Professor Mike Baird
Organometallics, Catalysis and Polymer Chemistry

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BACKGROUND INFORMATION

Hon. B.Sc., McMaster University. M.A., Ph.D., University of Toronto.                               

Postdoctoral Fellow, Imperial College, London (with Prof. G. Wilkinson, FRS, Nobel Laureate).

Alexander von Humboldt Fellow, Technical University, Munich, 1975 (with Prof. E. O. Fischer, Nobel Laureate).                             

Fellow of the Chemical Institute of Canada.      

Chemistry Department Excellence in Teaching Award, 1982, 1989, 2002, 2003, 2009.                    

Alcan Lecture Award of the Chemical Institute of Canada, 1986.                                      

Inducted into the McMaster University Sports Hall of Fame, 1997.     

Prize for Excellence in Research, Queen's University, 1998.                                         

Catalysis Award of the Chemical Institute of Canada, 2002.                                                

Inaugural Inductee, Queen's University Athletic Coaches Hall of Fame, 2003.                

Elected Fellow of the Royal Society of Canada, 2003.

Canadian Catalysis Lectureship Award of the Canadian Catalysis Foundation and the Chemical Institute of Canada, 2009                                      

 

 

RESEARCH INTERESTS

Many branches of chemistry and materials science now interface with organometallic chemistry, defined as the study of compounds containing carbon-metal bonds. Thus organometallic chemistry research in our lab is interdisciplinary in nature and involves research on aspects of inorganic, organic, polymer, and catalysis chemistry. As outlined below and on the linked pages, we are currently working on a wide variety of research projects which offer opportunities for students and PDFs to gain both useful scientific knowledge and also experience with a number of important spectroscopic and analytical tools.

Projects to be initiated over the  next  year or so will give  new  graduate students opportunities to synthesize interesting organometallic compounds which have never been prepared before, to explore the use of organometallic compounds as catalysts for "green" chemistry and for making plastics biodegradable, to develop new initiators for polymer synthesis and to develop new catalytic applications of organometallic compounds to both  industrial processes and organic synthesis.

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Synthetic Organometallic Chemistry 

We have in the past few years initiated a new program of research into the synthesis and properties of phosphonium cyclopentadienylides and 1-indenylides such as methyldiphenylphosphonium 1-indenylide (I), a type of aromatic ylide ligand which shows great promise but which has been little investigated. Such ligands are interesting because they are intermediate in donor properties between anionic cyclopentadienide and neutral arene ligands, and because the 1-indenylide ligands form planar chiral complexes on coordination, as in II. Thus they may have very interesting properties as enantioselective catalysts since the chirality exists very close to the metal.

We have earlier prepared and studied I, and more recently we have also prepared the corresponding analogues Me2PhP-1-C9H6 and  Ph3P-1-C9H6. We are now involved in the synthesis of series of  complexes of the types  [(h5-ylide)TiCl3]PF6, [(h5-ylide)2TiCl2][PF6]2 and [Cp(h5-ylide)TiCl2]PF6, with intentions of extending this chemistry to zirconium and hafnium. Of potentially great significance, we shall investigate the use of the new compounds as catalysts for polymerization of propylene and 1-alkenes since the chirality of the complexes should result in significant degrees of tacticity in the polymers formed. In addition, the new titanium complexes are structurally very similar to titanocene derivatives which we have previously studied as anticancer drugs and, in collaboration with colleagues in the Cancer Research Labs at Queen’s, we shall also investigate their cytotoxic properties.

Moving to the platinum metals, we have synthesized complexes of the types [CpRu(h5-ylide)]PF6 (III) and (h5-ylide)RuCl2, and will in the very near future assess these for potential catalytic properties and as anti-cancer drugs. On another tack, recognizing the enhanced stabilities of complexes of chelating ligands, we are preparing the chelating ligands 1-C9H6PPh2(CH2)nPPh2 (IV). These should  coordinate to metals via both the five-membered ring and the pendant phosphine and, depending on n, the bonded C5 ring will be more or less skewed relative to the metal-C5 ring centroid. This will in turn induce subtle changes to the chemistry of the compounds and hence to catalytic properties. New chemistry involving rhodium is also in the works, with again the potential to make new compounds with potentially interesting catalytic properties.

These studies provide opportunities for new graduate students to both develop their synthetic skills and become adept at the use of NMR and IR spectroscopy, gas chromatography, mass spectrometry and X-ray crystallography. Compounds which have never before seen the light of day will be prepared, and potentially very interesting catalytic properties will be investigated.

 

Catalytic (“Green”) Organometallic Chemistry for Organic Synthesis 

A wide variety of palladium-catalyzed C-C, C-N and C-O bond forming methodologies are available through the 2010 Nobel Prize winning chemistry pioneered by e.g. Heck, Suzuki and Negishi, etc. Unfortunately procedures for synthesizing the necessary catalysts, which are palladium complexes of the type PdL2 (L = tertiary phosphine), are not always readily available because of uncertainties in the modes of preparation of the catalyst systems. However, as we have recently reported (Norton et al. J. Org. Chem. 2009, 74, 6674), Pd(h3-1-PhC3H4)(h5-C5H5) (V) reacts readily with two equivalents of L as shown to form compounds of the type PdL2 in a much more atom efficient manner than is normally the custom. Compound V is air-, water- and thermally stable, and is thus very user friendly. It is, in fact, quite likely the best route to the catalytic species PdL2.

We are currently demonstrating that solutions of PdL2, generated from V, exhibit enhanced catalytic activities for a variety of C-C, C-N and C-O cross-coupling processes, a result which we attribute to our procedure being able to convert essentially all of the metal to PdL2 and thus to our achieving higher concentrations of active PdL2 species than is the case using conventional precursors. Current research is extending the scope of our investigation to other cross-coupling reactions and other ligands L which have not previously been properly assessed. Future research will also investigate the use of analogous nickel based catalyst systems, as there is reason to believe that they will catalyze types of cross-coupling reactions not induced by palladium. Success in these ventures will greatly increase the breadth and usefulness of catalytic cross-coupling methodologies.

This topic provides opportunities for new graduate students to carry out a wide range of  catalyst studies. It will be of special interest to candidates with interests in organic chemistry and who wish to  become adept at the use of NMR and IR spectroscopy, gas chromatography and mass spectrometry.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

        Contact Information

         Professor Mike Baird,  
         Chernoff Hall, Queen's University,

         90 Bader Lane,
         Kingston, ON K7L 3N6
        

         Room: CHE 402 (Office), CHE 434 (Lab) 
         Office Telephone: 613-533-2614  
         Laboratory Telephone: 613-533-6000  ext. 74669  

         Fax: 613-533-6669

          e-mail: bairdmc@chem.queensu.ca

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Alkene Polymerization

 

Our recent research has focused on the use of catalysts to synthesize polyalkenes containing polar functionality (to alter physical and mechanical properties or to induce biodegradability), and on mechanisms of Ziegler catalysis. Our current research on functionalized polymers is discussed below and here we discuss mechanistic work on metallocene-based polymerization catalysts, which has exceeded all expectations. Thus we have shed light on several controversial aspects of metallocene polymer-ization catalysis, and we were the first to find a way to directly observe simple alkyl alkene species [Cp2Zr(Me)(CH2=CMeCH2CHMe2)]+ (VI: Sauriol et al., Angew. Chem., Int. Ed. 2009, 48, 3342). This is of a type universally believed to be intermediates in Ziegler polymerization processes, but never previously observed because of high proclivities to migratory insertion. The compounds exhibit unusually asymmetric alkene coordination and very unusual exchange processes such as intramolecular “flipping” between alkene faces and rotation of the =CMeCH2CHMe2 relative to the H2C= group.

 

 

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Different but equally strange behaviour was subsequently observed with the titanium analogue which rearranges, via migratory insertion and an unprecedented 1,5-s bond metathesis reaction involving e-agostic species, to give [Cp2Ti(CH2CHMeCH2CHMe2)]+ (VII) in which the italicized hydrogen atom engages in a very rare type of b-agostic interaction. If you are wondering what on earth all this means, see Sauriol et al., J. Am. Chem. Soc. 2010, 132, 13357.

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This work is significance because of both its novelty and the light it has shed on mechanisms of alkene polymerizations by metallocenes. Our future research will focus on zirconium chemistry by carrying out low temperature NMR studies on complexes of the type [Cp2Zr(Me)(alkene)]+ (alkene = 2,2-disubstituted-1-alkenes). We need to learn more about this class of compounds and we shall also attempt to isolate stable examples and characterize them  crystallographically. We shall also investigate alkene complexes of chiral, C2-symmetric zirconocenes which catalyze isospecific polymerization of e.g. propylene. There is much interest in the diastereomeric interactions in complexes of such prochiral alkenes, but it has to this point been impossible to study coordinated alkene intermediates directly. We can now do this, and we shall via e.g. NOESY experiments and with complementary DFT calculations to be carried out by theoretical collaborators. Note that  every “simple” reaction which we have carried out in this context so far has produced exciting results which were totally unexpected and which significantly expanded fundamental knowledge of both alkene complexes and metallocene catalyzed polymerization processes.

This project provides opportunities for new graduate students to specialize in the utilization of NMR techniques. All of the research involves intensive use of our high field instruments at low temperatures

 

 

Anticancer drugs        

Anticancer drugs based on platinum compounds have long been known for their efficacy, and we are working on a class of organotitanium compounds with similar properties but displaying a different mechanism of cytotoxicity and exhibiting lower toxicity than platinum-based drugs. We design and synthesize potential new drugs, and these are screened for their abilities to inhibit tumour growth in collaboration with medical scientists in the Cancer Research Lab at Queen's. To date sufficient compounds have been found to exhibit useful potencies against several cancer cell lines that structure-cytotoxicity relationships are becoming apparent. Current and future work will build on these successes and also expand into trying to gain an understanding of the mechanism(s) by which the new drugs work. 

This project provides opportunities for new graduate students to to gain expertise in the  synthesis and characterization of new compounds (both spectroscopically and crystallographically), and to collaborate with scientists in the Cancer Research labs at Queen's in the assessment of the potential new drugs which we shall make.