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Synthesis and comparative studies of ruthenium complexes for metal-mediated carbon-hydrogen activation and olefin hydroarylation catalysis.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Synthesis and comparative studies of ruthenium complexes for metal-mediated carbon-hydrogen activation and olefin hydroarylation catalysis./
Author:	Foley, Nicholas Adam.
Description:	463 p.
Notes:	Adviser: T. Brent Gunnoe.
Contained By:	Dissertation Abstracts International70-01B.
Subject:	Chemistry, Inorganic. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3345371
ISBN:	9781109006544

Synthesis and comparative studies of ruthenium complexes for metal-mediated carbon-hydrogen activation and olefin hydroarylation catalysis.
Foley, Nicholas Adam.

Synthesis and comparative studies of ruthenium complexes for metal-mediated carbon-hydrogen activation and olefin hydroarylation catalysis. - 463 p.

Adviser: T. Brent Gunnoe.

Thesis (Ph.D.)--North Carolina State University, 2009.

TpRu(CO)(NCMe)Ph catalyzes the addition of aromatic C-H bonds across double bonds (i.e., olefin hydroarylation). Second generation TpRu(L)(NCMe)R {L = PMe3, P(OCH2)3CEt or P(pyr)3; pyr = pyrollyl; R = Me or Ph} complexes were synthesized to compare olefin hydroarylation activity versus the parent CO analog (Chapters 2 through 4). Experimental and computational studies indicate that TpRu(L)(NCMe)Ph initiates ethylene hydrophenylation by dissociation of NCMe, coordination of ethylene, insertion of ethylene into the Ru-Ph bond, coordination of benzene and C-H activation of benzene to release the olefin hydroarylation product ethyl benzene. Previously, kinetic isotope effect studies indicated that the C-H activation step is the rate determining step for the overall catalytic cycle.

ISBN: 9781109006544Subjects--Topical Terms:

517253
Chemistry, Inorganic.

Synthesis and comparative studies of ruthenium complexes for metal-mediated carbon-hydrogen activation and olefin hydroarylation catalysis.
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020 $a 9781109006544
035 $a (UMI)AAI3345371
035 $a AAI3345371
040 $a UMI $c UMI
100 1 $a Foley, Nicholas Adam. $3 1064638
245 1 0 $a Synthesis and comparative studies of ruthenium complexes for metal-mediated carbon-hydrogen activation and olefin hydroarylation catalysis.
300 $a 463 p.
500 $a Adviser: T. Brent Gunnoe.
500 $a Source: Dissertation Abstracts International, Volume: 70-01, Section: B, page: 0284.
502 $a Thesis (Ph.D.)--North Carolina State University, 2009.
520 $a TpRu(CO)(NCMe)Ph catalyzes the addition of aromatic C-H bonds across double bonds (i.e., olefin hydroarylation). Second generation TpRu(L)(NCMe)R {L = PMe3, P(OCH2)3CEt or P(pyr)3; pyr = pyrollyl; R = Me or Ph} complexes were synthesized to compare olefin hydroarylation activity versus the parent CO analog (Chapters 2 through 4). Experimental and computational studies indicate that TpRu(L)(NCMe)Ph initiates ethylene hydrophenylation by dissociation of NCMe, coordination of ethylene, insertion of ethylene into the Ru-Ph bond, coordination of benzene and C-H activation of benzene to release the olefin hydroarylation product ethyl benzene. Previously, kinetic isotope effect studies indicated that the C-H activation step is the rate determining step for the overall catalytic cycle.
520 $a Kinetic studies indicate the stronger donating PMe3 and P(OCH 2)3CEt ligands increase the rate of degenerate benzene C-H activation for TpRu(L)(NCMe)Ph systems relative to TpRu(CO)(NCMe)Ph. Hammett studies and kinetic isotope effect studies are consistent with a C-H activation mechanism which proceeds by a sigma-bond metathesis pathway. Increasing the acidity of the C-H hydrogen, and the basicity of the ligand receiving the hydrogen, accelerates C-H activation.
520 $a In benzene and ethylene mixtures, TpRu(L)(NCMe)Ph systems have decreased catalytic activity for ethylene hydrophenylation with the PMe3 and P(OCH2)3CEt systems decomposing to TpRu(L)(eta 3-C4H7) analogs. Increased metal electron density raises the activation barrier to olefin insertion allowing ethylene C-H activation to become competitive with ethylene insertion leading to TpRu(L)(eta 3-C4H7) formation. The P(pyr)3 ligand is electronically similar to CO, but its large steric bulk makes ethylene coordination endergonic, inhibiting entry into a catalytic ethylene hydrophenylation cycle.
520 $a In Chapter 5, TpRu(PMe3)(NCMe)Me stoichiometrically activates the sp3 bonds of acetonitrile, acetone and nitromethane to form TpRu(PMe3)(NCMe)CH2CN, TpRu(PMe3){kappa2-O,N-OC(Me)C(H)C(Me)NH} and TpRu(PMe3){kappa2-O,N-N(O)C(H)(NO 2)}, respectively. Experimental and computational studies suggest that C-H activation is promoted by thermodynamically favourable coordination via the heteroatomic functionality, increased basicity of the ligand receiving the hydrogen and substrate acidity. Additionally, TpRu(PMe3)(NCMe)Me mediates subsequent C-C/C-N bond-forming reactions with acetonitrile and acetone.
520 $a In Chapter 6, a series of cationic [EpRu(L)(L')R][A-] and [C(pz)4Ru(L)(L')R][A-] [Ep = tris(pyrazolyl)ethane; L = PMe3, P(OCH2)3CEt, or CO; L' = PPh 3, NCMe or THF; R = Me or Ph; A- = BAr'4, BPh4 or OTf; BAr'4 = {tetrakis(3,5-trifluoromethyl)phenyl}borate; pz = pyrazolyl] complexes were synthesized and tested for olefin hydroarylation activity. [EpRu(CO)(NCMe)Ph][A-] (A- = BAr' 4 or BPh4) was found to catalyze a 2 -- 3 turnovers of ethyl benzene in ethylene and benzene mixtures. Cyclic voltammetry gave strongly positive irreversible oxidative potentials suggesting poor catalysis is linked to the greater electron deficiency of the complexes, relative to TpRu(CO)(NCMe)Ph. A successful cationic Ru olefin hydroarylation catalyst will likely have a Ru(III/II) redox potential near 1 V.
520 $a TpaRu(CO)(NCMe)Ph {Tpa = allyl-tris(pyrazolyl)borate} was synthesized with the intention to attach it to the surface of mesoporous silica nanoparticles (MSN) in Chapter 7. In collaboration with another research group a prototype was developed. Initial catalytic studies showed no activity for ethylene hydrophenylation. Characterization of the new prototype {TpRu(CO)(NCMe)Ph-MSN} is challenging. IR spectroscopy suggests the Ru ligand structure was adversely altered by the MSN attachment process. New reaction schemes are proposed for the synthesis of TpRu(CO)(NCMe)Ph-MSN.
520 $a Finally in Chapter 8, the detection and isolation of the low yield contaminant ClTpRu(PPh3)2H {ClTp = chlorotris(pyrazolyl)borate} from the known synthesis of TpRu(PPh3)2Cl is reported. The mechanism of the H/Cl metathesis at the Tp boron is suspected to form from intermediates leading to the formation of TpRu(PPh3) 2Cl. ClTpRu(PPh3)2H was found to react with CH2Cl2 and CHCl3 to form ClTpRu(PPh3)2Cl. Both complexes were characterized with single crystal X-ray diffraction studies and 11B NMR spectroscopy. This report serves as an important warning that careful characterization for purity of TpRu(PPh3)2Cl, a common catalyst precursor, must be carried out following its synthesis.
590 $a School code: 0155.
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Chemistry, Organic. $3 516206
690 $a 0488
690 $a 0490
710 2 $a North Carolina State University. $3 1018772
773 0 $t Dissertation Abstracts International $g 70-01B.
790 $a 0155
790 1 0 $a Gunnoe, T. Brent, $e advisor
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3345371