenols Energetics of some Fundamental Processes Hydrogen Bonding Abilities of Phenols Open Theoretical Problems Acknowledgements

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“…The STO-3G MO calculations with a standard geometry (39) yielded an internal barrier of 2.8 kcall moly clearly much too high and comparable to the overestimate of 1.7 kcal/mol for phenol (34). Optimization of the geometry of the S-H bond gave a CSH bond angle of 95.8" (CND0/2 yields 98" (9)) and a C-S bond length of 1.762 A.…”

Section: Molecular Orbital Calculationsmentioning

confidence: 99%

In-plane and out-of-plane conformational preferences of the sulfhydryl group in some halothiophenol derivatives

Schaefer¹,

Parr²

1979

Can. J. Chem.

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. Can. J. Chem. 57, 1421Chem. 57, (1979.Long-range spin-spin coupling constants between sulfhydryl protons and ring protons in some halothiophenol derivatives in CC14 solutions are reported. In contrast to the come sponding phenol derivatives, substantial amounts of out-of-plane conformers are present at 305 K for all but 2,6-dichlorothiophenol. The cis and trans conformers differ by only about 0.2 kcallmol in free energy for 2,4-dibromothiophenol and 2,4-dichlorothiophenol, in good agreement with a recent analysis of the dipole moment observed for the latter compound. The barrier to internal rotation of the sulfhydryl group is considerably smaller than for a hydroxyl group and rough estimates are given for the barrier in a few compounds. For example, the barrier in 2,3,5,6-tetrafluorothiophenol is lower than in 2,6-dichlorothiophenol. STO-3G MO calculations overestimate the internal barrier to rotation of the sulfhydryl group, but yield charge densities for this group which indicate that a major cause of the relative weakness of its intramolecular hydrogen bonds resides in its lack of polarity.TED SCHAEFER et WILLIAM J. E. PARR. Can. J. Chem. 57, 1421 (1979.On rapporte les constantes de couplage a longue distance entre les protons sulfhydryles et ceux du cycle de quelques derives halothiophenols en solution dans le CC14. Par opposition aux rksultats obtenus avec les dbives ph6noliques correspondants, il en resulte que, dans tous les cas, except6 le dichloro-2,6 thiophknol, des quantites importantes de conformkres qui ne sont pas dans le plan a 305 K. L'Bnergie libre des conform&res cis et trans ne diffkre que par 0.2 kcall mol dans le cas des dibromo-2,4 et dichloro-2,4 thioph6nols; ce resultat est en bon accord avec une analyse recente du moment dipolaire observe pour ce dernier compos6. La barrikre a la rotation interne du groupe sulfhydryle est beaucoup plus faible que dans le cas du groupe hydroxyle et l'on donne des Bvaluations grossikres pour cette rotation dans quelques composes. Par exemple, la barrikre dans le tetrafluoro-2,3,5,6 thiophenol est plus basse que dans le dichloro-2,6 thiophenol. Des calculs de OM STO-3G donnent une evaluation trop Blevke pour la barrikre interne 5 la rotation du groupe sulfhydryle; toutefois les densites de charge qu'ils fournissent indiquent que la cause principale de la faiblesse relative de ses liaisons hydrogkne intramoleculaires provient de son manque de polaritk.[Traduit par le journal] Introduction It has been shown ( 1 4 ) that the use of stereospecific long-range spin-spin coupling constants between hydroxyl and ring protons or 19F nuclei in halophenol derivatives is perhaps one of the best ways to determine the conformational preferences of the hydroxyl group. For example, for 2,4-dihalophenols there exists little doubt that in CCl, or C,Hl, solution greater than 90% of 1 exists in the form l a (cis) near room temperature.For the corresponding halothiophenol derivatives,

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Corrigenda

Abstract: On p. 309, the entries 3 and 4 in the Table for X = CN should be: q J X ) = -0-029, &,(OH) = + 0.009 Product Characterization in the Thermal Bond-relocation of the syn-and anti-9-Methylbicyclo [6,1 ,O] nona-2,4,6-trienes

Cited by 13 publications

References 0 publications

Comparison of the intramolecular hydrogen bonds and of the internal barrier to rotation the hydroxyl and sulfhydryl groups in 2-methoxyphenol and 2-methoxythiophenol

Comparison of the intramolecular hydrogen bonds and of the internal barrier to rotation the hydroxyl and sulfhydryl groups in 2-methoxyphenol and 2-methoxythiophenol

General and Theoretical Aspects of Phenols

In-plane and out-of-plane conformational preferences of the sulfhydryl group in some halothiophenol derivatives

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