ISSN:
0894-3230
Keywords:
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Kinetic studies were carried out on the reactions of anilines with 2-cyano-2-propyl and 1-cyanocyclooctyl arenesulfonates in acetonitrile at 50·0°C. The second-order rate constants for the former are in general greater than those for the latter but the rates of the two become comparable for a strong nucleofuge. The cross-interaction constants, ρXZ (and βXZ), are considerably smaller (ca -0·04) than those for the primary (ca 0·33) and secondary (ca 0·12) compounds. The negative sign and small magnitude are consistent with a dissociative SN2 mechanism with a loose transition state structure. The ab initio MO theoretical results for Cl- + RCl ClR + Cl- at the MP2 level (MP2/6-31 + G*//MP2/6-31 + G*) confirm the looseness of the transition state for the tertiary (R) alkyl compounds. The average r(Cl…Cl) value is 47middot;88 ± 0·03 Å, which is larger than those for the reactions at primary (4·68 ± 0·02 Å) and secondary (4·80 ± 07middot;02 Å) carbon centers. Thus a looser transition state with a smaller magnitude of ρXZ for the tertiary carbon centers has a larger theoretical r(Cl…Cl) value.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
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