Ultrafast Infrared Study of the UV Photodissociation of Mn2(CO)10

Owrutsky, J. C.; Baronavski, A. P.

doi:10.1007/978-3-642-80314-7_105

Cited by 3 publications

(3 citation statements)

References 7 publications

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“…In contrast to the monometal carbonyl complexes, dimanganese decacarbonyl (DMDC) presents new challenges. Within the context of reaction dynamics probed with nonequilibrium 2DIR, DMDC is an attractive system since two different photoproducts, Mn(CO) 5 and Mn 2 (CO) 9 , can be generated depending on the choice of UV pump wavelength. − The ground state geometry is a staggered D 4 d symmetry with four IR active vibrations: 1983 cm −1 (B 2 ), doubly degenerate 2014 cm −1 (E), 2044 cm −1 (B 2 ) [FTIR shown in Figure ]. Thus, in the terminal carbonyl stretching region there are six Raman active modes that are not observed in the IR spectrum .…”

Section: Experimental Studies Of Metal Carbonylsmentioning

confidence: 99%

Two-Dimensional Infrared Spectroscopy of Metal Carbonyls

et al. 2009

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Metal carbonyl complexes offer both rich chemistry and complex vibrational spectroscopy due to strong coupling among the carbonyl stretches. Using two-dimensional infrared (2DIR) spectroscopy, it is possible to resolve the underlying transitions between vibrational energy levels, determine the orientations and relative magnitude of the corresponding transition dipole moments, measure the coupling between modes due to the anharmonicity of the potential, and probe energy redistribution among the modes as well as energy relaxation to other degrees of freedom. Measurements on metal carbonyl complexes have played, and continue to play, a crucial role in facilitating the development of 2DIR spectroscopy. These compounds have provided powerful demonstrations of the unique ability of 2DIR spectroscopy to resolve vibrational structure and dynamics in multimode systems. In addition, invaluable new information has been obtained on metal-to-ligand charge transfer processes, solvent-solute interactions and fluxionality. Since transition metal complexes play important roles in catalysis and as dye sensitizers for semiconductor nanoparticle photocatalysis, detailed probes of equilibrium and phototriggered dynamics should aid our understanding of these key catalytic systems. The richness and level of detail provided by the 2DIR spectra of metal carbonyl complexes turn them into extremely useful model systems for testing the accuracy of ab initio quantum chemical calculations. Accurate modeling of the 2DIR spectra of solvated metal carbonyl complexes requires the development of new theoretical and computational tools beyond those employed in the standard analysis of one-dimensional IR spectra, and represents an ongoing challenge to currently available computational methodologies. These challenges are further compounded by the increasing interest in triggered 2DIR experiments that involve nonequilibrium vibrational dynamics on multiple electronic potential surfaces. In this Account, we review the various metal carbonyl complexes studied via 2DIR spectroscopy and outline the theoretical approaches used in order to model the spectra. The capabilities of 2DIR spectroscopy and its interplay with modern ab initio calculations are demonstrated in the context of the metal carbonyl complex Mn(2)(CO)(10) recently studied in our lab. Continued progress in experimental implementation and theoretical analysis will enable transient 2D spectroscopy to provide structurally sensitive details of complex, highly interacting nonequilibrium processes that are central to diverse chemical transformations.

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Section: Experimental Studies Of Metal Carbonylsmentioning

confidence: 99%

Two-Dimensional Infrared Spectroscopy of Metal Carbonyls

et al. 2009

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“…These studies corroborate the great interest in the initial steps of CO photolysis from metal carbonyls and underline the multifaceted reaction pathways that may occur. In the gas phase, depending on the excitation wavelength used, several to all CO ligands can be liberated, and even quantum control of the photochemistry of Fe(CO) 5 was demonstrated; , in the liquid phase, usually one but in some solvents also two of the CO ligands are released on an ultrafast time scale after absorption of one UV photon. − Among other substances studied in solution are, for example, metal carbonyls with only CO ligands − (even with two − or three bonded metal atoms) but also complexes with, for example, cyclopentadienyl − and more complex organic ligands, which may even perform photochelation upon CO dissociation. , …”

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Ultrafast Photochemistry of a Manganese-Tricarbonyl CO-Releasing Molecule (CORM) in Aqueous Solution

Rudolf

Kanal

Knorr

et al. 2013

J. Phys. Chem. Lett.

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Ultraviolet irradiation of a manganese-tricarbonyl CO-releasing molecule (CORM) in water eventually leads to the liberation of some of the carbon monoxide ligands. By ultraviolet pump/mid-infrared probe femtosecond transient absorption spectroscopy in combination with quantum chemical calculations, we could disclose for the exemplary compound [Mn(CO)3(tpm)](+) (tpm = tris(2-pyrazolyl)methane) that only one of the three carbonyl ligands is photochemically dissociated on an ultrafast time scale and that some molecules may undergo geminate recombination.

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“…In this respect, the development of time-resolved infrared spectroscopy (TRIR) over the past decades has had a tremendous impact in our understanding of excited-state properties, photophysics, and photochemistry of transition metal complexes . TRIR is also routinely applied to ultrafast events involving nuclear motion and it has frequently been applied to transition metal chemistry to probe dynamics initiated by ultraviolet (UV) or visible (vis) triggering pulses. − Changes associated with band intensities, bandwidths, and band positions of the IR transients provide valuable information, not only on reactive dynamics but also on intra- and intermolecular relaxation pathways and their time scales . The latter, known also as vibrational cooling, is related to nonradiative dissipation of energy into the surrounding solvent. , …”

Section: Introductionmentioning

confidence: 99%

Role of Vibrational Dynamics in Electronic Relaxation of Cr(acac)₃

et al. 2015

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Ultrafast energy relaxation of Cr(acac)3 dissolved in tetrachloroethylene (TCE) is studied by time-resolved infrared (TRIR) spectroscopy by using electronic and vibrational excitation. After electronic excitation at 400 or 345 nm, the ground state recovers in two time scales: 15 ps (major pathway) and 800 ps (minor pathway), corresponding to fast electronic transition to the ground state and intermediate trapping on the long-lived (2)E state followed by intersystem crossing (ISC) to the ground state. The quantum yield for the fast recovery of the ground state depends on the excitation wavelength, being higher for 345 nm. Vibrational cooling (VC) occurs on the electronic excited states with a time constant of ∼7 ps and on the ground electronic state with a time constant of ∼12 ps. A kinetic model that explains the observed dynamics is presented. The key point of the model is that the ground-state recovery occurs via thermally activated back-intersystem-crossing (b-ISC) to the quartet manifold presumably via multiple curve crossings that are sampled while the system is vibrationally hot. This underlines the importance of vibrational cooling as a determining factor for the electronic relaxation chain. Vibrational excitation of the νC═C and νCO vibrations also revealed a subpicosecond (300-700 fs) intramolecular vibrational redistribution (IVR) process from the localized vibrational states to the bath of vibrational excitations.

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Ultrafast Infrared Study of the UV Photodissociation of Mn2(CO)10

Cited by 3 publications

References 7 publications

Two-Dimensional Infrared Spectroscopy of Metal Carbonyls

Two-Dimensional Infrared Spectroscopy of Metal Carbonyls

Ultrafast Photochemistry of a Manganese-Tricarbonyl CO-Releasing Molecule (CORM) in Aqueous Solution

Role of Vibrational Dynamics in Electronic Relaxation of Cr(acac)₃

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Ultrafast Infrared Study of the UV Photodissociation of Mn2(CO)10

Cited by 3 publications

References 7 publications

Two-Dimensional Infrared Spectroscopy of Metal Carbonyls

Two-Dimensional Infrared Spectroscopy of Metal Carbonyls

Ultrafast Photochemistry of a Manganese-Tricarbonyl CO-Releasing Molecule (CORM) in Aqueous Solution

Role of Vibrational Dynamics in Electronic Relaxation of Cr(acac)3

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Role of Vibrational Dynamics in Electronic Relaxation of Cr(acac)₃