Author Affiliations
1State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China2University of Chinese Academy of Sciences, Beijing 100049, China3Beijing National Laboratory for Molecular Sciences and CAS Research/Education Center of Excellence in Molecular Sciences, Beijing 100190, Chinashow less
Fig. 1. The IRPD spectra of [Co$_n$(N
2)
1]$^+$ for $n$=8-17. The dotted red line serves to guide the eye. Its slight tilt with cluster size indicates a conceivable cooperative polarization effect. Note the variation in the observed peak positions and splittings. Multiple major peaks likely indicate cluster core isomers, spin isomers or N
2 bonding isomers while weak sidebands to the blue may arise from combination bands (N
2 stretching and wagging modes). Note the "jump" of the major peak from $n$=9 to $n$=10. Reprinted with permission from Ref.[
27] © 2015 The Royal Society of Chemistry.
Fig. 1. Several modes of N
2 coordination to transition metal centers. Adapted from Ref.[
34] © 2019 Wiley-VCH.
Fig. 2. Typical intermediates for N$\equiv$N bond dissociation. Adapted from Ref.[35] © 2020 American Chemical Society.
Fig. 2. (a) A comparison on frontier orbitals of TaC
-, TaC
2-, TaC
3-, and TaC
4-. The atomic orbital compositions of Ta are given. The highlighted orbital has matched symmetry with the $\pi^*$ orbital of N
2. (b) A favorable orbital overlap between TaC
4- and N
2. Adapted from Ref.[
28] © 2018 American Chemical Society.
Fig. 3. The experimental photoelectron spectra and DFT calculated lowest-lying structures of (a) V
5N
5- and (b) V
5N$_7$
-. (c) The molecular orbital interaction between V
5N
5- and the side-on-end-on coordinated N
2 unit. The experimental VDE values in eV are given. Adapted from Ref.[
34] © 2019 Wiley-VCH.
Fig. 4. The experimental photoelectron spectra of (a1, a2) Ta
3N
3H$_{0, 1}$
- and (b1, b2) Ta
3N
5H$_{0, 1}$
- and the quantum chemistry calculated structures, relative energies, and VDEs (in square brackets) of (c1) Ta
3N
3- and (c2) Ta
3N
3H
-. Adapted from Ref.[
33] © 2019 American Chemical Society.
Fig. 5. The DFT calculated potential energy profiles for the reactions of (a) Ta
3N
3H
- and (b) Ta
3N
3- with N
2. The zero-point vibration-corrected energies ($\Delta H_0$ in eV) and some bond lengths in pm are given. Adapted from Ref.[
33] © 2019 American Chemical Society.
Fig. 6. The mass spectra for the reaction of mass-selected Ta
2C
4- with (a) He and (b) 0.1 Pa $^{14}$N
2 for about 7 ms and for the CID of mass-selected (c-f) Ta
2C
4$^{14}$N
2- and (g) Ta
2C
4$^{15}$N
2$^{-}$ with 0.05 Pa Xe. The center-of-mass collisional energy ($E_\textrm{c}$) is given. The peaks marked with asterisks are due to water impurities. Reprinted with permission from Ref.[
29] © 2019 American Chemical Society.
Fig. 7. The quantum chemistry calculated potential energy profile for Ta
2C
4-+N
2$\rightarrow$Ta
2C
3N+CN
-. The relative energies ($\Delta H_0$ in eV) with respect to the separate reactants (Ta
2C
4-+N
2) are given. Adapted from Ref.[
29] © 2019 American Chemical Society.
Fig. 8. Mass spectra for the reaction of Ta
2N$^+$ with (a) Ar at 5.0$\times$10$^{-3}$ mPa and (b) $^{15}$N
2 at 5.0$\times$10$^{-3}$ mPa after a reaction time of 8 s at ambient temperature. Adapted from Ref.[
31] © 2019 National Academy of Sciences.
Fig. 9. The quantum chemistry calculated potential energy profile for the catalytic reaction of Ta
2N$^+$ with N
2. The relative energies ($\Delta H_0$ in eV) with respect to the separate reactants (Ta
2N$^+$+ N
2) are given. Adapted from Ref.[
31] © 2019 National Academy of Sciences.
Fig. 10. Potential-energy profile for V
3C
4- (R3)+N
2$\rightarrow$V
3C
4N
2-(P3/P4) in the restricted closed-shell singlet state. Energies in eV and selected bond lengths in pm are given. Adapted from Ref.[
35] © 2020 American Chemical Society.
Fig. 11. Molecular orbital interactions between the occupied orbitals ($\psi_y$ and $\psi_{xz}$) of (a) V
3C
4- and (b) V
3- with the unoccupied orbitals ($\pi_x^*$ and $\pi_y^*$) of the N
2 unit. Adapted from Ref.[
35] © 2020 American Chemical Society.
Table 1. Experimentally and theoretically studied reactions between gas-phase species and N2.