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Georgios C. Vougioukalakis

Bio: Georgios C. Vougioukalakis is an academic researcher from National and Kapodistrian University of Athens. The author has contributed to research in topics: Ene reaction & Ruthenium. The author has an hindex of 21, co-authored 80 publications receiving 3256 citations. Previous affiliations of Georgios C. Vougioukalakis include California Institute of Technology & Massachusetts Institute of Technology.
Topics: Ene reaction, Ruthenium, Alkene, Metathesis, Chemistry


Papers
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Journal ArticleDOI
TL;DR: The fascinating story of olefin (or alkene) metathesis began almost five decades ago, when Anderson and Merckling reported the first carbon-carbon double-bond rearrangement reaction in the titanium-catalyzed polymerization of norbornene.
Abstract: The fascinating story of olefin (or alkene) metathesis (eq 1) began almost five decades ago, when Anderson and Merckling reported the first carbon-carbon double-bond rearrangement reaction in the titanium-catalyzed polymerization of norbornene. Nine years later, Banks and Bailey reported “a new disproportionation reaction . . . in which olefins are converted to homologues of shorter and longer carbon chains...”. In 1967, Calderon and co-workers named this metal-catalyzed redistribution of carbon-carbon double bonds olefin metathesis, from the Greek word “μeτάθeση”, which means change of position. These contributions have since served as the foundation for an amazing research field, and olefin metathesis currently represents a powerful transformation in chemical synthesis, attracting a vast amount of interest both in industry and academia.

1,696 citations

Journal ArticleDOI
TL;DR: In this paper, a review article traces the discovery that were instrumental to the evolution of DSSCs, taking a critical look at the principles of the operation mechanism and insisting on the most important recent developments in the field.

222 citations

Journal ArticleDOI
TL;DR: In this critical review, all published techniques for the creation of an orifice, as well as for the expansion of an existing one, on the fullerene framework are surveyed.
Abstract: Open-cage fullerene derivatives have excited organic chemists’ creativity over the past decade. These adducts, generated via consecutive cleavage of σ- and π-carbon–carbon bonds on the fullerene cage, allow small atoms or molecules to pass through their opening and be placed inside the cavity. Restoration of the ruptured fullerene back to the pristine fullerene cage affords the corresponding endohedral complexes. This “molecular surgery” approach has been proposed as an alternative to the synthesis of endohedral fullerenes via the conventional physical methods of production, which restrict the availability of endohedral fullerenes to milligram quantities after laborious isolation procedures. In this critical review, we survey all published techniques for the creation of an orifice, as well as for the expansion of an existing one, on the fullerene framework. Successful encapsulation experiments employing cage-opened fullerene derivatives are also comprehensively discussed (160 references).

206 citations

Journal ArticleDOI
TL;DR: This Minireview summarizes the strategies for the sequestration of ruthenium impurities from olefin metathesis post-reaction mixtures, thus comprising a practical guide for synthetic chemists employing rutenium-catalyzed metatheses reactions in the synthesis of organic or polymeric materials.
Abstract: Summary and Outlook The complete removal of ruthenium residues from olefinmetathesis reaction products is rather challenging and oftenposes serious problems. In addition to pharmaceuticalchemistry applications, where the acceptable ruthenium con-tent is <5 ppm in the final compound, efficient purificationof olefin metathesis products is also highly important in thecase of polymeric materials, especially when these are to beused in electronics and other technologically advanced ap-plications. Equally important, unsuccessful exclusion ofruthenium impurities during the production of fine chemi-cals invokes the danger of undesired side-reactions in subse-quent steps.The objective of the present Minireview is to thoroughlydiscuss all available strategies for the removal of rutheniumimpurities from olefin metathesis post-reaction mixtures. Inview of the fact that there are many different approachesdealing with this problem, the assembly of this work willserve as a valuable guide for the synthetic chemist utilizingruthenium catalyzed metathesis reactions in the synthesis ofeither organic or polymeric materials.

125 citations

Journal ArticleDOI
TL;DR: A new family of ruthenium-based olefin metathesis catalysts bearing a series of thiazole-2-ylidene ligands has been prepared, and theosphine-free catalysts of this family are more stable than their phosphine-containing counterparts, exhibiting pseudo-first-order kinetics in the ring-closing of diethyldiallyl malonate.
Abstract: A new family of ruthenium-based olefin metathesis catalysts bearing a series of thiazole-2-ylidene ligands has been prepared. These complexes are readily accessible in one step from commercially available (PCy_3)_2Cl_2Ru CHPh or (PCy_3)Cl_2Ru CH(o-iPrO−Ph) and have been fully characterized. The X-ray crystal structures of four of these complexes are disclosed. In the solid state, the aryl substituents of the thiazole-2-ylidene ligands are located above the empty coordination site of the ruthenium center. Despite the decreased steric bulk of their ligands, all of the complexes reported herein efficiently promote benchmark olefin metathesis reactions such as the ring-closing of diethyldiallyl and diethylallylmethallyl malonate and the ring-opening metathesis polymerization of 1,5-cyclooctadiene and norbornene, as well as the cross metathesis of allyl benzene with cis-1,4-diacetoxy-2-butene and the macrocyclic ring-closing of a 14-membered lactone. The phosphine-free catalysts of this family are more stable than their phosphine-containing counterparts, exhibiting pseudo-first-order kinetics in the ring-closing of diethyldiallyl malonate. Upon removing the steric bulk from the ortho positions of the N-aryl group of the thiazole-2-ylidene ligands, the phosphine-free catalysts lose stability, but when the substituents become too bulky the resulting catalysts show prolonged induction periods. Among five thiazole-2-ylidene ligands examined, 3-(2,4,6-trimethylphenyl)- and 3-(2,6-diethylphenyl)-4,5-dimethylthiazol-2-ylidene afforded the most efficient and stable catalysts. In the cross metathesis reaction of allyl benzene with cis-1,4-diacetoxy-2-butene increasing the steric bulk at the ortho positions of the N-aryl substituents results in catalysts that are more Z-selective.

114 citations


Cited by
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Journal ArticleDOI
26 Jun 2014-Nature
TL;DR: A concise overview of N-heterocyclic carbenes in modern chemistry is provided, summarizing their general properties and uses and highlighting how these features are being exploited in a selection of pioneering recent studies.
Abstract: The successful isolation and characterization of an N-heterocyclic carbene in 1991 opened up a new class of organic compounds for investigation. From these beginnings as academic curiosities, N-heterocyclic carbenes today rank among the most powerful tools in organic chemistry, with numerous applications in commercially important processes. Here we provide a concise overview of N-heterocyclic carbenes in modern chemistry, summarizing their general properties and uses and highlighting how these features are being exploited in a selection of pioneering recent studies.

2,932 citations

Journal ArticleDOI
TL;DR: The fascinating story of olefin (or alkene) metathesis began almost five decades ago, when Anderson and Merckling reported the first carbon-carbon double-bond rearrangement reaction in the titanium-catalyzed polymerization of norbornene.
Abstract: The fascinating story of olefin (or alkene) metathesis (eq 1) began almost five decades ago, when Anderson and Merckling reported the first carbon-carbon double-bond rearrangement reaction in the titanium-catalyzed polymerization of norbornene. Nine years later, Banks and Bailey reported “a new disproportionation reaction . . . in which olefins are converted to homologues of shorter and longer carbon chains...”. In 1967, Calderon and co-workers named this metal-catalyzed redistribution of carbon-carbon double bonds olefin metathesis, from the Greek word “μeτάθeση”, which means change of position. These contributions have since served as the foundation for an amazing research field, and olefin metathesis currently represents a powerful transformation in chemical synthesis, attracting a vast amount of interest both in industry and academia.

1,696 citations

Journal ArticleDOI
TL;DR: This Review concludes with a conclusion that further research is needed into the determinants of infectious disease and the immune system in order to treat these diseases and provide effective treatments.
Abstract: We gratefully acknowledge funding and support from King Abdullah University of Science and Technology (KAUST). Thanks are also due to the KAUST communication department for designing several images for this Review.

1,497 citations