University of Lodz, Poland
We have studied the catalysis of organic reactions in binary solvent mixtures and concentrated solutions of inorganic salts. These reactions include: metalloene reactions of aldehydes, ketones and tin phenoxides, hydrostannylation of alkenes and free radical additions leading to formation of new carbon-carbon bonds. We have been interested in explanation of the catalytic effect of different lithium salts on studied reactions. We have attributed it to the large “internal pressure” of the solvent, increase of its polarity and viscosity, Lewis acidity and facilitation of formation of the transition state.
Biography:
Dr. Wojciech J. Kinart was born on the 17th of May 1953 in Łódź. He graduated from the University of Łódź in 1977. On the 17th of April, 1980, he was awarded the Ph.D Degree in Chemistry. In 1996 he was awarded the habilitation degree in Chemistry at the University of Łódź. He is the author of 120 papers, two chapters in Comprehensive Heterocyclic Chemistry III, Oxford, 2008; and one chapter in Tin Chemistry: Fundamentals, Frontiers and Applications, Wiley, 2008. Research areas of his interest include: organometallic chemistry, organic and organometallic peroxides, ene reaction and metalloene reaction, physicochemical studies of equilibria in liquid solvent mixtures.
Xiamen University, China
The formation of metal-carbon bonds is a fundamental principle in organometallic chemistry. Construction of organometallics with more than two metal-carbon σ bonds remains a great challenge. Recently, we reported a novel organometallic complex, metallapentalyne, containing three metal-carbon σ bonds in the equatorial plane. X-ray study reveals that the carbyne angle is only 129.5°, which is the smallest carbyne angles observed thus far. Theoretical study shows that it is the first example of planar Möbius aromatic species. Metallapentalyne formally consists of a seven-atoms carbon chain and a transition metal (M+7C). Thereafter, with the extension of this carbon chain (ranging from seven atoms to twelve atoms), a series carbon-based polydentate organometallics (M+8C to M+12C) chelates containing four or five metal-carbon bonds were synthesized. For all of these complexes, the binding atoms, even the backbones are carbon atoms. These carbon-based polydentate chelates are named as “carbolong complexes”. A number of exceptional organometallic complexes delineated in this work. For example, M+8C represents the first example of σ-aromaticity in an unsaturated three-membered ring; M+10C is the first metal-bridged tricyclic aromatic system, in which the metal center is shared by three aromatic five-membered rings; M+12C represents the upper limit of coordination number of a metal atom bonding with carbon ligands in a planar geometry. In general, organometallic complexes are highly sensitive towards air, water and heat. However, these new metallacycles exhibit remarkable stability, which can even be stable at 100oC in air. Unique properties, such as aggregation induced emission enhancement, large stokes shifts and long lifetime (Nat. Chem. 2013, 5, 698) broad absorption from the ultraviolet-visible to the near-infrared region (Angew. Chem. Int. Ed. 2015, 54, 6181) and excellent photoacoustic and photothermal properties (Sci. Adv. 2016, 2, e1601031) have been demonstrated. Application of these carbonlong complexes on biomedicine and solar energy utilization is in progress in our laboratory.
Biography:
Dr. Haiping Xia was worked in Department of Chemistry, Xiamen University from 1999–2018. He has been Chair, Professor in Department of Chemistry, Southern University of Science and Technology from 2018-Present.
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