✦ LIBER ✦

MNDO calculations of proton and methyl-and ethyl-cation affinities of neutral carbon, nitrogen, and oxygen bases

✍ Scribed by George P. Ford; John D. Scribner

Publisher: John Wiley and Sons
Year: 1983
Tongue: English
Weight: 739 KB
Volume: 4
Category: Article
ISSN: 0192-8651
DOI: 10.1002/jcc.540040419

No coin nor oath required. For personal study only.

✦ Synopsis

Proton affinities (PA) of 80 neutral bases were calculated using the semiempirical molecular orbital procedure MNDO. These were compared with the corresponding experimental and, where available, ab initio STO-SG and 4-31G data. For the 12 bases studied which led to ions which were not hyperconjugatively stabilized, the mean absolute error between the calculated and experimental values was 7.2 kcal mol-'. However, a plot of these data revealed a clear tendency of MNDO to underestimate the PAS of the more basic molecules. Where hyperconjugative stabilization of the ion was possible, the calculated PAS were underestimated by a further 7-10 kcal mot1 for each attached alkyl group. Calculated and observed methyl-and ethyl-cation affinities were compared for 18 bases with qualitatively similar results.

📜 SIMILAR VOLUMES

Effects of alkylation upon the proton af

Effects of alkylation upon the proton affinities of nitrogen and oxygen bases

✍ Paul Redfern; Steve Scheiner 📂 Article 📅 1985 🏛 John Wiley and Sons 🌐 English ⚖ 502 KB

## Abstract The protonation energies of alkylated derivatives of NH~3~ and OH~2~ are calculated at the Hartree–Fock level with the split‐valence 4‐31G basis set. The methyl, dimethyl, and ethyl amines are studied; oxygen bases include methanol, dimethylether, and ethanol. The geometries of each mol

Basis set and correlation effects on com

Basis set and correlation effects on computed proton affinities of some oxygen and nitrogen bases

✍ Janet E. Del Bene 📂 Article 📅 1985 🏛 John Wiley and Sons 🌐 English ⚖ 374 KB

Basis set expansion and correlation effects on the computed proton afhities of the oxygen and nitrogen bases CH30H, H&O, CO, CH3NHz, CH2NH, and HCN have been evaluated. Basis set enhancements lead to systematic changes in computed proton ainities. These effects appear to be additive, and are greater

A theoretical study of the effects of si

A theoretical study of the effects of silyl and methyl groups on acid-base reactions at oxygen, nitrogen and carbon

✍ A.C. Hopkinson; M.H. Lien 📂 Article 📅 1983 🏛 Elsevier Science 🌐 English ⚖ 963 KB

Determination of aqueous inclusion compl

Determination of aqueous inclusion complexation constants and stoichiometry of alkyl(methyl)-methylimidazolium-based ionic liquid cations and neutral cyclodextrins by affinity capillary electrophoresis

✍ Yannis François; Anne Varenne; Juliette Sirieix-Plenet; Pierre Gareil 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 English ⚖ 489 KB 👁 1 views

## Abstract Affinity CE (ACE) method was developed to characterize the complex formation between seven alkyl(methyl)methylimidazolium‐based ionic liquid (IL) cations and eight neutral cyclodextrins (CD). The effective mobility data of the IL cations were processed according to classical nonlinear a

Neutral and Cationic Methyl Complexes of

Neutral and Cationic Methyl Complexes of Platinum(II) with 6-Substituted 2,2′-Bipyridines: Synthesis, Characterisation and Reactivity with Carbon Monoxide − Molecular Structures of [PtCl(methyl)(6-ethyl-2,2′-bipyridine)] and of [Pt(methyl)(acetonitrile)(6-ethyl-2,2′-bipyridine)][BF4]

✍ Angelino Doppiu; Maria Agostina Cinellu; Giovanni Minghetti; Sergio Stoccoro; An 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 386 KB 👁 2 views

Platinum / N ligands / Methyl complexes /

The calculation of 1H, 13C, 14N isotropi

The calculation of 1H, 13C, 14N isotropic and anisotropic hyperfine interactions for the 3-methyl indole cation and neutral radicals using hybrid density functional methods: models for in vivo tryptophan-based radicals

✍ Patrick J. O'Malley; Darryl A. Ellson 📂 Article 📅 1996 🏛 Elsevier Science 🌐 English ⚖ 384 KB

Density functional methods are used to calculate the isotropic and anisotropic hyperfine interactions for the 3-methyl indole cation and neutral free radicals. Calculated couplings are compared with experimental determinations for in vivo tryptophan-based radicals. The cation and anion radicals can