Chemical behavior of charge-transfer complexes. VII. Solvolysis of alkyl arenesulfonate donors in the presence of aromatic acceptors

1978 ◽  
Vol 56 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Allan K. Colter ◽  
Robert E. C. Turkos
Keyword(s):  
Acetic Acid ◽  
Charge Transfer ◽  
Kinetic Data ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Chemical Behavior ◽  
Measurable Rate ◽  
Leaving Groups

Rates of solvolysis of several ethyl and 2-propyl arenesulfonates having π donor leaving groups were measured in the absence of accepter and in the presence of the π acceptors 1,3,5-trinitrobenzene (TNB) and 2,4,7-trinitrofluorenone (TNF). With four of the nine combinations investigated, added accepter produced small but measurable rate enhancements. Ester–TNF 1:1 association constants were measured spectrophotometrically at 20, 30, and 40 °C in acetic acid for 2-propyl 4-methoxy-1-naphthalenesulfonate (3b), 4,8-dimethoxy-1-naphthalenesulfonate (4), 3,7-dimethyl-1-naphthalenesulfonate (5), and 1-pyrenesulfonate (6). From the equilibrium and kinetic data, the reactivity of the 1:1 ester–TNF complex relative to that of the uncomplexed ester (kc/ku) in acetolysis at 85.73 °C was estimated to be lessthan 4.2 and 1.4 for 3b and 4, respectively, 4.4 ± 2.0 for 5, and 2.8 ± 0.4 for 6. The value of kc/ku for 6 determined from analysis of the kinetic data alone is 2.7 ± 0.8.

Correlation of kinetic data of 1,3-dipolar cycloadditions of C-benzoyl-N-phenylnitrones with the homo energies of furan derivatives

1981 ◽  
Vol 46 (6) ◽  
pp. 1504-1512 ◽  
Author(s):  
Lubor Fišera ◽  
Anton Gáplovský ◽  
Hans-Joachim Timpe ◽  
Jaroslav Kováč
Keyword(s):  
Charge Transfer ◽  
Rate Constants ◽  
Kinetic Data ◽  
Empirical Equation ◽  
Dipolar Cycloaddition ◽  
Charge Transfer Complexes ◽  
Electron Affinities ◽  
Furan Derivatives ◽  
Dipolar Cycloadditions ◽  
Experimental Values

Application of PMO treatment to 1,3-dipolar cycloaddition of C-benzoyl-N-phenylnitrone with furan derivatives is described. Ionization potentials of 2-R-substituted furan derivatives (R = H, CH3, C2H5, CH2OH, CH2OCOCH3, C6H5, CHO) and 2,5-dimethylfurane representing experimental values of the HOMO energies have been determined from energies of the respective charge-transfer complexes with TCNE. Good correlation between IP and k2 rate constants indicates that the reaction is controlled by the LUMO(nitrone)/HOMO(furan deriv.) interaction. Electron affinities of the furan derivatives were determined from IP and energies of π-π* transitions using empirical equation ΔE(π-π*) = IP-EA-450.58 kJ mol-1.

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