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Sridevi V. Shinde Sarika Sinha Prof. Dr. Kumaravel Somasundaram Prof. Dr. Ashoka G. Samuelson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(39):12278-12291
Neutral half‐sandwich organometallic ruthenium(II) complexes of the type [(η6‐cymene)RuCl2(L)] ( H1 – H10 ), where L represents a heterocyclic ligand, have been synthesized and characterized spectroscopically. The structures of five complexes were also established by single‐crystal X‐ray diffraction confirming a piano‐stool geometry with η6 coordination of the arene ligand. Hydrogen bonding between the N? H group of the heterocycle and a chlorine atom attached to Ru stabilizes the metal–ligand interaction. Complexes coordinated to a mercaptobenzothiazole framework ( H1 ) or mercaptobenzoxazole ( H6 ) showed high cytotoxicity against several cancer cells but not against normal cells. In vitro studies have shown that the inhibition of cancer cell growth involves primarily G1‐phase arrest as well as the generation of reactive oxygen species (ROS). The complexes are found to bind DNA in a non‐intercalative fashion and cause unwinding of plasmid DNA in a cell‐free medium. Surprisingly, the cytotoxic complexes H1 and H6 differ in their interaction with DNA, as observed by biophysical studies, they either cause a biphasic melting of the DNA or the inhibition of topoisomerase IIα activity, respectively. Substitution of the aromatic ring of the heterocycle or adding a second hydrogen‐bond donor on the heterocycle reduces the cytotoxicity. 相似文献
994.
Prof. Dr. José Luis García Ruano Dr. José Alemán Leyre Marzo Dr. Cuauhtémoc Alvarado Dr. Mariola Tortosa Dr. Sergio Díaz‐Tendero Dr. Alberto Fraile 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8414-8422
We describe the unexpected behavior of the arylsulfonylacetylenes, which suffer an “anti‐Michael” addition of organolithiums producing their alkynylation under very mild conditions. The broad scope, excellent yields, and simplicity of the experimental procedure are the main features of this methodology. A rational explanation of all these results can be achieved by theoretical calculations, which suggest that the association of the organolithiums to the electrophile is a previous step of their intramolecular attack and is responsible for the unexpected “anti‐Michael” reactions observed for substituted sulfonylacetylenes. 相似文献
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Jessica Cid Dr. Jorge J. Carbó Dr. Elena Fernández 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12794-12802
Most trivalent boron reagents are electrophiles owing to the vacancy for two electrons to fill the outer orbital of boron; however, interestingly, trivalent boron compounds can change their electrophilic character to a nucleophilic character by only changing the nature of the substituents on the boron atoms. With the help of computational tools, we have analyzed the structural‐ and electronic properties of boryl fragments that were either bonded to main‐group metals or coordinated to transition‐metals/rare‐earth‐metals and we have designed a map that might help to identify certain trends. This trend map will be useful for selecting an appropriate trivalent boron compound, depending on the sought reactivity. 相似文献
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