Substituent effects conjugative electron donation

The effects of cyclic 6n electron conjugation have been found in the optimized geometries of pentazole 17 [102] and hexazine 18 [97], The N=N bond is longer than the isolated double bond in NH=NH. The N-N single bond in the tetrazadiene moiety is shorter than the single bond in NH NH. The bond lengths in 18 are nearly intermediate between those in NH NH and NH=NH. The aromatic character of pentazoles was supported by the effect of electron donating substituents on the thermodynamic and kinetic stabilization [103],... 

An extended form of (39) has been used to analyse kinetic substituent effects on bromination of alkenes GRaC=CR()R) , where G is a conjugatively electron-donating group and R is alkyl (Bienvenue-Goetz and Dubois, 1981). 

Type of Transition (Fig. 2) Designation of Transition State Designation Intensity Conjugative Effects Lengthening Conjugation Solvent Effects Increase Polarity Effect of Electron Donating Substituents... 

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