{"id":{"repo_id":"umn","oai_identifier":"oai:conservancy.umn.edu:11299/279776"},"canonical_url":"https://search.dev.ndltd.org/etd/umn/oai:conservancy.umn.edu:11299/279776","repository":{"repo_id":"umn","name":"University of Minnesota","base_url":"https://conservancy.umn.edu/server/oai/request"},"display":{"title":"Probing Solvation Shell Dynamics of Organometallic Complexes via Two-Dimensional Infrared Spectroscopy","abstract":"This thesis examines the application of Fourier transform infrared spectroscopy (FTIR) and two dimensional infrared spectroscopy (2D-IR) to organometallic complexes in various solvents. FTIR spectroscopy shows the fundamental vibrational modes of a complex, yielding a spectrum that acts as a molecular fingerprint that allows for identification of chemical species and functional groups within a system. The one-dimensional nature of FTIR spectroscopy, however, occludes broadening information that directly informs the environmental effects that the oscillator is experiencing. Additionally, the limited resolution of an FTIR spectrum prevents analysis of cross peaks, which arise as a result of phenomena such as intramolecular vibrational redistribution (IVR), vibrational energy transfer (VET), or chemical exchange. To interrogate these hidden features, I used 2D-IR spectroscopy to disentangle broadening effects and assess cross peak phenomena. The first study covered in this thesis features three homologous group VIII metal carbonyls: triiron dodecacarbonyl (Fe₃(CO)₁₂), triruthenium dodecacarbonyl (Ru₃(CO)₁₂), and triosmium dodecacarbonyl (Os₃(CO)₁₂). In this set, the mass of ruthenium is twice as large as iron, and the mass of osmium is quadruple the mass of iron. Despite the differences in mass of the central metallic atom, each complex possesses the same D₃ₕ symmetry, allowing for assessment of solvation shell dynamics pertaining to the same high frequency mode for each species. In this study, the E1 axial carbonyl mode was selected as the vibrational probe and the solvent, THF, was not varied. Analysis of solvation shell dynamics revealed subtle, but measurable effects arising from the vibrational heavy atom effect (VHAE). The solvation shell was further impacted by the fluxional nature of some of the complexes. The deviation due to fluxional structure was especially pronounced in Fe₃(CO)₁₂, leading to larger inhomogeneous amplitudes relative to the other complexes. In the second study presented in this thesis, the same complexes in THF were assessed via 2D-IR spectroscopy. Instead of assessing solvation shell dynamics, the uphill cross peak between the axial carbonyl modes were characterized. The normalized volumes of the cross peaks were then plotted as a function of the waiting time (Tw) and fit to a biexponential decay with an offset. This revealed a short time component, which corresponded to the IVR rate, and a long time component, which corresponded to the VET rate. Additionally, the off-diagonal anharmonicities, which indicate coupling, were also measured. Analysis of the IVR and VET rates revealed trends that coincided with the mass of the central metallic atom, such that Fe₃(CO)₁₂ had the fastest IVR and VET rates, while osmium had the slowest IVR and VET rates. These rates were inversely proportional to the off-diagonal anharmonicities, such that Fe₃(CO)₁₂, which had the fastest rates, had the largest anharmonicity, suggesting stronger vibrational coupling. The trend in anharmonicity also coincides with the relative angles and distances between axial carbonyls. Lastly, I performed pump-probe spectroscopy on phenyl selenocyanate (PhSeCN) in four different solvents. The solvents selected covered nonpolar solvents as well as halogenated, protic, and aprotic polar solvents. The pump-probe decay data was then fit to a biexponential decay, from which two time constants were obtained. The short time constant represents reorientation time, and the long time constant represents vibrational energy relaxation (VER). From these parameters, I was able to conclude that the reorientation time was largely affected by the viscosity of the solvent. The VER decays, however, were primarily driven by the presence of low frequency modes that ultimately donate vibrational energy to the phonon bath.","abstract_html":"This thesis examines the application of Fourier transform infrared spectroscopy (FTIR) and two dimensional infrared spectroscopy (2D-IR) to organometallic complexes in various solvents. FTIR spectroscopy shows the fundamental vibrational modes of a complex, yielding a spectrum that acts as a molecular fingerprint that allows for identification of chemical species and functional groups within a system. The one-dimensional nature of FTIR spectroscopy, however, occludes broadening information that directly informs the environmental effects that the oscillator is experiencing. Additionally, the limited resolution of an FTIR spectrum prevents analysis of cross peaks, which arise as a result of phenomena such as intramolecular vibrational redistribution (IVR), vibrational energy transfer (VET), or chemical exchange. To interrogate these hidden features, I used 2D-IR spectroscopy to disentangle broadening effects and assess cross peak phenomena. The first study covered in this thesis features three homologous group VIII metal carbonyls: triiron dodecacarbonyl (Fe₃(CO)₁₂), triruthenium dodecacarbonyl (Ru₃(CO)₁₂), and triosmium dodecacarbonyl (Os₃(CO)₁₂). In this set, the mass of ruthenium is twice as large as iron, and the mass of osmium is quadruple the mass of iron. Despite the differences in mass of the central metallic atom, each complex possesses the same D₃ₕ symmetry, allowing for assessment of solvation shell dynamics pertaining to the same high frequency mode for each species. In this study, the E1 axial carbonyl mode was selected as the vibrational probe and the solvent, THF, was not varied. Analysis of solvation shell dynamics revealed subtle, but measurable effects arising from the vibrational heavy atom effect (VHAE). The solvation shell was further impacted by the fluxional nature of some of the complexes. The deviation due to fluxional structure was especially pronounced in Fe₃(CO)₁₂, leading to larger inhomogeneous amplitudes relative to the other complexes. In the second study presented in this thesis, the same complexes in THF were assessed via 2D-IR spectroscopy. Instead of assessing solvation shell dynamics, the uphill cross peak between the axial carbonyl modes were characterized. The normalized volumes of the cross peaks were then plotted as a function of the waiting time (Tw) and fit to a biexponential decay with an offset. This revealed a short time component, which corresponded to the IVR rate, and a long time component, which corresponded to the VET rate. Additionally, the off-diagonal anharmonicities, which indicate coupling, were also measured. Analysis of the IVR and VET rates revealed trends that coincided with the mass of the central metallic atom, such that Fe₃(CO)₁₂ had the fastest IVR and VET rates, while osmium had the slowest IVR and VET rates. These rates were inversely proportional to the off-diagonal anharmonicities, such that Fe₃(CO)₁₂, which had the fastest rates, had the largest anharmonicity, suggesting stronger vibrational coupling. The trend in anharmonicity also coincides with the relative angles and distances between axial carbonyls. Lastly, I performed pump-probe spectroscopy on phenyl selenocyanate (PhSeCN) in four different solvents. The solvents selected covered nonpolar solvents as well as halogenated, protic, and aprotic polar solvents. The pump-probe decay data was then fit to a biexponential decay, from which two time constants were obtained. The short time constant represents reorientation time, and the long time constant represents vibrational energy relaxation (VER). From these parameters, I was able to conclude that the reorientation time was largely affected by the viscosity of the solvent. The VER decays, however, were primarily driven by the presence of low frequency modes that ultimately donate vibrational energy to the phonon bath.","abstract_has_math":false,"creators":["Rey, Melissa"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-01","date_published":"2026-01","updated_at":"2026-07-24T05:19:44Z","subjects":["2D-IR","organometallic","spectroscopy","VHAE"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/11299/279776","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Rey, Melissa"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-04-02T21:17:36Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-01"]},{"key":"dc:type","label":"Dc Type","values":["Thesis or Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["2D-IR","organometallic","spectroscopy","VHAE"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/11299/279776"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["University of Minnesota Ph.D. dissertation. January 2026. Major: Chemistry. Advisor: Aaron Massari. 1 computer file (PDF); xvii, 108 pages."]},{"key":"dc:description.abstract","label":"Abstract","values":["This thesis examines the application of Fourier transform infrared spectroscopy (FTIR) and two dimensional infrared spectroscopy (2D-IR) to organometallic complexes in various solvents. FTIR spectroscopy shows the fundamental vibrational modes of a complex, yielding a spectrum that acts as a molecular fingerprint that allows for identification of chemical species and functional groups within a system. The one-dimensional nature of FTIR spectroscopy, however, occludes broadening information that directly informs the environmental effects that the oscillator is experiencing. Additionally, the limited resolution of an FTIR spectrum prevents analysis of cross peaks, which arise as a result of phenomena such as intramolecular vibrational redistribution (IVR), vibrational energy transfer (VET), or chemical exchange. To interrogate these hidden features, I used 2D-IR spectroscopy to disentangle broadening effects and assess cross peak phenomena. The first study covered in this thesis features three homologous group VIII metal carbonyls: triiron dodecacarbonyl (Fe₃(CO)₁₂), triruthenium dodecacarbonyl (Ru₃(CO)₁₂), and triosmium dodecacarbonyl (Os₃(CO)₁₂). In this set, the mass of ruthenium is twice as large as iron, and the mass of osmium is quadruple the mass of iron. Despite the differences in mass of the central metallic atom, each complex possesses the same D₃ₕ symmetry, allowing for assessment of solvation shell dynamics pertaining to the same high frequency mode for each species. In this study, the E1 axial carbonyl mode was selected as the vibrational probe and the solvent, THF, was not varied. Analysis of solvation shell dynamics revealed subtle, but measurable effects arising from the vibrational heavy atom effect (VHAE). The solvation shell was further impacted by the fluxional nature of some of the complexes. The deviation due to fluxional structure was especially pronounced in Fe₃(CO)₁₂, leading to larger inhomogeneous amplitudes relative to the other complexes. In the second study presented in this thesis, the same complexes in THF were assessed via 2D-IR spectroscopy. Instead of assessing solvation shell dynamics, the uphill cross peak between the axial carbonyl modes were characterized. The normalized volumes of the cross peaks were then plotted as a function of the waiting time (Tw) and fit to a biexponential decay with an offset. This revealed a short time component, which corresponded to the IVR rate, and a long time component, which corresponded to the VET rate. Additionally, the off-diagonal anharmonicities, which indicate coupling, were also measured. Analysis of the IVR and VET rates revealed trends that coincided with the mass of the central metallic atom, such that Fe₃(CO)₁₂ had the fastest IVR and VET rates, while osmium had the slowest IVR and VET rates. These rates were inversely proportional to the off-diagonal anharmonicities, such that Fe₃(CO)₁₂, which had the fastest rates, had the largest anharmonicity, suggesting stronger vibrational coupling. The trend in anharmonicity also coincides with the relative angles and distances between axial carbonyls. Lastly, I performed pump-probe spectroscopy on phenyl selenocyanate (PhSeCN) in four different solvents. The solvents selected covered nonpolar solvents as well as halogenated, protic, and aprotic polar solvents. The pump-probe decay data was then fit to a biexponential decay, from which two time constants were obtained. The short time constant represents reorientation time, and the long time constant represents vibrational energy relaxation (VER). From these parameters, I was able to conclude that the reorientation time was largely affected by the viscosity of the solvent. The VER decays, however, were primarily driven by the presence of low frequency modes that ultimately donate vibrational energy to the phonon bath."]},{"key":"dc:title","label":"Title","values":["Probing Solvation Shell Dynamics of Organometallic Complexes via Two-Dimensional Infrared Spectroscopy"]}]}],"canonical_facts":{"dc:creator":["Rey, Melissa"],"dc:date.accessioned":["2026-04-02T21:17:36Z"],"dc:date.issued":["2026-01"],"dc:description":["University of Minnesota Ph.D. dissertation. January 2026. Major: Chemistry. Advisor: Aaron Massari. 1 computer file (PDF); xvii, 108 pages."],"dc:description.abstract":["This thesis examines the application of Fourier transform infrared spectroscopy (FTIR) and two dimensional infrared spectroscopy (2D-IR) to organometallic complexes in various solvents. FTIR spectroscopy shows the fundamental vibrational modes of a complex, yielding a spectrum that acts as a molecular fingerprint that allows for identification of chemical species and functional groups within a system. The one-dimensional nature of FTIR spectroscopy, however, occludes broadening information that directly informs the environmental effects that the oscillator is experiencing. Additionally, the limited resolution of an FTIR spectrum prevents analysis of cross peaks, which arise as a result of phenomena such as intramolecular vibrational redistribution (IVR), vibrational energy transfer (VET), or chemical exchange. To interrogate these hidden features, I used 2D-IR spectroscopy to disentangle broadening effects and assess cross peak phenomena. The first study covered in this thesis features three homologous group VIII metal carbonyls: triiron dodecacarbonyl (Fe₃(CO)₁₂), triruthenium dodecacarbonyl (Ru₃(CO)₁₂), and triosmium dodecacarbonyl (Os₃(CO)₁₂). In this set, the mass of ruthenium is twice as large as iron, and the mass of osmium is quadruple the mass of iron. Despite the differences in mass of the central metallic atom, each complex possesses the same D₃ₕ symmetry, allowing for assessment of solvation shell dynamics pertaining to the same high frequency mode for each species. In this study, the E1 axial carbonyl mode was selected as the vibrational probe and the solvent, THF, was not varied. Analysis of solvation shell dynamics revealed subtle, but measurable effects arising from the vibrational heavy atom effect (VHAE). The solvation shell was further impacted by the fluxional nature of some of the complexes. The deviation due to fluxional structure was especially pronounced in Fe₃(CO)₁₂, leading to larger inhomogeneous amplitudes relative to the other complexes. In the second study presented in this thesis, the same complexes in THF were assessed via 2D-IR spectroscopy. Instead of assessing solvation shell dynamics, the uphill cross peak between the axial carbonyl modes were characterized. The normalized volumes of the cross peaks were then plotted as a function of the waiting time (Tw) and fit to a biexponential decay with an offset. This revealed a short time component, which corresponded to the IVR rate, and a long time component, which corresponded to the VET rate. Additionally, the off-diagonal anharmonicities, which indicate coupling, were also measured. Analysis of the IVR and VET rates revealed trends that coincided with the mass of the central metallic atom, such that Fe₃(CO)₁₂ had the fastest IVR and VET rates, while osmium had the slowest IVR and VET rates. These rates were inversely proportional to the off-diagonal anharmonicities, such that Fe₃(CO)₁₂, which had the fastest rates, had the largest anharmonicity, suggesting stronger vibrational coupling. The trend in anharmonicity also coincides with the relative angles and distances between axial carbonyls. Lastly, I performed pump-probe spectroscopy on phenyl selenocyanate (PhSeCN) in four different solvents. The solvents selected covered nonpolar solvents as well as halogenated, protic, and aprotic polar solvents. The pump-probe decay data was then fit to a biexponential decay, from which two time constants were obtained. The short time constant represents reorientation time, and the long time constant represents vibrational energy relaxation (VER). From these parameters, I was able to conclude that the reorientation time was largely affected by the viscosity of the solvent. The VER decays, however, were primarily driven by the presence of low frequency modes that ultimately donate vibrational energy to the phonon bath."],"dc:identifier.uri":["https://hdl.handle.net/11299/279776"],"dc:language.iso":["en"],"dc:subject":["2D-IR","organometallic","spectroscopy","VHAE"],"dc:title":["Probing Solvation Shell Dynamics of Organometallic Complexes via Two-Dimensional Infrared Spectroscopy"],"dc:type":["Thesis or Dissertation"]},"updated_at":"2026-07-24T05:19:44Z"}