Polyenes and vision
نویسندگان
چکیده
منابع مشابه
Energetics and dynamics of the low-lying electronic states of constrained polyenes: implications for infinite polyenes.
Steady-state and ultrafast transient absorption spectra were obtained for a series of conformationally constrained, isomerically pure polyenes with 5-23 conjugated double bonds (N). These data and fluorescence spectra of the shorter polyenes reveal the N dependence of the energies of six (1)B(u)(+) and two (1)A(g)(-) excited states. The (1)B(u)(+) states converge to a common infinite polyene li...
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Essential fatty acids (EFAs) and their long-chain polyenes (LCPs) are indispensable for human development and health. Because humans cannot synthesize EFAs and can only ineffectively synthesize LCPs, EFAs need to be consumed as part of the diet. Consequently, the polyunsaturated fatty acid (PUFA) status of the developing fetus depends on that of its mother, as confirmed by the positive relation...
متن کاملQuantum interference in polyenes.
The explicit form of the zeroth Green's function in the Hückel model, approximated by the negative of the inverse of the Hückel matrix, has direct quantum interference consequences for molecular conductance. We derive a set of rules for transmission between two electrodes attached to a polyene, when the molecule is extended by an even number of carbons at either end (transmission unchanged) or ...
متن کاملGenealogy of Conjugated Acyclic Polyenes.
Based on the total π-electron energies Eπs of Hückel Molecular Orbital (HMO) method for all the possible isomers of conjugated acyclic polyenes (C₂nH₂n+2) up to n = 7, the structure-stability relation of the possible isomers was analyzed. It was shown that the mean length of conjugation L can roughly predict the ordering of stability among isomers, while the Z-index, or Hosoya-index, can almost...
متن کاملOptical Spectroscopy of Long Polyenes
We have synthesized a homologous series of soluble, linearly conjugated oligomers and related polymers using molybdenum alkylidene catalysts. We have developed HPLC procedures to isolate the oligomers according to their chain lengths and have obtained the absorption spectra of the purified oligomers in room temperature solutions and in 77 K glasses. The oligomer absorption spectra are structure...
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ژورنال
عنوان ژورنال: Chemistry & Biology
سال: 1996
ISSN: 1074-5521
DOI: 10.1016/s1074-5521(96)90105-2