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OPPORTUNITIES IN HOMOGENEOUS AND SINGLE-SITE HETEROGENEOUS CATALYSIS Tobin Marks, DOE Catalysis Workshop May 2002 OPPORTUNITIES IN HOMOGENEOUS AND SINGLE-SITE HETEROGENEOUS CATALYSIS Tobin Marks, DOE Catalysis Workshop May 2002 I. III. IV. V. VII. Current Drivers New Tools and Techniques Single-Site Polymerization. Catalysis Materials Multi-Site Catalysts and Cocatalysts Carbon-Heteroatom Bond Formation Homogeneous-Heterogeneous Interface Biomimetic/Supramolecular, Enantioselective Catalysis VIII. Opportunities and Needed Resources

CURRENT DRIVERS FOR RESEARCH IN HOMOGENEOUS (HETEROGENEOUS) CATALYSIS ENORMOUS ECONOMIC IMPORTANCE!! – Environmental (Green CURRENT DRIVERS FOR RESEARCH IN HOMOGENEOUS (HETEROGENEOUS) CATALYSIS ENORMOUS ECONOMIC IMPORTANCE!! – Environmental (Green Chemistry, Atom Efficiency, Waste Remediation, Recycling) – Polymeric Materials (New Polymers and Polymer Architectures, New Monomers, New Processes) – Pharmaceuticals and Fine Chemicals (Demand for Greater Chemo-, Regio-, Stereo-, and Enantioselectivity) – Feedstocks (Practical Alternatives to Petroleum and Natural Gas) – Cost of Energy (More Efficient, Selective Processes) – Completely New Materials (e. g. , Carbon Nanotubes) – Cost Squeeze in Chemical Industry – Declining Corporate Investment in Basic Research

NEW TOOLS FOR HOMOGENEOUS (HETEROGENEOUS) CATALYSIS RESEARCH SIMPLE TO EXPENSIVE • New and In NEW TOOLS FOR HOMOGENEOUS (HETEROGENEOUS) CATALYSIS RESEARCH SIMPLE TO EXPENSIVE • New and In Situ Spectroscopies (NMR, EPR, IR/Raman, SPM, EM, X-Ray, EXAFS/XANES) • Synthetic Techniques (Exotic Ligands, New Elements, Solid State, Sol-Gel, Nanoscale) • Reaction Techniques (Combinatorial, High-Pressure, Polymerization) • Computational (DFT, ab initio, MD, combinations) • New Characterization Techniques (Calorimetry, Polymer, Isotopic, Stop-Flow, Chiral GC/HPLC)

A NEW GENERATION OF POLYOLEFINS A NEW GENERATION OF POLYOLEFINS

Creating Highly Electrophilic d 0 “Cations” On Surfaces In Solution Important Questions • What Creating Highly Electrophilic d 0 “Cations” On Surfaces In Solution Important Questions • What are the Thermodynamic Constraints on Metallocenium Formation? • What is the Structural and Dynamic Nature of the M+ - - X- Interaction? • How Does the M+ - - X- Interaction Modulate Catalytic Properties? • What is the Ultimate X-?

Organo-Lewis Acid Abstraction Chemistry Metallocene “Constrained Geometry” • M+. . . H 3 CB(C Organo-Lewis Acid Abstraction Chemistry Metallocene “Constrained Geometry” • M+. . . H 3 CB(C 6 F 5)3 - Interaction Largely Electrostatic • Extremely Active Polymerization Catalysts

Alkyl Group Effects on Ion Pair Formation and Structural Reorganization Energetics Calorimetry and Dynamic Alkyl Group Effects on Ion Pair Formation and Structural Reorganization Energetics Calorimetry and Dynamic NMR Data - H formation H ‡ reorganization H (kcal/mol) + B(C 6 F 5)3 CH 3 B(C 6 F 5)3 M = Zr R = CH 3 27 24 24 Reaction Coordinate Bulkier R = Alkyl Groups Hformation More Negative (More Exothermic); H‡reorganization. Smaller Polar Solvents H‡reorganization Smaller; Bulkier R Less Sensitive Cyclopentadienyl Alkyl Substitution Hformation More Negative (More Exothermic)

1. 32 1. 3 AB INITIO COMPUTED 2. 80 Å REACTION COORDINATE FOR OLEFIN 1. 32 1. 3 AB INITIO COMPUTED 2. 80 Å REACTION COORDINATE FOR OLEFIN INSERTION 2. 05 2. 0 2. 37 5 6. 49 1. 4 1 2. 1 4 2. 16 E (kcal/mol) 4. 72 Transition State 6 2. 37 Å Kinetic Product 1. 55 2. 09 1. 53 2. 93 6. 62 5. 48 8 3. 5 3. 0 2. 5 2. 0 1. 5 Reaction Coordinate in Benzene [Ethylene]—[CH 3 Ti] Distance (Å)

MODULATING CATION-ANION INTERACTION WITH PBAL 2 M(CH 3)2 + Ph 3 C+PBA- rac-Me 2 MODULATING CATION-ANION INTERACTION WITH PBAL 2 M(CH 3)2 + Ph 3 C+PBA- rac-Me 2 Si(Ind)2 Zr(CH 3)+PBA- + Ph 3 CCH 3 CGCZr(CH 3)+PBA- • Cation-Anion Interaction Very Sensitive to L 2 M (19 F NMR, Crystal Structure) • Olefin Polymerization Activity Very Sensitive to L 2 M

Are There Anion Effects on Me 2 C(Cp)(Flu)Zr. Me 2 -Mediated Propylene Polymerization ? Are There Anion Effects on Me 2 C(Cp)(Flu)Zr. Me 2 -Mediated Propylene Polymerization ? Syndiospecific Enchainment Mechanism : Does chain swinging require ion pair reorganization ? An ideal system to evaluate ion pairing effects !

Polypropylene 13 C NMR Spectra Me 2 C(Cp)(Flu)Zr. Me 2 + Cocatalysts rrrr Results Polypropylene 13 C NMR Spectra Me 2 C(Cp)(Flu)Zr. Me 2 + Cocatalysts rrrr Results Concentration Independent Over 32 - Fold Range [mm] rrrr % B(C 6 F 5)3 (Borane) 69 PBB [m] rrmr rmmr [m] [mm] rrrm(r) rrmm rrrm(m) 84 B(C 6 F 5)4 - (Borate) 84 PBA 91 15. 0 15. 5 15. 0 14. 5 14. 0 ppm

LONG CHAIN BRANCH FORMATION IN ETHYLENE POLYMERIZATION Macromonomer Branch Formation How to make reinsertion LONG CHAIN BRANCH FORMATION IN ETHYLENE POLYMERIZATION Macromonomer Branch Formation How to make reinsertion more probable ?

CATALYST NUCLEARITY MATRIX CATALYST NUCLEARITY MATRIX

Grand Challenges in Catalytic Single-Site Polymerization 1. Nonpolar + Polar Monomer Copolymerization = acrylate, Grand Challenges in Catalytic Single-Site Polymerization 1. Nonpolar + Polar Monomer Copolymerization = acrylate, vinyl acetate, vinyl chloride, acrylonitrile 2. Control of Polymer Architecture Controlled Comonomer Incorporation Telechelic long chain branching Controlled Branching hard + soft Block Structures Controlled Tacticity Stars, Dendrimers

Palladium-Catalyzed Hydroamination of 1, 3 -Dienes Mechanism in the presence of acid Mechanism in Palladium-Catalyzed Hydroamination of 1, 3 -Dienes Mechanism in the presence of acid Mechanism in the absence of acid Löber, O; Kawatsura, M. ; Hartwig, J. F. J. Am. Chem. Soc. 2001, 123, 4366 -4367

Use of Imido Complexes in Catalytic Hydroamination and Enantioselective Reactions of Allenes SO 2 Use of Imido Complexes in Catalytic Hydroamination and Enantioselective Reactions of Allenes SO 2 Ar NMe 2 N Ti N NMe 2 SO 2 Ar 5 mol% NH 2 · Ar 75 C Ar N C 6 H 6 CH 3 79 - 95% Ar N Zr THF + Ph. CH C Racemic 1. 8 equiv CHPh 25 C -THF Ar N Ph H H Zr + Ph H 1 equiv C C 0. 8 equiv 98 % ee Al 2 O 3 1 equiv H C C C H Ph Ph (S) 90 % ee H Ph Ph (R) (S, S) Ackermann, L. ; Bergman, R. G. “A Highly Reactive and Selective Precatalyst for Intramolecular Hydroamination Reactions” Org. Let. 2002; 4, 1475. Sweeney, Z. K. ; Salsman, J. L. ; Andersen, R. A. ; Bergman, R. G. “Synthesis of Chiral, Enantiopure Zirconocene Imido Complexes: Highly Selective Kinetic Resolution and Stereoinversion of Allenes, and Evidence for a Non-Concerted [2+2] Cycloaddition/Retrocyclization Reaction Mechanism, ” Angew. Chem. Int. Ed. Engl. 2000, 39, 2339. C

Catalytic Pathways for d 0, fn-Metal Mediated C-Heteroatom Bond Formation New Routes to Heteroatom-Substituted Catalytic Pathways for d 0, fn-Metal Mediated C-Heteroatom Bond Formation New Routes to Heteroatom-Substituted Molecules and Polymers

THERMODYNAMICALLY BASED STRATEGIES FOR CATALYTIC HETEROATOM ADDITION EXAMPLE: Olefinic Substrates Intramolecular EXPECTATIONS • S, THERMODYNAMICALLY BASED STRATEGIES FOR CATALYTIC HETEROATOM ADDITION EXAMPLE: Olefinic Substrates Intramolecular EXPECTATIONS • S, S‡ Favor Intramolecular Process • Hii < Hi • kii > ki • Hi (X): CH 3 H < Pr 2, NR 2 < SR, OR (X = Heteroatom Group) Intermolecular

Diastereoselectivity in Aminodiene Cyclization Good to excellent 2, 5 -trans (80% de), and 2, Diastereoselectivity in Aminodiene Cyclization Good to excellent 2, 5 -trans (80% de), and 2, 6 -cis (99% de) diastereoselectivities Concise synthesis of (±)-pinidine with excellent stereocontrols (2, 6 cis and trans-alkene)

Is Hydrophosphination Analogous? Is Hydrophosphination Analogous?

Metallocene – Metal Oxide Chemisorption 1. Lewis Acid Surfaces (Dehydroxylated Al 2 O 3, Metallocene – Metal Oxide Chemisorption 1. Lewis Acid Surfaces (Dehydroxylated Al 2 O 3, Mg. Cl 2) High Catalytic Activity Active Sites ~8% 2. Weak Brønsted Acid Surfaces (Si. O 2, Partially Dehydroxylated Al 2 O 3) Poorly Electrophilic Negligible Catalytic Activity

Catalysis with Organozirconium Hydrocarbyls Supported on Sulfated Zirconia Solid BrØnsted Super Acid Most active Catalysis with Organozirconium Hydrocarbyls Supported on Sulfated Zirconia Solid BrØnsted Super Acid Most active benzene hydrogenation catalyst known Polymerization activity varies with coordinative unsaturation: Zr. R 4 > Cp. Zr. R 3 > Cp 2 Zr. R 2

Scott’s Cr/Si. O 2 Ethylene Polymerization Catalyst S. Scott, J. Aijou J. Am. Chem. Scott’s Cr/Si. O 2 Ethylene Polymerization Catalyst S. Scott, J. Aijou J. Am. Chem. Soc. 2000, 122(37), 8968 -76. S. Scott, J. Aijou Chem. Eng. Sci. 2001, 56, 4155 -68.

Alkane Metathesis by Basset ethane metathesis propane metathesis isobutane metathesis Vidal, V. , et. Alkane Metathesis by Basset ethane metathesis propane metathesis isobutane metathesis Vidal, V. , et. al. Science, 1997, 276, 99 – 102.

Bifunctional Single-Site Supported Catalysts • Tailored Supports • Molecular Precursors (chemo-, regio-, stereoselectivity) Ziegler Bifunctional Single-Site Supported Catalysts • Tailored Supports • Molecular Precursors (chemo-, regio-, stereoselectivity) Ziegler Site Oligomerization Site ROMP Site Chain Transfer Site Cationic Site Anionic Site Second Ziegler Site Hydrogenation Site Close Proximity Multiple Coupled Transformations

Structure of Carbonic Anhydrase A Metalloenzyme CO 2 + H 2 O H 2 Structure of Carbonic Anhydrase A Metalloenzyme CO 2 + H 2 O H 2 CO 3 Nt ~ 107 – 109 sec-1 Now with Cd: T. W. Lane and F. M. M Morel Proc. Nat. Acad. Sci. USA 2000, 97, 4627 -4631

Artificial Enzyme for Olefin Epoxidation º • Encapsulation of catalyst ==> 100 -fold increase Artificial Enzyme for Olefin Epoxidation º • Encapsulation of catalyst ==> 100 -fold increase in lifetime. • Incorporation of ligands predictably modifies the internal cavity size to induce substrate selectivity Nguyen, Hupp and coworkers

Cyclic Carbonates from CO 2 + Epoxides Nguyen and coworkers Cyclic Carbonates from CO 2 + Epoxides Nguyen and coworkers

High Activity Allows Polymerization of More Sterically Hindered Monomers • Kinetic resolutions of inexpensive High Activity Allows Polymerization of More Sterically Hindered Monomers • Kinetic resolutions of inexpensive monomers for production of chiral polymers and resolved olefin monomers S Me 2 Si Zr Cl Cl + MAO R, S R + (isotactic)poly( S-3, 4 -dimethylpentene-1) s= k. S > 12 k. R John Bercaw, et al

Thermal, Catalytic, Regiospecific Functionalization of Alkanes (RBpin) • terminal product only steric preference for Thermal, Catalytic, Regiospecific Functionalization of Alkanes (RBpin) • terminal product only steric preference for a linear metal-alkyl complex Chen, H. ; Schlecht, S. ; Semple, T. C. ; Hartwig, J. F. Science 2000, 287(5460), 1995 -1997

Electrochemical Synthesis of Diamines Yudin and coworkers Electrochemical Synthesis of Diamines Yudin and coworkers

SUMMARY. FUTURE OPPORTUNITIES • MULTINUCLEAR / MULTIFUNCTIONAL CATALYSTS – Multisite Substrate Activation, Conversion – SUMMARY. FUTURE OPPORTUNITIES • MULTINUCLEAR / MULTIFUNCTIONAL CATALYSTS – Multisite Substrate Activation, Conversion – New Polymer Architectures, Modifications • NEW SURFACES – New Molecular Catalyst Activation Routes – Single-Site Ensembles • NEW OR IMPROVED TRANSFORMATIONS – Improved Selectivity (Chemo-, Regio-, Enantio-) – C-Heteroatom Formation (C-O, C-N, C-P, C-S, etc. ) – Abundant Feedstocks (CO 2, Si. O 2, Saturated Hydrocarbons, Biomass, Bioproducts, Waste) – Atom-Efficient, Heat-Efficient Transformations • NEW ELEMENTS, LIGANDS, COCATALYSTS – Early Transition Metals, Lanthanides, Actinides – Ligand Engineering – Cocatalyst Engineering

Catalytic Cycle for Aryl Ether Synthesis Catalytic Cycle for Aryl Ether Synthesis