Atomic Metal Ion Chemistry

1
Atomic Metal Ion Chemistry in the Gas
Phase Diethard K. Bohme Ion Chemistry
Laboratory Department of Chemistry Centre for
Research in Mass Spectrometry Centre for Research
in Earth Space Science York University,
Toronto, Canada Department of Chemistry Memorial
University October 2, 2007
2
Chemical Mass Spectrometry

• ? Create ions (in an ion source).
• Look at ions (with a mass spectrometer).
• resolve m/z,
  (dissociate), count
• ? Look at ions react (in a reaction cell).

Ernest Rutherford Ions are jolly little
beggars, you can almost see them
3

• Chemical Mass Spectrometry at York, since 2000
  
• 2000 Invention of ICP/DRC/MS
• (S. Tanner, V. Baranov, then at
  MDS/SCIEX)
• - Dynamic Reaction Cell (DRC) for the chemical
• resolution of isobaric interferences in
  elemental analysis
• - requires chemical data base for atomic-ion
  reactions.
• ? NSERC/NRC/MDS SCIEX/York Partnership.
• ? ICP/SIFT tandem mass spectrometer
• 2003 Suppression of chemical noise in MS, etc.
• (T. Covey, MDS SCIEX)
• ? NSERC/MDS SCIEX/York Partnership
• ESI/qQ/SIFT/QqQ multipole ms

4

• OUTLINE
• ICP/SIFT tandem mass spectrometer
• (the universal atomic ion chemical mass
  spec)
• - Periodicities in Reactivities
• - The Special Case of Lanthanides
• - Atomic Cations as Catalysts
• - Influence of Ligation
• - Chemical Resolution of Atomic Isobars in
• ICP/DRC/MS a Case Study
• ESI/qQ/SIFT/QqQ multipole mass spectrometer
• (the ultimate chemical mass spectrometer)

5

• The Universal Atomic Ion
• Chemical Mass Spectrometer

6
The ICP/SIFT/QqQ instrument
Argon Plasma 5500 K P 1 atm
Aqueous solution of the atomic salt is injected
via a nebulizer into the Ar plasma
__________________________________________________
__________________________________________________
______ An Inductively-Coupled Plasma /
Selected-Ion Flow Tube Mass Spectrometer Study of
the Chemical Resolution of Isobaric
Interferences. G.K. Koyanagi, V.I. Baranov, S.
Tanner and D.K. Bohme, J. Anal. At. Spectr. 15,
1207-1210 (2000).
7
Periodic Table of Atomic Salt Solutions
8

• Attractive Features of the ICP Ion Source
• ? intense ca.1011 ions s-1 in first quad (Ar
  with
• 0.1 metal ions), ca. 107 ions cm-3 in flow
  tube
• defined thermal population of electronic states
• at ca. 5500 K which relaxes toward 295 K.
• ? rapid time to change metal ions ca. 30 s
• ? stable not hours but weeks
• versatile almost universal source of atomic
• ions

9
Reactions of atomic cations Nb with N2O
Primary Oxidation and Nitration Nb N2O ? NbO
N2 ? NbN NO Further Oxidation NbO
N2O ? NbO2 N2 NbN N2O ? NbNO
N2 Clustering with N2O NbO2 N2O ?
NbO2(N2O) NbO2(N2O) N2O ?NbO2(N2O)2
NbO2(N2O)2 N2O ?NbO2(N2O)3 NbNO N2O ?
NbNO(N2O) NbNO(N2O) N2O?NbNO(N2O)2
NbNO(N2O)2 N2O?NbNO(N2O)3
__________________________________________________
______________ V.V. Lavrov et al., J. Phys. Chem.
A 106 (2002) 4581.
10
Surfing the Periodic Table
59 atomic cations
Some MO oxide ions
1000 5000 2500
15 different molecules O2, NO, N2O, NO2, CO2,
CS2, OCS, D2O, NH3, CH4, CH3F, CH3Cl, SF6, C6H6,
C6F6
11
Web Data Base
61 atomic cations x 15 molecules 915
reactions !! http//www.chem.yorku.ca/profs/bohme
/research/research.html
12
Periodicities in Reactivities
13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
n up to 4 !
17
k/kc
OA (M) /kcal mol-1
18
(No Transcript)
19
Kinetic barrier due to electron interaction
during bond redisposition (conventional
activation barrier).
20
Kinetic Barriers Due to Constraints in Electronic
Spin
Slow and spin forbiddena for formation of ground
state MO. k ?rHo
(cm3 s-1) (kcal mol-1) Cr
(X6S) N2O ? CrO (4?-) N2 lt1.5x10-13
-46 Mn (7S) N2O ? MnO (5?) N2 lt10-13
-28 Co(3F) N2O ? CoO (5?) N2
lt1.1x10-12 -35 Ni(2D) N2O ? NiO (4?-)
N2 lt6.3x10-13 -33 Mo (6S) N2O ? MoO
(4?-) N2 lt3.4x10-13 -77 Ru(4F) N2O
? RuO (6?) N2 lt3.3x10-13 -48 a If
overall spin is not conserved, a kinetic barrier
is present because a curve crossing is required
to change the spin multiplicity so that overall
spin can be conserved.
21
The special Case of Lanthanides
22
Ln XO ? Ln ? LnO X
Two non-f valence electrons are required for
the lanthanide cation to participate in
bonding with O. This can be achieved by the
promotion of a 4f electron
4fn5d06s1 to 4fn-15d16s1. (For La,
Ce, and Lu, the promotion corresponds to d2 ?
d1s1 or s2 ? d1s1) Exothermic reactions
controlled by the availability of valence
electrons for bonding. So can expect a
correlation between reaction rate and electron
promotion energy PE !
23
Barriers to Electron Promotion
Ln N2O ? LnO N2
__________________________________________________
__ G.K. Koyanagi, D.K. Bohme. J. Phys. Chem. A
105, 8964 (2001)
24
Arrhenius would be interested!
kexp kc e-PE/RT
25
Atomic Ions as Catalysts
26
O-atom Transport Catalysis
M N2O ? MO N2
MO CO ? M CO2
M
N2O
CO2
N2
CO
MO
N2O CO ? N2 CO2
Need OA(N2) lt OA(M) lt OA(CO) 40 kcal
mol-1 lt OA(M) lt 127 kcal mol-1 No kinetic
constraints

27
GAUSSIAN98 B3LYP/sdd/6-311G
V. Blagojevic, G. Orlova, D. K Bohme, J. Am.
Chem. Soc. 127 (2005) 3545.
28
Establishing a Catalytic Cycle in the Reaction
Region
Reducing reagent CO
Oxidizing reagent N2O
Catalytic Cycle
M
MO
Key features

• Moderate pressure in the flow tube (0.35 Torr
  He)
• Nearly universal source of single charged atomic
  cations

29
Catalyzed Reduction of N2O by CO
N2O CO ? N2 CO2
Investigated with 59 cations (26 in the TD
window) Observed with10 atomic cations Ca,
Fe, Ge Sr Ba, Os, Ir, Pt Eu, Yb

30
N2O CO ? N2 CO2
59 cations were studied 26 lie in the TD
window 10 are catalytic
31
Catalytic reduction of NxOy by CO
NO2
M
Observed for Fe, Ge Sr Ba, Os, Ir Eu, Yb
CO2
CO
MO
(2) NO
M
CO2
CO
MO
N2O
Blagojevic et al. Angew. Chem. Int. Ed. 2003, 42,
4923-4927
M
CO2
CO
N2
MO
32
Catalytic reduction of NxOy by H2
NO2
M
H2O
H2
MO
(2) NO
Observed for Ca,Fe, Sr, Os, Ir
M
H2O
H2
MO
N2O
M
H2O
H2
N2
MO
33
Influence of Ligation
34
Metal-Cation Ligation on Curved Carbonaceous
Surfaces
35
Reactions of atomic cations with benzene

• M C6H6
• ? M(C6H6)
• C6H6 M
• MC6H4 H2
• MC4H4
• C2H2

G.K. Koyanagi, D.K. Bohme. Int.J.MassSpectrom.
227 (2003) 563.

36
(No Transcript)
37
(No Transcript)
38
(No Transcript)
39
(No Transcript)
40
Catalytic oxidation of benzene
M C6H6 ? MC6H6 M Fe, Cr, Co MC6H6
O2 ? M (C6H6O2) C6H6 O2 ? (C6H6O2)
Caraiman Bohme J. Phys. Chem. A 2002,
106, 9705-17.
catechol
41
Proposed tetrahedral structure for Sr(C60)4
ICP/SIFT/QQQ mass spectrum
42
Chemical Resolution of Atomic
Isobars in ICP/DRC/MS a Case Study
43
A CASE STUDY The 87Rb (s0) / 87Sr (s1)
Interference in age determination of magnetic
rocks. L.J. Moens et al, J. Anal. At. Spectrom.
16 (2001) 991-994 - needed Sr
isotope ratios in the presence of
a Rb interference, - used CH3F in the
dynamic reaction cell, and - measured
intensities of SrF M CH3F ? MF CH3
found to be fast with Sr(s1) / not
with Rb(s0)
44
The 87Rb (s0) / 87Sr (s1) Interference
Rb (s0) CH3F ? Rb.CH3F 100 k ? 1.3x10-12
cm3 s-1 ? RbF CH3 0
Sr (s1) CH3F ? Sr.CH3F 4 k
1.4x10-11 cm3 s-1 ? SrF CH3 96
45
The 87Rb (s0) / 87Sr (s1) Interference (contd)
Rb (s0) SF6 ? NR k ? 1x10-13 cm3 s-1
Sr (s1) SF6 ? SrF SF5
97 k 5.7x10-10 cm3 s-1 ? SrSF5 F
3
46
ICP/SIFT Results at 295 K, 0.35 Torr
He Rb(s0) Sr(s1)
BR k/cm3s-1 BR k/cm3s-1 M CH3F ?
M.CH3F 1 1.3x10-12 0.04
1.4x10-11 ? MF CH3 0
0.96 M CH3Cl ? M.CH3Cl 1
5.1x10-13 0 3.9x10-11 ?
MCl CH3 0 0.99
? CH2Cl MH 0
0.01 M N2O ? MO N2 lt10-13
1 6.3x10-11 M CO2 ? M.CO2
lt5x10-13 1 ?6x10-13 M CS2
? M.CS2 lt10-12 1
1.1x10-11 M OCS ? M.OCS 1
4.0x10-13 0.50 3.9x10-13 ?
MS CO 0.50 M SF6
? MF SF5 lt10-13 0.97
5.7x10-10 ? MSF5 F
0.03 M D2O ? M.D2O 1
3.0x10-13 0.50 4.0x10-13
? MOD D 0.50 M NH3 ?
M.NH3 1 5.5x10-13 1
4.9x10-13
47
Discontinuities in reactivity provide an
opportunity for chemical resolution
M SF6 ? MFn SF6-n ? M(SF6 ) ? SFn
MF6-n
C. Ping and D.K. Bohme, J. Phys.Chem. A, in
preparation.
48
2. The Ultimate Chemical Mass
Spectrometer
49
The ESI/qQ/SIFT/QqQ instrument
__________________________________________________
_______________________________________ A novel
chemical reactor suited for studies of
biophysical chemistry construction and
evaluation of a selected ion flow tube utilizing
an electrospray ion source and a triple
quadrupole detection system. G.K. Koyanagi et
al. Int. J. Mass Spectrom. 265, 295-301 (2007).
50
Chemical Reactions of Atomic Metal Dications
51
Ozonolysis of Metal Dications
Oxidation of Ca is Initiated by Charge
Separation.
Ca O3 ? CaO O2 (k 1.5 10-9 cm3
s-1)   CaO O3 ? CaO2 O2   (k 5 10-10
cm3 s-1) CaO2 O3 ? CaO3 O2 (k 6
10-10 cm3 s-1)
100 ?M CaAcetate in H2O/CH3OH (1/1)
52
Ba ? BaO3 ? BaO6 ? BaO9 ?
BaO12 1
2 3
4
k1 1.1 10-11 cm3 s-1 k2 2.9 10-10 cm3
s-1 k3 1.2 10-10 cm3 s-1 k4 1.8 10-10 cm3
s-1
0.011
10 ?M BaCl2 in H2O/CH3OH (1/1)
53
D2O hydrolysis of Ca2 Ba2 in He at 0.35
Torr and 295 K.
54
D2O Hydrolysis of Metal Dications
M RE/eV Products k/ cm3 s-1
Higher-order
Products --------------------------------------
--------------------------------------------------
--------------------- Mg2 15.0 Mg
D2O 1.4x10-9 MgOD, D3O
Ca2 11.9 Ca2D2O
2.3x10-11 Ca2D2O CaOD D3O
7.9x10-10 CaOD(D2O)1-5 Sr2 11.0
Sr2D2O lt 1x10-12
Sr2(D2O)2-8 Ba2 10.0 Ba2D2O
6.7x10-12 Ba2(D2O)2-7 ---------------------
--------------------------------------------------
-------------------------------------------------
IE(D2O) 12.6 eV
55
Multiply-Charged Metallated Biological Ions
56
DNA is intrinsically very stable (thanks to
Mother Nature)!
k295 / cm3 molecule-1 s-1 O3
lt10-13 No oxidation O2 lt10-13
N2O lt10-13 D2O lt10-13 No hydration
C6H6 lt10-13 No intercalation HBr fast
Protonation
Hydrobromination
?Goacid (HBr) 1331 kJ mol-1 HBr
will protonate H2PO4- in the gas phase
(AGTCTG-5H)5-
 
57
Protonation and Hydrobromination of
(AGTCTG-5H)5- by HBr
50 ?M in 20/80 CH3OH/H2O
58
Rate coefficients (in units of 10-9 cm3
molecules-1 s-1) for reactions with HBr in He at
(0.35?0.01) Torr and (292?2) K.
Anion kobs kcap
kobs/kcap PT (AGTCTG 5H)5-
3.2 4.27 0.68 73 (AGTCTG
4H)4- 2.6 3.35 0.78 84
(AGTCTG 3H)3- 1.9 2.47
0.77 20 (AGTCTG 2H)2-
1.3 1.62 0.80 0 Ni(AGTCTG
5H)3- gt 1 Ni(AGTCTG 4H)2- gt
1 0   The
processes observed with nickellated species with
HBr were similar to those for non-metallated
anions - trianion underwent protonation and
hydrobromination - dianion underwent only
hydrobromination.
59

• We have learned that
• ? Periodic trends in the reactivities of atomic
  metal cations
• now can be measured routinely in the absence
  or presence
• of ligands.
• ? These trends are governed by thermodynamics,
  by
• intrinsic barriers, by spin, or by electronic
  structure
• effects.
• ? Atomic cations can catalyze the transport of
  an O atom
• from one molecule to another.
• ? Atomic metal cations can activate benzene and
  catalyze its
• oxidation.
• Atomic metal cations can attach to C60 and
  perhaps
• catalyze the reduction of N2O while attached.

60
and that

• ESI provides a means to study the reactivities
  of free
• and solvated atomic metal dications.
• ESI provides a means to measure the
  reactivities of
• metallated biological anions.
• ? DNA-like anions appear to be intrinsically
  very stable.
• Even the chemistry of metallated DNA-like
  anions now
• can be invetigated in the gas phase.

61
Acknowledgments
Greg Koyanagi Stefan Feil Janna
Anichina Voislav Blagojevic Michael
Jarvis Andrea Dasic Tuba Gozet Sara Hashemi Mike
Duhig Svitlana Shcherbyna