منابع مشابه
Genealogy 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...
متن کاملEnergetics 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...
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 کاملThe Enol Ether Synthesis of Polyenes
Convenient methods for the preparation of 1-alkoxydienes are reviewed. It is shown that 1-alkoxydienes are very reactive and can be successfully used for the synthesis of polyene compounds. These include some important natural products, such as polyene aldehydes, vitamin A aldehyde, the ethers and esters of vitamin A, f3-ionolidenacetaldehyde, f3-C,9-aldehyde and other related compounds. A conv...
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ژورنال
عنوان ژورنال: Photochemistry and Photobiology
سال: 1975
ISSN: 0031-8655,1751-1097
DOI: 10.1111/j.1751-1097.1975.tb06751.x