1. Covalent and Noncovalent Interactions between Boron and Argon
An infrared photodissociation spectroscopic study on argon-boron oxide cation complexes
Jiaye Jin, Mingfei Zhou
Fudan University , Shanghai, China
Good morning everyone. I am Jiaye Jin from Fudan university, Shanghai, China.
Today, it is my great honor to be here and have this opportunity to discuss with you about the covalent and noncovalent interactions between boron and argon. I will mainly introduce our infrared photodissociation spectroscopic study on argon-boron oxide cation complexes
Talk TE01, 72th ISMS, June 2017

2. Outline Introduction Experimental Setup Results and discussion Summary
Importance
Previous work on Ar-B interaction
Experimental Setup
Laser ablation source
Infrared photodissociation spectroscopy
Results and discussion
Mass spectra and observed IPRD spectra
Simulation and calculation of cations
Bonding analysis on Ar-B interaction
Summary
this is the outline for the topic

3. Covalent Argon Compounds
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Covalent Argon Compounds
HArF
Only experimentally known neutral molecule
Covalent H-Ar bond
Electrostatic Ar-F bond
HAr+
Gas phase and cosmic dust
Nature of H-Ar bond
Ar : H+ (Lewis acid)
∇2ρ
Researches of covalent interactions between lighter noble gases and other elements offer a challenging field. The lighter rare gases are more chemically inert than the heavier ones.
For covalent argon compounds, the hydridoargon fluoride is the only experimentally known neutral molecule containing a chemically bound argon atom. It is only stable in low temperature argon matrix. Theoretical simulations indicate that the hydrogen-argon bond is covalent, whereas the argon-fluorine bond is noncovalent. And more, the bare cation has been observed in the gas phase and detected in cosmic dust
In this case, H+ (hydrogen cations) acts as a strong Lewis acid. And thus, argon gives lone-pair electrons to H+. Following this, many compounds with argon – metal interactions have been studied, but no covalent bond has been found.
H-Ar σ bond
L. Khriachtchev et al. Nature, 2000, 406, 874;
N. Runeberg, et al. J. Chem. Phys., 2001, 114, 836;
M. Barlow, et al Science, 2013, 342, 1343.

4. Is it possible for boron-argon bond?
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Is it possible for boron-argon bond?
Boron atom is also a famous Lewis acidic center
Is it possible for boron-argon bond?
Boron atom is also a famous Lewis acidic center.

5. Is it possible for boron-argon bond?
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Is it possible for boron-argon bond?
Mass studies
Theoretical predictions
BAr+, ArBF2+ and ArBFn2+
F. Grandinetti, Eur. J. Mass. Spectromet., 2011, 17, 423
D. Schröder, et al. Int. J. Mass Spectromet., 2012, 323, 2
FAr-BO, FAr-BN- , FAr-BF2 , and HArBF+
W. Hu, et al. Chem. Phys. L., 2005, 402, 514
W. Hu, et al. Phys. Chem. Chem. Phys., 2013, 15, 9701
T. K. Ghanty, et al. J. Phys. Chem. A, 2013, 117, 10772
F. Grandinett, et al. J. Phys. Chem. A, 2007, 111, 10144
∇2ρ
Many efforts have been paid on searching for chemical bonding between argon and boron.
There are some mass studies. they point out the formation of these argon complexes (BAr+, ArBF2 or ArBFn2+) due to the strong dative interaction. And, there are also many theoretical predictions for compounds containing argon-boron bonds. The pattern of density distribution suggests the covalent bonding.

6. IRPD (Infrared photodissociation) spectroscopy
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Our works on boron-argon bond
Mass study
Theoretical simulation
[ArBxOy]+
And here, we offer the first spectroscopic identification for the argon boron oxide cations complexes, and provide a discussion on the argon and boron bond.
IRPD (Infrared photodissociation) spectroscopy

7. Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Infrared photodissociation spectroscopy with laser ablation ion source.*
At this section, I will introduce the equipment for the experiments. Details can be found in the reference.
*G. Wang, et al. Sci. China Chem., 2014, 57, 172

8. Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Infrared photodissociation spectroscopy with laser ablation ion source.*
O2/He, or O2/Ar/He, 10 a.t.m.
532nm 10mJ/pulse
(11B or 10B)
[ArBxOy]+
The boron oxide cation clusters were produced by laser ablation of an isotopic enriched target. The ablation laser is the second harmonic of a pulse Nd:YAG laser
*G. Wang, et al. Sci. China Chem., 2014, 57, 172

9. Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Infrared photodissociation spectroscopy with laser ablation ion source.*
mass gate
Then, the cation clusters are analysed with a time-of-flight mass spectrometer. So, we can get the mass spectra.
The ions of interest are mass selected and subjected to infrared photodissociation chamber.
Flight direction
Mass Spectrum
*G. Wang, et al. Sci. China Chem., 2014, 57, 172

10. Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Infrared photodissociation spectroscopy with laser ablation ion source.*
mass gate
Flight direction
*G. Wang, et al. Sci. China Chem., 2014, 57, 172

11. Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Infrared photodissociation spectroscopy with laser ablation ion source.*
IR Spectrum
Fragment yield
Wavenumber (cm-1)
Secondary mass spectrometer
Dissociation
Mass Spectrum
[ArBxOy]+
BxOy+
The dissociation laser is focused onto the ions. If the excited vibrational energy reaches some dissociation potential energy surfaces, the ion can lose fragments.
We can detect the signal of fragment and parent ion with secondary tof. In this experiment, we selected the argon complexes and monitored fragment yield of the bare cations.
The IR spectra are recorded fragments yield by scanning the wavenumber of dissociation laser.
Tunable dissociation IR laser (LaserVision)
(0.5mJ - 1.5mJ in 1200cm cm-1)
*G. Wang, et al. Sci. China Chem., 2014, 57, 172

12. Mass spectra Introduction Methods Results Discussion Summary
Acknowledgements
Mass spectra
B3O4+
B4O6+
B3O5+
B5O7+
B4O5+
B4O7+
11B + O2/He
[ArB3O4]+
[ArB3O5]+
[ArB4O6]+
[ArB4O7]+
[ArB5O7]+
[ArB4O5]+
Here, we display a typical mass spectra of boron oxide cation clusters.
Upper figure is the mass spectrum produced in helium and oxygen. Peak due to 11B3O4+ is the most intense peaks in the mass spectrum; Bottom figure shows the mass spectrum with 10% argon seeded in the gas. The 11B3O4+ peak also remains as the most intense peak, but the relative intensities of others are highly reduced.
Many argon complexes have formed.
11B + O2/Ar/He

13. Mass spectra Introduction Methods Results Discussion Summary
Acknowledgements
Mass spectra
B3O4+
B4O6+
B3O5+
B5O7+
B4O5+
B4O7+
11B + O2/He
[ArB3O5]+
[ArB4O6]+
These argon boron oxide ion complexes have quite high abundance.
Today, we may focus on the labelled cations in the mass spectra first
11B + O2/Ar/He
[ArB3O4]+
[ArB5O7]+

14. IR Spectra -BO Introduction Methods Results Discussion Summary
Acknowledgements
IR Spectra
10B/11B = – 1.036
-BO
[Ar11B3O4]+
[Ar11B3O5]+
[Ar11B4O5]+
[Ar11B4O6]+
[Ar11B4O7]+
[Ar11B5O7]+
This slide shows the IR spectra of cations. The isotopic ratio of the vibrational frequency indicate that all these bands are BO stretching vibrations.
Obviously, there are three ranges in the spectra. Empirically, the bands here (above 2050 cm-1) are assigned as stretching vibrations of terminally bonded BO fragments; the bands here (in the range of cm-1) can be assigned as vibrations of aggregated boron-oxide, and the bands near here (1200 cm-1) fall into the region of B-O single bond stretching.
The spectrum of [Ar11B3O4]+ cation is greatly different from others`; whereas other five cations have similar spectral structure in the second and third range, suggesting that [Ar11B3O5]+ may be the core structure of the following five cations.
L. Andrews, et al. J. Chem. Phys., 1991, 95, 8697.

15. [ArB3O4]+ uB O Introduction Methods Results Discussion Summary
Acknowledgements
[ArB3O4]+
uB O
IRPD signal
IR intensity (harmonic)
B3O4+
De = 3.4 kcal/mol
≈ 1189 cm-1
- Ar
[ArB3O4]+
Let's see the simulation.
Our calculation predicts the lowest energy structure of ArB3O4+ to be C2v symmetry with a BO chain and a weak bound argon atom, whereas the bare cation is linear.
The dissociation energy for the argon atom is only 3.4 kcal/mol, lower than the energy of dissociation laser, leading to an efficient dissociation process. These facts suggest a weak interaction between the boron and argon.
Simulated spectra: B3LYP-D3/aug-cc-pVTZ
Optimized geometries: CCSD(t)/cc-pVTZ.

16. [ArB3O5]+ uOBOBO u(asy. BO2) uB-O C2V 3B2 Introduction Methods Results
Discussion
Summary
Acknowledgements
[ArB3O5]+
2.004
1.439
136.7
1.309
C2V 3B2
1.280
151.5
1.475
uOBOBO
u(asy. BO2)
uB-O
IRPD signal
IR intensity (harmonic)
B3O5+
De = 16.2 kcal/mol
≈ 5666 cm-1
- Ar
[ArB3O5]+
Our calculations predict these cations to be C2v symmetry and 3B2 state. They all involve a boroxol ring.
The assignments of the three observed IR bands from high to low wavenumber are asymmetry stretching mode of OBO moiety, stretching mode of aggregated OBOBO, and stretching mode of BO single bond on the boroxol ring. The argon atom makes the boroxol ring more like hexagon, leading to the red-shift of OBO vibrational mode and the blue-shift of BO stretching mode in the simulation spectra.
The dissociation energy for the argon atom is 16.2 kcal/mol, which means the cation must adsorb at least three photons for losing argon atom, causing a low efficient dissociation process. These results suggest a very strong interaction between the boron and argon.
Simulated spectra: B3LYP-D3/aug-cc-pVTZ
Optimized geometries: CCSD(t)/cc-pVTZ.

17. [ArB4O5]+ uB-O uB O u(asy. BO2) Introduction Methods Results
Discussion
Summary
Acknowledgements
[ArB4O5]+
Cs 2A’
uB-O
u(asy. BO2)
uB O
Cs 2A’
IRPD signal
IR intensity (harmonic)
+0.1 kcal/mol
0.0 kcal/mol
For ArB4O5+, two isoenergic isomers contribute to the observed spectra for the cation. They are all in Cs symmetry and 2A’ state.
The dissociation energy of the argon atom is also large, nearly 15 kcal/mol.
SOMO
De = 15.0 kcal/mol
Simulated spectra: B3LYP-D3/aug-cc-pVTZ

18. [ArB4O6]+ uB-O u(asy. BO2) uB O Cs 2A’ SOMO Introduction Methods
Results
Discussion
Summary
Acknowledgements
[ArB4O6]+
Cs 2A’
uB-O
u(asy. BO2)
uB O
IRPD signal
IR intensity (harmonic)
+0.2 kcal/mol
0.0 kcal/mol
SOMO
Then, for the ArB4O6+, there are also two isoenergic isomers that contribute to the IRPD. They are both in Cs symmetry and 2A’ state.
De = 16.3 kcal/mol
Simulated spectra: B3LYP-D3/aug-cc-pVTZ

19. [ArB5O7]+ uB-O uB O u(asy. BO2) Introduction Methods Results
Discussion
Summary
Acknowledgements
[ArB5O7]+
C2v 1A1
Cs 1A’
uB-O
u(asy. BO2)
uB O
+0.2 kcal/mol
IRPD signal
IR intensity (harmonic)
+0.0 kcal/mol
0.0 kcal/mol
For the ArB5O7+ cation, three isoenergic isomers contribute to the observed spectra. They are all in singlet state, but two of them are in C2v symmetry, the other one is in Cs symmetry.
The cations have the largest value of dissociation energy in the series of cations, implying the BO moiety slightly enhances the argon boron interaction.
De = 16.4 kcal/mol
Simulated spectra: B3LYP-D3/aug-cc-pVTZ

20. Ar-B interaction Introduction Methods Results Discussion Summary
Acknowledgements
Ar-B interaction
[Ar-B3O4]+
[Ar-B3O5]+
[Ar-B4O5]+
[Ar-B4O6]+
[Ar-B5O7]+
Bond Length
2.851
2.004
2.016
2.002
2.001
Bond order
0.015
0.543
0.528
0.545
0.547
Bond type
no bond
σ bond
Q(Ar)
0.036
0.355
0.347
0.357
0.358 De
3.4
16.2
15.0
16.3
16.4
let`s see the property of Ar-B interaction.
The predicted bond length for the ArB3O4+ is much longer than others, whereas the boroxol cations all have a shorter bond length near 2.00 angstrom, which are close to the sum of the covalent radii of argon atom and boron atom. The bond orders for boroxol cations are all larger than half order. The NBO calculations suggest the interactions between argon and boroxol ring are all sigma bonds. No chemical bond is found in this chain cation(ArB3O4+). There is also some positive charge transfer from boroxol rings to argon atoms.
So, these results all imply the argon boron interactions in later four cations are dative in nature.
NBO analysis was calculated at B3lyp/AUG-cc-pVTZ level. The bond length (given in Å) and De (dissociation energy, in kcal/mol) were calculated at CCSD(t)/cc-pVTZ level.
r1(B) = 0.85 Å; r1(Ar) = 0.96 Å *
*P. Pyykkö, et al. Chem. Eur. J., 2009, 15, 186.

21. EDA-NOCV view Introduction Methods Results Discussion Summary
Acknowledgements
EDA-NOCV view
EDA-NOCV : energy decomposition analysis with natural orbitals for chemical valence*
Ar + BO chain:
weak interaction
Ar + boroxol ring:
donative bond
The energy decomposition analysis with natural orbital for chemical valence can give a detail view of the argon boron bonding. The sigma orbital interaction contributes most to the attraction interactions of two kinds of cations. And thus, this slide displays the deformation density of the sigma orbital interaction and pairwise natural orbitals.
The shape of the deformation densities for [Ar-B3O4]+ implies that the orbital interaction only causes the charge transfer from argon to the region between argon and boron. This kind of interaction can be considered as an ion-induced weak dipole interaction.
The shape of the deformation densities for argon boroxol cation indicates that the charge flow comes mainly from the lone-pair electrons at argon to the BO2 moiety of the boroxol ring, which leads to charge accumulation at the boron atom and the two O-B bonds.
Why there are so huge gap between two kinds of bond situations?
Although the LUMO orbital of the chain cation has very similar spatial distribution as those of the boroxol ring cations, it lies much higher than the HOMO orbital of argon atom, on the contrary the LUMO orbital of the boroxol ring cations lies even lower than the HOMO orbital of argon. These results can explain a weak donation interaction between argon and BO chain, and strong interaction between argon and boroxol ring.
low-lying LUMO orbital of the boroxol ring cation leads to the strong interaction.
DEorbs : orbital interaction energy of pairwise s interaction.
Dr: deformation density. charge flux is red  blue. (BP86/TZ2P level)
*M. Mitoraj, et al. J. Chem. Theory Comput., 2009, 5, 962

22. [ArB3O4]+ cation is a weakly bound complex with a BO chain structure.
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
The cations represent the very first examples of infrared spectroscopic study on boron-argon bonding in the gas phase.
[ArB3O4]+ cation is a weakly bound complex with a BO chain structure.
[ArB3O5]+, [ArB4O5]+, [ArB4O6]+ and [ArB5O7]+ cations all involve an argon-boron covalent bond and an boroxol ring.
Argon can donate lone pair to the suitable and low unoccupied molecular orbital for forming covalent compounds.
Here is the summary
The cations represent the very first examples of infrared spectroscopic study on boron-argon bonding in the gas phase.
[ArB3O4]+ cation is a weakly bound complex with a BO chain structure.
[ArB3O5]+, [ArB4O5]+, [ArB4O6]+ and [ArB5O7]+ cations all involve an argon-boron covalent bond and an boroxol ring.
Argon can donate lone pair to the suitable and low-lying unoccupied molecular orbital for forming covalent compounds.

23. National Natural Science Foundation of China
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Advisor:
Dr. Mingfei Zhou
Zhou Group:
Dr. Guanjun Wang
Wei Li (FA09)
Yuhong Liu
Much thanks for your attention.
I am very thankful for Prof. Zhou`s advises and help from the group members.
I also thank the National Natural Science Foundation of China and Ministry of Science and Technology for funding the researches.
Dr. Guanjun Wang provide some guild on the spectroscopy
Wei Li gave some help on the bonding analysis, She will have a presentation on Friday.
Yuhong Liu, undergraduate in our group. She and Me did the experiment.
Funding:
National Natural Science Foundation of China
Ministry of Science and Technology

24. Q&A

25. Q&A

27. What is EDA-NOCV ? A bond A-B between two fragments A and B
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
What is EDA-NOCV ?
A bond A-B between two fragments A and B
ΔEint, Interaction energy
∆ 𝐸 𝑖𝑛𝑡 =∆ 𝐸 elstate + ∆ 𝐸 𝑝𝑎𝑢𝑙𝑖 + ∆ 𝐸 𝑜𝑟𝑏
∆ 𝐸 𝑜𝑟𝑏 = k ∆𝐸 𝑘 𝑜𝑟𝑏 = 𝑘=1 𝑁 2 𝑣 𝑘 [− 𝐹 −𝑘,−𝑘 𝑇𝑆 + 𝐹 𝑘,𝑘 𝑇𝑆 ]
∆𝐸 𝑘 𝑜𝑟𝑏 ~∆ 𝜌 𝑘
Electrostatic interaction
Pauli repulsion
Contribution of pairwise NOCV pair
We are concerned about the bond between fragment with frozen geometries
The interaction energy can be dived into three terms: …
For each pairwise NOCV, the orbital energy and density can be calculated.
Diagonal transition state Kohn-Sham matrix elements corresponding to NOCV with the eigenvalues 𝑣 𝑘
M. Mitoraj, et al. J. Chem. Theory Comput., 2009, 5, 962

28. Details of EDA-NOCV Introduction Methods Results Discussion Summary
Acknowledgements
Details of EDA-NOCV
Table. Energy decomposition analysis of [ArB3O4]+, and, [ArB3O5]+ at the BP86/TZ2P level using the CCSD(T)/cc-pVTZ optimized geometries. Energy values are given in kcal/mol.
Dr(σ)
Species
Ar-B3O5+(3B2)
Ar-B3O4+(1A1)
ΔEint
-19.7
-2.3
ΔEpauli
53.1
6.2
ΔEelstata
-15.0[20.7%]
­-1.6[18.8%]
ΔEorba
-57.8[79.3%]
-6.9[81.2%]
ΔEorb σb
-44.7(77.3%)
-5.1(73.9%)
ΔEorb π
-8.6(14.9%)
ΔEorb(rest)
-4.5(7.8%)
-1.8(26.1%)
Dr(π)
This slides shows the details of EDA-NOCV
The energy values are given in the table, and the figures are the all deformation density.
All the terms in interaction energy for ArB3O5+ are much larger the ArB3O4+
The pi orbital interaction may also be a dipole interaction of the pi orbital of argon atom.
Dr(π)

29. [ArB3O4]+ isomers Introduction Methods Results Discussion Summary
Acknowledgements
[ArB3O4]+ isomers
This slide display the simulated results of different isomers of ArB3O4+
B3LYP/aug-cc-pVTZ, a= 0.986
Energy in kcal/mol

30. [ArB3O5]+ isomers Introduction Methods Results Discussion Summary
Acknowledgements
[ArB3O5]+ isomers
This slide display the simulated results of different isomers of ArB3O5+
B3LYP/aug-cc-pVTZ, a =1.0
Energy in kcal/mol

31. Shift of bands SOMO of [ArB4O5]+ C2V 3B2 Cs 2A’ C2V 1A1 Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Shift of bands
BO moiety slightly enhance the Ar-B bond strength.
The SOMO orbitals on B3O3 ring also effect on the bond.
This slide show the shift of bands. First, you can find that the BO moiety slightly enhance the Ar-B bond strength and cause a slightly red shift of the BO2 vibrational mode in those three cations; second, the bond length and frequency of ArB4O5+ is not in the trend. The delocalized SOMO orbital of the cation can give the explanation.
SOMO of [ArB4O5]+
C2V 3B2
Cs 2A’
C2V 1A1

32. Delocalized bonds in [ArBxOy]+
Introduction
Methods
Results
Discussion
Summary
Acknowledgements
Delocalized bonds in [ArBxOy]+
[Ar-B3O4]+
[Ar-B3O5]+
[Ar-B4O5]+
[Ar-B4O6]+
[Ar-B5O7]+
4 × 3c-2e π bonds
3× 3c-2e π bonds
5× 3c-2e π bonds
1× 3c-1e π bonds
We found many multi bonds in the argon boron complexes.
Three 3c-2e bond on the boroxol ring suggest the aromatic property of the species.
5× 3c-2e π bonds
7× 3c-2e π bonds
The results are given by AdNDP methods. (Adaptive Natural Density Partitioning)
A. I. Boldyrev et al. Phys. Chem. Chem. Phys., 2008, 10, 5207