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Structural and Mechanistic Aspects of Copper Catalyzed Atom Transfer Radical Addition Reactions in the Presence of Reducing Agents William T. Eckenhoff and Tomislav Pintauer Department of Chemistry and Biochemistry Duquesne University Pittsburgh, PA 15282 1 Thesis Defense

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  • 1. Structural and Mechanistic Aspects ofCopper Catalyzed Atom Transfer Radical Addition Reactions in the Presence ofReducing AgentsWilliam T. Eckenhoff and Tomislav PintauerDepartment of Chemistry and BiochemistryDuquesne UniversityPittsburgh, PA 15282 Thesis Defense 1

2. Kharasch Addition Reaction Free Radical MechanismInitiation:CN Initiated by light or radical AIBN+ N2CN initiators (e.g. AIBN)CN + Br3C Brki+ CBr3 Br PRINCIPLE PROBLEMS:Propagation: kp R- Unavoidable radical-radicalkaddBr3CBr3CCBr3 +Rtermination reactions R R n R(kt1.0109 M-1s-1) Brktr- Repeating radical addition to Br3C+ Br3C Br Br3C+ CBr3 RRalkene to generate oligomers/monoadductpolymersTermination:radical-radical coupling- Low chain transfer constantktCBr3 + CBr3Br3C CBr3(ktr/kp) CNCN CNSOLUTIONS: + kt- Search for better halogen CNR kttransfer agents (transition metal Br3C + Br3C RBr3CCBr3 Rcomplexes)etc.RKharasch, M. S.; Jensen, E. V.; Urry, W. H. Science 1945, 102, 128. 2 3. Transition Metal Catalyzed (TMC) ATRA Transition metal complexes of Fe, Ru, Co, Ni and Cu areparticularly effective halogen transfer agents. Variety of alkenes and alkyl halides can be utilized. ka,1ka,2 K1= K2= kd,1kd,2X kd,1 kd,1kd,2 kd,2R XCuILmX R R TO ACHIEVE HIGH YIELDS: R - Radical concentration must be nR low (ka,1 and ka,2ka,2 and ka,20) CuIILmX2RR R - The formation of oligomers/ polymers should be suppressed Rkt (kd,2[CuIILmX]>>kp[alkene])R kt RkaddRR R R etc. R Minisci, F. Acc. Chem. Rec. 1975, 8, 165.L=complexing ligand Clark, A. J. Chem. Soc. Rev. 2002, 31, 1.X=halide or pseudo halide Severin, K. Curr. Org. Chem. 2006, 10, 217. 3 4. TMC ATRA in Organic Synthesis Can be conducted intermolecularly and intramolecularly. Atom transfer radical cyclization (ATRC) is a particularlyattractive tool because it enables synthesis of functionalizedring systems. -lactones and -lactams ClCl CCl3 Cl CH3CN, 110 oC OOCuCl (30 mol%) 16 hO OCascade TMC ATRA95% yieldOO O O DCE, 80 oC ClOEtCl OEt CCl3Cl Cl ClClCuCl/bpy (25 mol%) H18 h ONO NCH3CN, RT Cl CuCl/bpy (5 mol%) 61% yield 15 minSO3CH3SO3CH3 91% yieldClark, A. J. Chem. Soc. Rev. 2002, 31, 1.Yang, D.; Yan, Y. -L.; Zheng, B. -F.; Gao, Q.; Zhu, N.-Y. Org. Lett. 2006, 8, 5757. 4 5. TMC ATRA is not Widely Used in OrganicSynthesisSciFinder Scholar Search as of February 1, 2010 5 6. Current Drawbacks of TMC ATRA TMC ATRA despite being discovered nearly 20 years before tinmediated radical addition to olefins and iodine atom transferradical addition is still not fully utilized as technique in organicsynthesis. The principal reason is that TMC ATRA typically requiresbetween 5 and 30 mol% of catalyst relative to alkene. Problems in product separation and catalyst recycling. Process is environmentally unfriendly and expensive.Methodologies developed to overcome these drawbacks:Design of solid supported catalystsUse of biphasic systems (fluorous solvents)Development of highly active complexes based on liganddesignCatalyst regeneration in the presence of reducingagentsClark, A. J. Chem. Soc. Rev. 2002, 31, 1.6 7. Catalyst Regeneration in the Presence of Reducing Agents The rate of alkene consumption in ATRA depends onII the ratio of Iconcentrations of activator (Cu ) and deactivator (Cu -X):d[M] k addK ATRA [M][RX][CuI]= k add [M][R ] = dt[CuII X] Deactivator accumulates during the process as a result ofradical termination reactions. Reducing agents can be used to regenerate activator.ka,1 MtnLm + R Xkd,1 Mtn+1LmX + R Originally developed for ktatom transfer radicalpolymerization (ATRP). R RCNCN AIBN Successfully applied toX ATRA catalyzed by copper(II) N2Eckenhoff, W. T.; Pintauer, T. Cat. Rev. - Sci. Eng. 2010, 51, 1-59.Ricardo, C.; Pintauer, T. Chem. Comm. 2009, 21, 3029-3031.and ruthenium(III) complexes.Pintauer, T.; Matyjaszewski, K. Chem. Soc. Rev. 2008, 37, 1087.Eckenhoff, W. T.; Garrity, S. T.; Pintauer, T. Eur. J. Inorg. Chem. 2008, 563.Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2007, 46, 5844.Quebatte, L.; Thommes, K.; Severin, K. J. Am. Chem. Soc. 2006, 128, 7440.Matyjaszewski, K.; Jakubowski, W.; Min, K.; Tang, W.; Huang, J.; Braunecker, W. A.; Tsarevsky, N. V. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 15309. 7 8. TMC-ATRA in the Presence of Reducing Agents8 9. ATRA Catalyzed by CuI(TPMA)Cl Complex in thePresence of Reducing Agent AIBNTPMA IEntryAlkeneRCl[Alkene]0/[Cu ]0 Yield (%) TON1 1-hexene CCl4 10000:1 72 720025000:1 98 49003 1-octene CCl4 10000:1 67 670045000:1 87 43505 styreneCCl41000:1 424206 500:1 542707 250:1 852128 methyl acrylateCCl41000:1 606009 1-hexeneCHCl31000:1 56560 10 1-octeneCHCl3 500:1 49245 11 styrene CHCl31000:1 58580 12 methyl acrylate CHCl31000:1 63630 Can be conducted using either copper(I) or copper(II) complex. TONs for 1-octene (4350-6700) and 1-hexene (4900-7200) highest so far for coppermediated ATRA. Previous TONs ranged between 0.1 and 10!Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2007, 46, 5844. 9 10. ATRA Catalyzed by [CuII(TPMA)Br][Br] Complex in the Presence of Reducing Agent AIBNEntryAlkeneRBr [Alkene]0:[CuII]0Yield (%) TON1 methyl acrylate CBr4 / 32 /2 200,000:181(76)1.61053 100,000:1949.41044styreneCBr4 / 72 / Highest TONs for5 200,000:195(86)1.9105 copper mediated6 100,000:1999.9104 ATRA7 methyl acrylate CHBr31,000:1 575.7102Highly efficient8 500:1663.3102 ATRA in the9styreneCHBr310,000:1707.0103 presence of 105,000:1 773.9103 5-100 ppm of 111,000:1 929.2102 copper 12 1-hexeneCHBr310,000:161(59)6.1103 13 1-octeneCHBr310,000:169(54)6.9103 14 1-deceneCHBr310,000:163(64)6.3103 Eckenhoff, W. T.; Garrity, S. T.; Pintauer, T. Eur. J. Inorg. Chem. 2008, 563. 10 11. Copper Catalyzed ATRA of Highly Active Alkenes Alkenes with high propagation rate constants in free radicalpolymerization require large catalyst loadings. Competing radical polymerization initiated by AIBN at elevatedtemperatures. Solution is to utilize redox reducing agents (ascorbic acid, glucose,magnesium, etc.) or low temperature free radical initiators such as V-70 kp (M-1 s-1) Alkene 60oC25oC 2.8x1041.3x104 3.1x1041.5x104 7.9x1033.4x103Pintauer, T.; Eckenhoff, W.T.; Balili, M. N. C.; Biernesser, A. B.; Noonan, S. J.; Ricardo, C.; Taylor, M. J. W. Chem. Eur. J. 2009, 15, 38.11Beuermann, S.; Buback, M. Prog. Poly. Sci. 2002, 27, 191-254 12. Highly Efficient Ambient Temperature ATRA inthe Presence of V-70 as a Reducing Agent For simple -olefins, efficient ATRA was achieved using as littleIIas 0.002 mol% of [Cu (TPMA)X][X] complexes (20 ppm!!!). Reactions were also very efficient for methyl acrylate, methylmethacrylate and vinyl acetate.Pintauer, T.; Eckenhoff, W.T.; Balili, M. N. C.; Biernesser, A. B.; Noonan, S. J.; Ricardo, C.; Taylor, M. J. W. Chem. Eur. J. 2009, 15, 38. 12 13. Structural Features of CuI(TPMA)Cl and [CuII(TPMA)Cl][Cl] Complexes CuI(TPMA)Cl[CuII(TPMA)Cl][Cl] Copper(I) and copper(II) complexes are structurally similar. 13Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2007, 46, 5844. 14. Structural Features of CuI(TPMA)Br and [CuII(TPMA)Br][Br] ComplexesCuI(TPMA)Br[CuII(TPMA)Br][Br] Copper(I) and copper(II) complexes are structurally similar.Eckenhoff, W. T.; Garrity, S. T.; Pintauer, T. Eur. J. Inorg. Chem. 2008, 563.14 15. Questions about ATRA Mechanism The role of halide anion coordination to [CuI(TPMA)]+ remainsunclear. Nature of ATRA(ISET or OSET)? Equilibrium constant for ATRA can be expressed in terms of:KETMtnLm Mtn+1Lm + e Electron Transfer For a given alkyl halideX + eKEA XElectron Affinity KATRA will depend onKBH KET and KHPR-X R + X Bond HomolysisKATRA=KEAKBHKHPKETKHPX + Mtn+1Lm Mtn+1LmXHalidophilicity KATRAKATRA= KETKHPMtnLm + RXMtn+1LmX + RKEAKBH 15 Lin, C.Y.; Coote, M.L.; Gennaro, A.; Matyjaszewski, K. J. Am. Chem. Soc. 2008, 130(38), 12762-12774 16. Correlating Redox Potential with Catalyst ActivityMore Reducing CuIBr ComplexesHigher Activity in ATRA NN N NNNR R NNNNNRN NRRN N NN NN N RN N0 -50 -100 -150-200 -250-300 -350-400-450 -500E1/2 / mV v.s. SCEQiu, J.; Matyjaszewski, K.; Thouin, L.; Amatore, C. Macromol. Chem. Phys. 2000, 201, 1625-1631. 16 17. Cyclic Voltammetry of [CuI(TPMA)][A] Complexes Complex Supp. Elect.E1/2 /mV Ep / mVipa/ipc [CuI(TPMA)][BPh4] TBA-BPh4 -3971071.17 TBA-Br -6991090.94 [CuI(TPMA)][ClO4] TBA-ClO4 -422 940.95 TBA-Br -706 970.92[CuI(TPMA)][PF6]TBA-PF6 -421 880.94 TBA-Br -711 880.91 CuI(TPMA)Br TBA-Br -720 931.08 CuI(TPMA)Cl TBA-Cl -7421111.16 Potentials are reported vs. Fc/Fc+. Coordination+ of bromide anion toI[Cu (TPMA)] results in a formationof much more reducing CuI(TPMA)Br complex. Based on CV (KATRA), CuI(TPMA)Brcomplex should be a MILLIONtimes more active in ATRA. Eckenhoff, W. T.; Pintauer, T. unpublished results17 Eckenhoff, W. T.; Garrity, S. T.; Pintauer, T. Eur. J. Inorg. Chem. 2008, 563. 18. Cyclic Voltammetry of [CuI(TPMA)][A] Complexes TBA-Br was titratedinto a solution of[CuI(TPMA)BPh4]and was observedto quantitativelydisplace BPh4 fromcopper(I) complex. Explains effect ofsupporting salt onE1/2 on [CuI(TPMA)X]complexes. Displays stronglyaffinity of Br- to Cu(I).Eckenhoff, W. T.; Pintauer, T. unpublished results Eckenhoff, W. T.; Pintauer, T. unpublished results 3018 19. Conductivity of Copper ComplexesComplexConductivity (S)CuI(TPMA)Cl2.64(0.01)CuI(TPMA)Br3.01(0.02) CuI(TPMA)ClO4 5.50(0.05) CuI(TPMA)BPh4 6.29(0.02) CuI(TPMA)PF66.39(0.11) Conductance of copper(I) species reflect degree of ioniccharacter. Complexes with halide anions were found to have lessconductivity than those with non-coordination counter-ions. Suggests association in solutionEckenhoff, W. T.; Pintauer, T. unpublished results 19 20. Catalytic Performance of [CuII(TPMA)][A]Complexes in ATRAComplexR-X Alkene Alkene:Catalyst Conversion Selectivity Yield[Cu(TPMA)Cl][Cl] CCl4 Hexene5000:1 100% 100% 100%[Cu(TPMA)Cl][ClO4] 100% 100% 100%[Cu(TPMA)Cl][PF6]100% 100% 100%[Cu(TPMA)Cl][BPh4] 100% 100% 100%[Cu(TPMA)Cl][Cl] CCl4 Octene5000:199% 100%99%[Cu(TPMA)Cl][ClO4]99% 100%99%[Cu(TPMA)Cl][PF6] 99% 100%99%[Cu(TPMA)Cl][BPh4]95% 100%95%[Cu(TPMA)Cl][Cl] CCl4 Styrene 1000:176% 59% 45%[Cu(TPMA)Cl][ClO4]83% 60% 50%[Cu(TPMA)Cl][PF6] 81% 60% 49%[Cu(TPMA)Cl][BPh4]79% 59% 47%[Cu(TPMA)Cl][Cl] CCl4Methyl Acylate 1000:1 100% 45% 45%[Cu(TPMA)Cl][ClO4] 100% 48% 48%[Cu(TPMA)Cl][PF6]100% 48% 48%[Cu(TPMA)Cl][BPh4] 100% 44% 44%Reactions performed at 60oC in CH3CN, [alkene]0:[R-X]0:[AIBN]0=1:1:0.05, [alkene]0=2.10 M. Conv., Prod., and Yieldsdetermined by 1H NMR The counter-ion appears to have little or no effect on catalyticperformance in ATRA in the presence of AIBN. Does the counter-ion effect the rate of alkene consumption? Eckenhoff, W. T.; Pintauer, T. unpublished results20 21. Catalytic Performance of [CuII(TPMA)X][Y]Complexes in ATRA with AIBN04 00II [1-Oct] :[CCl ] :[AIBN] :[Cu ] =5000:5000:250:1 0 Rate of consumption of alkeneis independent on counter-ion. Rate should depend only onAIBN concentration. However, product distribution(particularly for highly activealkenes) MUST depend oncatalyst nature (ka and kd) k p [alkene]Controls thek d [CuII ]product yieldkaRX + CuILXR + CuIILX2 kdReactions performed at 60oC in CH3CN, [alkene]0:[CCl4]0:[AIBN]0=1:1:0.05, [alkene]0=2.10 M. Conv. determined by 1H NMREckenhoff, W. T.; Pintauer, T. unpublished results 21 22. Catalytic Performance of [CuI(TPMA)Y]Complexes in ATRA without AIBN Using 50:1 alkene to[MA]0:[CCl4]0:[Cu]0=50:50:1copper ratio, withoutAIBN present, complexeswith non-coordinatingcounter-ions were moreactive ComplexKATRA (10-7) [CuI(TPMA)Cl]2.21(0.07) [CuI(TPMA)ClO4]4.65 (0.03) [CuI(TPMA)BPh4]4.48 (0.07) Reactions performed at 60oC in CH3CN, [alkene]0:[CCl4]0 =1:1,Eckenhoff, W. T.; Pintauer, T. unpublished results [alkene]0=2.10 M. Conv. determined by 1H NMR22 23. Structural Features of CuI(TPMA)Br in Solution 1H NMR400 MHz, (CD3)2CO Low T 1H NMR consistent with X-ray structure. Proton / ppm H1 0.60 H2 0.12 H3 0.05 H4-0.32 H5 0.10 Broadening of the spectra is induced by fluxional processes:1. TPMA dissociation2. Br- dissociation Dimer formation unlikely (inequivalent methylene protons). 23Eckenhoff, W. T.; Garrity, S. T.; Pintauer, T. Eur. J. Inorg. Chem. 2008, 563. 24. Solution Equilibria for CuI(TPMA)X Complexes Addition of TBA-Br results TPMA signals shiftingtowards free ligand. Binding of TPMA is probably in equilibrium driven298 Kto the uncomplexed form.Possible Reasons for TPMA Fluxionality1. Halide dissociation2. TPMA arm dissociationEckenhoff, W. T.; Pintauer, T. Unpublished results24 25. Structural Features of [CuI(TPMA)(CH3CN)][BPh4]Axial elongation of Cu-N bondSimilar to CuI(TPMA)XCu1-N1=2.430(6) Cu1-N2=2.069(6) Cu1-N3=2.077(6) Cu1-N4=2.122(6) Cu1-N5=1.990(6) Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2010, 49(22), 10617-10626 25 26. Structural Features of [CuI(TPMA)]2[ClO4]2 First example of a dimer where one arm of TPMA ligand coordinates to the second metal center1H NMR (400 MHz, (CD3)2CO)Distorted TetrahedralCu1-N1=2.2590(13) Cu1-N2=1.9909(12) Cu1-N3=2.2213(16) Cu1-N4=1.9593(13) Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2010, 49(22), 10617-10626 26Eckenhoff, W. T.; Pintauer, T. Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 2008, 49(2), 282. 27. Structural Features of [CuI(TPMA)(CH3CN)][BPh4] 1H NMR (400 MHz, (CD3)2CO) [CuI(TPMA)][BPh4]Trigonal PyramidalCu1-N1=2.211(3) 180 K Cu1-Cu2=2.832(5) [CuI(TPMA)]2[ClO4]2[CuI(TPMA)BPh4]90% Monomeric10% Dimeric27Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2010, 49(22), 10617-10626 28. Structural Features of [(CuI(TPMA))-Br][BPh4] Originated from Iattempted synthesis of [Cu (TPMA)BPh4] by salt metathesis with [CuI(TPMA)Br]Shows another motif of copper(I) stabilization not previously consideredAlso indicates strong preference for halide bindingBimetallic Distorted TetrahedralCu1-N1=2.429(2) Cu1-N2=2.067(2) Cu1-N3=2.131(2) Cu1-N4=2.065(2) Cu1-Br1=2.5228(4) 28Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2010, 49(22), 10617-10626 29. 1HNMR of CuI(TPMA)Br with Excess TPMA 1HK NMR (400 MHz) CuI(TPMA)Br + TPMA* CuI(TPMA)*Br + TPMA(CD3)2CO432 ln(k/T)10 -1 -2 -3 0.0035 0.004 0.0045 0.005 0.00551/T(K)H=2.96 KJS=-60 J K-1G=43.25 KJ(10.3 kcal)Eckenhoff, W. T.; Pintauer, T. Unpublished results29 30. TPMA Arm Dissociation from Copper(I) Center Large coordinating ligands can displace single arm of TPMA. Also demonstrated previously with 1,4-diisocyanobenzene.Cu-Nax 2.325 Cu-Neq 2.085, 2.052 Cu-Ndis 2.523 Cu-Ndp 1.998 Molecular Structure of [CuI(TPMA)2(4,4-dipyridyl)][BPh4]2Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2010, 49(22), 10617-10626Hsu, S.C.; Chien, S.S.; Chen, H.H.; Chiang, M.Y. J. Chin. Chem. Soc. 2007, 54(3), 685-69230 31. ATRA Inhibition with PPh3 PPh3 bonds strongly to copper,displacing a pyridyl arm Tetrahedral geometry Oxidatively stable in air Pyridine signals shifted upfield fromPPh3 donation/weaker Py coordination 31P NMR shows downfield shiftMolecular Structure of [CuI(TPMA)2PPh3][BPh4]2Py -CH+ PPh3Cu-Nax 2.214 BPh4 PPh3Cu-Neq 2.073, 2.114BPh4 -N-CH2-Cu-Ndis 3.327 BPh4Py -CHPy -CHCu-P 2.1853 Eckenhoff, W. T.; Pintauer, T. Inorg. Chem. 2010, 49(22), 10617-10626 Tyeklar, Z.; Jacobson, R. R.; Wei, N.; Murthy, N. N.; Zubieta, J.; Karlin, K. D.J. Am. Chem. Soc. 1993, 115, 2677-2689. 31 32. ATRA Inhibition with PPh3 Addition of more thanstoichiometric quantities ofPPh3 inhibited ATRA, but smallamounts had little effect Rate decreased by a factor of10, almost completely stoppedwith 20 eq. of PPh3 with the[Cu(TPMA)Cl][Cl] catalyst Similar effect found with P-(OBu)4 AlkeneR-X Alk./Cat.0 Eq. PPh320 Eq. PPh340 Eq. PPh3 1-HexeneCCl4 5000:1100%95% 78% 1-OcteneCCl4 5000:1100%76% 22% Styrene CCl4 1000:1 26% 0% Methyl Acrylate CCl4 1000:1 44%28% Reactions performed at 60oC in CH3CN, [alkene]0:[R-X]0:[AIBN]0=1:1:0.05, [alkene]0=2.21 M. Yields determined by 1H NMR Eckenhoff, W. T.; Pintauer, T. unpublished results 32 33. ATRA in the presence of PPh3 ATRA catalyzed by [Cu(TPMA)PPh3][BPh4] proceeds similarlyto [Cu(TPMA)Cl][Cl]. R-X homolytic cleavage might occur through PPh3 dissociationor partial TPMA dissociation Large excesses of PPh3 can cause total TPMA displacement,producing a complex that is ATRA inactive[CuI(PPh3)(PPh3)][BPh4] [CuI(PPh3)3CH3CN][ClO4]Cu-P1: 2.3199(15) Cu-P1: 2.3150(5) Cu-P2: 2.3169(15) Cu-P2: 2.3362(5) Cu-P3: 2.3086(15) Cu-P3: 2.3147(5) Cu-P4: 3.9551(17) Cu-N1: 2.1010(17) Eckenhoff, W. T.; Pintauer, T. unpublished results 33 34. Copper complexes with TDAPA Ligand Very similar ligandstructure to highlyactive ligands Coordinates tocopper similarly 34 35. [CuII(TDAPA)X][Y] Performance in ATRA Copper Complexes with the TDAPA ligand showed very littleATRA activity Ligand dissociation should be much slower as compared toTPMA Slight counter-ion effect observed[Alkene]0:[CCl4]0:[AIBN]0:[CuII]0=250:250:12.5:1AlkeneAnionYield 1-hexeneCl-24% 1-octene 25% 1-hexeneBPh4-60% 1-octene 45% 1-hexene BF4-55% 1-octene 59%Reactions performed at 60oC in CH3CN, [alkene]0=2.39 M.Yields determined by 1H NMREckenhoff, W. T.; Pintauer, T. unpublished results 35 36. Conclusions Synthesis, characterization- and exceptional activity of [CuII -(TPMA)X][X] (X=Br and Cl ) complexes in ATRA ofpolyhalogenated compounds to alkenes in the presence ofreducing agent AIBN was presented. [CuII(TPMA)Br][Br] in conjunction with AIBN effectively catalyzedATRA of CBr4 and CHBr3 to alkenes with concentrations between5 and 100 ppm, which is the lowest number achieved in coppermediated ATRA. Structural and mechanistic studies indicate that partial TPMAdissociation may be required for ATRA. The rate of alkene consumption was found to depend only on theAIBN concentration. In the absence of AIBN, copper(I) complexes with non-coordinating counter-ions were found to proceed faster than thecorresponding chloride analogues.36 37. Acknowledgments Advisor: Dr. Pintauer Duquesne University Committee members: Dr. Basu Dr. Fleming Outside Reader: Dr. Matyjaszewski My Family: Dana Eckenhoff Parents - Drs Roderic and Maryellen Eckenhoff37 38. AcknowledgmentsGraduate Students Undergraduate Students Dr. Marielle Balili Sean Noonan Carolynne Ricardo Matthew Taylor April Hill Ashley Biernesser Raj Kaur Tom Ribelli Merton Pajibo 38 39. AcknowledgmentsSpecial Thanks to: The Bayer School Instrumentation Staff Dan Bodnar Dave Hardesty Lance Crosby Ian Welsh Sandy Russell, Amy Stroyne, Heather Costello 40. AcknowledgmentsFunding NSF Career Award (CHE-0844131) Duquesne University Start-up Grant NSF X-ray Facility Grant (CRIF-0234872) NSF NMR Grant (CHE-0614785)Thank You!40