Introduction. ± Sigmatropic shiftamers are (so far hypothetical) organic polymers in which localized electrons and/or atoms can be transported along the polymer chains by sequential sigmatropic shifts [1]. Recently, we described a shiftamer for the net transport of H-atoms along a polyacetylene chain via [1,7] shifts (Scheme 1) [1b]. We now show variants of this system that allow for the net tr...

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Ring-whizzing was investigated by hybrid DFT methods in a number of polyene-Pt(diphosphinylethane) complexes. The polyenes included cyclopropenium(+), cyclobutadiene, cyclopentadienyl(+), hexafluorobenzene, cycloheptatrienyl(+), cyclooctatetraene, octafluorooctatetraene, 6-radialene, pentalene, phenalenium(+), naphthalene and octafluoronaphthalene. The HOMO of a d(10) ML2 group (with b2 symmetr...

Annatto and its derivatives are members of carotenoids with long-chain conjugated polyenes, which are widely used as food additives and antioxidant. However, carotenoids can also act as pro-oxidant under certain circumstances. To explore the biochemical behavior of annatto and its derivatives, the DNA damage effects by norbixin to the copper(II) ions mediated DNA damage was evaluated herein. It...

Hebeka, Elias K. (Rutgers, The State University, New Brunswick, N.J.), and Morris Solotorovsky. Development of resistance to polyene antibiotics in Candida albicans. J. Bacteriol. 89:1533-1539. 1965.-Strains of Candida albicans resistant to the polyenes candidin and amphotericin B, but not to nystatin, were developed by sub-culturing the organism in gradually increasing concentrations of the an...

It is a fundamental property of conjugated systems to accept a proton or Lewis acid and form a stable carbonium ion. Polyenes that are protonated or add Lewis acids in this manner undergo substantial red shifts. For example, vitamin A(1) acetate absorbs at 350 mmicro in neutral and at 650 mmicro in acidic benzene solution. The fundamental basis for absorption of polyene systems was described in...

A one-pot metathetic ring opening of substituted bicyclo[3.2.0]heptenones to linear polyene ketones is described. The reaction proceeds with conservation of the endocyclic (Z)-double bond. Exo-substituted vinylcyclobutanones result in (4Z,6E)-configured trienones, while endo-substituted phenyl derivatives generate (4Z,6Z)-configured dienones.

We describe and extend the formalism of state-specific analytic density matrix renormalization group (DMRG) energy gradients, first used by Liu et al. [J. Chem. Theor. Comput. 2013, 9, 4462]. We introduce a DMRG wave function maximum overlap following technique to facilitate state-specific DMRG excited-state optimization. Using DMRG configuration interaction (DMRG-CI) gradients, we relax the lo...

the alternative double bonds and conjugation in the polyene compounds are one of the main properties in these compounds. each carbon-carbon bonds in a polyene compound along the chain has appreciable double-bond character. the p-electrons are therefore not localized but are relatively free to move throughout the entire carbon skeleton as an one-dimensional box. the skeleton be considered as a r...