Dissertation/Thesis Abstract

Functionalization and applications of the pentamethylcyclopentadienyl ruthenium moiety
by Fairchild, Robert Michael, Ph.D., Georgetown University, 2008, 220; 3339906
Abstract (Summary)

Synthetic routes to [Cp*Ru(eta6-arene)]+ (Cp* = pentamethylclopentadienyl anion) and functionalized [Cp*(R)Ru(eta6-arene)]+/[Cp*(R)Ru(CH3CN)3]+ compounds have been developed. Specifically, the synthesis of [Cp*Ru(arene)]+ compounds is achieved in near quantitative yield by microwave reaction of [Cp*Ru(mu3-Cl)]4 with arenes in aqueous media. Alternatively, pendant arm bearing [Cp*(R)Ru(eta6-arene)]+ and [Cp*(R)Ru(CH3CN)3]+ compounds (R = OH, OR and NR1R2) are synthesized by the attack of water, alcohol, alkoxide, or amine nucleophiles on the readily available tetramethylfulvene complex [(eta6-C5Me4CH2)RuCl(mu-Cl)]2 or its simple acetonitrile derivative, [(eta6-C5Me4CH2)Ru(CH3CN)Cl2]. The [Cp*(R)Ru(eta6-arene)]+ compounds can generally be quantitatively converted back into [Cp*(R)Ru(CH3CN)31+ species by UV photolysis in CH3CN. Altogether, these novel synthetic methods, coupled with previously developed synthetic protocols, have been exploited in the synthesis of anion binding cryptophanes and organometallic linkers for [Cp*Ru]+ impregnated coordination polymers.

The metalation of the exterior arene faces of a variety of cryptophanes yields supramolecular capsules with pi-acidic cavities capable of encapsulating anions. 1H and 19F NMR spectroscopy establishes the selective binding of anions in NO2CD3 solution and allows the affinity of the cavity for different anions to be determined. Interestingly, the binding of more basic anions to the exterior of the cryptophane results in an "electrostatic allosteric effect" wherein the thermodynamic affinity of the cavity for anions is reduced. Additionally, binding of the oversized, conformationally fluxional, bis-trifluoromethanesulfonimidate anion is achieved with the largest cryptophane receptor, which is capable of trapping two distinct conformations of the guest within the host's cavity.

Lastly, with the goal of synthesizing [Cp*Ru]+ impregnated coordination polymers for catalytic applications, a variety of [Cp*Ru]+ and [Cp*(R)Ru]+ containing organometallic ligands are investigated. Solvothermal reaction of [Cp*Ru]+ metalated 1,4- and 1,3-benzenedicarboxylic acids results in the formation of 3D and 2D porous coordination polymers. Although the tightly packed materials are incapable of demetalation, the robust materials reversibly adsorb H2O. Additionally, the 3D organometallic coordination polymer displays interesting gating adsorption behavior.

Indexing (document details)
Advisor: Holman, K. Travis
School: Georgetown University
School Location: United States -- District of Columbia
Source: DAI-B 69/12, Dissertation Abstracts International
Subjects: Inorganic chemistry, Organic chemistry
Keywords: Cryptophane, Cyclopentadiene, Pendant arm, Pentamethylcyclopentadienyl, Ruthenium
Publication Number: 3339906
ISBN: 978-0-549-93954-2
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