Optical Excitation of Co+.cntdot.N2

Asher, R.L.; Bellert, D.; Buthelezi, T.; Brucat, P.J.

doi:10.1021/j100004a002

Cited by 26 publications

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“…Lessen et al also used 18 O substitution to assign the vibrational quantum numbering in V + (H 2 O). 10 Figure 3 shows the observed shift from Co + (H 2 16 O) to Co + (H 2 18 O) for the first three peaks in each of the four electronic states. For the higher-energy bands, C and D, the observed shifts lie along the solid line, indicating that the first observed peak is due to the v 3 ′ = 0 ← v 3 ″ = 0 transition.…”

Section: Resultsmentioning

confidence: 99%

Dissociation Energy and Electronic and Vibrational Spectroscopy of Co⁺(H₂O) and Its Isotopomers

et al. 2012

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The electronic spectra of Co(+)(H(2)O), Co(+)(HOD), and Co(+)(D(2)O) have been measured from 13,500 to 18,400 cm(-1) using photodissociation spectroscopy. Transitions to four excited electronic states with vibrational and partially resolved rotational structure are observed. Each electronic transition has an extended progression in the metal-ligand stretch, v(3), and the absolute vibrational quantum numbering is assigned by comparing isotopic shifts between Co(+)(H(2)(16)O) and Co(+)(H(2)(18)O). For the low-lying excited electronic states, the first observed transition is to v(3)' = 1. This allows the Co(+)-(H(2)O) binding energy to be determined as D(0)(0 K)(Co(+)-H(2)O) = 13730 ± 90 cm(-1) (164.2 ± 1.1 kJ/mol). The photodissociation spectrum shows a well-resolved K(a) band structure due to rotation about the Co-O axis. This permits determination of the spin rotation constants ε(aa)" = -6 cm(-1) and ε(aa)' = 4 cm(-1). However, the K(a) rotational structure depends on v(3)'. These perturbations in the spectrum make the rotational constants unreliable. From the nuclear spin statistics of the rotational structure, the ground state is assigned as (3)B(1). The electronic transitions observed are from the Co(+)(H(2)O) ground state, which correlates to the cobalt ion's (3)F, 3d(8) ground state, to excited states which correlate to the (3)F, 3d(7)4s and (3)P, 3d(8) excited states of Co(+). These excited states of Co(+) interact less strongly with water than the ground state. As a result, the excited states are less tightly bound and have longer metal-ligand bonds. Calculations at the CCSD(T)/aug-cc-pVTZ level also predict that binding to Co(+) increases the H-O-H angle in water from 104.1° to 106.8°, as the metal removes electron density from the oxygen lone pairs. The O-H stretching frequencies of the ground electronic state of Co(+)(H(2)O) and Co(+)(HOD) have been measured by combining IR excitation with visible photodissociation in a double resonance experiment. In Co(+)(H(2)O) the O-H symmetric stretch is ν(1)" = 3609.7 ± 1 cm(-1). The antisymmetric stretch is ν(5)" = 3679.5 ± 2 cm(-1). These values are 47 and 76 cm(-1), respectively, lower than those in bare H(2)O. In Co(+)(HOD) the O-H stretch is observed at 3650 cm(-1), a red shift of 57 cm(-1) relative to bare HOD.

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Section: Resultsmentioning

confidence: 99%

Dissociation Energy and Electronic and Vibrational Spectroscopy of Co⁺(H₂O) and Its Isotopomers

et al. 2012

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“…It is found (Table 3) that the additional rotational energy on the product side (two linear molecules In cal/(mol'K). 6 In kcal/mol. compared to only one linear molecule on the educt side) is almost compensated for by the thermal energy in the low-energy rocking modes of Fe(N2)+ (A(AH) = +0.17 kcal/mol).…”

Section: Methodsmentioning

confidence: 99%

“…Bond lengths are given in bohr, and total interaction energies (kcal/mol) are with respect to Fe+ (6D) and N2 (12g+). For comparison, the corresponding results for the linear geometries within the CCSD(T) approximation are (a) bond lengths 4.550 bohr (6 ), 3.693 bohr (4 -); (b) total interaction energy 9.0 kcal/mol (6 ), 11.7 kcal/mol (4 ", using the Fe+ 4F-6D separation from the CCSD calculations).…”

Section: 8mentioning

confidence: 99%

Generation and Structural Characterization of the Cationic Iron-Dinitrogen Complex Fe(N2)+

Schwarz¹,

Heinemann²,

Schwarz³

1995

J. Phys. Chem.

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Gas-phase experiments in conjunction with CCSD(T) calculations were used to characterize the Fe(N2)+ complex in terms of electronic structure and binding energy. Theory clearly indicates a clear preference for an end-on structure of the N2 ligand to the transition-metal cation, resulting in a 4state. At the highest level of theory, including estimated corrections, the binding energy amounts to 11.9 ± 2.3 kcal/mol. From ligand exchange reactions, equilibration measurements, and theoretical considerations we further conclude N2 is at least 1 kcal/mol more strongly bound to Fe+ than CO2 and 1.7 ± 1.5 kcal/mol more strongly bound that Xe. Entropy drives the replacement of N2 by Xe in the Fe(N2)+ complex at 300 K.

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“…Transition metal complexes with nitrogen are of course well-known in inorganic and organometallic chemistry because of the widespread importance of nitrogen activation in chemistry and biology. Transition metal neutral and ionic complexes with N 2 have been studied extensively with mass spectrometry and optical spectroscopy as well as computational chemistry. − Actinide–nitrogen complexes are much less common, and the presence of f electrons is expected to have a strong influence on their bonding. In this study we employ UV–vis and infrared photodissociation measurements to investigate U + (N 2 ) n complexes.…”

Section: Introductionmentioning

confidence: 99%

Photodissociation and Infrared Spectroscopy of Uranium–Nitrogen Cation Complexes

et al. 2021

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Laser vaporization of uranium in a pulsed supersonic expansion of nitrogen is used to produce complexes of the form U + (N 2 ) n (n = 1−8). These ions are mass selected in a reflectron time-of-flight spectrometer and studied with visible and UV laser fixed-frequency photodissociation and with tunable infrared laser photodissociation spectroscopy. The dissociation patterns and spectroscopy of U + (N 2 ) n indicate that N 2 ligands are intact molecules and that there is no insertion chemistry resulting in UN + or NUN + . Fixed frequency photodissociation at 532 and 355 nm indicate that the U + −N 2 bond dissociation energy varies little with changing coordination. The photon energy and the number of ligands eliminated allow an estimate of the average U + −N 2 dissociation energy of 12 kcal/mol. Infrared bands are observed for these complexes near the N−N stretch vibration via elimination of N 2 molecules. These resonances are observed to be shifted about 130 cm −1 to the red from the free-N 2 frequency for complexes with n = 3−8. Density functional theory indicates that U + is most stable in the sextet state in these complexes and that N 2 molecules bind in end-on configurations. The fully coordinated complex is predicted to be U + (N 2 ) 8 , which has a cubic structure. The vibrational frequencies predicted by theory are consistently lower than those in the experiment, independent of the isomeric structure or spin state of the complexes. Despite its failure to reproduce the infrared spectra, theory provides an average U + −N 2 dissociation energy of 11.8 ± 0.5 kcal/mol, in good agreement with the value from the experiments.

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Optical Excitation of Co+.cntdot.N2

Cited by 26 publications

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Dissociation Energy and Electronic and Vibrational Spectroscopy of Co⁺(H₂O) and Its Isotopomers

Dissociation Energy and Electronic and Vibrational Spectroscopy of Co⁺(H₂O) and Its Isotopomers

Generation and Structural Characterization of the Cationic Iron-Dinitrogen Complex Fe(N2)+

Photodissociation and Infrared Spectroscopy of Uranium–Nitrogen Cation Complexes

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Optical Excitation of Co+.cntdot.N2

Cited by 26 publications

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Dissociation Energy and Electronic and Vibrational Spectroscopy of Co+(H2O) and Its Isotopomers

Dissociation Energy and Electronic and Vibrational Spectroscopy of Co+(H2O) and Its Isotopomers

Generation and Structural Characterization of the Cationic Iron-Dinitrogen Complex Fe(N2)+

Photodissociation and Infrared Spectroscopy of Uranium–Nitrogen Cation Complexes

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Dissociation Energy and Electronic and Vibrational Spectroscopy of Co⁺(H₂O) and Its Isotopomers

Dissociation Energy and Electronic and Vibrational Spectroscopy of Co⁺(H₂O) and Its Isotopomers