Hydrogen Bonding in Thiols<sup>1</sup>

Marcus, Sheldon H.; Miller, Sidney I.

doi:10.1021/ja00968a008

Cited by 60 publications

(22 citation statements)

References 5 publications

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“…Because The concentrations of the solutions in Table 2 are 0.5 M or less. At these concentrations chemical shift (27) and infrared (28) studies suggest that perhaps only about 1 % of the solute molecules are associated. Of course, the solvent molecules are ~nteracting with the solute molecules by dispersion forces, if in no other way.…”

Section: Resultsmentioning

confidence: 95%

The para substituent dependence of the internal rotational barrier in benzenethiol

Schaefer¹,

Parr²

1977

Can. J. Chem.

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. J. Chem. 55, 552 (1977).On the basis of the observed spin-spin coupling constants between the sulfhydryl and ring protons and a hindered rotor treatment of the twofold barrier to internal rotation in a series of para substituted benzenethiol derivatives, it is argued that V2 is essentially zero in p-aminobenzenethiol and is 2.5 + 0.2 kcal/mol in p-nitrobenzenethiol; having intermediate values for the methoxy, fluoro, methyl, and bromo derivatives in solution. The results are based on an assumed relationship between the four-bond and the fictitious six-bond couplings to the sulfhydryl proton. The conclusions are consistent with the observed magnitudes of the couplings oper six and seven bonds, respectively, between the sulfhydryl proton and the fluorine nucleus and the methyl protons in the appropriate derivatives; as well as with the coupling between the sulfhydryl and methyl protons in 4-bromo-3-methylbenzenethiol. The experimental barriers are compared with ab initio molecular orbital calculations of their substituent dependence.TED SCHAEFER et WILLIAM J. E. PARR. Can. J. Chem. 55, 552 (1977).En se basant sur les constantes de couplage spin-spin observees entre les protons sulfhydryles et les protons du cycle et en traitant comme un rotor empCchC la barriere binaire la rotation interne dans une serie de benzenethiols substituts enpam, on suggtre que V2 est pratiquement Cgal a zero dans lep-aminobenzenethiol et a 2.5 i 0.2 kcal/mol dans lep-nitrobenzenethiol; en solution, les valeurs sont intermediaires pour les derives methoxy-, fluoro-, methyl-et bromo-. Ces resultats sont bases sur une relation hypothktique entre les couplages a travers quatre liaisons et sur les couplages fictifs a travers six liaisons pour le proton sulfhydryle. Les conclusions sont en accord avec les ordres de g r a n d e~~r observes respectivement pour les couplages a travers six et sept liaisons entre le proton sulfhydryle et le noyau de fluor et les protons des methyles dans des derives appropries: ces conclusions sont aussi en accord avec le couplage entre les protons sulfhydryles et methyles du bromo-4 methyl-3 benzenethiol. On compare les barrieres experimentales avec les rtsultats de calculs ab inirio d'orbitales moltculaires predisant leur dependance sur les substituants.[Traduit par le journal]

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Section: Resultsmentioning

confidence: 95%

The para substituent dependence of the internal rotational barrier in benzenethiol

Schaefer¹,

Parr²

1977

Can. J. Chem.

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“…Natural collision coordinates [6] are very useful in formulating the three-dimensional reactive problem [7]. Euler angles (Ocpx) orient a set of body-fixed axes relative to a nonrotating CM frame, and internal variables (spy) fix the size and shape of the three-body triangle.…”

Section: A Coordinates and Harniltonianmentioning

confidence: 99%

Three-dimensional quantum mechanical studies of the H + H2 and F + H2 reactions

Redmon

Wyatt

2009

Int. J. Quantum Chem.

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New results are presented for quantum mechanical reactive scattering in H + H,, including a comparison of close-coupling cross sections for para to ortho conversion with results obtained through momentum decoupling approximations. Information-theoretic analysis of product rotational distributions is given for one total energy. Results are also presented of the first three-dimensional coupled-channel study of the F + H, reaction, showing thcenergy dependence of the probability distribution for vibrational excitation and population inversion.

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“…It is also distinct from the minimum-energy reaction path (MERP) which, as Murrell [22] has shown, has the most satisfactory definition with respect to normal coordinates q for all points on it, so that the line of steepest descent will be that for which [bW(q)/ dq,],=, is a maximum and [dW(q)/bqs]s+r = 0; W(q) is the PES. The term reaction coordinate is used here as a curve of reference [27,28] with a desirable general similarity to the MERP, with respect to which the MERP could be defined.…”

Section: The Zero Virial Reaction Coordinatementioning

confidence: 99%

Some applications of the virial theorem to molecular force fields: The zero virial reaction coordinate and diatomic potentials from the normalized kinetic field functions

Nalewajski

2009

Int. J. Quantum Chem.

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For a fixed-angle potential energy surface (PES), W(Q), following the zero virial path (ZVP), on which 2," Q, -V,W(Q) = 0, provides an efficient way for locating the transition state and generating a g o d approximation to the minimum-energy reaction path; vector Q = (Q1, . . . , QN) stands for nuclear coordinates. An algorithm which employs the ZVP following is proposed for exploring PESS when starting from the reactant (or product) region. It seems that this approach allows one to avoid some discontinuities in the reaction coordinate, which often result from the "bottom-following" procedures. The implications of the integral forms of the virial theorem are examined and a new way of constructing potential energy functions W ( R ) for diatomic molecules is proposed. It starts with the normalization of the kinetic component T ( R ) of the potential: J-0" [ T ( R ) -T ( m ) ]dR = ZAZB. where ZA and ZB are the nuclear charges and R is the internuclear distance. The modified potentials are derived for four different analytical representations of T ( R ) , Tx(R) (X = M, R, RM, and HH) by the Morse, Rydberg, Rosen-Morse, and Hulbert-Hirschfelder functions, respectively. The three-parameter modified potentials ( X = M, R, and RM) are tested against known spectroscopic data for H: and Hz. The modified potentials require one less experimental constant to fit the potential parameters than do their original analogs. It follows that the Morse and Rydberg functions constitute satisfactory representations of the kinetic component T(R), and that enforcing its normalization improves predictions of spectroscopic constants and relations between them.

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Hydrogen Bonding in Thiols¹

Cited by 60 publications

References 5 publications

The para substituent dependence of the internal rotational barrier in benzenethiol

The para substituent dependence of the internal rotational barrier in benzenethiol

Three-dimensional quantum mechanical studies of the H + H2 and F + H2 reactions

Some applications of the virial theorem to molecular force fields: The zero virial reaction coordinate and diatomic potentials from the normalized kinetic field functions

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Hydrogen Bonding in Thiols1

Cited by 60 publications

References 5 publications

The para substituent dependence of the internal rotational barrier in benzenethiol

The para substituent dependence of the internal rotational barrier in benzenethiol

Three-dimensional quantum mechanical studies of the H + H2 and F + H2 reactions

Some applications of the virial theorem to molecular force fields: The zero virial reaction coordinate and diatomic potentials from the normalized kinetic field functions

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Product

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Hydrogen Bonding in Thiols¹