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Lab Member

Alexander V. Polezhaev

Biography

Alexander V. Polezhaev was born in Moscow, Russia in 1984. An interest in chemistry appeared in high-school and he began study chemistry in Moscow city high-school №171 chemical lyceum. Prior to his graduate career, Alexander was an active undergraduate researcher at Moscow State University with Acad. Nikolay S. Zefirov working on melatonin derivatization for biological activities investigations. He received his specialist degree in organic chemistry in 2006 and then joined prof. A.A Koridze research group in A.N. Nesmeyanov Institute of Organoelement Chemistry. His Ph.D. research involves synthetic organometallic and coordination chemistries and catalysis, including the exploration of small molecule coordination and activation with arene and ferrocene-based pincer complexes and alkane dehydrogenation. During this work, two absolutely new types of complexes were found: metallocenium ions which could be considered as models of intermediates in electrophilic substitution in ferrocene core and cationic metallocenylidene ruthenium pincer complex – analogs of alpha-ferrocenylcarbocations. Additionally, he has teaching experience in Moscow city high-school №171 chemical lyceum and A.N. Kolmogorov high-school supervising talented pupils on his first steps in science. Alexander received his Ph.D. in 2011 and then got a researcher position in N.E. Bauman Moscow State Technical University. He worked as independent researcher in polymer composite material chemistry developing self-healing materials for application in constructions and antibacterial polymers for medicine; two patents resulted from this work.He is interested in various branches of organometallic and polymer chemistry: platinum metal complexes, small molecules activation, metallocene derivatization, homogenous catalysis, non-innocent ligands, self-healing polymers, antibacterial polymers and also in bioorganometallic chemistry.

Research Projects

Alexander Polezhaev’s research goal is to develop new active species that combine two functionalities, unsaturated carbon atom (carbene) and unsaturated metal center, in one molecule. This approach includes simultaneous formation of both functionalities by elimination of a proton from imidazolium fragment and a counterion from the metal center. To realize this in practice, our ligands must fix the metal in β-position to the carbene and prevent rearrangement and formation of a direct metal-carbene bond (Scheme 1).

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Scheme 1. Unusual metal-supported free carbene.

Those species contains highly active nucleophilic and electrophilic centers in one molecule; such bifunctional character makes them attractive in numerous processes. We target small molecules such as carbon dioxide, dinitrogen, dihydrogen and nitrous oxide to incorporate them in catalytic processes leading to valuable chemicals. Our approach combines classic transition metal assisted activation of small molecules (Scheme 2) with carbene-derived organocatalysis. Those species can also be considered as intramolecular Frustrated Lewis Pairs and we expect reactivity related to that known for such systems.

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Scheme 2. Bifunctional activation of small-molecules with metal and carbene

We also anticipate non-innocent behavior from our ligands in the activation process, such as possible electron-shuttling from substrate to metal and back. We also expect that this ligand class direct could stabilize unusual transition metal oxidation states.

Lab Member

Dr. Skye Fortier

Biography

Skye Fortier is a native of the Southwest, born and raised in the far West Texas town of El Paso, which is directly located on the US/Mexico border. As an undergraduate, Skye attended the University of Texas at El Paso (UTEP) where he received a MARC (Minority Access to Research Careers) scholarship. As a MARC scholar, Skye worked under the direction of Prof. Keith Pannell investigating the photochemically induced formation of carbon-silicon bonds utilizing ‘Fp’ precursors (Fp = CpFe(CO)2). After graduating in 2005, Skye worked for one year as a high school science teacher at Irvin High School in El Paso teaching freshmen and junior classes.In 2006, Skye entered the graduate program at the University of California, Santa Barbara (UCSB). At UCSB, Skye worked in Prof. Trevor Hayton’s laboratory investigating the organometallic chemistry of uranium. In particular, his studies in the Hayton laboratory focused on the synthesis of high-valent homoleptic molecules and uranium complexes featuring metal-ligand multiple bonds. Graduating from UCSB with his Ph.D. in Fall 2011, Skye traded in the West Coast for the Midwest in order to work as a postdoctoral researcher under the joint supervision of Profs. Mindiola and Caulton. At IU, he is investigating the synthesis, reactivity, and redox chemistry of metal complexes supported by non-innocent, redox-active frameworks. Skye is a recipient of an NSF American Competitiveness in Chemistry Postdoctoral Fellowship.

Research Projects

My research is broadly targeted towards investigating the synthesis, reactivity, and redox chemistry of low-valent, first-row transition metal complexes supported by non-innocent, redox-active frameworks. The ultimate goal of this work is to develop electron-rich complexes, incorporating inexpensive earth abundant metals, for use in catalysis and group transfer chemistry.

Currently, my project is centered on examining the use of a brand new redox-active ligand platform, namely the indigo derivedN,N’-diaryldiimines (best known as ‘Nindigo’) recently developed by the Hicks’ Group at the University of Victoria. Nindigo is novel in the sense that it is binucleating, consisting of two nacnac-type fragments. Moreover, Nindigo is a modular system; the sterics of the imine substituents can be tuned depending on the aniline used during the condensation reaction with indigo. Finally, Nindigo is highly conjugated which is clearly evinced by itsintensedeep purple color – staining all that it touches!

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It has been established that free Nindigo can readily undergo a two-electron oxidation process to generate neutral, stable dehydroNindigo species. In principle, this means that Nindigo possesses the capacity to act as an electronic reservoir capable of releasing electrons. When complexed to a metal, it is anticipated that a synergetic metal-ligand effect will occur affording multi-electron reactivity that extends beyond the capabilities of the metal center itself.

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My research has revealed that Nindigo can be readily deprotonated using silylamide bases. For instance, treatment of H2dmp2Nindigo (dmp = 2,6-dimethylphenyl) with 2 equivalents of Li[N(SiMe3)2] readily affords dmp2Nindigo[Li(THF)2]2in good yields.

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Reaction of dmp2Nindigo[Li(THF)2]2with metal halides, namely CoCl2and FeCl2, affords the tetrahedral metal ‘-ate’ complexes dmp2Nindigo[MCl{Li(THF)3Cl}]2(M = Co, Fe).

Additionally, reaction of H2dipp2Nindigo (dipp = 2,6-diisopropylphenyl) with Co(NR2)2(R = SiMe3) yields the tetrahedral Co(II) complex dipp2Nindigo[Co(NR2)(THF)]2. In a similar fashion, I intend to use M(NR2)2with Nindigo to generate other Nindigo[M(NR2)]2species.

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These complexes will serve as the platform for my investigation into the reactivity of first-row transition metal Nindigo systems.

Finally, it should be noted that given Nindigo is both highly conjugated and binucleating, the potential for intramolecular metal-metal communication exists which could allow for interesting magnetic and electronic properties. Indeed, I have found that analysis of paramagnetic dipp2Nindigo[Co(NR2)(THF)]2by SQUID magnetometry reveals antiferromagnetic coupling between the Co(II) centers at low temperatures.

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