Infrared Spectroscopy of New Molecules and Clusters - PowerPoint Presentation

Slide1

Infrared Spectroscopy of New Molecules and Clusters

F

UDAN

U

NIVERSITY

Mingfei Zhou(周鸣飞)Department of Chemistry, Fudan University(复旦大学化学系激光化学研究所)

72

th

International Symposium on Molecular Spectroscopy

June 19-23,

2017

,

UIUC Slide2

What constitutes a

chemical bond

What kinds of chemical bonds can be formed

What structures molecules

can have How to create the world as or even better than Him？ ---make new & useful moleculesResearch Interests

Preparation, infrared spectroscopic and theoretical characterization of structure, bonding and reactivity of new molecules and clustersSlide3

Outline

High Oxidation State

Iridium tetroxide cation with a formal oxidation state +IX

Nature, 2014, 514, 475 Oxidation state +V of lanthanides Angew. Chem. Int. Ed. 2016, 55, 6896; Chem. Sci. 2017, 8, 4035Fe(+VII) oxidation state in FeO4

- Phys. Chem. Chem. Phys. 2016, 18,31125. Donor-Acceptor Bonding Carbonyl Complexes CO bonding with Lewis acids BeO and BeCO3 Angew

. Chem. Int. Ed. 2015, 54,

124

Electron sharing or donor-acceptor bonding in B(CO)

2

-

Angew

. Chem. Int. Ed. 2015, 54,

11078

B

3

(CO)

3

+

complex featuring the smallest

-aromatic B

3

+

Angew

. Chem. Int. Ed.

2016, 55, 2078

One electron donor CO ligand

Chem

. Eur. J. 2016, 22, 2376

Carbonyl complexes featuring metal-metal triple bonding

Angew

. Chem. Int. Ed.

DOI: 10.1002/anie.201703525 Slide4

Collinear Tandem Time-of-Flight Mass Spectrometer

Infrared

Photodissociation

Spectroscopy

AB+ ~ lSlide5

G. C. Pimentel et al. J. Chem. Phys. 1954, 22, 1943

Trapping reactive intermediates and free radicals

Pulsed Laser

IR Source

Detector

Reagents inlet

Target

4K

CsI

Matrix Isolation Infrared Absorption Spectroscopy

Spectral assignment-- Isotopic substitutionSlide6

A central concept in chemistry

1. High Oxidation State

The term "oxidation" was first used by

Antoine Lavoisier

to mean reaction of a substance with oxygen; The substance loses electrons upon being oxidized; The “oxidation state” concept was introduced by Latimer in 1938; Oxidation states were one of the intellectual stepping stones that Mendeleev used to derive the PT； An indicator of the

degree of oxidation (loss of electrons) of an atom in a chemical compoundSlide7

M.

Kaupp

et al., Coord. Chem. Rev., 2009, 253, 606

The highest experimentally known oxidation state of any chemical element so far is

+VIII Ru+VIIIO4Os+VIIIO4Xe

+VIIIO41. High Oxidation StateIs a higher oxidation state than +VIII possible?

What is the highest

achievable

oxidation state of any chemical elements in the Periodic Table?Slide8

The element

iridium

(5d

7 6s2

) with nine valence electrons would have the greatest chance of being oxidized beyond the +VIII oxidation stateC. K. Jørgensen, Oxidation numbers and Oxidation States, Springer, New York, 1969The probable candidates are the cationic species [IrO4]

+ and the anionic species [IrO5]-

1. High Oxidation StateSlide9

There is some evidence for a short-lived [IrO

4

]+ species generated by

 decay of the unstable

193Os isotopomer of OsO4 P. Rother et al. Radiochim. Acta, 1969, 11, 203

Quantum chemical calculations predicted that iridium tetroxide cation is stableD. Himmel, et al. Chem. Phys. Chem. 2010, 11 , 865

1.1 +IX

Oxidation State

of

Iridium

The existence of Ir

IX

O

4

+

requires experimental verificationSlide10

Mass spectra of the iridium oxide cations produced by pulsed laser vaporization of iridium in expansion of (a) O

2

/He, and (b) O

2

/ArPreparation and spectroscopic characterization of IrO4+ in gas phaseIR photon energy in 900−1200 cm−1

region: 10.8−14.4 kJ mol−1

Rare gas atom tagging

1.1 +IX

Oxidation State

of

IridiumSlide11

Infrared

photodissociation

spectrum

of [193IrO4]+∙Ar

IrO4+,Td: one IR active T

2

mode

C

3v

: E + A

1

(2:1)

Ar

-induced

symmetry

reduction

& mode splitting

Ar

-coordination mode:

Face (



3

)

Edge (



2

)

Vertex(



1

)

1.1 +IX

Oxidation State

of

IridiumSlide12

Infrared

photodissociation

spectra of [193

IrO4

]+∙Arn

1.1 +IX

Oxidation State

of

IridiumSlide13

HOMO (T

1

)

HOMO-1 (T

2

)

HOMO-2 (A

1

)

HOMO-3 (T

2

)

HOMO-4 (E)

HOMO-5 (T

2

)

HOMO-6 (A

1

)

the same as OsO

4

IrO

4

+

with T

d

symmetry has an d

0

electron configuration with iridium in oxidation state +IX

Molecular orbital pictures of singlet IrO

4

+

1.1 +IX

Oxidation State

of

IridiumSlide14

Computed potential energy diagram (B3LYP results) of the isomers of [IrO

4

]+

G. J. Wang et al. Nature, 2014, 514, 475

1.1 +IX Oxidation State of IridiumSlide15

PtO

4

2+

is in fact a Pt(+VI) species!!!

Is Oxidation State Higher Than +IX Possible?Slide16

PtO

4

+

is a Pt(+II) species

d-shell collapses in radius and energy+IX is the highest experimentally achievable oxidation state for stable chemical elements in PTIs Oxidation State Higher Than

+IX Possible?Slide17

Ln

: 4f 5d 6s

C

ontracted radial distribution of 4f orbitals

1.2 +V Oxidation State of LanthanidesSlide18

Pr: 4f

3

6s

2 (+V)

IPs: Pr:5.42, 10.55, 21.62, 38.95, 57.45 eV V: 6.74, 14.65, 29.31, 46.71, 65.23 eVNd: 4f3 5d1 6s

2 (+V, +VI)1.2 +V Oxidation State of LanthanidesIs a higher oxidation state than +IV possible for lanthanides?Slide19

Praseodymium is also quadri- valent, possibly occasionally pentavalent

S. Hopkins, J. Chem. Edu. 1936, 13, 363.

Y2

O3 should promote the oxidation of praseodymium to the pentavalent state by forming the compound YPrO4 W. Prandtl & G. Rieder, Z. Anorg. Chem. 1938, 238, 225

The claimed Pr(+V) in solid states were later refuted J. D. McCullough, J. Am. Chem. Soc., 1950, 72 , 1386; J. Kleinberg, J. Chem. Educ., 1952, 29, 324

After 50 years, the

Pr

(+V) was believed to exist in gas-phase PrO

3

-

S. P.

Willson

& L. Andrews J. Phys. Chem. A, 1999, 103, 3171

PrO

3

-

is in fact a

Pr

(+IV) species

J. Su et al. Sci. China Chem. 2016, 59, 442.

1.2 +V Oxidation State of LanthanidesSlide20

2





,

Pr (4f1)The removal or oxidization of the remaining 4f electron from PrO2 would lead to the [PrO2]+ cation with

Pr(+V) oxidation state[(PrVO2)

+

(O

2

)

x

]

and [(

Nd

V

O

2

)

+

(O

2

)

x

]

cation

complexes

in gas phase

[(



2

-O

2

)Pr

v

O

2

] and

NPrO

neutral molecules

in noble gas

matrices

1.2 +V Oxidation State of LanthanidesSlide21

Mass spectra of the praseodymium oxide

cation

complexes

1.2 +V Oxidation State of Lanthanides

Preparation of praseodymium oxide cation complexes in gas phaseSlide22

Experimental and simulated IR spectra of [(PrO

2

)

+

(O2)6]

1.2 +V Oxidation State of LanthanidesSlide23

HOMO (2



u

)

HOMO-1(2u)HOMO-1(2u)HOMO-2 (1g)HOMO-3(1g)HOMO-3(1g)Frontier canonical Kohn−Sham valence MO envelopes of the linear singlet PrO2+

cationPrO2+ is a Pr(+V) species

1.2 +V Oxidation State of Lanthanides

Pr

: 4f/5d

O: 2pSlide24

Preparation of PrO

4

neutral molecule in solid argon

PrO

2 neutral can be oxidized by O2 in forming [(O2-

)(PrO2)+]Deposition at 4 KAnneal at 25 K

UV irradiation

Anneal at 30 K

1.2 +V Oxidation State of LanthanidesSlide25

C

2v

,

2A

2HOMOSOMOZhou & Li et al. Angew. Chem. Int. Ed. 2016, 55, 6896.

1.2 +V Oxidation State of LanthanidesPrO4 is a Pr(+V) species Slide26

Preparation of praseodymium nitride-oxide in noble gas matrices

Deposition at 4 K

Anneal at 10 K

Anneal at 12 K

Visible irradiation1.2 +V Oxidation State of LanthanidesPr + NO 

NPrO in NePr-NPr-OSlide27

1



B3LYP

CCSD(T)

Covalent triple bond radii: Pr + N = 1.28 + 0.54= 1.82 Å Pr+ O = 1.28 + 0.53= 1.83 Å

P. Pyykko, et al. Chem. Eur. J. 2005, 11, 3511Mayer bond order1.2 +V Oxidation State of Lanthanides

Li & Zhou et al. Chem. Sci. 2017, 8, 4035

NPrO

is a pentavalent species Slide28

IR

spectra

of the [

NdO

n]+ cation complexes MO envelopes of the 2

 state NdO2+1.2 +V Oxidation State of LanthanidesNdO

2

+

is a

Nd

(+V) speciesSlide29

synergic



donation

 backdonationCO: (1σ)2(2σ)2(3σ)2(4σ)2(1π)

4(5σ)2(2π)0Dewar−

Chatt

−

Duncanson

bonding

model

2. Donor-Acceptor Bonding Carbonyl Complexes

One electron donor CO ligand

Carbonyl complexes featuring U-Fe triple bondingSlide30

Infrared spectra of boron carbonyls in solid argon

2.1 One-Electron Donor Carbonyl Ligand

The terminally bonded CO ligands are classical two-electron donors

Octet rule:

B(CO)3: 9 e X[B(CO)

3]+: 2e (B) + 2e (CO)×3 = 8 e Deposition at 4 K

Anneal at 30 K

Anneal at 35 KSlide31

Optimized geometry at CCSD(T)/cc-

pVDZ

level

B(CO)

3 → B(CO)2 + CO De = 10.9 kcal/molDensity of the unpaired electron

2.1. One-Electron Donor Carbonyl LigandThe tilted CO ligand serves as a one-electron donor ligandSlide32

Energy levels of the frontier Kohn−Sham valence MOs of

B(CO)

3

2.1 One-Electron Donor Carbonyl LigandSlide33

IR spectra of C(CO)

3

+

and C(CO)

4+Zhou & Frenking

, Chem. Eur. J. 2016, 22,2376C(CO)3+

---B(CO)

3

isoelectronic

Mass spectrum of C(CO)

n

+

complexes

Graphite + CO/He

2.1 One-Electron Donor Carbonyl LigandSlide34

Nguyen, T. et al. Science 2005, 310, 844

Cotton, F. A. et al. Science 1964, 145, 1305

2.2. Carbonyl

Complexes Featuring

U-Fe

Triple BondingActinide-transition metal multiple bondingLiddle, S. T. et al. Angew. Chem. Int. Ed., 2009, 48, 1077; Chem. Eur. J. 2011, 17, 6909Slide35

Mass spectrum of iron−uranium carbonyl anion complexes

Fe(CO)

3

-

--- building block2.2. Carbonyl Complexes Featuring U-Fe Triple BondingSlide36

Mass

spectra

of iron−uranium carbonyl anion complexes

12

CO 13CO 2.2. Carbonyl Complexes Featuring U-Fe

Triple BondingSlide37

Infrared

photodissociation

spectra of

UFe(CO)3

- and OUFe(CO)3- 2.2. Carbonyl Complexes Featuring U-Fe Triple BondingSlide38

Experimental

spectrum

and PBE simulated IR spectra of

UFe

(CO)3- isomers (The relative energies are given in kcal/mol)2.2. Carbonyl Complexes Featuring U-Fe

Triple BondingSlide39

Covalent triple bond radii:

U + Fe = 1.18 + 1.02= 2.20 Å

P. Pyykko, et al. Chem. Eur. J. 2005, 11, 3511

2.212.162.02.6

Mayer bond orderC3v, 4A1

C

3v

,

2

A

2

2.2. Carbonyl

Complexes Featuring

U-Fe

Triple Bonding

Bond lengthSlide40

KS molecular orbitals of the quartet ground state UFe(CO)

3

-

U 5f U 7s Fe 3d  CO 2*

U (6d/5f) - Fe (3d) U (6d/5f) - Fe (3d) 2.2. Carbonyl

Complexes Featuring

U-Fe

Triple BondingSlide41

Bonding scheme of the C

3v

structure of 4

A1-UFe(CO)

3- U (5f)3(6d)1(7s)2 + Fe(CO)3

- (2A1)  U+IFe-II(CO)

3

-

One electron sharing

 bond

Two Fe  U dative  bonds

2.2. Carbonyl

Complexes Featuring

U-Fe

Triple BondingSlide42

KS molecular orbitals of OUFe(CO)

3

-

U 5f

U 7s Fe 3d  CO 2*

U (6d/5f) - Fe (3d) U (6d/5f) - Fe (3d) 

SOMO

(2a

2

)

HOMO

(12a

1

)

HOMO-1

(10e)

HOMO-2

(11a

1

)

HOMO-3

(9e)

UO (5f)

1

(6d)

1

(7s)

2

+ Fe(CO)

3

-

(

2

A

1

)

 OU

+III

Fe

-II

(CO)

3

-

One electron sharing

 bond

Two Fe  U dative  bonds

2.2. Carbonyl

Complexes Featuring

U-Fe

Triple BondingSlide43

interaction fragments

U-Fe(CO)

3

-

U (5K, f2f16dσ1

7s2) + Fe(CO)3- (2A1)

OU-Fe(CO)

3

-

UO (

3

H, f

σ

1

f



1

7s

2

)

+ Fe(CO)

3

-

(

2

A

1

)



E

int

-135.0

-141.0



E

Pauli

388.9

372.9



E

elstat

-285.3 (54.5%)

-268.0 (52.2%)



E

orb

-238.5 (45.5%)

-245.9 (47.8%)



E

orb

(



)

-84.4

-59.7



E

orb

(



)

-41.5

-56.4



E

orb

(



//)

-41.5

-56.4

Energy decomposition analysis of

UFe

(CO)

3

-

and

OUFe

(CO)

3

-

at the PBE/TZ2P level

2.2. Carbonyl

Complexes Featuring

U-Fe

Triple BondingSlide44

Deformation densities



of the pairwise orbital interactions



(

)() (



)

 

UFe

(CO)

3

-

OUFe

(CO)

3

-

Li & Zhou,

Angew

. Chem. Int. Ed. 2017, in press

2.2. Carbonyl

Complexes Featuring

U-Fe

Triple BondingSlide45

Conclusions

Infrared spectroscopic experiments on mass-selected [IrO

4

]+Arn (n = 1-4) cations show that the iridium tetroxide cation is formed with iridium in the formal oxidation state +IX; Infrared spectroscopic studies on PrO2+

and NdO2+ complexes and the PrO4 and NPrO molecules confirm that formal oxidation state +V is viable for some lanthanide elements;

Some new carbonyl complexes have been prepared via donor-acceptor bonding strategy that exhibiting unusual bonding characters.Slide46

Acknowledgements

Sebastian Riedel

(

Berlin)

Financial support from NNSFC and MSTCollaboratorsJun Li (Tsinghua)Gernot

Frenking (Marburg)Research groupChaoxian

Chi

(ECUT

)Slide47

Thank you very much for your attention!