ISSN:
1432-2234
Keywords:
Polymethines, α, ω- substituted
;
Polymethines, energy spectrum of ∼
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The analysis of the experimental data for the energy of the longest wavelength optical transitions Δɛ n,opt of substituted polymethines X $$\dddot ---$$ (CH)2n+1 $$\dddot ---$$ X shows that in the asymptotic case (n→∞) Δɛ∞,opt does not tend to zero, as it follows from the empirically established correlations, but has a finite, non-zero value. It is shown that the energy gap of odd polymethines is the same as that of the even polymethines - the polyenes (ΔE ∞∼2 eV). The substituents (X ε N, O, B) are responsible for the appearance of levels in the gap. These, depending on the substituent character, are vacant (X ≡ B) or occupied (X ≡ N, O). The transition from or to such a level determines the longest wavelength optical transition energy of polymethines.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00550335
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