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The purpose of this research was to characterize the rhodium exchanged NaX and NaY zeolites as propylene hydroformylation catalysts. Catalytic activity was measured in a differential bed reactor. Flow in situ infrared spectroscopy was used to probe the coordination chemistry of the zeolite modified rhodium carbonyls. The catalytic activity of rhodium zeolites at atmospheric pressure and between 100-150ºC was measured. The rate of n-butyraldehyde production was approximately 5x10⁻³ moles/g-Rh hr at 150°C. Regioselectivity was dependent upon pretreatment. Precarbonylation with carbon monoxide, drying with air, and heating with N₂ prior to hydroformylation conditions produced a straight to branched isomer ratio (n/i) of 1.9-2.3. Partial reduction with 10% H₂ in N₂ at 127°C lowered n/i to 1.3. Hydrogenation to propane was 3-10 times faster than the hydroformylation rate at 150°C. Catalytic activity was sensitive to cation exchange conditions. Rhodium form, pH, temperature, and salt concentration altered catalyst behavior. Only RhCl₃•3H₂O preparations on NaY zeolite produced above 80ºC, a pH above 4, and a salt concentration of 0.1N NaCl were required in order to produce an active hydroformylation catalyst. Ammine complexes did not activate under any circumstances. It was found that the degree of hydration controlled the formation of rhodium carbonyls. On NaY, the hydrated rhodium zeolite reacted with CO at 120ºC to form Rh₆(CO)₁₆. By drying the zeolite in air at 190ºC, two rhodium dicarbonyls, Rh(CO)₂(O_z)₂-NaY and Rh(CO)₂(O_z)(H₂O)-NaY, were formed. The rhodium carbonyls were reacted with n-hexyl diphenylphosphine to determine rhodium locations. Rh(CO)₂(O_z)₂-NaY was located at the surface while the other two species were located within the zeolite cages. One dicarbonyl species, Rh(CO)₂(O_z)₂-NaX, was observed on NaX. It was determined by reactions with phosphines that this species resides in the zeolite cages. Reaction intermediates identified by FTIR under hydroformylation conditions suggested that the heterogeneous catalyst proceeds through a mechanism similar to that occurring in solution. Heterogeneous reaction orders also agreed with those reported for homogeneous hydroformylations. Addition of dimethylphenylphosphine (DMP) to the rhodium zeolites significantly increased regioselectivity. Rates were slightly less than those from the unmodified rhodium carbonyls. However, the phosphine modified rhodium zeolites deactivated within 16 hours. Continuous exposure to DMP decreased the rate of deactivation. / Ph. D.

Hydrogen sulfide (H₂S) was recognized as a critical signaling molecule in mammals nearly two decades ago. Since this discovery biologists and chemists have worked in concert to demonstrate the physiological roles of H₂S as well as the therapeutic benefit of exogenous H₂S delivery. As the understanding of H₂S physiology has increased, the role(s) of other sulfur-containing molecules as potential players in cellular signaling and redox homeostasis has begun to emerge. This creates new and exciting challenges for chemists to synthesize compounds that release a signaling compound in response to specific, biologically relevant stimuli. Preparation of these signaling compound donor molecules will facilitate further elucidation of the complex chemical interplay within mammalian cells. To this end we report on two systems for the sustained release of H₂S, as well as other sulfur signaling molecules. The first system discussed is based on the N-thiocarboxyanhydride (NTA) motif. NTAs were demonstrated to release carbonyl sulfide (COS), a potential sulfur signaling molecule, in response to biologically available nucleophiles. The released COS is shown to be rapidly converted to H₂S in the presence of the ubiquitous enzyme carbonic anhydrase (CA). A synthetic route that affords NTAs with reactive functionalities was devised and the functional "parent" NTAs were successfully conjugated to a variety of substrates, ranging from small molecules to polymers. These functional NTAs provide a platform from which a library of NTA-based COS/H₂S may be readily prepared convergently in an effort to move towards H₂S-releasing drug and polymer conjugates. Additionally, preliminary in vitro cytotoxicity studies indicate that NTAs are noncytotoxic at concentrations above 100 µM. The second system discussed in this dissertation leverages the 1,6-benzyl elimination reaction (or self-immolative reaction) to facilitate the release of a persulfide (R–SSH) from a small molecule prodrug platform as well as a separate system that releases COS/H₂S from a polymer. The self-immolative persulfide prodrug was designed to be responsive to reactive oxygen species (ROS) and demonstrates efficacy as an antioxidant in vitro. Furthermore, the polymeric COS/H₂S self-immolative system was designed to respond to reducing agents, including H₂S itself, and shows promise as a H₂S signal amplification platform. / Doctor of Philosophy / Hydrogen sulfide (H₂S) has long been recognized as a malodorous and toxic byproduct of industrial chemical processes. However, the discovery of H₂S as a key signaling molecule in mammals has drastically shifted the paradigm of H₂S research over the last two decades. Research into the production and roles of H₂S in the body is ongoing, but has pointed to the implication of changes in H₂S production to the onset of a variety of disease states, including cardiovascular disease and Alzheimer’s. As alterations in the body’s production of H₂S have been correlated to certain disease states, collaborative research efforts among biologists and chemists have demonstrated the utility of H₂S-based therapeutics in helping to alleviate these disease states. Our understanding of the roles of H₂S in the body, and potential benefits derived from H₂S-releasing drugs, can only continue to advance with the development and improvement of H₂S releasing compounds. The first portion of this dissertation focuses on the synthesis of a new class of H₂S-releasing compounds, termed N-thiocarboxyanhydrides (NTAs). NTAs release H₂S through an intermediate sulfur-containing molecule, carbonyl sulfide (COS), which may have signaling properties independent of H₂S. The COS that is released from the NTAs is rapidly converted to H₂S by the action of the ubiquitous enzyme carbonic anhydrase. A variety of functional NTAs were synthesized, which in turn were used to prepare a small library of NTA-based COS/H₂S releasing compounds. This work informs the preparation of H₂S-drug or H₂S-polymer conjugates. The second portion of this dissertation examines a class of compounds broadly termed self-immolative prodrugs. The self-immolative prodrug platform was leveraged to release H₂S, or persulfides (R–SSH), another class of sulfur-containing molecules of biological interest. The self-immolative persulfide prodrug system was designed to be responsive to reactive oxygen species (ROS), a harmful cellular byproduct. The persulfide donor was successful in mitigating the harmful effects of ROS in heart cells. Independently, a polymeric self-immolative H₂S releasing system was designed to depolymerize in the presence of H₂S, resulting in the generation of 6-8-fold excess of H₂S upon depolymerization. We envision the self-immolative H₂S-releasing polymer will show promise in biological applications where a vast excess of H₂S is needed rapidly.

No / The Raman spectrum of budesonide is reported for the first time, and molecular assignments are proposed on the basis of ab initio BLYP DFT calculations with a 6-31 G* basis set and vibrational wavenumbers predicted on a quasi-harmonic approximation. Comparison with previously published infrared data has explained several spectral features, and the relative band intensities in the CO and CC stretching regions are interpreted. The results from this study provide data that can be used for the preparative process monitoring of budesonide, an important steroidal pharmaceutical in various dosage forms, and its interaction with excipients and other components.

The phenomenon luminescence rigidochromism has been reported since the 1970s in tricarbonyldiimine complexes with a general formula [R(CO)3LX] using conventional unipolar diimine ligands such as 2,2;-bipyridine or 1,10-phenanthroline as L, and halogens or simple solvents as X. As a major part of this dissertation, microwave-assisted synthesis, purification, characterization and detailed photoluminescence studies of the complex fac-[ReCl(CO)3L], 1, where L = 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl]-N,N-diethylbenzenamine are reported. The employment of microwaves in the preparation of 1 decreased the reaction time from 48 to 2 hours compared to the conventional reflux method. Stoichiometry variations allows for selective preparation of either a mononuclear, 1, or binuclear, fac-[Re2Cl2(CO)6], 2, complex. The photophysical properties of 1 were analyzed finding that it possesses significant luminescence rigidochromism. The steady state photoluminescence emission spectra of 1 in solution shift from 550 nm in frozen media to 610 nm when the matrix becomes fluid. Moreover, a very sensitive emission spectral analysis of 0.1 K temperatures steps shows a smooth transition through the glass transition temperature of the solvent host. Furthermore, synthetic modifications to L have attained a family of ambipolar compounds that have tunable photophysical, thermophysical and other material properties that render them promising candidates for potential applications in organic electronics and/or sensors - either as is or for their future complexes with various transition metals and lanthanides.

Trälim utgör en stor del av alla lim globalt och är avgörande för skapandet av träkompositmaterial, som många industrier och produkter är beroende av. Bland de vanligaste trälimmen använder flera formaldehyd som en väsentlig komponent i deras polymera struktur. Medan formaldehyd är ett allmänt använt, billigt och pålitligt material, är det också giftigt och har generellt ursprung från petroleumkällor. Ett ersättningsmaterial med di- eller polyaldehydisk funktionalitet av grönt ursprung är därför önskvärt för framtida trälimkemi. En potentiell lösning involverar att oxidera polysackarider såsom stärkelse och dextrin för att funktionalisera de upprepande glukosenheterna med aldehyder, ketoner och karboxylsyror. Här visas att Fenton-liknande förhållanden, med väteperoxid som oxidationsmedel och järn som katalysator, kan användas för att utföra reaktionen effektivt under atmosfäriska förhållanden, vilket producerar minimala biprodukter såsom vätgas, vatten och järnkomplex. Betydande funktionalisering observerades i en lågmolekylviktsfraktion som frigörs från polysackariden vid oxidation, en fraktion som traditionellt förloras under upparbetning via centrifugering. Detta arbete antyder att retention av denna lågmolekylviktsfraktion i produktblandningen kan förbättra framtida limegenskaper vid låg grad av oxidation i material med hög polymerisationsgrad, även om kvarhållande av depolymeriserade fraktioner från material med lägre polymeriseringsgrad, såsom dextrin, kanske inte ger de önskade polyaldehydiska produkterna i tillräckliga koncentrationer. Kvarhållandet av lågmolekylviktsfraktionen antyder också att stora mängder oxidationsmedel och katalysator bör undvikas, eftersom högre oxidationsgrad kan resultera i oönskade monofunktionella molekyler på grund av hög depolymerisation. / Wood adhesives comprise a large part of all adhesives globally and are essential in creation of wood composite materials, which many industries and products are entirely reliant on. Amongst the most common wood adhesives, several utilize formaldehyde as an essential component of their polymeric structure. While formaldehyde is a widely used, cheap and reliable material, it is also toxic, and generally derived from petroleum sources. A replacement with di- or poly-aldehydic functionality of green origin is therefore desirable for future wood adhesive chemistry. One potential solution involves oxidizing polysaccharides such as starch and dextrin, to functionalize the repeating glucose units with aldehydes, ketones, and carboxylic acids. Herein, it is demonstrated that Fenton-type conditions, using hydrogen peroxide as oxidant and iron as catalyst, can be used to perform the reaction efficiently in atmospheric conditions, producing minimal byproducts such as hydrogen gas, water, and iron complexes. Significant functionalization was observed in a small molecular weight fraction released from the polysaccharide upon oxidation, a fraction which is traditionally lost during workup via centrifugation. This work suggests that retention of this small molecular weight fraction in the product mixture may enhance future adhesive properties at low degrees of oxidation in materials with high degrees of polymerization, though retention of depolymerized fractions of lower chain length materials such as dextrin may not provide the targeted poly-aldehydic products in sufficient concentrations. The retention of the small molecular weight fraction also suggests that large amounts of oxidant and catalyst should be avoided, as higher degree of oxidation may result in undesired mono-functional molecules due to higher degrees depolymerization.

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