Fluorocations of Krypton, Xenon and Bromine(VII) · PDF fileFLUOROCATIONS OF KRYPTON, XENON AND BROMINE(VII)..... '. By. ... Fluorocations of Krypton, Xenon and Bromine(VII) ... of

I,

,.

FLUOROCATI~NS OF KRYPTON, XENON A«D BROMINE(VLI)

,

.~

J

\

.,:

...

'.

TO MY PARENTS '"

i

(

\

( .

" .

,.

FLUOROCATIONS OF KRYPTON, XENON AND BROMINE(VII)... ..

'. By. (

GARY JOrscHROBIlGEtl. !'l.S .. M.Sc.

A Thesis

..

I,,j

Submitted to the Faculty oJ'Graduate Studies

in Partial Fulfilment of the Requirements

for ,the Degree

Ooct~r Df ~Ailosophy

. ?'M'cMaster Universi ty

December 1973

..

GARY JOHN SCHROMLGEN· 1977"

..

---I

..

!OOCTO~ OF PHILOSOpHY (1973)(CheRn stry)

McMASTER UNIVERSnlYHamilton, Ontario

•TITLE: Fluorocations of Krypton, Xenon and Bromine(VII)

AUTHOR: Gary John! Schrobilgen, B.S. (Loras College),.... i •. M.Sc. (£\rock University) ..

SUPERVISOR: Professor R. J. Gillespie

NUMBER OF PAGES: xv, 219

SCOPE AND CONTENTS:

I

conditions and are probably the most potent oxidants presently known.I

Although the major.ity of the noble gas compounds studied in. + - +-this work can be approxlmatly formulated as NgFx MF6 or ~9fXOy MF6 ~

direct vibrational spectroscopic evidence for a weak covalent inter-•

action between the cation and a fluorine on the anion has been obtained+. -in the case of the krypton (II) salts and XeF3 SbF6 The X-ray

, . + -crystal structure of XeF3 SbF6 has also been determin~d and supports

tbe vi ew that these II fl uori ne bri dge i nteracti ons exhi bi t a substanti a1

degree of covalent ~haracter. consequ\n~~ the electron pair repulsion

.theory, which has proven highly successful jn predicting the geometries-,-

of isolated molecules has' also proven useful in assessing the preferred.I •

the fluorine-br-idged anion _and cation in sch id!9

relative geometr;e~ of+ -XeF3 SbF6 " and related noble gas compounds:

•

\

"

iii

ACKNOWLEDGEMENTS) \

The a~thor wishes to thank his research director, Professor R.

J. Gillespie,. for his sincere interest in and encouragement of this

work.

Thanks are also due to the technical staff of McMaster University

for their maintenance of the nmr and laser Raman facilities and their

aid in constructi~g much of the apparatus. Much appreciation is also

extended to Mrs. Jan Gallo who typed this thesis.

The author also wishes to thank Drs. P. Boldrini and P. Ireland+ -who determined t~e si~gle crystal X-ray structure of 8-XeF3 SbF6 '

which is discussed in this thesis.

Financial assistance from. the National Research Council of

Canada" which provided sc~olarships for 1970-1973, is gratefully

acknowledged.

TABLE OF CONTENTS

Page·

1

1

2

2

2

4

5

5

7

8

8

9

.,'-12 -12

"12

(i) General

(i i) "Xenon Fl uori des

(i i 1) Xenon Oxyfluorides

(iv) Xenon Oxides

(v) Krypton Fluorides

(vi) Radon Fluorides

(i) ·The Valence Shell Electron Pair Repulsion(VSEPR) Theo'ry

,(ii) Flu~rine Bridge Interactions

(E) H;gh-R~solution 19r 'NMR Studies of Noble-Gas.~

Compounds 14

(C) Fluoro- and Oxyfluor~cations of the Noble Gases

(i) General

(ii) Applications of Noble-Gas Cation Chemistry

(D) Structural Aspects of the Noble-Gas Compoundsand Their Cations

Introducti onII

(A) Hi'sto~ical

(B) Noble-Gas Fluorides, Oxyfluorides and Oxides

CHAPTER I:

'J, (F) Pur.pose of the Present Work 17

CHAPTER II~ Experimental

(A) V~cuum Techriiques

(i)

(11 )

General Comments,

VaCUlI1l Lines

19'

19

19

19

.ff

.v

(iii) Valves

(iv) Preparative Apparatus

(B) Preparation and Purification of StartingMaterials

( 1) Fl uori ne

(ii) Ine~t Atmospheres

(iii) Xenon Difluoride

(iv) - Xenon Tetrafluoride

(v) Xenon Hexa.f'l uoride

(vi) Xenon OXYfluorides

(vii) . Krypton Difluoride

(viii) Fluoride Acceptors

(ix) Solvents'

'(x) Othe'r Ma teri a1s \

Preparation of Salts of the NOble-~Cations

and Related Compounds

General Comments

+ -and XeF3 SbF6+and xeOF3 SbF6

50

48

43

31

31

31

32

33

34

35

J7

39

39

40

..47

47

44

45

45

42

42

. Page

24

27

Previously Reported Compoun~s of Xenon

(FXe)2S03F+ASF6-

F5XeS03F+ -XeF3 Sb2F11+ -XeOF3 Sb2F

11+ -Xe02F Sb2F11

+ - + - +-KrF Sb2F11 ' KrF SbF6 ' Kr2F3 SbF6 and+ - 'Kr2F3' SbF6 -xKrF2+ - + - +-a-KrF A~f~ , ,8:KrF AsF6 ' Kr2F3 AsFS

and Kr2f 3 AsF6

(ix)

(1)

(i i)

(iii)

(i v)

(v)

(vi)

(vi i)

(viii)

(e)

vi

(D) Instrumentation

(x)

(xi)

(xi i)

(xi i i)

(xi v)

+ ­KrF PtF6+ - + -BrF6 AsF6 and BrF6 Sb2F11

+ -Attempted Synthesis of BrF6 AsF6 byOther Means

Displacement Reaction between NOF and+ -BrF6 AsF6'+ -BrF4 Sb2F11

Page

52

53

53

54

55

55

(i) Nuclear Magnetic Resonance Spectroscopy 55

(ii) Laser Raman Spectroscopy 56

(iii) Sample Preparation 57

CHAPTER III: 19 F Nuclear Magnetic Resonance Studies of Some Xenon(II)Compounds

" Introduction

"Resu1ts and Di scuss ion

(A) Xenon(II} Fluorosulfates

(B) The XeF+ Cation

(C~ The xe2F3+ Cation

(0) Empirical Correlations

60 ,60

60

60

64-"\"

67 ,'1\

71

.CHAPTER IV: A 19F NMR and Raman Study of the {FXe)2S03F+ Cation;

The Preparation and Characterization of(FXe)2S03F+ASF6- 74

.~

Introduction 74

Results and Discussion

(A) 19F N~m Spectroscopy\

(8) Preparation of (FXe)Zso3F+ASF6-'

vii

75

75

78

(c)

( D)

+Decomposition of (F~~)2S03F

Raman Spectroscopy

Page

79

81

CHAPTER V: ' A 19F Nuclear Magnetic.Cation and F

SXeS0

3F

Introduction

,---- +Resonance Study of the XeFS '

88

88

"

97

Results and Discussion 89• +CA) NMR Spectra of Solutions of XeF6 and XeFS

Salts in HF, HS03F and BrFS 89

(B) Preparation of F~XeS03F and the Solution NMRSpectra of F5XeS03.F and XeF6 93..

(C) . Solvent Effects 96

(D) Temperature Dependence of the Equatorial129Xe_19 F Coupling Constant

(E) Double Resonance Experiments 99

CHAPTER VI: The xeF3+, XeOF3

+ and xe02

F+ Cations~ Their Preparationand Characterization by 19F NMR Spectrosco~y 99

Introduction

Results and Discussion.(A)

(B)

(C)

, (D)

Preparation and Properties

19F NMR Spectroscopy

+(1) XflF3+(11 ) XeOF3+

(i i i) Xe02

F

Empirical Correlation of the 129Xe_19F Coupling

Constant and the 19F Chemical Shift

Correlation of the NMR Parameters with theOxidation St.ate of Xenon'

101

102

102

105

105

107

110

112

115

"

..

Results' and Oiscussion

CHAPTER VII: The Crystal Structure and Raman Spectrum of+ -8-XeF

3SbF

6

Introduction

(A)

( B)

ee)

•Crystal Data

DescriptioQ and Discussion of the Structure+ -Raman Spectrum of B-XeF

3SbF

S

116

116 ~

117

117

117

129

Results and Discussion

Syntheses, Properti~s and Reactions, I

19F NMR Spectroscopy

Th~ KrF+ and Kr 2F3+ Cations: The+ - , + + -

KrF MF6 ' KrF Sb2F11 ' Kr 2F3 MFSand Their Characterization by 19FSpectroscopy ~

lntroduc ti on

CHAPTER VI I I:

(A)

(B)

(C) Raman

(i) .

(i i)

(; i i)

(iv)

(v)

Prepara ti on of+ -and Kr 2F3 MF6 -xKrF2

NNR and Raman

...Spectrosc'opy

+ - (' + -KrF MF6 and KrF Sb2F11Valence Stretching Force Constants

+ +of ~rF and XeF+ -' +-Kr

2F3

SbF6

and Kr2

F3

AsF6

+ - + -Kr2

F3

SbF6

-XKrF2

and Kr 2F3 ASF6 -xKrF2The Question of the Purity of the

+ -Kr2F3 MF6 'Salts

137

138

138

138

143

149 ~149

165

169

177

181

CHAPTER IX: The Hexafluorobromine(VII) Cation, BrF6+: The Pre­paration of BrF6+ASF6- and BrF6+Sb2F

11- and Their

Character-ization by 19F NMR and Raman Spectroscopy

ix

183

CHAPTER X:

REFERENCES

Introduction

. Results and Disc;:ussion

. ~A) 19F NMR Spectroscopy

(B) Raman Spectroscopy.(C) Reaction of BrF6+ with Oxygen and Xenon

(D) Attempted Synthesis of BrF7Summary

Concl usions

(A) Introduction

(B) 19F NMR Spectroscopic Studies of Noble-GasSpecies

(e) Fluorine-Bridge Interactions

(0) '~uture Directions for Research

• I

X\

!l

Page

183

183

183

190

197

198

198

200

ZOO

200

'202

208

211

"

,

LIST OF TABLES

Table

1.1 )The Noble-Gas Cations and Their First Discovery

7~3 Equations for Least Squares PlanesI

- ' ....-7.4 Raman ppectra and Assignmen~ 'of a-XeF3 SbF6 and~ + -a-XeF3 SbF

Q

3.1

3.2

3.3

3.4

4.1

4.2

4.3

5.1

5.2

6.1

7.1

7.2

~ .The Known Molecular Geometries of Noble-Gas Compounds

Noble-Gas Compounds Studied by 19F NMR SpectroscopyPri or to thi s \~ork-

19F NMR Parameters for XeF2 , FXeS03

F and Xe(S03F)2

19F NMR Parameters for the XeF+ and Xe2

F3+ Cations

Variation ~f 19F Chemical Shift and 129Xe _19 F CouplingConstant for the XeF+ Ion with Solvent Composition

Correlations among the 19F NMR Parameters, Xe-F BondDistances and Xe-F Stretching Frequencies

19F NMR'Parameters for the (FXe)2S03F+ Cation andRelated Systems

The Raman Spectra 0: FXeS03F, Xe(S03F)2 and(FXe)2S03F+ASF6-

Vibrational Frequencies for Bridging ~03F Groups in I02S03F,'. +

(CH3)2Sn (S03F)2' 'S~F4S03F and ,(FXe)2S03F

NMR Parameters for the xeFs+ Cation in Various Solvents

Variation of the Fluorine-an-Xenon Line Width for Solutionsof XeF6 and FSXeS03 F in C1FS and BrFS19 . + + +F NMR Parameters for XeF3 ' XeOF3 and Xe02F in SbF5Solution .

0+_lntera:tomic Ois:tances (A) and Angles (deg.) for B-XeF3 SbF6Comparison of the Structures of XeF3+, BrF 3 and C1F3

Page

10

13

16

62

66

68

72

77

83

85

91

95

109

120

122

123

130

xi·

Table

7.5

8.1

Correlation Diagram for the xeF3+ Modes19 + +F NMR Parameters for Kr2F3 ' KrF andXenon Analogs

+ -of B-XeF3 SbF6KrF2 and Thei r

Page'

133

144

/

8.2

8.3

8.4

8.5

8.6

8.7

8.8

9.1

9.2

9.3

10.1

+ -Raman Spectra and Assignments for 'Some KrF MF6 Saltsand Their Xenon Analogs

I'

Raman Spectr.a of KrF+~b2F11- and xeF+Sb2F1i-Description of the Vibrational Modes and Correlations for

-Oh and C4V Molecules

Vibrational Frequencies for Some MFSX and MF6 Species

Correlation of the Valence Stretchin9 Force Constants andBond Lengths of NgF2, N9F+ and Some Monohalofluorides

, + .Raman Spectra of Some Kr2F3 Salts and ':heir _Xeno~ Analogs

Correlation Diagram f~r 0 h,' C· and C Symmetries¢o (bV S

19 + . +F NMR Parameters for the BrF6 and BrF4 Ions. + -' + - +Raman Spectra of BrF6 Sb2F11 ' BrF6 AsF6 and BrF4 Sb2F11

and Their Assignments+Vibrational Frequencies and Assignments of the' BrFS Cation

and Some Related Species

Observed Vibrational.!requencies and Structural Parametersof Some Xenon( II) Compounds

xii

150

151

160

161

'-166

170

175

185

191

195

205

'~,

j

LIST OF FIGURES

Figure

2.1 General purpose vacuum li~e a~d HF distillation appqratus 20

2.2 General purpose fluorine line 21I"

2.3 Diagram of the glass line used to prepare krypton difluoride 22

2.4 V~cuum diaphragm valve for the manipulation of corr6sivefluorides 26

2.5 Fluroplastic preparative apparatus 28."

2.6

3.1

3.2

3.3

4.1 -

4.2I

5.1

5.2

5.3

Apparatus for the storage and handling of KrF2The 19F nmr spectrum (58.3 MHz) of a solution ofFXeS0

3F (~ 0.5 m) in HS0

3F solvent

The 19F nmr spectrum (56.4 MHz, -62°) of the Xe 2F3+

cation (0.67 m Xe2F3+AsF6- in BrFS solvent)

c~rrelat;on of ~he 19F chemical Shi;t (019 ) and th~129X~_19F coupling con\tant (J129 19) f~r some ~enon(II)c~mpounds Xe- F

The 19F nmr spectrum (56.4,MHz) of a solution of(FXe)2s03F+ASF6- (0.92 m) prepared by.dissolvingXe2F3+AsF6- in HS03F at -78 0

The Raman spectrum (-90°) of soli~ (FXe)2S03F*ASF6­contained ,; n a glass sa~ple tube

The 19F nmr spectrum (56.4 MHz, 26°) of the X~F5+ cation+ _ d

(4.87 m XeFS SoF6 in HF solution)

Variation of the equatorial fluorine-xenon-129 couplingconstant of the xeFs+ cation with 1fT (0.481 m XeF6 and1.40 m SbF

Sin' HS03F solution)

The 19F nmr·spectrum (56.4 MHz, -81°) of the equatorialfluorines of the xe'F5+ cation (tV I,m F5X~S03f in HS03Fsolution); unperturbed arid with simul~aneous irradiat1bnof the 129 Xe transitions

xiii

30

63

70

73

76

82

90

98

lOP

•