Publications by authors named "Ramakrishna Samudrala"

The report that the central bond photoisomerization of the 1,3,5-hexatrienes (Hts) is highly inefficient has encouraged theoreticians to seek conical intersections (CIs) at geometries that can explain rapid nonradiative return to the initially excited isomer. Because they are photochemically silent, torsional relaxations about the terminal double bonds of the Hts have not been evaluated as significant radiationless decay pathways. Study of the photoisomerization of trans,trans,trans- and trans,cis,trans-1,6-dideuterio-1,3,5-hexatrienes ( ttt- and tct-Ht) addresses this issue.

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In glassy isopentane at 77 K, 1-phenyl-4-(4-pyridyl)-cis-1,cis-3-butadiene (cc-PPyB) and 1-phenyl-4-(4-pyridyl)-cis-1,trans-3-butadiene (ct-PPyB) can undergo simultaneous two-bond photoisomerization. Under the same conditions, 1-phenyl-4-(4-pyridyl)-trans-1,cis-3-butadiene (tc-PPyB) gives tt-PPyB, the ultimate photoproduct in all cases.

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Donor-σ-Acceptor (D-σ-A) molecules, arrayed in a monolayer between electrodes, can serve as molecular rectifiers. Using perylene-3,4,9,10-tetracarboxylic bisimide (PBI) as the acceptor allows the attachment of the donor group to one imide nitrogen and a solubilizing swallowtail, normally a long (e.g.

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A number of N,N'-disubstituted perylenetetracarboxylic diimides have been reported to bind effectively to DNA that adopts G-quadruplex motifs. In some cases, this binding may actively drive the transition from single-strand DNA to the quadruplex form. The perylenediimides in the reported cases all have amine-containing side chains, which are thought to interact with the grooves of the quadruplex and help dictate the selectivity of these compounds for quadruplex versus duplex DNA.

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