Catalytic activity of group nine metallo-porphyrins towards small molecule activation and substrate reactions in conventional and novel ionic liquid media / Sounak Sarkar.

Format:

Book

Manuscript

Thesis/Dissertation

Author/Creator:

Sarkar, Sounak.

Contributor:

Wayland, Bradford B., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Penn dissertations--Chemistry.

Chemistry--Penn dissertations.

Local Subjects:

Penn dissertations--Chemistry.

Chemistry--Penn dissertations.

Physical Description:

xxx, 231 pages : illustrations (some color) ; 29 cm

Production:

2011.

Summary:

The core objective of this thesis has been to investigate the thermodynamic, kinetic and reactivity behaviors of group 9 metalloporphyrins in a wide range of solvents and reaction media in order to develop reliable, atom-economic and environment friendly catalysts and catalytic systems for activation of small molecules like H2, O2, CO and straight chain alkenes and catalytic transformation of these substrates to commercially viable products and intermediates for commodity chemical manufacturing and renewable energy resources.

Equilibrium thermodynamic studies with methanol soluble rhodium porphyrins allowed experimental evaluation of Rh-OCH3 Bond Dissociation Free Energy (BDFE) for (porphyrin)Rh-OCH3 complex. Study of kinetics for simultaneous proton and ligand (methanol) exchange processes in solutions of rhodium porphyrins in methanol/benzene mixed solvent systems showed that rate of proton exchange between two opposite faces of the metalloporphyrin was found to follow a second order dependence on the concentration of methanol in the reaction mixture. The rate of exchange of methanol coordinated to the metal center of meso-tetra(mesityl)porphyrin rhodium(III) species (TMP)Rh III(OCH3)(CH3OH) with methanol molecules in bulk solvent showed unusual undulations with increase in bulk methanol concentration in the reaction medium which has been explained in this thesis to be occurring due to fluctuation in viscosity dependent diffusion free energy for non-ideal methanol/benzene mixed solvent system.

Equilibrium thermodynamics for reactions of rhodium porphyrin in methanol with a range of small molecule substrates like methanol, H2, CO, aldehydes, activated and inactivated alkenes have been reported in this thesis. The comprehensive dataset for thermodynamic, kinetic and reaction properties of rhodium porphyrins in methanol thus obtained augments the already existing database for solution thermodynamic and reaction properties of rhodium porphyrins in benzene and water.

The prospect of using water soluble cobalt complex of meso-tetra(3,5-disulfonatomesityl) porphyrin (TMPS) as an inexpensive catalyst for oxidation and oxidative cleavage of terminal olefins to generate respectively vicinal diols and aldehydes in environmentally responsible fashion in water using molecular dioxygen as terminal oxidant has been discussed.

A series of partially deuterated, low-viscosity, low melting N-butylpyridinium(d5) based ionic liquids were designed as base-stable, environment friendly and thermochemically inert reaction media which would also double as optically transparent spectroscopic solvent for allowing mechanistic evaluation of Rhodium(I) porphyrin catalyzed anti-Markovnikov hydroxylation of terminal unactivated alkenes to generate primary alcohols using conventional 1H NMR and electronic spectroscopic instrumentations. The viability of these newly developed partially deuterated ionic liquids as suitable alternatives for conventional organic solvents for supporting the proposed mechanism-guided rhodium porphyrin catalyzed anti-Markovnikov hydroxylation of unactivated terminal alkenes has been established by preliminary proof-of-principle experiments.

Notes:

Adviser: Bradford B. Wayland.

Thesis (Ph.D. in Chemistry) -- University of Pennsylvania, 2011.

Includes bibliographical references.