The OsO3F+ and μ-F(OsO3F)2+ cations

Inorg. Chem. 2002, 41, 259−277

The OsO F⁺and µ-F(OsO F)₂⁺Cations: Their Syntheses and Study by

3

Raman and ¹⁹F NMR Spectroscopy and Electron Structure Calculations

and X-ray Crystal Structures of [OsO F][PnF₆] (Pn ) As, Sb),

3

[OsO F][HF]₂[AsF₆], [OsO F][HF][SbF₆], and [OsO F][Sb₃F₁₆]^†

3

,‡

Michael Gerken,^‡David A. Dixon,^§and Gary J. Schrobilgen*

Department of Chemistry, McMaster UniVersity, Hamilton, Ontario L8S 4M1, Canada, and

William R. Wiley EnVironmental Molecular Sciences Laboratory, Pacific Northwest National

Laboratory, 906 Battelle BlVd., P.O. Box 999, KI-83, Richland, Washington 99352

Received July 20, 2001

The fluoride ion donor properties of OsO F have been investigated. The salts [OsO F][AsF ], [OsO F][HF]₂[AsF ],

3

2

3

6

3

6

µ-F(OsO F)₂[AsF ], [OsO F][HF]₂[SbF ], and [OsO F][HF][SbF ] have been prepared by reaction of OsO F with

3

6

3

6

3

6

3 2

AsF and SbF in HF solvent and have been characterized in the solid state by Raman spectroscopy. The single-

5

crystal X-ray diffraction studies of [OsO F][AsF ] (P2₁/n, a ) 7.0001(11) Å, b ) 11.0620(11) Å, c ) 8.8629(13)

3

6

Å, â ) 92.270(7)°, Z ) 4, and R ) 0.0401 at −126 °C), [OsO F][SbF ] (P2₁/c, a ) 5.4772(14) Å, b ) 10.115(3)

1

3

6

Å, c ) 12.234(3) Å, â ) 99.321(5)°, Z ) 4, and R ) 0.0325 at −173 °C), [OsO F][HF]₂[AsF ] (P2₁/n, a )

1

3

6

5.1491(9) Å, b ) 8.129(2) Å, c ) 19.636(7) Å, â ) 95.099(7)°, Z ) 4, and R ) 0.0348 at −117 °C), and

1

[OsO F][HF][SbF ] (Pc, a ) 5.244(4) Å, b ) 9.646(6) Å, c ) 15.269(10) Å, â ) 97.154(13)°, Z ) 4, and R )

3

6

1

0.0558 at −133 °C) have shown that the OsO F⁺cations exhibit strong contacts to the anions and HF solvent

3

molecules giving rise to cyclic, dimeric structures in which the osmium atoms have coordination numbers of 6. The

reaction of OsO F with neat SbF yielded [OsO F][Sb₃F ], which has been characterized by ¹⁹F NMR spectroscopy

3

2

5

3

16

in SbF and SO ClF solvents and by Raman spectroscopy and single-crystal X-ray diffraction in the solid state

5

2

(P42h₁m, a ) 10.076(6) Å, c ) 7.585(8) Å, Z ) 2, and R ) 0.0858 at −113 °C). The weak fluoride ion basicity

1

of the Sb₃F ^-anion resulted in an OsO F⁺cation (C point symmetry) that is well isolated from the anion and in

16

3

3v

which the osmium is four-coordinate. The geometrical parameters and vibrational frequencies of OsO F⁺, ReO F,

3

µ-F(OsO F)₂⁺, (FO Os--FPnF ) , and (FO Os--(HF)₂--FPnF ) (Pn ) As, Sb) have been calculated using density

3

5 2

3

5 2

functional theory methods.

Introduction

distorted octahedral cis-dioxo arrangement about the osmium

atoms in the crystal structure of [µ-F(OsO₂F₃)₂][Sb₂F₁₁],

which was isolated by crystallization from SbF₅/HF mixtures.

Failure to obtain a crystal structure containing the trigonal

The fluoride ion donor chemistry of Os(VIII) has thus far

been limited to cations derived from cis-OsO₂F₄.¹The latter

are formed by reaction of cis-OsO₂F₄with the strong Lewis

acid fluoride ion acceptors, AsF₅and SbF₅. The dinuclear

fluorine-bridged [F₃O₂Os--F--OsO₂F₃]⁺cation exhibits a

+

bipyramidal OsO₂F₃cation is indicative of the reluctance

of this osmium(VIII) dioxo species to lower its coordination

number below 6. Consequently, the OsO₂F₃⁺cation has only

been observed by ¹⁹F NMR spectroscopy with the weakly

nucleophilic, polymeric Sb_nF_5n+1^-anion as the counteranion

in the highly acidic, strong fluoride ion acceptor solvent,

SbF₅.

^†Dedicated to our colleague Professor Karl O. Christe on the occasion

of his 65th birthday and in appreciation of his long friendship and his many

outstanding synthetic and structural contributions to the field of inorganic

fluorine chemistry.

* To whom correspondence should be addressed. E-mail: SCHROBIL@

McMASTER.CA.

The fluoride ion acceptor properties of OsO₃F₂have been

established by the formation of the distorted octahedral fac-

^‡McMaster University.

^§Pacific Northwest National Laboratory.

-

OsO₃F₃anion in the salts [K][OsO₃F₃],^2,3[Rb][OsO₃F₃],²

(1) Casteel, W. J., Jr.; Dixon, D. A.; Mercier, H. P.; Schrobilgen, G. J.

Inorg. Chem. 1996, 37, 340.

[Cs][OsO₃F₃],^2,3[Ag][OsO₃F₃],^2,3[NO][OsO₃F₃],⁴and

Published on Web 12/21/2001

Inorganic Chemistry, Vol. 41, No. 2, 2002 259

Gerken et al.

[N(CH₃)₄][OsO₃F₃].⁴The preferred coordination number of

osmium(VIII) trioxo species also appears to be 6, which has

been found for the fac-OsO₃F₃^-anion in [N(CH₃)₄][OsO₃F₃]⁴

as well as in the low-temperature phase of the neutral parent

compound, (OsO₃F₂)_∞,⁵which exists as a fluorine bridged

polymeric chain in the solid state.

The fluoride ion donor properties of OsO₃F₂have been

investigated for the first time in the present study. Because

ReO₃F has been prepared⁶and characterized by vibrational,^7-9

microwave,¹⁰and UV spectroscopy,⁹the isoelectronic OsO₃F⁺

cation was anticipated to be isolable as salts derived from

the strong fluoride ion acceptors, AsF₅and SbF₅.

solvent suggests stabilization by coordination of HF mol-

+

ecules to the Os₂O₆F₃⁺cation. The formation of the Os₂O₆F₃

cation from [OsO₃F][AsF₆] (eq 3) can be reversed by addition

2[OsO₃F][AsF₆] {^HF} [µ-F(OsO₃F)₂][AsF₆] + AsF₅(3)

[µ-F(OsO₃F)₂][AsF₆] ^{-HF, RT}8 [OsO₃F][AsF₆] + OsO₃F₂

(4)

of excess AsF₅to the HF solution. The very low solubility

of [µ-F(OsO₃F)₂][AsF₆] in HF solvent prevented crystal

growth. Solutions of solvated [OsO₃F][AsF₆] in HF solvent

are unstable, dissociating to OsO₃F₂and AsF₅in under 1

min at room temperature. The ¹⁹F NMR spectrum of OsO₃F₂

in the presence of a 13.5-fold molar excess of AsF₅in HF

solvent at -80 °C showed a broad singlet at -132.2 ppm

(∆ν_1/2) 500 Hz), which is attributed to fast fluorine

Results and Discussion

+

Syntheses of the OsO₃F⁺and Os₂O₆F₃Cations and

Solution Characterization of the OsO₃F⁺Cation by ¹⁹F

NMR Spectroscopy. Osmium trioxide difluoride, which is

insoluble in HF, reacts with excess AsF₅in HF according to

eq 1, yielding a yellow-orange solution of solvated [OsO₃F]-

[AsF₆]. The [OsO₃F][AsF₆] salt is expected to be strongly

solvated in HF solvent as suggested by the crystal structure

of [OsO₃F][HF]₂[AsF₆] (see X-ray Crystallography, part c).

Stoichiometric amounts of AsF₅did not result in complete

dissolution of OsO₃F₂, presumably because of the competing

reaction with HF solvent (eq 2) or the need to use the stronger

-

exchange among the OsO₃F⁺cation, AsF₆, As₂F_{11 ,}AsF₅,

and HF solvent.

At room temperature, OsO₃F₂was very soluble in HF

solutions containing stoichiometric amounts of SbF₅and

yielded a yellow solution of solvated [OsO₃F][SbF₆] (eq 1)

from which yellow [OsO₃F][HF][SbF₆] slowly crystallized

at -78 °C (see X-ray Crystallography, part d). Removal of

HF solvent under vacuum at -78 °C yielded [OsO₃F][HF]-

[SbF₆], which melted at approximately 45 °C and was stable

to brief pumping at room temperature but resulted in partial

removal of solvated HF upon pumping for more than 5 min

at room temperature. Complete conversion to [OsO₃F][SbF₆]

was not possible, presumably because the dissociation

pressure of coordinated HF is very low at room temperature

and competes with the decomposition of [OsO₃F][SbF₆] at

temperatures close to and above room temperature. Pumping

at 45 °C led to a decrease in the relative Raman intensities

of the symmetric Os-O stretching bands assigned to [OsO₃F]-

[SbF₆] when compared with those of [OsO₃F][HF][SbF₆].

Although [OsO₃F][SbF₆] could not be isolated in bulk as a

pure solid, a crystal of [OsO₃F][SbF₆] suitable for X-ray

structure determination was selected from a mixture that had

been obtained from an HF solution of [OsO₃F][SbF₆] (see

X-ray Crystallography, part b). Upon slow removal of HF

solvent from a solution containing solvated [OsO₃F][SbF₆],

orange [OsO₃F][HF]₂[SbF₆] crystallized at high concentra-

tion. One HF molecule was readily lost under dynamic

vacuum at -78 °C, yielding [OsO₃F][HF][SbF₆].

OsO₃F₂+ PnF₅^{HF, RT}8 [OsO₃F][PnF₆]_HFPn ) As, Sb (1)

2HF + AsF₅f [H₂F][AsF₆]

(2)

Lewis acid (AsF₅)_nto depolymerize (OsO₃F₂)_∞. Slow removal

of the HF solvent at -78 °C initially yielded orange crystals

having the composition [OsO₃F][HF]₂[AsF₆] (see X-ray

Crystallography, part c). Further pumping at -78 °C resulted

in the loss of both HF solvent molecules, yielding straw-

yellow [OsO₃F][AsF₆], which was unstable at ambient

temperatures, dissociating to OsO₃F₂and AsF₅. Crystals of

solvent-free [OsO₃F][AsF₆] were grown from HF solvent at

-78 °C in the presence of an excess of AsF₅(see X-ray

Crystallography, part a).

Attempts to redissolve [OsO₃F][AsF₆] in HF solvent

resulted in loss of AsF₅and precipitation of orange [Os₂O₆F₃]-

[AsF₆] according to eq 3, which was identified by Raman

spectroscopy. Removal of HF solvent yielded a mixture of

solid [OsO₃F][AsF₆], OsO₃F₂and small amounts of [Os₂O₆F₃]-

[AsF₆], which were identified by Raman spectroscopy and

resulted from partial dissociation according to eq 4. The

instability of [µ-F(OsO₃F)₂][AsF₆] in the absence of HF

Dissolution of OsO₃F₂in neat SbF₅at 55 °C gave rise to

a yellow solution according to eq 5. Below 55 °C, the

OsO₃F₂+ nSbF₅^{SbF , 55 °C}8 [OsO₃F][Sb_nF_5n+1

]

(5)

5

(2) Jones, P. J.; Levason, W.; Tajik, M. J. Fluorine Chem. 1984, 25, 195.

(3) Hepworth, M. A.; Robinson, P. L. Inorg. Nucl. Chem. 1957, 4, 24.

(4) Gerken, M.; Dixon, D. A.; Schrobilgen, G. J. Inorg. Chem. 2000, 39,

4244.

(5) Bougon, R.; Buu, B.; Seppelt, K. Chem. Ber. 1993, 126, 1331.

(6) Aynsley, E. E.; Hair, M. L. J. Chem. Phys. 1958, 3747.

(7) Selig, H.; El-Gad, U. J. Inorg. Nucl. Chem. 1973, 35, 3517.

(8) Beattie, I. R.; Crocombe, R. A.; Ogden, J. S. J. Chem. Soc., Dalton

Trans. 1977, 1481.

(9) Brisdon, A. K.; Holloway, J. H.; Hope, E. G.; Townson, P. J.; Levason,

W.; Ogden, J. S. J Chem. Soc., Dalton Trans. 1991, 3127.

(10) Lotspeich, J. F.; Javan, A.; Engelbrecht, A. J. Chem. Phys. 1959, 31,

633.

solubility of [OsO₃F][Sb_nF_5n+1] decreased dramatically and

straw-yellow [OsO₃F][Sb₃F₁₆] crystallized from SbF₅solvent.

The empirical formula was established by mass balance after

removal of excess SbF₅at room temperature and was

confirmed by X-ray crystallography (see X-ray Crystal-

lography, part e). The weakly fluoro-basic Sb₃F₁₆^-anion is

required to stabilize the unsolvated, distorted tetrahedra

OsO₃F⁺cation and is indicative of the weak fluoride ion

260 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

Table 1. Summary of Crystal Data and Refinement Results for [OsO₃F][AsF₆], [OsO₃F][SbF₆], [OsO₃F][HF]₂[AsF₆], [OsO₃F][HF][SbF₆], and

[OsO₃F][Sb₃F₁₆]

[OsO₃F][AsF₆]

[OsO₃F][SbF₆]

[OsO₃F][HF]₂[AsF₆]

[OsO₃F][HF][SbF₆]

[OsO₃F][Sb₃F₁₆]

formula

space group

a (Å)

b (Å)

c (Å)

AsF₇O₃Os

P2₁/n (No. 14)

7.0001(11)

11.0620(11)

8.8629(13)

90

92.270(7)

90

685.8(2)

4

F₇O₃OsSb

P2₁/c (No. 14)

5.4772(14)

10.115(3)

12.234(3)

90

99.321(5)

90

668.8(3)

4

H₂AsF₉O₃Os

P2₁/n (No. 14)

5.1491(9)

8.129(2)

19.636(7)

90

95.099(7)

90

818.7(4)

4

HF₈O₃OsSb

Pc (No. 7)

5.244(4)

9.646(6)

15.269(10)

90

97.154(13)

90

766.4(10)

4

F₁₇O₃OsSb₃

P4h2₁m (No. 113)

10.076(6)

7.585(8)

90

770.1(10)

2

926.45

R (deg)

â (deg)

γ (deg)

V (Å³)

Z (molecules/unit cell)

mol wt

446.12

4.321

492.95

4.896

486.14

3.944

512.96

4.446

calcd density (g cm^-3

)

3.995

µ (mm^-1

final agreement factors

)

23.494

23.132

19.730

20.215

13.617

R₁^a) 0.0401

wR₂^b) 0.0797

R₁^a) 0.0325

wR₂^b) 0.0772

R₁^a) 0.0348

wR₂^b) 0.0864

R₁^a) 0.0558

wR₂^b) 0.1198

R₁^a) 0.0858

wR₂^b) 0.1871

^aR₁) ∑|F_o| - |F_c|/∑|F_o|. ^bwR₂) ∑|(|F_o| - |F_c|)w^1/2|/∑(|F_o|w).

donor properties of OsO₃F₂and the high electrophilicity of

the OsO₃F⁺cation. Dissolution of [OsO₃F][Sb₃F₁₆] in HF

solvent resulted in a precipitate at -78 °C, which was

identified as [OsO₃F][HF][SbF₆] by Raman spectroscopy.

Although [OsO₃F][AsF₆] was isolated from HF solutions in

the presence of excess AsF₅, unsolvated [OsO₃F][SbF₆] did

not form from an HF solution containing a 2-fold molar

excess of SbF₅. This may be a consequence of the lower

magnitudes of the one-bond ¹⁸⁷Os-¹⁹F coupling constants

-

found for cis-OsO₂F₄(35.1 and 59.4 Hz)¹⁵and fac-OsO₃F₃

(32 Hz)⁴and the low abundance of ¹⁸⁷Os (1.64%), the ¹⁸⁷Os

satellites are presumably hidden as a consequence of the

breath of the central ¹⁹F signal (∆ν_1/2) 140 Hz).

X-ray Crystallography. Details of the data collection

parameters and other crystallographic information for [OsO₃F]-

[AsF₆], [OsO₃F][SbF₆], [OsO₃F][HF]₂[AsF₆], [OsO₃F][HF]-

[SbF₆], and [OsO₃F][Sb₃F₁₆] are provided in Table 1, and

important bond lengths, angles and contacts are listed in

Tables 2 and 3.

-

nucleophilicity of SbF₆^-when compared with that of AsF₆;

therefore, the OsO₃F⁺cation is coordinatively less saturated

-

in the unsolvated SbF₆salt so that the vacant osmium

coordination site accommodates an HF solvent molecule

instead. This reasoning is not, however, corroborated by

X-ray crystallographic data, which show stronger Os--F

contacts in [OsO₃F][SbF₆] than in [OsO₃F][AsF₆] (see X-ray

Crystallography, parts a and b).

(a) [OsO₃F][AsF₆]. The crystal structure of [OsO₃F][AsF₆]

-

consists of OsO₃F⁺cations and AsF₆anions which are

bridged through a fluorine of the AsF₆^-anion. Two cation-

anion pairs are linked to each other by two additional Os--

F-As bridges forming a cyclic dimer which is located on a

crystallographic inversion center (Figure 1). The dimers are,

in turn, stacked in columns parallel to the a axis (Figure 9,

Supporting Information).

The ¹⁹F NMR spectrum of OsO₃F₂dissolved in neat SbF₅

at 55 °C gives rise to a broad singlet for the OsO₃F⁺cation

at 70.9 ppm (∆ν_1/2) 360 Hz) and to broad Sb_nF_5n+1^-/(SbF₅)_n

resonances at -91.5 (shoulder), -105.7 ppm (∆ν_1/2≈ 5400

Hz), and -128.1 (∆ν_1/2≈ 5800 Hz). The ¹⁹F resonance of

the OsO₃F⁺cation is significantly more shielded than those

The OsO₃F⁺cation is distorted from the expected C_3Vpoint

symmetry with one Os-O bond that is significantly longer

(1.711(8) Å) than the other two (1.674(9) and 1.679(9) Å).

Each cation forms two short (2.450(7) and 2.666(7) Å) Os--F

contacts and one long (3.072(8) Å) Os‚‚‚F contact with the

+

of the OsO₂F₃cation (122.4 and 129.5 ppm),¹which is

consistent with a decrease in the number of strongly electron

withdrawing fluorine ligands. This trend, however, is op-

posite to that observed for xenon(VI) oxide fluorides.¹¹The

¹⁹F NMR spectrum of [OsO₃F][Sb₃F₁₆] dissolved in SO₂-

ClF solvent at -100 °C showed a singlet at 77.1 ppm

corresponding to the OsO₃F⁺cation. The resonances of the

cis-fluorine-bridged Sb₃F₁₆^-and Sb₂F₁₁^-anions and of SO₂-

ClF‚SbF₅were observed in the F-on-Sb region.¹²The NMR

parameters of the anions and the SO₂ClF adduct are in good

agreement with the previously reported values.^13,14Ap-

-

fluorines of the AsF₆anions. The fluorine contacts are

directed through the three less repulsive, trigonal OOF faces

of the OsO₃F⁺distorted tetrahedron, and not through the

(12) The ¹⁹F NMR spectrum of [OsO₃F][Sb₃F₁₆] in SO₂ClF solvent

contained signals that are assigned to the SO₂ClF‚SbF₅adduct

(F-on-S, 94.40 ppm (s); F₁, -143.08 ppm (q); F₂, -105.63 ppm (d);

-

²J(F_1-F₂) ) 96 Hz), the Sb₂F₁₁anion (F₁, -136.04 ppm (q);

F₂, -113.79 ppm (dd); F₃, -90.99 ppm (m); ²J(F_1-F₂) ) 103 Hz;

-

²J(F_1-F₃) ) 61 Hz), and the Sb₃F₁₆anion (F₁, -140.32 ppm (q);

F₂, -112.18 ppm (dd); F₃, -89.66 ppm; F₄, -128.19 ppm (dt);

F₅, -108.23 ppm (m); ²J(F_1-F₂) ) 57 Hz; ²J(F_2-F₃) ) 99 Hz;

-

proximately 70% of the Sb₃F₁₆anions were dissociated in

2

²J(F_3-F₄) ) 37 Hz; J(F_4-F₅) ) 134 Hz); the numbering scheme of

Gillespie et al. is used.^13,14Abbreviations denote the following: singlet

(s); doublet (d); quintet (q); multiplet (m); doublet of doublets (dd);

doublet of triplets (dt); broad (br).

SO₂ClF solution according to eq 6. In view of the small

Sb₃F₁₆^-+ SO₂ClF ^{SO ClF, -100 °C}8 Sb₂F₁₁^-+ SO₂ClF‚SbF₅

2

(13) Dean, P. A. W.; Gillespie, R. J. J. Am. Chem. Soc. 1969, 91, 7260.

(14) Bacon, J.; Dean, P. A. W.; Gillespie, R. J. Can. J. Chem. 1970, 48,

3413.

(15) Christe, K. O.; Dixon, D. A.; Mack, H. G.; Oberhammer, H.; Pagelot,

A.; Sanders, J. C. P.; Schrobilgen, G. J. J. Am. Chem. Soc. 1993, 115,

11279.

(6)

(11) Gerken, M.; Schrobilgen, G. J. Coord. Chem. ReV. 2000, 197, 335.

Inorganic Chemistry, Vol. 41, No. 2, 2002 261

Gerken et al.

Table 2. Experimental Bond Lengths (Å), Bond Angles (deg), and Contacts (Å) in [OsO₃F][PnF₆] (Pn ) As, Sb), and [OsO₃F][HF]₂[AsF₆] and

Calculated Geometries for (FO₃Os--FPnF₅)₂and (FO₃Os--(HF)₂--FAsF₅)₂at the LDFT and NLDFT Levels of Theory

expt

calcd(LDFT)^a

calcd(NLDFT)^b

expt

calcd(LDFT)^a

calcd(NLDFT)^b

[OsO₃F][AsF₆]

Os(1)-O(1)

1.712(8)

1.678(9)

2.451(7)

3.072(8)

1.677(7)

1.695(8)

1.693(7)

105.1(4)

104.6(4)

75.6(3)

111.4(4)

75.8(3)

138.4(4)

87.3(3)

89.7(4)

89.4(4)

92.3(4)

88.2(4)

89.7(4)

91.0(4)

103.6(2)

76.0(3)

1.700/1.700

1.702/1.703

2.288/2.287

1.715

1.718

2.417

Os(1)-O(2)

Os(1)-F(1)

Os(1)--F(4)

As(1)-F(2)

As(1)-F(4)

As(1)-F(6)

1.673(9)

1.782(7)

2.666(7)

1.776(7)

1.746(7)

1.685(8)

1.698/1.698

1.854/1.855

2.289/2.289

1.841/1.843

1.886/1.885

1.718/1.719

1.713

1.879

2.293

1.873

1.936

1.749

Os(1)-O(3)

Os(1)--F(2)

Os(1)‚‚‚F(5)

As(1)-F(3)

1.728/1.729

1.734/1.736

1.732/1.733

105.2/105.3

101.6/101.6

80.3/80.3

101.9/101.9

76.2/76.2

134.4/134.3

83.8/83.8

89.2/89.2

85.1/85.1

94.7/94.7

85.1/85.1

90.7/90.6

92.6/92.6

98.9/99.0

82.7/82.7

1.759

1.763

1.764

105.0

102.5

78.8

99.0

78.0

145.0

84.0

90.4

84.8

94.4

86.1

88.9

92.1

93.7

85.3

As(1)-F(5)

As(1)-F(7)

O(1)-Os(1)-O(2)

O(2)-Os(1)-O(3)

O(1)-Os(1)--F(2)

O(3)-Os(1)-F(1)

O(3)-Os(1)--F(2)

As(1)-F(2)--Os(1)

F(2)-As(1)-F(4)

F(2)-As(1)-F(6)

F(3)-As(1)-F(4)

F(3)-As(1)-F(6)

F(4)-As(1)-F(5)

F(4)-As(1)-F(7)

F(5)-As(1)-F(7)

F(2)--Os(1)--F(4A)

O(2)-Os(1)--F(4)

O(1)-Os(1)-O(3)

O(1)-Os(1)-F(1)

O(2)-Os(1)-F(1)

O(2)-Os(1)--F(2)

F(1)-Os(1)--F(2)

F(2)-As(1)-F(3)

F(2)-As(1)-F(5)

F(2)-As(1)-F(7)

F(3)-As(1)-F(5)

F(3)-As(1)-F(7)

F(4)-As(1)-F(6)

F(5)-As(1)-F(6)

F(6)-As(1)-F(7)

F(1)-Os(1)--F(4A)

O(1)-Os(1)--F(4)

108.4(4)

120.4(4)

105.6(4)

179.0(4)

73.5(3)

89.9(4)

88.3(4)

177.0(4)

177.1(5)

90.8(4)

176.6(4)

90.0(4)

93.2(4)

66.8(3)

73.0(4)

105.1/105.1

135.8/135.8

102.7/102.7

174.5/174.4

73.0/73.0

104.2

137.8

103.6

175.8

72.2

86.5/86.4

87.1/87.1

87.0

87.3

174.5/174.4

168.8/168.7

92.9/92.9

173.0/173.0

94.4/94.4

96.4/96.4

71.5/71.5

79.0/79.0

172.9

169.7

92.5

174.3

94.1

96.7

72.1

80.1

[OsO₃F][SbF₆]

Os(1)-O(1)

1.708(7)

1.696(7)

2.236(6)

1.976(6)

1.939(6)

1.848(6)

102.2(3)

103.9(4)

79.6(3)

100.1(3)

87.7(3)

135.7(3)

85.5(2)

87.8(2)

87.1(3)

91.8(3)

87.0(3)

90.9(3)

92.1(3)

79.2(3)

88.9(3)

1.704/1.704

1.703/1.703

2.222/2.222

1.841/1.843

2.039/2.039

1.902/1.902

105.2/105.3

101.6/101.6

80.3/80.3

101.9/101.9

76.2/76.2

134.4/134.3

83.8/83.8

89.2/89.2

85.1/85.1

94.7/94.7

85.1/85.1

90.7/90.6

92.6/92.6

98.9/99.0

82.7/82.7

1.716

1.718

2.327

2.046

2.070

1.933

103.8

103.3

79.9

98.4

84.3

144.7

85.4

87.2

83.9

96.6

82.2

90.7

92.7

84.5

87.3

Os(1)-O(2)

1.681(8)

1.844(6)

2.315(6)

1.845(6)

1.846(6)

102.8(3)

145.0(3)

97.5(3)

167.4(3)

75.3(2)

88.1(2)

86.7(2)

176.2(3)

172.5(3)

92.7(2)

173.2(2)

93.4(3)

95.9(3)

73.9(2)

77.8(3)

1.700/1.700

1.866/1.866

2.234/2.234

1.903/1.903

1.910/1.910

1.912/1.912

105.1/105.1

135.8/135.8

102.7/102.7

174.5/174.4

73.0/73.0

1.715

1.885

2.305

1.934

1.940

103.8

142.6

99.7

Os(1)-O(3)

Os(1)-F(1)

Os(1)--F(2)

Os(1)--F(4)

Sb(1)-F(2)

Sb(1)-F(3)

Sb(1)-F(4)

Sb(1)-F(5)

Sb(1)-F(6)

Sb(1)-F(7)

O(1)-Os(1)-O(2)

O(2)-Os(1)-O(3)

O(1)-Os(1)--F(2)

O(3)-Os(1)-F(1)

O(3)-Os(1)--F(2)

Sb(1)-F(2)--Os(1)

F(2)-Sb(1)-F(4)

F(2)-Sb(1)-F(6)

F(3)-Sb(1)-F(4)

F(3)-Sb(1)-F(6)

F(4)-Sb(1)-F(5)

F(4)-Sb(1)-F(7)

F(5)-Sb(1)-F(7)

F(2)sOs(1)--F(4A)

O(2)-Os(1)--F(4)

O(1)-Os(1)-O(3)

O(1)-Os(1)-F(1)

O(2)-Os(1)-F(1)

O(2)-Os(1)--F(2)

F(1)-Os(1)--F(2)

F(2)-Sb(1)-F(3)

F(2)-Sb(1)-F(5)

F(2)-Sb(1)-F(7)

F(3)-Sb(1)-F(5)

F(3)-Sb(1)-F(7)

F(4)-Sb(1)-F(6)

F(5)-Sb(1)-F(6)

F(6)-Sb(1)-F(7)

F(1)-Os(1)--F(4A)

O(1)-Os(1)--F(4)

170.3

72.9

85.5

86.5/86.4

87.1/87.1

86.6

174.5/174.4

168.8/168.7

92.9/92.9

173.0/173.0

94.4/94.4

96.4/96.4

71.5/71.5

79.0/79.0

176.2

164.5

94.3

172.6

96.4

96.6

72.4

80.0

[OsO₃F][HF]₂[AsF₆]

Os(1)-O(1)

1.694(6)

1.719(6)

2.282(5)

1.823(4)

1.703(5)

1.706(5)

2.429(8)

1.704/1.704

1.709/1.708

2.158/2.158

1.886/1.887

1.738/1.737

1.732/1.732

2.298/2.298

1.099/1.100

1.051/1.052

103.7/103.7

103.4/103.4

97.2/97.2

86.9/87.0

80.7/80.6

163.7/163.6

80.7/80.5

78.1/77.8

1.721/1.721

1.721/1.720

2.334/2.336

1.963/1.964

1.767/1.767

1.762/1.762

2.388/2.389

1.027/1.027

1.000/0.999

103.2/103.2

104.4/104.4

100.4/100.4

87.9/87.9

Os(1)-O(2)

1.669(6)

1.804(5)

2.231(4)

1.735(5)

1.696(5)

1.690(5)

2.512(8)

1.700/1.700

1.873/1.872

2.227/2.231

1.857/1.854

1.727/1.727

1.719/1.719

2.327/2.329

1.200/1.199

1.283/1.280

103.4/103.5

97.3/97.4

146.1/146.0

167.1/167.1

73.8/73.8

90.4/90.7

72.6/72.7

124.9/124.2

86.7/86.3

84.7/84.9

85.2/85.5

86.0/85.7

93.2/93.6

93.6/93.5

97.4/97.2

1.724/1.713

1.894/1.893

2.236/2.240

1.855/1.856

1.759/1.760

1.749/1.749

2.451/2.451

1.361/1.363

1.457/1.458

103.0/103.2

96.0/95.9

144.1/144.0

166.3/166.3

73.8/73.8

86.6/86.4

71.3/71.4

131.2/130.7

86.3/86.2

84.1/84.2

86.5/86.7

87.0/87.0

92.1/92.2

94.5/94.5

96.6/96.6

Os(1)-O(3)

Os(1)-F(1)

Os(1)--F(2)

Os(1)--F(3)

As(1)-F(3)

As(1)-F(4)

As(1)-F(5)

As(1)-F(6)

As(1)-F(7)

As(1)-F(8)

F(2)‚‚‚F(9)

F(9)‚‚‚F(4)

F(2)-H(1)

H(1)--F(9)

F(9)-H(2)

H(2)--F(4A)

O(1)-Os(1)-O(2)

O(2)-Os(1)-O(3)

O(2)-Os(1)-F(1)

O(2)-Os(1)--F(3)

O(3)-Os(1)--F(3)

O(2)-Os(1)--F(2)

O(3)-Os(1)--F(2)

F(3)--Os(1)--F(2)

F(3)-As(1)-F(4)

F(3)-As(1)-F(6)

F(3)-As(1)-F(8)

F(4)-As(1)-F(6)

F(4)-As(1)-F(8)

F(5)-As(1)-F(7)

F(6)-As(1)-F(7)

F(7)-As(1)-F(8)

H(2)-F(9)--H(1)

Os(1)--F(2)-H(1)

103.0(3)

103.5(3)

101.2(3)

87.5(2)

78.2(2)

169.1(2)

78.0(2)

82.3(2)

86.1(2)

88.2(2)

178.6(2)

174.3(2)

92.6(3)

173.4(2)

90.9(3)

93.5(3)

O(1)-Os(1)-O(3)

O(1)-Os(1)-F(1)

O(3)-Os(1)-F(1)

O(1)-Os(1)--F(3)

F(1)-Os(1)--F(3)

O(1)-Os(1)--F(2)

F(1)-Os(1)--F(2)

As(1)-F(3)--Os(1)

F(3)-As(1)-F(5)

F(3)-As(1)-F(7)

F(4)-As(1)-F(5)

F(4)-As(1)-F(7)

F(5)-As(1)-F(6)

F(5)-As(1)-F(8)

F(6)-As(1)-F(8)

F(9)-H(2)--F(4A)

F(2)-H(1)--F(9)

As(1)-F(4)--H(2A)

102.4(3)

100.0(3)

141.7(3)

169.0(2)

74.1(2)

87.1(3)

72.6(2)

138.8(2)

86.6(2)

87.0(2)

89.3(3)

88.5(2)

90.7(3)

92.8(2)

93.1(3)

81.6/81.6

168.0/168.2

79.7/79.5

81.5/81.6

84.0/83.8

83.8/83.9

88.3/88.1

87.6/87.8

174.2/174.6

172.0/172.0

90.5/90.8

168.3/168.2

94.4/94.1

94.2/94.4

112.5/112.7

121.2/121.3

175.7/175.6

171.6/171.6

91.8/91.8

169.0/169.1

92.9/92.8

94.7/94.6

115.2/115.3

121.4/121.8

172.5/172.8

177.2/177.0

121.2/119.0

171.6/171.6

178.2/178.3

122.7/123.1

^aThe two calculated values represent the distances and angles that are symmetry related in the crystal structure. ^bThe two calculated distances and angles

that are symmetry related in the crystal structure do not differ significantly.

262 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

Table 3. Experimental Bond Lengths (Å), Bond Angles (deg), and

Contacts (Å) in [OsO₃F][HF][SbF₆], and [OsO₃F][Sb₃F₁₆]

[OsO₃F][HF][SbF₆]

Os(1)-O(12) 1.66(2)

Os(1)-O(13) 1.68(2)

Os(1)-O(11) 1.70(2)

Os(1)--F(12) 2.236(14)

Os(2)-O(22) 1.76(2)

Os(1)-F(11) 1.847(13) Os(1)--F(13) 2.23(2)

Os(2)-O(21) 1.68(2)

Os(2)-F(21) 1.82(2)

Sb(1)-F(13) 1.96(2)

Sb(1)-F(16) 1.913(14) Sb(1)-F(17) 1.85(2)

Sb(2)-F(23) 1.977(14) Sb(2)-F(24) 1.86(2)

Sb(2)-F(26) 1.93(2)

F(12)‚‚‚F(26) 2.38(2)

Os(2)-O(23) 1.70(2)

Os(2)--F(23) 2.240(14) Os(2)--F(22) 2.27(2)

Sb(1)-F(14) 1.87(2)

Sb(1)-F(15) 1.86(2)

Sb(1)-F(18) 1.846(14)

Sb(2)-F(25) 1.850(14)

Sb(2)-F(28) 1.84(2)

Sb(2)-F(27) 1.87(2)

O(11)-Os(1)-O(12)

O(11)-Os(1)-F(11)

O(11)-Os(1)--F(13)

O(12)-Os(1)-F(11)

O(12)-Os(1)--F(13)

O(13)-Os(1)--F(12)

F(11)-Os(1)--F(12)

F(12)-Os(1)--F(13)

O(21)-Os(2)-O(23)

O(21)-Os(2)--F(22)

O(22)-Os(2)-O(23)

O(22)-Os(2)--F(22)

O(23)-Os(2)-F(21)

O(23)-Os(2)--F(23)

F(21)-Os(2)--F(23)

Sb(1)-F(13)--Os(1)

F(13)-Sb(1)-F(18)

F(13)-Sb(1)-F(15)

F(13)-Sb(1)-F(16)

F(23)-Sb(2)-F(25)

F(23)-Sb(2)-F(27)

103.1(9)

O(11)-Os(1)-O(13)

O(11)-Os(1)--F(12)

102.9(8)

168.7(7)

103.8(8)

87.4(7)

142.7(7)

80.1(7)

73.1(5)

101.4(9)

100.0(8)

170.1(7)

143.4(8)

79.8(7)

169.5(7)

73.8(7)

83.2(5)

137.7(7)

86.5(6)

87.8(7)

175.1(6)

88.1(6)

84.6(6)

101.2(8)

87.1(8)

98.0(7)

167.8(7)

78.2(7)

72.9(5)

82.0(5)

102.7(9)

87.5(7)

102.4(9)

77.9(7)

101.3(8)

86.5(7)

74.3(6)

151.8(7)

179.2(6)

89.1(6)

87.1(6)

86.4(6)

85.3(6)

O(12)-Os(1)-O(13)

O(12)-Os(1)--F(12)

O(13)-Os(1)-F(11)

O(13)-Os(1)--F(13)

F(11)-Os(1)--F(13)

O(21)-Os(2)-O(22)

O(21)-Os(2)-F(21)

O(21)-Os(2)--F(23)

O(22)-Os(2)-F(21)

O(22)-Os(2)--F(23)

O(23)-Os(2)--F(22)

F(21)-Os(2)--F(22)

F(23)--Os(2)--F(22)

Sb(2)-F(23)--Os(2)

F(13)-Sb(1)-F(17)

F(13)-Sb(1)-F(14)

F(23)-Sb(2)-F(28)

F(23)-Sb(2)-F(24)

F(23)-Sb(2)-F(26)

-

Figure 1. Views of (a) the OsO₃F⁺cation and its contacts with AsF₆

[OsO₃F][Sb₃F₁₆

]

anions in the [OsO₃F][AsF₆] structure and (b) the ([OsO₃F][AsF₆])₂dimer.

Os(1)-FOA

Sb(1)-F(3)

Sb(2)-F(12)

1.68(3) Sb(1)-F(2)

1.84(4) Sb(1)-F(1)

1.87(3)

Thermal ellipsoids are shown at the 50% probability level.

1.88(4) F(1)-Sb(2)

2.19(3) Sb(2)-F(10A) 1.77(6)

1.78(4) Sb(2)-F(11B) 1.80(5) Sb(2)-F(10B) 1.87(6)

Sb(2)-F(11A) 1.91(5) Os(1)‚‚‚F(10A) 2.85(6) Os(1)‚‚‚F(10B) 2.83(6)

(b) [OsO₃F][SbF₆]. The structure of [OsO₃F][SbF₆]

consists of fluorine-bridged (FO₃Os--FSbF₅)₂dimers (Figure

10, Supporting Information), as found in the structure of

[OsO₃F][AsF₆]. The coordination number of osmium is

expanded to 6 with a facial OsO₃F₃arrangement. The

distortion of the OsO₃F⁺cation from the expected C_3Vpoint

symmetry is more pronounced in [OsO₃F][SbF₆] than in the

AsF₆^-salt, which is a consequence of the two shorter Os--F

contacts (2.236(6) and 2.315(6) Å) in the SbF₆^-compound,

and results in significant elongation of the Os(1)-F(1) bond

(1.844(6) Å) when compared with that of the AsF₆^-analogue

(1.782(7) Å). As a consequence of the stronger Os--F

contacts, the F(1)-Os(1)-O(1) angle in [OsO₃F][SbF₆]

(145.0(3)°) is more open and the F(1)-Os(1)-O(2)/O(3)

angles (97.5(3)/100.1(3)°) are more closed than in [OsO₃F]-

[AsF₆]. The shorter Os--F contacts in the crystal structure

of [OsO₃F][SbF₆] compared with those in [OsO₃F][AsF₆] are

in good agreement with the calculated values for the (FO₃-

Os--FPnF₅)₂dimers (see Computational Results, part c).

(c) [OsO₃F][HF]₂[AsF₆]. The crystal structure of [OsO₃-

F][HF]₂[AsF₆] consists of cyclic dimers comprising two

AsF₆^-anions fluorine bridged to the OsO₃F⁺cations which

are, in turn, bridged through two hydrogen bonded (HF)₂

moieties to a second cation-anion pair (Figure 2). These

cyclic dimers, aligned parallel to the (10¹/₂) plane, are located

on a cystallographic inversion center and are stacked in

columns parallel to the a axis (Figure 11, Supporting

Information).

FOA#1-Os(1)-OFA

F(1)-Sb(1)-F(2)

104(2)

85(2)

78(2)

81(2)

173.8(14)

91(2)

OFA-Os(1)-FOA#2

F(1)-Sb(1)-F(3)

Sb(1)-F(1)-Sb(2)

F(1)-Sb(2)-F(11A)

F(1C)-Sb(2)-F(10A)

112.5(10)

90.8(14)

146(2)

83(2)

F(2)-Sb(1)-F(3)

F(1)-Sb(2)-F(10B)

F(1)-Sb(2)-F(12)

F(1C)-Sb(2)-F(11B)

87(2)

OOO face, such that they are located on the sides opposite

to the Os-O bonds. Extension of the coordination sphere to

include the Os‚‚‚F secondary contacts results in a mono-

capped octahedral geometry about Os in which the three

oxygen atoms are cis to one another (Figure 1). The longer

Os-O(1) bond is opposite to the longest Os‚‚‚F contact and

is likely a consequence of the steric crowding caused by the

two short Os--F contacts in the vinicity of O(1). The short

Os--F contacts join two anions and two cations to form a

cyclic (FO₃Os--FAsF₅)₂dimer having two short contacts

(2.450(7) Å) and two longer contacts (2.666(7) Å). This

contrasts with the four nearly equivalent and shorter Os--F

contacts (2.287 to 2.289 Å) found in the fully optimized

LDFT gas-phase geometry of this dimer (see Computational

Results, part c). The NLDFT geometry optimization gives

better agreement with the experimental geometry but gives

a less pronounced difference in the Os--F contacts (2.293

and 2.417 Å) than the experimental geometry. Two cis-

-

fluorines of the AsF₆anion form two strong contacts to

the cation resulting in elongation of both As-F bonds (1.776-

(7) and 1.746(7) Å) relative to the four remaining As-F

bonds (1.695(8)-1.677(7) Å) and in lowering of the anion

point symmetry to C_2Vor lower.

The OsO₃F⁺cation deviates significantly from the ideal

C_3Vstructure with one short (1.666(6) Å) and two long

Inorganic Chemistry, Vol. 41, No. 2, 2002 263

Gerken et al.

Figure 2. View of the ([OsO₃F][HF]₂[AsF₆])₂dimer structural unit.

Thermal ellipsoids are shown at the 50% probability level.

Figure 3. View of the asymmetric unit of [OsO₃F][HF][SbF₆]. Thermal

ellipsoids are shown at the 50% probability level. The hydrogen atoms of

coordinated HF molecules were not refined and are, therefore, not shown.

(1.694(6) and 1.704(6) Å) Os-O bonds. The Os-F bond

length in the cation (1.804(5) Å) is similar to that in [OsO₃F]-

[AsF₆] (1.787(7) Å); however, unlike the latter structure and

similar to the [OsO₃F][SbF₆] structure, the O-Os-F bond

angles in [OsO₃F][HF]₂[AsF₆] (100.0(3), 102.4(3), and 141.6-

(3)°) are significantly distorted from the ideal C_3Vsymmetry

of the free OsO₃F⁺cation as a result of secondary contacts

with one fluorine from an AsF₆^-anion and one fluorine from

an HF solvent molecule. The resulting OsO₃F₃moiety

resembles the facial arrangement of the oxygen and fluorine

atoms found for the fac-OsO₃F₃^-anion in [N(CH₃)₄][OsO₃-

F₃].⁴The Os--F contacts (2.230(4) and 2.279(5) Å) are similar

to those found in [OsO₃F][SbF₆] but are much shorter than

those in [OsO₃F][AsF₆] (2.450(7) Å). This structure, together

with that of [OsO₃F][HF][SbF₆] (vide infra), represent rare

examples of HF molecules coordinated to metal centers. The

only other reported examples are [La][HF]₂[AsF₆]₃¹⁶and [(η⁵-

C₅Me₅)NbF₄(HF)AsF₃]₂.¹⁷In the latter structure, HF also

bridges two metal centers. The F(2)‚‚‚F(9) and F(9)‚‚‚F(4A)

distances in [OsO₃F][HF]₂[AsF₆] are 2.429(8) and 2.512(8)

Å, respectively, and are shorter than the F‚‚‚F distance in

[(η⁵-C₅Me₅)NbF₄(HF)AsF₃]₂(2.686 Å),¹⁷indicating stronger

hydrogen-bonding interactions in the [OsO₃F][HF]₂[AsF₆]

structure. The F‚‚‚F distances in [OsO₃F][HF]₂[AsF₆] are,

however, significantly greater than that found for bifluoride

in [N(CH₃)₄][HF₂] (2.213(4) Å)¹⁸and are also significantly

greater than the F‚‚‚F distances in trans-[Ru(dmpe)₂(H)-

(FHF)] (2.276(8) Å),¹⁹trans-Pd(PPh₃)₂Me(FHF) (2.31 Å),²⁰

Mo(PMe₃)₄(H)₂F(FHF) (2.351(8) Å),²¹WF(H)₂(FHF)(PMe₃)₄

(2.389(6) Å),²²and NiF(HF)(C₄N₂F₂H)(PEt₃)₂(2.400(6) Å),²³

where one HF molecule is hydrogen-bridged to a fluorine

ligand of the metal center. The previously reported structures,

however, contain a terminal HF molecule and can, alterna-

tively, be described as an HF₂ligand coordinated to the

metal.

The symmetry of the AsF₆^-anion is lowered to C_2Vpoint

symmetry or lower by formation of As-F--Os and As-F--

HF bridges, which are cis to one another, producing

significantly elongated As-F bonds of 1.823(4) and 1.735-

(5) Å, respectively, when compared with the remaining four

As-F bonds (1.689(4)-1.705(5) Å).

-

(d) [OsO₃F][HF][SbF₆]. The [OsO₃F][HF][SbF₆] salt

crystallizes in the noncentrosymmetric Pc space group as a

2:1 twin preventing a proper absorption correction. As a

consequence, it was not possible to refine the fluorine and

oxygen atoms anisotropically. The relatively large errors in

the bond lengths and bond angles prevented a detailed

comparison with related structures. Two fluorine-bridged

OsO₃F⁺/SbF₆^-ion pairs were defined in the asymmetric unit

(Figure 3). One HF molecule bridges the osmium center and

a fluorine of the SbF₆^-anion of another OsO₃F⁺/SbF₆^-ion

pair, resulting in a helical arrangement comprised of alternat-

-

ing OsO₃F⁺and SbF₆ions running parallel to the a axis

(Figure 12, Supporting Information). The bond lengths and

angles in both crystallographically independent anion-cation

pairs are the same within 3σ.

All metric parameters involving osmium in [OsO₃F][HF]-

[SbF₆] are the same, within 3σ, as those in [OsO₃F][HF]₂-

[AsF₆]. As in the case of [OsO₃F][HF]₂[AsF₆], the primary

coordination sphere of the OsO₃F⁺cation is expanded to six

(16) Mazej, Z.; Borrmann, H.; Lutar, K.; Zˇemva, B. Inorg. Chem. 1998,

37, 5912.

(17) Roesky, H. W.; Sotoodeh, M.; Xu, Y. M.; Schrumpf, F.; Noltemeyer,

M. Z. Anorg. Allg. Chem. 1990, 580, 131.

(18) Wilson, W. W.; Christe, K. O.; Feng, J.-a.; Bau, R. Can. J. Chem.

1989, 67, 1898.

(19) Whittlesey, M. K.; Perutz, R. N.; Greener, B.; Moore, M. H. J. Chem.

Soc., Chem. Commun. 1997, 187.

-

by fluorine bridge formation with an SbF₆anion and an

HF molecule, resulting in fac-OsO₃F₃coordination. One

F-Os-O bond angle of the OsO₃F⁺cation is also signifi-

cantly larger (142.7(7)/143.4(8)°) than the remaining two

angles (98.0(7)/100.0(8) and 101.2/101.3(8)°).

(20) Roe, D. C.; Marshall, W. J.; Davidson, F.; Soper, P. D.; Grushin, V.

V. Organometallics 2000, 19, 4575.

(21) Murphy, V. J.; Hascall, T.; Chen, J. Y. Parkin, G. J. Am. Chem. Soc.

1996, 118, 7428.

(e) [OsO₃F][Sb₃F₁₆]. The crystal structure of [OsO₃F]-

[Sb₃F₁₆] consists of well-separated OsO₃F⁺cations and cis-

(22) Murphy, V. J.; Rabinovich, D.; Hascall, T.; Klooster, W. T.; Koetzle,

T. F.; Parkin, G. J. Am. Chem. Soc. 1998, 120, 4372.

(23) Braun, T.; Foxon, S. P.; Perutz, R. N.; Walton, P. H. Angew. Chem.

1999, 38, 3326; Angew. Chem., Int. Ed. Engl. 1999, 111, 3543.

264 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

Figure 4. View of the OsO₃F⁺and Sb₃F₁₆ions. Thermal ellipsoids are

-

shown at the 50% probability level.

-

fluorine-bridged Sb₃F₁₆anions. The OsO₃F⁺cation is

located on a special position (4h..) resulting in a positional

disorder of the symmetry-related oxygen and fluorine atoms.

A disorder between two different orientations was resolved

for the Sb₃F₁₆^-anion (Figure 4). The disorders in the cation

and anion prevented the anisotropic refinement of all the

fluorine and oxygen atoms, giving rise to a relatively large

Figure 5. Raman spectra of (a) microcrystalline [OsO₃F][Sb₃F₁₆] recorded

in a Pyrex glass capillary at -165 °C using 1064-nm excitation and (b)

1

microscrystalline [OsO₃F][AsF₆] recorded in a /₄-in. FEP sample tube at

-150 °C using 647.1-nm excitation. Asterisks (*) denote FEP sample tube

lines.

-

R factor. The cis-fluorine-bridged Sb₃F₁₆anions pack in

the (110) and (1h10) planes in such a way that they form

square-based channels parallel to the c axis that are filled

with rows of OsO₃F⁺cations (Figure 13, Supporting

Information). The first coordination sphere around osmium

is essentially tetrahedral with an average Os-O/F bond

length of 1.68(3) Å, which is the same as the average of the

Os-O and Os-F bond lengths in [OsO₃F][AsF₆], [OsO₃F]-

[SbF₆], [OsO₃F][HF]₂[AsF₆], and [OsO₃F][HF][SbF₆]. The

osmium atom also has long contacts to a fluorine of each of

-

four Sb₃F₁₆anions (Os‚‚‚F(10B/10A); 2.83(6)/2.85(6) Å)

with a trajectory through the center of each trigonal face of

the tetrahedral cation, giving rise to a second tetrahedral

coordination sphere. The Sb₃F₁₆^-anion adopts a cis-fluorine-

-

bridged geometry, as found for the Sb₃F₁₆and Sb₄F₂₁

anions in the crystal structures of [XeN(SO₂F)₂][Sb₃F₁₆],²⁴

[OCNCO][Sb₃F₁₆],²⁵[Cl₃][Sb₃F₁₆],²⁶and [Xe₂][Sb₄F₂₁],²⁷

respectively. This geometry was also found in SO₂ClF

solutions of [OsO₃F][Sb₃F₁₆] by ¹⁹F NMR spectroscopy and

Figure 6. Raman spectra recorded in ¹/₄-in. FEP sample tubes using 647.1-

nm excitation: (a) microcrystalline [OsO₃F][HF][SbF₆] at -165 °C; (b)

microcrystalline [OsO₃F][HF][SbF₆] containing [OsO₃F][SbF₆] at -150 °C.

Asterisks (*) denote FEP sample tube lines and daggers (†) denote bands

arising from [OsO₃F][SbF₆].

-

contrasts with the structure of [Br₂][Sb₃F₁₆] in which Sb₃F₁₆

-

was found to contain a trans-fluorine-bridged Sb₃F₁₆

anion.²⁸The high standard deviations in the bond lengths

-

and bond angles of the Sb₃F₁₆anion prevent detailed

characterized by low-temperature Raman spectroscopy (Fig-

ures 5-8), and the observed Raman frequencies and their

assignments are given in Tables 4-8. The free OsO₃F⁺cation

is expected to have C_3Vpoint symmetry with the vibrational

modes spanning the irreducible representations 3A₁+ 3E,

where all modes are infrared and Raman active. The

vibrational assignments are based on the frequencies and

assignments derived from DFT calculations (see Computa-

tional Results) and are also listed in Tables 4-8.

comparisons with related anion structures.

Raman Spectroscopy. The [OsO₃F][Sb₃F₁₆], [OsO₃F]-

[PnF₆] (Pn ) As, Sb), [OsO₃F][HF][SbF₆], [OsO₃F][HF]₂-

[PnF₆] (Pn ) As, Sb), and [µ-F(OsO₃F)₂][AsF₆] salts were

(24) Faggiani, R.; Kennepohl, D. K.; Lock, C. J. L.; Schrobilgen, G. J.

Inorg. Chem. 1986, 25, 563.

(25) Bernhardi, I.; Drews, T.; Seppelt, K. Angew. Chem. 1999, 111, 2370;

Angew. Chem., Int. Ed. Engl. 1999, 38, 2232.

(26) Drews, T.; Koch, W.; Seppelt, K. J. Am. Chem. Soc. 1999, 121, 4379.

(27) Drews, T.; Seppelt, K. Angew. Chem. 1997, 109, 264; Angew. Chem.,

Int. Ed. Engl. 1997, 36, 273.

(28) Edwards, A. J.; Jones, G. R.; Sills, R. J. J. Chem. Soc., Chem. Commun.

1968, 1527.

(a) [OsO₃F][Sb₃F₁₆]. The low-temperature Raman spec-

trum of [OsO₃F][Sb₃F₁₆] contains six bands attributed to the

OsO₃F⁺cation and anion bands in the Sb-F stretching and

Inorganic Chemistry, Vol. 41, No. 2, 2002 265

Gerken et al.

Table 4. Experimental Raman Frequencies for [OsO₃F][Sb₃F₁₆] and Calculated Vibrational Frequencies for OsO₃F⁺and ReO₃F and Their Assignments

freq, cm^-1

OsO₃F⁺

ReO₃F

calcd^c(LDFT)

assgnt: MO₃F (C_3V)

M ) Os, Re

obsd^a,b

calcd^c(LDFT)

calcd(NLDFT)

obsd^d

1002(100)

992(53)

745(9)

372(36)

333(4)

1038(4)

1024(81)

755(47)

346(0)

305(1)

224(4)

998(4)

984(75)

715(45)

336(0)

295(1)

217(4)

1017.5

983

701

354

318.5

237

1032(15)

998(271)

712(86)

338(2)

294(7)

222(4)

ν₁(A₁), ν_s(MO₃)

ν₄(E), ν_as(MO₃)

ν₂(A₁), ν_s(MF)

ν₅(E), δ_as(MO₃)

ν₃(A₁), δ_s(MO₃)

ν₆(E), δ(FMO)

238(21)

731(3)

707(25)

701(87)

696(10), sh

666(7)

Sb₃F₁₆^-, ν(SbF)

656(92)

652(56)

588(18)

298(7)

}

271(9)

248(13)

242(16)

218(9)

212(3)

125(6)

84(86)

71(7)

60(6)

Sb₃F₁₆^-, δ(SbF)

^aSpectrum recorded on the microcrystalline solid in a Pyrex glass capillary at -165 °C using 1064-nm excitation. Abbreviation (sh) denotes a shoulder.

^bValues in parentheses denote relative experimental Raman intensities. ^cInfrared intensities in km mol^-1are given in parentheses. ^dInfrared frequencies

from a N₂matrix; data from ref 8.

Figure 8. Raman spectra of microcrystalline [µ-F(OsO₃F)₂][AsF₆] under

1

HF solvent recorded in a /₄-in. FEP sample tube at -80 °C using 647.1-

nm excitation. Asterisks (*) denote FEP sample tube lines.

[Sb₃F₁₆],²⁴and [ReF₆][Sb₃F₁₆],³¹the Raman frequencies and

-

intensities attributed to the Sb₃F₁₆anion in [PF₄][Sb₃F₁₆]

show the best agreement with those of [OsO₃F][Sb₃F₁₆].

The Raman frequencies of the OsO₃F⁺cation agree well

with those calculated using DFT calculations. The presence

of only two Os-O stretching bands (ν₁(A₁) and ν₄(E)) is

Figure 7. Raman spectra recorded in ¹/₄-in. FEP sample tubes using 647.1-

consistent with the C_3Vpoint symmetry of the OsO₃F⁺cation

nm excitation: (a) microcrystalline [OsO₃F][HF]₂[AsF₆] at -140 °C; (b)

and is confirmed by the high symmetry of the disordered

cation in the crystal structure of [OsO₃F][Sb₃F₁₆] (see X-ray

Crystallography, part c). The Os-O stretches of the OsO₃F⁺

cation (992, 1002 cm^-1) appear at significantly higher

frequencies than those of the matrix-isolated neutral parent

molecule, monomeric OsO₃F₂(929.0, 946.5 cm^-1),³²which

is in accord with stronger and less polar Os-O bonds. The

Re-O stretching frequencies of isoelectronic ReO₃F agree

microcrystalline [OsO₃F][HF]₂[SbF₆] under HF solvent at -80 °C. Asterisks

(*) denote FEP sample tube lines.

F-Sb-F bending regions. The frequencies and intensities

-

of the Raman bands for the Sb₃F₁₆anion reported in the

literature vary significantly depending on the nature of the

countercation. Among the five known Sb₃F₁₆^-salts that have

been characterized by Raman spectroscopy, i.e., [ClCO]-

[Sb₃F₁₆],²⁹[OCNCO][Sb₃F₁₆],²⁵[PF₄][Sb₃F₁₆],³⁰[XeN(SO₂F)₂]-

(31) Schrobilgen, G. J.; Holloway, J. H.; Russell, D. R.; J. Chem. Soc.,

Dalton Trans. 1984, 1411.

(32) Beattie, I. R.; Blayden, H. E.; Crocombe, R. A.; Jones, P. J.; Ogden,

J. S. J. Raman Spectrosc. 1976, 4, 313.

(29) Christe, K. O.; Hoge, B.; Boatz, J. A.; Prakash, G. K. S.; Olah, G. A.;

Sheehy, J. A. Inorg. Chem. 1999, 38, 3132.

(30) Chen, G. S. H.; Passmore, J. J. Chem. Soc., Dalton Trans. 1979, 1251.

266 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

Table 5. Raman Frequencies and Their Assignments for [OsO₃F][PnF₆] (Pn ) As, Sb)

[OsO₃F][AsF₆]^a

freq, cm^-1

[OsO₃F][SbF₆]^b

freq, cm^-1

calcd^d(NLDFT)

obsd^c

calcd^d(NLDFT)

assgnt

obsd^c

assgnt

972(38)

971(4)

962(123)

961(2)

958(168)

957(0)

969(42)

969(0)

960(136)

959(0)

957(165)

957(0)

996(100)

990(27)

995(100)

986(32)

Os-O stretches

}

986(50)

984(14), sh

709(233)

706(0)

685(308)

684(0)

660(237)

656(0)

654(82)

652(0)

606(27)

606(0)

499(253)

498(0)

692(65)

638(0)

637(56)

652(185)

648(0)

625(198)

624(0)

606(174)

605(0)

572(11)

572(0)

493(279)

492(0)

462(186)

442(0)

372(0)

371(6)

368(11)

368(0)

362(0)

362(12)

308(43)

301(0)

276(0)

272(0)

267(68)

265(86)

253(136)

251(0)

249(0)

247(29)

232(0)

231(6)

231(34)

222(44)

222(0)

209(0)

194(0)

192(10)

174(0)

167(16)

157(6)

155(0)

146(19)

143(0)

136(9)

122(0)

108(0)

102(1)

95(19)

94(0)

Sb-F stretches

Os-F stretches

}

725(8), sh

721(11)

666(21)

As-F stretches

}

656 sh

642(28)

As-F + Os-F stretches

As-F stretches

Sb-F stretches

}

576(5)

529(2)

As-F-Os bridging stretches

Sb-F-Os bridging stretches

446(158)

}

410(1)

397(10)

429(0)

376(0)

376(5)

369(0)

367(25)

359(0)

353(6)

351(92)

349(0)

341(114)

338(0)

329(87)

327(0)

318(7)

318(0)

313(0)

311(65)

300(7)

299(0)

264(45)

243(0)

232(14)

230(0)

230(68)

223(0)

211(0)

200(14)

191(0)

187(33)

171(1)

154(0)

150(12)

139(0)

131(0)

126(5)

116(0)

109(5)

104(18)

78(0)

387(16)

386 sh

374(13), sh

372(17)

358(8)

341(8)

276(3)

259(2)

244(3)

225(5)

221(8)

167(1)

152(3)

90(3)

73(0)

74(9)

60(0)

64(0)

58(6)

49(0)

54(0)

47(0)

44(1)

36(0)

39(1)

34(0)

32(0)

22(1)

9(0)

19(0)

0(0)

-24(1)

^aSpectrum recorded on the microcrystalline solid in a ¹/₄-in. FEP sample tube at -150 °C using 647.1-nm excitation. Bands arising from the FEP sample

1

tube were observed at 293 (2), 733 (9), and 746 (2) cm^-1

.

^bSpectrum recorded on the solid in admixture with [OsO₃F][HF][SbF₆] in a /₄-in. FEP sample

tube at -165 °C using 1064-nm excitation. ^cValues in parentheses denote relative Raman intensities. Abbreviation (sh) denotes a shoulder. ^dVibrational

frequencies were calculated for the optimized (NLDFT) structures of the (FO₃Os--FPnF₅)₂dimers. Infrared intensities in km mol^-1are given in parentheses.

Inorganic Chemistry, Vol. 41, No. 2, 2002 267

Gerken et al.

Table 6. Raman Frequencies and Their Assignments for

[OsO₃F][HF][SbF₆]

(b) [OsO₃F][AsF₆] and [OsO₃F][SbF₆]. The Raman

spectrum of [OsO₃F][AsF₆] is far more complex than

suggested by its simple ionic formulation. The observation

of 23 bands indicates a significant reduction of symmetry

from the ideal C_3Vpoint symmetry of the OsO₃F⁺cation and

O_hsymmetry of the AsF₆^-anion and is corroborated by the

crystallographic findings. The Raman frequencies of only

the most intense bands of [OsO₃F][SbF₆] have been observed

because [OsO₃F][SbF₆] could only be obtained as a minor

component in admixture with [OsO₃F][HF][SbF₆] (vide

supra). The Os-O stretching bands of [OsO₃F][SbF₆] are,

assgnt

freq,^acm^-1

OsO₃F⁺(C_3V)

ν_s(OsO₃)

SbF₆^-(C_4V)

981(33)

977(100)

972(21)

970(17)

965(16)

960(3)

ν_as(OsO₃)

685(3)

ν₈(E)

668(29)

652(13)

645(3)

ν₁(A₁)

ν_s(OsF)

-

ν₂(A₁)

ν₅(B₁)

however, in excellent agreement with those of the AsF₆

salt.

613(3)

609(3)

537(1)

The Os-O stretching frequencies in [OsO₃F][AsF₆] are

approximately 6 cm^-1lower than those in [OsO₃F][Sb₃F₁₆]

resulting from the higher nucleophilicity of the AsF₆^-anion,

which forms stronger fluorine bridge contacts to the OsO₃F⁺

cation in the solid state to give the (FO₃Os--FAsF₅)₂dimer

(see X-ray Crystallography, part a). These contacts distort

the OsO₃F⁺cation from C_3Vsymmetry, resulting in the

splitting of the doubly degenerate Os-O stretching mode

and the observation of three Os-O stretching bands. A

shoulder at 984 cm^-1is assigned to the in-phase, out-of-

phase coupling of the OsO₃modes in the dimer. The

assignments of the bands are based on the calculated

frequencies at the NLDFT level of theory (see Computational

Results and Table 4) and the rule of mutual exclusion of

Raman and infrared bands, which should hold for the

centrosymmetric (FO₃Os--FAsF₅)₂dimer. On the basis of the

calculated vibrational frequencies and comparisons with

vibrational spectra of [NgF][AsF₆] (Ng ) Kr, Xe),^34,35the

Os-F stretching mode in [OsO₃F][AsF₆] was distinguished

from the As-F stretching modes and is tentatively assigned

to the band at 666 cm^-1, which is significantly lower than

those of [OsO₃F][Sb₃F₁₆] (745 cm^-1) and [Os₂O₆F₃][AsF₆]

(708 cm^-1). Detailed assignments of the low-frequency

modes are not given because strong vibrational couplings

among these modes result in complex descriptions of their

motions.

(c) [OsO₃F][HF]₂[PnF₆] (Pn ) As, Sb) and [OsO₃F]-

[HF][SbF₆]. As in the case of [OsO₃F][AsF₆], the Raman

spectra of [OsO₃F][HF]₂[PnF₆] and [OsO₃F][HF][SbF₆]

indicate lowering of the cation and anion symmetries from

their respective ideal C_3Vand O_hpoint symmetries. The SbF₆^-

anion bands in [OsO₃F][HF][SbF₆] were assigned under C_4V

point symmetry on the basis of previous assignments;^34,35

however, the crystal structure shows that the anion sym-

metries are C_2Vor lower. The assignments of the Raman

spectra of [OsO₃F][HF]₂[PnF₆] are based on NLDFT calcula-

tions of the (FO₃Os--FPnF₅)₂dimers (see Computational

Results and Table 7). Vibrational bands at frequencies higher

than 1000 cm^-1, which are associated with the HF bridges,

were not observed in the Raman spectrum.

520(3)

515(2) sh

487(<0.5)

397(3)

390(17)

384(25)

380(16)

375(3)

ν₄(A₁)

δ_s(OsO₃)

345(<0.5)

312(2)

297(6)^b

275(1)

ν₉(E)

254(2)

239(1)

226(4)

187(3)

165(1)

155(<0.5)

135(<0.5)

120(1)

106(1)

^aSpectrum recorded on the microcrystalline solid in a ¹/₄-in. FEP sample

tube at -150 °C using 1064-nm excitation. Values in parentheses denote

relative intensities. Abbreviation (sh) denotes a shoulder. Bands arising from

the FEP sample tube were observed at 297 (6), 579 (1), 734 (8), and 751

(1) cm^-1, and a laser line at 84 (12) cm^-1was observed. ^bThis band overlaps

with a band arising from the FEP sample tube.

well with those of the cationic Os analogue and differ by

less than 15 cm^-1. The Raman band at 745 cm^-1is assigned

to the Os-F stretch, which is at significantly higher

frequency than those of the matrix-isolated OsO₃F₂monomer

(619.0, 646.0 cm^-1)³²and ReO₃F (701 cm^-1)⁸and is in

accord with the positive charge on OsO₃F⁺and a cor-

respondingly less polar Os-F bond. The asymmetric OsO₃

bend appears at 370 cm^-1, which is between the ReO₃

bending frequencies in ReO₃F obtained from an HF solution

(403 cm^-1)⁷and that determined in a N₂matrix (354 cm^-1).⁹

The ordering of the asymmetric (ν₅(E)) and symmetric

(ν₂(A₁)) bends, although counterintuitive considering the

significantly greater Raman intensity of the ν₅(E) band, is

based on the DFT calculations and on previous assignments

for ReO₃F^9,33and TcO₃F.³³

The [OsO₃F][Sb₃F₁₆] salt represents the best approximation

to a free OsO₃F⁺cation as evidenced by the absence of

splitting for the degenerate modes of OsO₃F⁺and the fact

that the stretching modes appear at the highest frequencies

when compared with those of other OsO₃F⁺salts (vide infra).

The Raman spectra of [OsO₃F][HF]₂[PnF₆] (Pn ) As, Sb)

are very similar, suggesting that the two compounds are

(34) Gillespie, R. J.; Schrobilgen, G. J. Inorg. Chem. 1976, 15, 22.

(35) Lehmann, J. F.; Dixon, D. A.; Schrobilgen, G. J. Inorg. Chem. 2001,

40, 3002.

(33) Binenboym, J.; El-Gad, U.; Selig, H. Inorg. Chem. 1974, 13, 319.

268 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

Table 7. Experimental and Calculated (NLDFT) Raman Frequencies and Their Assignments for [OsO₃F][HF]₂[PnF₆] (Pn ) As, Sb)

[OsO₃F][HF]₂[AsF₆]^a

[OsO₃F][HF]₂[SbF₆]^b

freq, cm^-1

calcd^d

freq, cm^-1

calcd^d

obsd^c

assgnt

obsd^c

assgnt

2947(2232)

2941(223)

2455(10 326)

2408(3)

1223(201)

1216(87)

969(101)

969(3)

959(1)

957(258)

956(31)

956(76)

941(22)

938(197)

853(42)

846(157)

768(2)

759(346)

699(227)

697(21)

685(180)

683(50)

2868(2207)

2863(78)

2381(11 674)

2334(8)

1222(198)

1218(52)

968(126)

968(22)

965(3)

963(236)

958(120)

957(1)

947(169)

947(6)

862(15)

858(157)

803(0)

787(305)

631(111)

631(1)

620(182)

642(161)

642(2)

620(3)

608(3)

607(170)

566(7)

566(6)

507(1)

506(59)

463(0)

460(228)

440(255)

429(0)

HF stretches

}

HF stretches/group rotations

HF bends/group rotations

}

Os-O stretches

Os-O stretches + HF bends/group rotations

Os-O stretches + HF bends/rotations

Os-O stretches

981(100)

971(97)

979(65)

Os-O stretches + HF bends/rotations 973(100)

Os-O stretches

}

959(26), sh

957(33)

963(25)

960(24)

Os-O stretches + HF bends/rotations 954(4)

945(3)

Os-O stretches + HF bends/rotations

HF bends/group rotations

}

728(26), sh^e

716(9)

688(5)

Sb-F stretches

Os-F stretches

}

As-F stretches

710(5)

674(22)

666(99)

664(151)

637(54)

658(22)

675(8)

646(8)

659(11)

651(9)

Os-F stretches

}

636(31)

Sb-F stretches

572(3)

}

602(14)

602(13)

502(0)

501(96)

464(92)

463(60)

415(172)

408(9)

As-F stretches

576(6)^e

491(6)

555(2)

Sb-F bridging + HF group stretches

Sb-F-Os bridging stretches

501(2)

}

As-F bridging + HF group stretches

}

391(31), sh

As-F-Os bridging stretches

388(51)^e

417(3)

398(11), sh

371(1)

371(2)

385(4)

384(64)

374(10)

372(0)

369(2)

369(1)

366(0)

378(24)^e

348(2)

393(42)

371(2)

366(1)

371(10)

364(10)

370(0)

365(2)

365(8)

351(4)

351(51)

327(152)

326(6)

324(95)

323(6)

316(7)

315(14)

296(1)

338(89)

334(1)

311(32)

311(4)

290(4)

289(0)

265(10)

264(0)

253(0)

250(173)

247(178)

242(0)

237(59)

235(0)

340(2)

330(3)

311(6)

358(10)

354(7), sh

306(5)

292(12)

289(10), sh^e

282(5), sh

261(3)

245(3)

281(8)

295(0)

274(0)

273(5)

260(3)

240(6)

234(0)

258(26)

258(4)

233(51)

228(0)

228(21)

209(5)

204(0)

186(35)

184(0)

240(3)

225(3)

218(3)

246(129)

240(14)

234(14)

230(72)

223(17)

216(0)

234(6)

227(6)

204(2)

188(1)

221(3)

215(3)

167(0)

166(4)

199(0)

197(67)

179(1)

161(1)

156(68)

155(39)

180(1)

145(1)

156(0)

210(3)

179(2)

152(33)

146(53)

136(0)

131(2)

129(0)

Inorganic Chemistry, Vol. 41, No. 2, 2002 269

Gerken et al.

Table 7 (Continued)

[OsO₃F][HF]₂[AsF₆]^a

calcd^d

[OsO₃F][HF]₂[SbF₆]^b

freq, cm^-1

obsd^c

assgnt

obsd^c

calcd^d

assgnt

167(2)

144(0)

139(1)

129(0)

117(21)

114(0)

83(5)

82(1)

70(0)

68(1)

63(1)

58(0)

41(0)

35(3)

35(0)

32(3)

19(0)

15(0)

13(0)

117(1)

115(0)

102(5)

100(1)

81(7)

80(0)

66(0)

64(0)

62(0)

62(1)

48(1)

43(0)

37(0)

35(4)

32(3)

29(0)

22(0)

19(0)

15(1)

11(0)

144(1)

123(1)

101(2)

93(2)

^aSpectrum recorded on the microcrystalline solid in a ¹/₄-in. FEP sample tube at -140 °C using 647.1-nm excitation. Bands arising from the FEP sample

tube were observed at 293 (14), 381 (30), 389 (30), 576 (6), 596 (1), 733 (43), and 750 (5) cm^-1^bSpectrum recorded on the solid under HF solvent in a

¹/₄-in. FEP sample tube at -80 °C using 647.1-nm excitation. Bands arising from the FEP sample tube were observed at 292 (12), 576 (3), 596 (1), 732 (31),

.

and 749 (3) cm^-1^cValues in parentheses denote relative Raman intensities. Abbreviation (sh) denotes a shoulder. ^dVibrational frequencies were calculated

.

for the optimized (NLDFT) structures of the (FO₃Os--(HF)₂--FPnF₅)₂dimers. Infrared intensities in km mol^-1are given in parentheses. ^eThis band overlaps

with a band arising from the FEP sample tube.

isostructural. Three Os-O stretching modes appear 16-20

cm^-1lower in the Raman spectrum of [OsO₃F][HF]₂[AsF₆]

than those of [OsO₃F][AsF₆]. The band splittings are

consistent with the distorted OsO₃F⁺cation found in the

crystal structure of [OsO₃F][HF]₂[AsF₆]. A shoulder at 959

cm^-1and the observed splittings of the Os-O stretching

bands in the Raman spectra of [OsO₃F][HF]₂[AsF₆] and

[OsO₃F][HF]₂[SbF₆], respectively, are likely the result of

vibrational coupling between two FO₃Os--FPnF₅moieties

which are bridged by two HF molecules in the structure of

[OsO₃F][HF]₂[AsF₆]. The Os-O stretches of [OsO₃F][HF]-

[SbF₆] have frequencies similar to those of [OsO₃F][HF]₂-

[PnF₆]. However, all three Os-O stretches of [OsO₃F][HF]-

[SbF₆] are split by 2-5 cm^-1, which may be attributable to

the stronger vibrational coupling that results from the shorter

HF bridge in the helical structure of [OsO₃F][HF][SbF₆] (see

X-ray Crystallography, part d). On the basis of the calculated

vibrational frequencies, comparisons with the vibrational

spectra of [NgF][PnF₆] (Ng ) Kr, Xe; Pn ) As, Sb),^34,35

and comparisons among those of the OsO₃F⁺salts, the Os-F

stretches of [OsO₃F][HF]₂[AsF₆], [OsO₃F][HF]₂[SbF₆], and

[OsO₃F][HF][SbF₆] were distinguished from the Pn-F

stretches and assigned to similar frequencies, namely, 652,

658, and 659 cm^-1, respectively. The bending modes in the

Raman spectra could not be assigned because of strong

vibrational coupling among these modes.

[OsO₃F][AsF₆] (984-996 [666]), [OsO₃F][HF]₂[AsF₆]

(957-981 [659]), and [OsO₃F][HF][SbF₆] (960-981 [652])

decrease with increasing strength of the Os--F contacts (2.83-

(6), 2.66(7)/2.451(7), 2.282(5)/2.231(4), and 2.23(2)/2.240-

(14)/2.236(14)/2.27(2) Å, respectively), reflecting the an-

ticipated decrease in the cationic nature of the OsO₃F moiety

with increasing fluorobasicity of the anion.

(d) [µ-F(OsO₃F)₂][AsF₆]. The Raman spectrum of [µ-F-

(OsO₃F)₂][AsF₆] exhibits six Os-O stretching bands con-

sistent with a fluorine-bridged µ-F(OsO₃F)₂⁺cation in which

the two OsO₃F moieties are vibrationally coupled to each

other. The splittings of the Os-O stretching bands range

from 3 to 5 cm^-1and agree very well with the degree of

+

coupling observed for the µ-F(cis-OsO₂F₃)₂cation.¹The

cation bands were assigned based on frequency calculations

for the gas-phase µ-F(OsO₃F)₂⁺cation at the LDFT level of

theory (see Computational Results and Table 8). The number

-

of bands associated with the AsF₆anion suggests a

significant reduction in anion symmetry from O_hto C_4Vor

lower point symmetry. The assignments of the anion

frequencies are based on those for [XeF][AsF₆].³⁴

The Raman band at 708 cm^-1is tentatively assigned to

one combination of the Os-F_t(F_t: terminal fluorine)

stretches and appears at lower frequency than that in [OsO₃F]-

[Sb₃F₁₆] (745 cm^-1), which is consistent with a lower charge

density in the dinuclear cation and a correspondingly lower

Os-F polarity. Similarly, the Os-O stretching frequencies

It was not possible to correlate the Os-O and Os-F

stretching frequencies of the different OsO₃F⁺salts directly

with their respective Os-O and Os-F bond lengths because

of disorder and experimental uncertainties in the bond lengths

found in the crystal structures. However, the Os-O [Os-F]

stretching frequencies of [OsO₃F][Sb₃F₁₆] (992-1002 [745]),

+

of the µ-F(OsO₃F)₂cation are lower by 35-48 cm^-1than

those of the OsO₃F⁺cation in [OsO₃F][Sb₃F₁₆]. Contacts

-

between the cation and the AsF₆anion and/or HF solvent

molecules are likely because the pentacoordinate osmium

in µ-F(OsO₃F)₂⁺is coordinately unsaturated and is supported

270 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

Table 8. Experimental and Calculated (LDFT) Raman Frequencies and Their Assignments for [µ-F(OsO₃F)₂][AsF₆]

freq, cm^{-1 a}

assgnt

+

[µ-F(OsO₃F)₂][AsF₆]

µ-F(OsO₃F)₂

+ c

obsd^a

calcd(LDFT)^b

µ-F(OsO₃F)₂

ν(Os′-O(1)′) + ν(Os′-O(3)′)

AsF₆^-(C_4V)

967(100)

963(91)

956(45)

953(44)

949(29), sh

944(10), sh

744(2)

1001(31)

1000(85)

999(14)

997(17)

990(38)

988(41)

ν(Os′-O(1)′) - ν(Os′-O(3)′)

ν(Os-O(3)) + ν(Os-O(1))

ν(Os′-O(2)′)

ν(Os-O(2))

ν₈(E)

708(8)

738(16)

730(189)

ν(Os′-F_t′) + ν(Os-F_t)

ν(Os′-F_t′) - ν(Os-F_t)

675(6)

651(5)

641(5)

ν₁(A₁)

ν₂(A₁)

603(2)

545(1)

ν₅(B₁)

493(<1)

478(1)

476(102)

390(0)

ν_as(Os--F_b--Os′)

448(1)

ν₄(A₁)

408(3), sh

402(10)

397(10)

384(36)

381(32), sh

365(4)

ν₃(A₁)

ν₁₀(E)

δ_s(O(2)′-Os′--F_b+ O(1)-Os--F_b)

ν₉(E)

ν₇(B₂)

356(3)

320(2)

336(0)

313(1)

312(2)

308(1)

298(0)

296(1)

292(1)

280(1)

269(7)

δ_s(O(3)-Os--F_b+ O(1)′-Os′--F_b)

δ(O(1)′-Os′-O(3)′)

δ(O(1)-Os-O(2)) + δ(O(1)′-Os′-O(2)′)

δ(O(2)-Os-O(3)) + δ(O(2)′-Os′-O(3)′)

δ(O(3)-Os-F_t) + δ(O(3)′-Os′-F_t′) + other δ(O-Os-F)

δ(O(3)-Os-F_t) - δ(O(3)′-Os′-F_t′) + other δ(O-Os-F)

δ(O(2)-Os-F_t) - δ(O(2)′-Os′-F_t′)

δ

_o.pl.(OsO₃) - δ_o.pl.(Os′-O′₃)

250(2)

240(4)

235(4)

182(2)

176(1)

167(1)

159(1)

152(1)

139(2)

117(1)

81(2)

δ(F_t-Os--F_b) + δ(F_t′-Os--F_b)

213(15)

192(169)

δ_s(F_t-Os--F_b)

δ_o.pl.(OsO₃) + δ_o.pl.(Os′O′₃)

147(0)

132(15)

127(5)

88(0)

54(1)

43(0)

antisym rocking of OsO₃F groups toward F_b

sym rocking of OsO₃F groups toward F_b

ν_s(Os--F_b--Os′)

δ

_i.p.(Os--F_b--Os′)

δ_o.o.p.(Os--F_b--Os′)

antisym torsion of OsO₃F groups around F_b

^aSpectrum recorded on the solid under liquid HF solvent in a ¹/₄-in. FEP sample tube at -80 °C using 647.1-nm excitation. Values in parentheses denote

relative Raman intensities. Abbreviation (sh) denotes a shoulder. Bands arising from the FEP sample tube were observed at 292 (8), 576 (2), 732 (18), and

751 (2) cm^-1^bInfrared intensities in km mol^-1are given in parentheses. ^cThe abbreviations i.p. and o.o.p. denote in-plane and out-of-plane bends, respectively.

.

by the significant lowering of the anion symmetry and the

instability of the cation in the absence of HF solvent (vide

supra). Consequently, assignments of the bending modes

based on the calculated frequencies for the gas-phase cation

must be viewed as tentative.

Computational Results. Previous work in our laboratories

has shown that electronic structure calculations, usually at

the density functional theory (DFT) level, are a valuable tool

for understanding the structures and vibrational frequencies

of transition metal oxide fluorides.^1,4,36For the Os complexes,

we benchmarked the method by calculating the geometry

and vibrational frequencies of OsO₄(Table 9) for which there

are well-established experimental values for the free mol-

ecules.^37,38The calculated bond distance for OsO₄is in very

good agreement with the experimental value. The calculated

harmonic stretching frequencies are higher than the experi-

mental anharmonic frequencies by 22 and 29 cm^-1. The

calculated frequencies of the bending modes are 4 and 6 cm^-1

lower than the experimental frequencies. This behavior is

typical of that found at the local DFT (LDFT) level; i.e., the

calculated stretching frequencies are too high and the bending

frequencies are too low.⁴

(a) OsO₃F⁺. The fully optimized geometry of OsO₃F⁺

cation possesses C_3Vsymmetry. The weighted average of the

calculated Os-O and Os-F bond lengths (1.721 Å, Table

9) is within 3σ of the average experimental bond length of

1.68(3) Å for the Os-O and Os-F bonds in the disordered

[OsO₃F][Sb₃F₁₆] structure. The calculated Os-O and Os-F

bond lengths in the OsO₃F⁺cation are shorter than the

(36) Christe, K. O.; Dixon, D. A.; Mack, H. G.; Oberhammer, H.; Pagelot,

A.; Sanders, J. C. P.; Schrobilgen, G. J. J. Am. Chem. Soc. 1993, 115,

11279.

(37) Krebs, B.; Hasse, K.-D. Acta Crystallogr., Sect. B 1976, 32, 1334.

(38) Huston, J. L.; Claassen, H. H. J. Chem. Phys. 1970, 52, 5646.

Inorganic Chemistry, Vol. 41, No. 2, 2002 271

Gerken et al.

Table 9. Calculated Geometries for OsO₄, OsO₃F⁺,^aReO₃F,^aF(OsO₃F)₂⁺, and the (FO₃Os--(HF)₂--FSbF₅)₂Dimer and Vibrational Frequencies

for OsO₄

OsO₄

calcd(LDFT)

1.717 Å

OsO₃F⁺

calcd(LDFT)

ReO₃F

expt^b

calcd(LDFT)

expt^c

Os-O

1.698 Å

1.727 Å

Os-O

1.690 Å

1.812 Å

110.9°

Re-O

1.703 Å

1.843 Å

110.6°

1.692(3) Å

1.859(8) Å

109.5(3)°

Os-F

Re-F

O-Os-F

F-Os-F

O-Re-F

108.0°

freq, cm^-1

965.2

ν₁(A)

ν₂(E)

ν₃(T₂)

ν₄(T₂)

994(0)

329(0)

982(316)

317(10)

333.1

960.1

322.7

[FO₃Os--F_b--OsO₃F]⁺, calcd(LDFT)

Os-O(1)/Os′-O(1)′

Os-O(2)/Os′-O(2)′

Os-O(3)/Os′-O(3)′

Os--F_b/Os--F_b

1.702/1.702 Å

1.708/1.707 Å

1.704/1.703 Å

2.129/2.140 Å

1.824/1.823 Å

O(1)-Os-O(2)/O(1)′-Os′-O(2)′

O(1)-Os-O(3)/O(1)′-Os′-O(3)′

117.5/117.4°

117.2/116.8°

116.9/116.7°

79.3/78.8°

81.1/80.6°

80.4/80.2°

99.5/99.8°

100.1/100.4°

99.7/100.2°

178.1/178.5°

138.4°

O(1)-Os--F_b--Os/Os--F_b--Os-O(1)

O(2)-Os--F_b--Os/Os--F_b--Os-O(2)

O(3)-Os--F_b--Os/Os--F_b--Os-O(3)

F_t-Os--F_b--Os/Os--F_b--Os-F_t

137.3/137.3°

17.0/16.7°

-102.4/-102.6°

165.8/151.4°

O(2)-Os-O(3)/O(2)′-Os′-O(3)′

O(1)-Os--F_b/O(1)′-Os′--F_b

O(2)-Os--F_b/O(2)′-Os′--F_b

O(3)-Os--F_b/O(3)′-Os′--F_b

O(1)-Os-F_t/O(1)′-Os′-F_t′

O(2)-Os-F_t/O(2)′-Os′-F_t′

O(3)-Os-F_t/O(3)′-Os′-F_t′

F_b--Os-F_t/F_b--Os′-F_t′

Os-F_t/Os′-F_t′

Os--F_b--Os′

d

(FO₃Os--(HF)₂--FSbF₅)₂

LDFT

NLDFT

LDFT

NLDFT

LDFT

NLDFT

Os-O(1)

Os-O(2)

Os-O(3)

Os-F(1)

Os--F(2)

1.703/1.703

1.702/1.702

1.708/1.708

1.871/1.872

2.155/2.156

2.226/2.221

2.033/2.034

2.017/2.017

1.914/1.914

1.907/1.908

1.908/1.908

1.905/1.905

1.103/1.103

1.192/1.193

1.056/1.056

1.270/1.272

1.719/1.719

1.715/1.715

1.721/1.720

1.891/1.890

2.320/2.320

2.264/2.265

2.089/2.089

2.026/2.026

1.945/1.945

1.940/1.940

1.939/1.939

1.935/1.935

1.031/1.031

1.353/1.352

1.005/1.005

1.430/1.431

2.382/2.383

2.434/2.434

O(1)-Os-O(2)

O(2)-Os-O(3)

O(2)-Os-F(1)

O(2)-Os--F(3)

O(3)-Os--F(3)

O(2)-Os--F(2)

O(3)-Os--F(2)

F(3)--Os--F(2)

F(3)-As-F(4)

F(3)-As-F(6)

F(3)-As-F(8)

F(4)-As-F(6)

F(4)-As-F(8)

F(5)-As-F(7)

F(6)-As-F(7)

F(7)-As-F(8)

H(2)-F(9)--H(1)

Os--F(2)-H(1)

103.9/103.9

103.2/103.2

96.9/96.9

86.1/86.1

80.1/80.2

163.7/163.6

80.8/80.8

79.0/78.9

82.4/82.2

88.5/88.3

172.2/172.3

170.8/170.6

89.9/90.0

166.1/166.1

95.4/95.4

94.7/94.6

115.2/115.2

122.9/122.9

103.3/103.3

104.1/104.1

99.8/99.8

87.9/87.8

80.7/80.7

167.8/167.8

79.9/79.9

81.3/81.4

84.6/84.7

86.8/86.7

175.7/175.8

171.3/171.3

91.3/91.2

167.6/167.5

93.6/93.6

95.3/95.2

117.1/117.2

122.0/122.1

O(1)-Os-O(3)

O(1)-Os-F(1)

O(3)-Os-F(1)

O(1)-Os--F(3)

F(1)-Os--F(3)

O(1)-Os--F(2)

F(1)-Os--F(2)

As-F(3)--Os

F(3)-As-F(5)

F(3)-As-F(7)

F(4)-As-F(5)

F(4)-As-F(7)

F(5)-As-F(6)

F(5)-As-F(8)

F(6)-As-F(8)

F(9)-H(2)--F(4A)

F(2)-H(1)--F(9)

As-F(4)--H(2A)

103.7103.7

98.2/97.8

145.6/145.8

168.0/167.9

73.6/73.8

90.2/90.3

72.7/72.8

125.1/124.6

85.0/85.0

84.5/84.3

85.3/85.2

84.3/84.5

93.4/93.2

94.5/94.7

99.3/99.4

176.7/176.5

178.3/178.3

122.9/122.7

103.3/103.3

97.5/97.5

143.5/143.5

166.6/166.6

72.9/73.0

86.7/86.8

71.6/71.6

132.4/132.0

84.1/84.2

85.5/85.5

Os--F(3)

Sb-F(3)

Sb-F(4)

Sb-F(5)

Sb-F(6)

Sb-F(7)

86.7/86.7

85.5/85.4

92.6/92.7

94.6/94.6

Sb-F(8)

F(2)-H(1)

H(1)--F(9)

F(9)-H(2)

H(2)--F(4A)

F(2)‚‚‚F(9)

F(9)‚‚‚F(4A)

97.4/97.4

175.7/175.8

178.7/178.7

127.4/127.6

^aThe vibrational frequencies for OsO₃F⁺and ReO₃F are given in Table 2. ^bBond lengths for crystalline OsO₄are from ref 37; Raman frequencies for

gaseous OsO₄are from ref 38. ^cBond lengths for ReO₃F are from a microwave study.^{10 d}The atom numbering scheme used for (FO₃Os--(HF)₂--FSbF₅)₂

is the same as that used in the crystal structure of [OsO₃F][HF]₂[AsF₆]; the two calculated values for each distance and angle refer to the two distances and

angles that are found to be symmetry related in the crystal structure of [OsO₃F][HF]₂[AsF₆].

4

calculated bond lengths in monomeric OsO₃F₂by 0.027

and 0.077 Å, respectively, consistent with cation formation.

The calculated geometrical parameters for ReO₃F (Table 9),

which is isoelectronic with the OsO₃F⁺cation, are in good

agreement with the experimental data, with the calculated

Re-F and Re-O bond distances being too short by 0.016

and 0.011 Å, respectively. This suggests that the bond

distances calculated for isolated OsO₃F⁺should be within

0.02 Å of the experimental values. Consistent with the

positive charge on OsO₃F⁺, the Os-O and Os-F bond

distances are shorter than the respective Re-O and Re-F

bond lengths of neutral isoelectronic ReO₃F.

systematic error at the LDFT level has been noted above.

The slightly larger deviation between the calculated and

experimental values in the Os-O stretches compared with

the Re-O stretching frequencies can be partially accounted

for by cation-anion contacts in the solid state, which would

lower the experimental values with respect to those calculated

for the gas-phase ion.

+

(b) µ-F(OsO₃F)₂. The fully optimized gas-phase geom-

+

etry of the µ-F(OsO₃F)₂cation calculated at the local

(LDFT) level of theory contains two slightly asymmetric

fluorine bridges with Os--F_b(2.129 Å) being slightly shorter

than Os′--F_b(2.140 Å). The calculated structure for the

dinuclear cation has a trigonal bipyramidal environment

about each osmium with the oxygens in the equatorial plane

and the terminal (F_t) and bridging fluorines (F_b) in the axial

positions (Table 9). The three equatorial oxygens are bent

The stretching frequencies for OsO₃F⁺(ReO₃F) (Table 4),

calculated at the LDFT level, are higher by 10-36 (11-16)

cm^-1than the experimental values, whereas the calculated

bending modes are lower by 14-18 (13-24.5) cm^-1. This

272 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

toward the weak axial Os--F_bbond with O-Os-F_tbond

angles close to 100°. The calculated Os-O and Os-F_tbond

lengths are intermediate with respect to those calculated for

monomeric OsO₃F₂⁴and the OsO₃F⁺cation. The calculated

Os-O and Os-F stretching frequencies for the µ-F(OsO₃F)₂⁺

cation (Table 8) agree well with the experimental values

considering the systematic error, with the experimental

stretching frequencies being 34-44 cm^-1higher than the

observed values. The large discrepancy between the calcu-

lated and experimental frequencies can also be attributed to

the expected contacts between the cation and the AsF₆^-anion

(see Raman Spectroscopy, part d). The antisymmetic Os--

F_b--Os′ stretching frequency was calculated to be 476 cm^-1.

The unambiguous assignment of an experimental frequency

to the bridging stretch is not possible because of the large

number of weak Raman bands in this region.

the nonlocal calculation better reproduced the experimental

results, giving larger differences between the Os(1)-F(2)

and Os(1)-F(4) bonds, which are consistent with the

experimental values. Examination of the structures of the

HF-bridged dimers at the nonlocal level shows that the H-F

bonds are elongated with respect to that of free HF (0.94 Å)

by 0.06 and 0.09 Å. The two H-F bonds of 1.00 and 1.03

Å are significantly shorter than the H-F bonds of 1.14 Å in

- 39

HF₂

while the other H--F interactions are much longer

(1.46 and 1.36 Å). Clearly, these species are closer to HF

-

molecules than to an HF₂anion in their structures. The

geometry at the local level is closer to the bifluoride anion

than to the HF molecule. The F‚‚‚F distances between the

HF molecules in the Os/As and Os/Sb dimers are 2.298 and

2.382 Å, respectively, compared with the experimental values

of 2.429(8) Å for the (FO₃Os--(HF)₂--FAsF₅)₂dimer and are

-

clearly similar to the F‚‚‚F distance of 2.278 Å in the HF₂

(c) (FO₃Os--FPnF₅)₂and (FO₃Os--(HF)₂--FPnF₅)₂. The

gas-phase geometries of the (FO₃Os--FPnF₅)₂and (FO₃Os--

(HF)₂--FPnF₅)₂dimers were calculated at the LDFT and

NLDFT level of theory, and their experimental centrosym-

metric symmetries were reproduced by the calculations with

good accuracy for the (FO₃Os--FAsF₅)₂dimer and with fair

agreement for the (FO₃Os--(HF)₂--FAsF₅)₂dimer (Table 2).

The calculated (FO₃Os--FAsF₅)₂dimer at the local DFT level

comprises two equivalent contacts between each osmium and

two bridging fluorines of 2.289 Å, contrasting with the

experimental structure, which contains two significantly

different bridges, i.e., Os(1)--F(4) (2.451(7) Å) and Os(1)--

F(2) (2.666(7) Å). The Os--F fluorine bridge bonds are

shorter by 0.377 and 0.162 Å in the LDFT calculations,

respectively. The calculations at the nonlocal level reproduce

the asymmetry of the F bridges in the experimental structure

of the (FO₃Os--FAsF₅)₂dimer with Os--F distances of 2.417

and 2.293 Å. The large interactions between the cations and

anions at the LDFT and NLDFT levels are consistent with

other work³⁵which shows that LDFT and NLDFT exaggerate

intermolecular interactions leading to interactions that are

too strong. While the calculated Os-O bond lengths in the

(FO₃Os--FPnF₅)₂dimers are the same as the experimental

values at the LDFT level, the calculated Os-O (NLDFT),

Os(1)-F(1) (LDFT and NLDFT), and terminal Pn-F (LDFT

and NLDFT) bond lengths are significantly longer than the

experimental values. In general, the bond lengths at the

nonlocal level are significantly longer than those calculated

at the local level.

The dimer structures with two HF molecules bridging an

OsO₃F/PnF₆cation/anion pair are difficult to describe, both

experimentally and computationally. Experimentally, it is

difficult to observe the hydrogen atoms by X-ray diffraction

and we have found it difficult to predict the structures of

isolated ion pairs with methods that are computationally fast

enough to deal with such large species.³⁵As noted above,

the computation tends to make the ion pair too strongly

bound. This arises because the pair is not embedded in a

crystalline environment so that each ion only sees the

adjacent charged species and is more strongly attracted to

it. Examination of the structures calculated at the local and

nonlocal levels for the dimers without (HF)₂showed that

anion.³⁹At the nonlocal level, the Os-F(H) bond distance

is quite long with 2.34 Å for the Os/As dimer and 2.32 Å

for the Os/Sb dimer, in reasonable agreement with the

experimental value of 2.282(5) Å for the Os/As dimer. As

expected, these distances are much shorter at the local level

with 2.16 Å for both dimers. This is consistent with the

higher predicted ionicity of the (HF)₂bridged species at the

local level, which is closer to an [FHF]^-anion, and should

lead to shorter and stronger H--F hydrogen bonding interac-

tions as calculated.

The HF molecules are, however, clearly elongated in the

dimer. The calculated frequency of the HF molecule at the

nonlocal level is 3984 cm^-1and at the local level it is 4009

cm^-1compared with an experimental harmonic value of 4139

cm^-1.⁴⁰The calculated frequencies at the nonlocal level for

the two shorter bonds are close to 2950 cm^-1and are in the

range 2400-2450 cm^-1for the two longer HF bonds. The

local values are significantly lower, at ca. 2500 cm^-1and

1800-1900 cm^-1, respectively. The calculated values for the

[FHF]^-anion at the local (nonlocal) level are 1912 (1668)

+

cm^-1for the asymmetric stretch ν₃(Σ_u), 1277 (1296) cm^-1

for the bend ν₂(Π_u), and 620 (602) cm^-1for the symmetric

+

stretch ν₁(Σ_g). The experimental frequencies for [HF₂]^-in

+

its [N(CH₃)₄]⁺salt are 596 cm^-1(ν₁(Σ_g)),¹⁷1264-1255

+

cm^-1(ν₂(Π_u)),⁴¹and 1376 cm^-1(ν₃(Σ_u)).⁴¹As noted above,

the H-F bond strength of the nonlocal dimer structure is

closer to that of a free HF molecule than to that of the [FHF]^-

anion, although the calculated frequencies are significantly

lower than those in free HF because the F-H bonds in the

dimer are calculated to be elongated by less than 0.1 Å.

However, for the structure at the local level, the lower

frequency stretches for the HF molecules are in the predicted

range for the asymmetric stretch of the [FHF]^-anion. The

calculated infrared spectra contain intense bands in the HF

stretching region. These correspond to asymmetric HF

stretches with extended HF bonds in an extremely polar

(39) Kawaguchi, K.; Hirota, E. J. Chem. Phys. 1987, 87, 6838.

(40) Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coor-

dination Compound, Part A, 5th ed.; John Wiley and Sons: New York,

1997; p.154.

(41) Harmon, K. M.; Lovelace, R. R. J. Phys. Chem. 1982, 86, 900.

Inorganic Chemistry, Vol. 41, No. 2, 2002 273

Gerken et al.

+

Table 10. Mulliken Charges, Mayer Valencies, and Mayer Bond Orders for OsO₄, OsO₃F⁺, ReO₃F, and µ-F(OsO₃F)₂

Mulliken Charges

+

OsO₄

OsO₃F⁺

ReO₃F

µ-F(OsO₃F)₂

Os

O

1.77

-0.44

Os

O

F

1.93

-0.23

-0.24

Re

O

F

1.73

-0.45

-0.39

Os/Os′

1.86/1.86

-0.28/-0.27

-0.34/-0.34

-0.28/-0.28

-0.43

O(1)/O(1)′

O(2)/O(2)′

O(3)/O(3)′

F_b

F_t/F_t′

-0.25/-0.25

Mayer Valencies

OsO₃F⁺

ReO₃F

µ-F(OsO₃F)₂

+

Os

O

5.96

2.25

Os

O

F

5.77

2.42

1.22

Re

O

F

5.85

2.25

1.00

Os/Os′

5.98/5.99

2.36/2.36

2.29/2.29

2.36/2.36

0.69

O(1)/O(1)′

O(2)/O(2)′

O(3)/O(3)′

F_b

F_t/F_t′

1.20/1.20

Mayer Bond Orders

+

OsO₃F⁺

ReO₃F

µ-F(OsO₃F)₂

Os-O(1)

Os-O

1.49

Os-O

Os-F

1.65

0.81

Re-O

Re-F

1.70

0.74

1.64

1.58

1.64

0.32

0.81

Os-O(2)

Os-O(3)

Os--F_b

Os-F_t

regime. This leads to a very large predicted infrared

absorption of the order of 10⁴km mol^-1in the 2000-3000

cm^-1region. Unfortunately, it was not possible to obtain

experimental infrared spectra of [OsO₃F][HF]₂[PnF₆] (Pn )

As and Sb), because the two compounds readily lose HF

upon isolation of the solids from HF solution.

frequency Sb-F stretching modes appears to be wrong on

the basis of the assumption that the Os-F stretching

frequencies of the two (FO₃Os--(HF)₂--FPnF₅)₂dimers do

not differ by more than 5 cm^-1, as predicted by the NLDFT

calculations. This is a consequence of the underestimated

terminal Sb-F bond strength. The low-frequency bending

and torsional modes of the dimers are strongly coupled and

are not assigned and discussed further.

The DFT calculations predict the interactions of the

isolated cations and anions to be too large when compared

with interactions in the solid state. As expected, local DFT

calculations which generally lead to overbinding for weak

interactions, lead to the largest errors. We have thus used

the nonlocal results in the discussion of the vibrational

frequencies, which are given in Tables 5 and 7 for [OsO₃F]-

[PnF₆] and [OsO₃F][HF]₂[PnF₆], respectively. There are some

generalities that are found. The Os-O stretches are all

predicted to be in the region of 955-975 cm^-1except for

the HF-bridged dimers where HF bends can mix and lower

the Os-O stretches to as low as 938 cm^-1. The Os-F

stretches are all predicted to be near 650 ( 10 cm^-1with

the HF dimers at the lower end. For the dimers not containing

bridging HF molecules, the stretches involving the bridging

F atoms are predicted to occur in two pairs with one pair

near 500 cm^-1and the second pair in the region 430-460

cm^-1. In the dimers containing bridging HF molecules, the

Os--F-Pn stretches occur as pairs in similar regions, i.e.,

430-440 cm^-1for the Sb dimer and at ca. 410 cm^-1for the

As dimer. The stretches of the As-F fluorines involved with

the HF molecules are in the range 460-500 cm^-1, and

mixing occurs with the HF group stretches and the motion

of the HF molecule moving between the Os and Pn atoms.

For comparison, the OsO₃F⁺frequencies at the nonlocal level

are given in Table 4. The Os-O and Os-F stretches in the

dimers are shifted to lower frequencies by 30 and 50-70

cm^-1, respectively, compared with the gas-phase OsO₃F⁺

cation. The sequence for the calculated Os-F and the high-

(d) Charges, Valencies, and Bond Orders. The calcu-

lated Mulliken charges, Mayer valencies, and Mayer bond

+

orders for OsO₄, OsO₃F⁺, ReO₃F, and µ-F(OsO₃F)₂are

given in Table 10. The calculated values for the (FO₃Os--

FAsF₅)₂and (FO₃Os--(HF)₂--FAsF₅)₂dimers are given in

Table 11 (Supporting Information) and will not be discussed.

Abstraction of a fluoride ion from OsO₃F₂leads to an

increase in the positive charge of osmium from 1.76⁴to 1.93

and a decrease in the Mayer valency of osmium from 6.31⁴

to 5.77. The negative charges on the oxygens and fluorines

and their valencies decrease when compared with those of

OsO₃F₂. Whereas the Os-O bond order increases only

slightly upon fluoride ion abstraction (from 1.63⁴to 1.65),

the Os-F bond becomes significantly less polar. The

calculated charges and valencies for osmium and oxygen and

the Os-O bond orders for the dinuclear [FO₃Os--F_b--

OsO₃F]⁺cation lie between those found for the OsO₃F⁺

cation and monomeric OsO₃F₂.⁴The Os-F_tbond order is

the same in the dinuclear cation as in OsO₃F⁺, and the

charges and valencies for the terminal fluorines in both

cations differ only slightly. The Os--F_bbond order (0.32) is

less than half of that for the terminal fluorines (0.81), and

the negative charge (-0.43) [valency (0.69)] on the bridging

fluorine is significantly higher [lower] than the negative

charge (-0.25) [valency (1.20)] for the terminal fluorine.

This reflects the high degree of ionicity of the fluorine bridge

bonds and agrees with the dissociation observed in the

274 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

+

experiment (see Syntheses of the OsO₃F⁺and µ-F(OsO₃F)₂

straw-yellow [OsO₃F][AsF₆]. Distillation of ca. 0.3 mL of HF onto

the solid resulted in a yellow solution above a heterogeneous

mixture of yellow ([OsO₃F][AsF₆]) and orange ([µ-F(OsO₃F)₂]-

[AsF₆]) solids at -78 °C, which was confirmed by Raman

spectroscopy. Thorough agitation at -78 °C resulted in an orange

precipitate comprised exclusively of [µ-F(OsO₃F)₂][AsF₆], which

presumably arises because [OsO₃F][AsF₆] has a significantly higher

solubility than [µ-F(OsO₃F)₂][AsF₆]. Condensation of an additional

0.4 mmol of AsF₅onto the mixture resulted in complete dissolution

of the solid close to room temperature and did not yield a precipitate

at -78 °C. Approximately 0.05 mL of HF was removed at -78

°C resulting in a yellow precipitate which was identified by Raman

spectroscopy as [OsO₃F][AsF₆]. After redissolving the precipitate

in the HF/AsF₅mixture at approximately room temperature, the

sample was cooled to -78 °C and yellow crystals grew over a 12

h period. The solvent was removed under dynamic vacuum at -78

°C, and yellow crystals were selected and mounted at -110 °C as

previously described.⁴The crystal used in this study had the

dimensions 0.12 × 0.10 × 0.10 mm³.

Cations and Solution Characterization of the OsO₃F⁺Cation

by ¹⁹F NMR Spectroscopy), which is facilitated by the

formation of contacts with anions and donor solvent mol-

ecules.

Conclusion

Osmium trioxide difluoride behaves as a fluoride ion donor

toward the strong Lewis acids AsF₅and SbF₅in HF solvent.

The OsO₃F⁺cation is highly electrophilic and expands its

coordination sphere in the solid state by the formation of

contacts with the AsF₆^-and SbF₆^-anions and HF molecules.

The X-ray crystal structures of [OsO₃F][HF]₂[AsF₆] and

[OsO₃F][HF][SbF₆] contain HF bridged cyclic (FO₃Os--

(HF)₂--FAsF₅)₂dimers and helical (FO₃Os--FH--FSbF₅)_∞

chains, respectively, that provide new and rare examples of

HF coordinated to metal centers. The resulting hexacoordi-

nation about osmium has a fac-trioxo arrangement. The

weakly nucleophilic Sb₃F₁₆^-anion and the absence of a donor

solvent such as HF are necessary to stabilize an OsO₃F⁺

cation having only weak contacts to the counteranion and

tetrahedral coordination. The dinuclear µ-F(OsO₃F)₂⁺cation

An NMR sample in a 4-mm. o.d. FEP tube was prepared using

0.0303 g (0.1097 mmol) of OsO₃F₂, 0.2 mL of HF, and 1.5 mmol

of AsF₅(ca. 13.5-fold molar excess).

Crystal Growth of [OsO₃F][HF]₂[AsF₆]. Crystals of [OsO₃F]-

[HF]₂[AsF₆] were obtained from a sample composed of 0.1032 g

(0.374 mmol) of OsO₃F₂and ca. 0.9 mmol of AsF₅in 0.85 mL of

HF. Orange crystals of [OsO₃F][HF]₂[AsF₆] were grown by slow

removal of the HF solvent and excess AsF₅under dynamic vacuum

at -78 °C. After almost complete removal of the HF solvent, a

portion of the crystalline sample turned yellow ([OsO₃F][AsF₆]).

Pumping was discontinued, and the FEP tube was immediately

back-filled with dry nitrogen while maintaining the sample at

-78 °C. Orange crystals were selected and mounted at -117 °C

as previously described.⁴The crystal used in this study had the

dimensions 0.25 × 0.20 × 0.05 mm³.

-

was observed by Raman spectroscopy with AsF₆as the

counteranion and was shown to readily dissociate, which is

consistent with the weak bridging Os--F bond length

calculated by LDFT methods.

Experimental Section

Apparatus and Materials. Volatile materials were handled on

vacuum lines constructed of nickel, stainless steel, FEP, and Pyrex,

and nonvolatile materials were handled in the atmosphere of a

drybox as previously described.⁴²

The starting compounds, OsO₃F₂,⁵AsF₅,⁴³SbF₅,⁴⁴and SbF₃,⁴¹

were prepared by standard literature methods. Sulfuryl chloride

fluoride, SO₂ClF (Aldrich), was purified by the standard literature

methods⁴⁵and stored over anhydrous KF. Anhydrous HF (Harshaw

Chemical Co.) was dried and purified by the standard literature

methods.⁴⁶

Synthesis of [OsO₃F][HF]₂[AsF₆], [µ-F(OsO₃F)₂][AsF₆], and

[OsO₃F][AsF₆] and Crystal Growth of [OsO₃F][AsF₆]. Inside a

drybox, 0.09203 g (0.333 mmol) of OsO₃F₂was loaded into a

¹/₄-in. o.d. FEP reaction tube equipped with a Kel-F valve.

Approximately 0.5 mL of HF was condensed into the tube at

-196 °C followed by condensation of ca. 0.7 mmol of AsF₅.

Osmium trioxide difluoride dissolved upon warming to ambient

temperature yielding a clear yellow-orange solution. The bulk of

the HF solvent and excess AsF₅were removed by pumping at

-78 °C for ca. 3 h and resulted in the formation of an orange,

crystalline precipitate under ca. 0.1 mL of HF, which was identified

by Raman spectroscopy as [OsO₃F][HF]₂[AsF₆]. Addition of ca.

0.5 mmol of AsF₅and 0.57 mL of HF followed by complete

removal of the HF solvent at -78 °C over a period of ca. 5 h yielded

Syntheses of [OsO₃F][HF][SbF₆] and [OsO₃F][HF]₂[SbF₆] and

Crystal Growth of [OsO₃F][HF][SbF₆]. Inside the drybox,

0.03962 g (0.2217 mmol) of SbF₃was transferred into the vertical

1

arm of a /₄-in. o.d. FEP T-shaped reactor equipped with a Kel-F

valve. After condensation of approximately 0.6 mL of HF onto the

SbF₃, the mixture was allowed to react with F₂at room temperature

until white solid SbF₃had completely reacted to form SbF₅and

had dissolved. Inside the drybox, 0.06342 g (0.2296 mmol) of

OsO₃F₂was added to the frozen solution. Warming to room

temperature yielded a clear, yellow-orange solution. Upon cooling

to -78 °C, clusters of orange needles grew and were identified as

[OsO₃F][HF]₂[SbF₆] by Raman spectroscopy. Removal of the HF

solvent at -78 °C and brief pumping at room temperature yielded

solid straw-yellow [OsO₃F][HF][SbF₆]. After redissolution of

[OsO₃F][HF][SbF₆] in approximately 0.6 mL of HF at room

temperature and cooling to -78 °C, orange, crystalline clusters and

yellow plates grew over a period of ca. 12 h. The HF supernatant

was decanted into the sidearm of the T-reactor, which was

subsequently heat sealed off at -196 °C under dynamic vacuum

while the crystals were dried at -75 °C under dynamic vacuum.

Yellow plates were selected and mounted at -100 °C as previously

described.⁴The crystal used in this study had the dimensions

0.08 × 0.04 × 0.03 mm³.

(42) Casteel, W. J., Jr.; Kolb, P.; LeBlond, N.; Mercier, H. P. A.;

Schrobilgen, G. J. Inorg. Chem. 1996, 35, 929.

(43) Mercier, H. P. A.; Sanders, J. C. P.; Schrobilgen, G. J.; Tsai, S. S.

Inorg. Chem. 1993, 32, 386.

(44) LeBlond, N.; Dixon, D. A.; Schrobilgen, G. J. Inorg. Chem. 2000,

39, 2473.

(45) Schrobilgen, G. J.; Holloway, J. H.; Granger, P.; Brevard, C. Inorg.

Chem. 1978, 17, 980.

In a separate experiment using 0.0538 g (0.3010 mmol) of SbF₃,

0.0695 g (0.2516 mmol) of OsO₃F₂and ca. 0.6 mL of HF, small

amounts of [OsO₃F][SbF₆] were observed by Raman spectroscopy

upon removal of the HF solvent (pumped on for 3 h at -78 °C

and for 5 min at room temperature). Pumping at room temperature

for 5 h did not increase the amount of [OsO₃F][SbF₆] significantly.

(46) Emara, A. A. A.; Schrobilgen, G. J. Inorg. Chem. 1992, 31, 1323.

Inorganic Chemistry, Vol. 41, No. 2, 2002 275

Gerken et al.

The sample liquified at 45 °C and was pumped on at this

temperature for a further 2 h using a mercury diffusion pump,

resulting in a decrease in the relative Raman intensities of the OsO₂

stretches of [OsO₃F][SbF₆] when compared with those of [OsO₃F]-

[HF][SbF₆]. Distillation of 0.6 mL of HF onto the solid resulted in

dissolution of the solid at room temperature and slow precipitation

of yellow [OsO₃F][HF][SbF₆]. Reduction of the solution volume

to 0.17 mL at -78 °C followed by redissolution of the solid at

room-temperature resulted in the precipitation of [OsO₃F][HF]₂-

[SbF₆] at -78 °C.

Successive difference Fourier syntheses revealed all light atoms,

which were assigned on the basis of their bond distances to the

heavy atoms. The final refinement was obtained by introducing a

2

weighting factor (w ) 1/[σ²(F_o) + (0.0839)²]) and anisotropic

thermal parameters for all non-hydrogen atoms in the [OsO₃F]-

[AsF₆] and [OsO₃F][HF]₂[AsF₆] structures, giving a residual, R₁,

of 0.0401 (wR₂) 0.0797), 0.0325 (wR₂) 0.0772), 0.0348

(wR₂) 0.0864), 0.0558 (wR₂) 0.1198), and 0.0858 (wR₂

)

0.1871) and maximum and minimum electron densities in the final

difference Fourier map of 1.636/-1.397, 2.420/-1.763, 1.446/

-1.280, 2.598/-2.327, and 2.209/-2.610 e Å^-3for [OsO₃F][AsF₆],

[OsO₃F][SbF₆], [OsO₃F][HF]₂[AsF₆], [OsO₃F][HF][SbF₆], and

[OsO₃F][Sb₃F₁₆], respectively. The residual electron densities were

located around the heavy atoms. The crystal containing [OsO₃F]-

[SbF₆] was a twin; in addition to the diffraction spots for [OsO₃F]-

[SbF₆], diffraction spots were present that were indexed to give a

cubic cell (a ) 10.088(2) Å). The determination of the content of

the cubic cell is still under investigation. As a consequence of the

twinning, only the Os and Sb atoms could be refined anisotropically.

The crystal of [OsO₃F][HF][SbF₆] was a merohedral twin (ca. 40:

60). Therefore, a proper absorption correction could not be

performed and the fluorine and oxygen atoms were refined

isotropically. In the structure of [OsO₃F][Sb₃F₁₆], the Os atom was

found on a special position (4h..) resulting in disorder among the

three O and the F atoms of the cation. In addition, the fluorine

Synthesis and Crystal Growth of [OsO₃F][Sb₃F₁₆]. Inside a

dry nitrogen filled glovebag, 0.9393 g (4.334 mmol) of SbF₅was

syringed into a ¹/₄-in. o.d. FEP reaction tube equipped with a Kel-F

valve, and 0.0847 g (0.3067 mmol) of OsO₃F₂was added to the

frozen SbF₅sample inside a drybox (ca. -140 °C). The reaction

mixture was warmed to 55 °C outside the drybox, yielding a clear

straw-yellow solution upon sonication. The solution was placed in

a water bath at 55 °C and allowed to cool to 35 °C for 2 h yielding

copious amounts of thin straw-yellow plates. Excess SbF₅was

removed under dynamic vacuum at ambient temperature over a

period of 5.5 h yielding 0.2906 g of straw-yellow plates of [OsO₃F]-

[Sb₃F₁₆] (theoretical, 0.2841 g) corresponding to a molar ratio of

SbF₅:OsO₃F₂) 3.1:1.0. Crystals were selected and mounted at

-120 °C as previously described.⁴The crystal used in this study

had the dimensions 0.14 × 0.10 × 0.005 mm³.

-

¹⁹F NMR sample of OsO₃F₂, dissolved in neat SbF₅, was

atoms in the Sb₃F₁₆anion were disordered between two orienta-

A

1

tions. As a consequence, the oxygen and fluorine atoms of the anion

and cation could only be refined isotropically.

prepared in a /₄-in. o.d. FEP tube equipped with a Kel-F valve

using 0.0538 g (0.1948 mmol) of OsO₃F₂and 2.41 g (11.1 mmol)

of SbF₅. Samples for ¹⁹F NMR spectroscopy were also prepared in

4-mm o.d. FEP tubes equipped with Kel-F valves by dissolving

0.0274 g (0.0296 mmol) [0.0302 g (0.0326 mmol)] of [OsO₃F]-

[Sb₃F₁₆] in ca. 0.35 mL of SO₂ClF [0.18 mL of HF], yielding a

clear yellow solution upon warming to -78 °C. Sample tubes were

heat sealed under dynamic vacuum at -196 °C.

Raman Spectroscopy. The low-temperature Raman spectra of

[OsO₃F][AsF₆] (-150 °C), [OsO₃F][HF]₂[AsF₆] (-140 °), [OsO₃F]-

[HF]₂[SbF₆] (-80 °C), and [µ-F(OsO₃F)₂][AsF₆] (-80 °C) were

excited using the 647.1 nm line of a Kr ion laser (Lexel Laser,

Inc., model 3550) and the spectra were recorded on a Jobin-Yvon

Mole S-3000 triple spectrograph system as previously described.⁴¹

1

The spectra were recorded in /₄-in. FEP sample tubes using the

X-ray Structure Determinations. (a) Collection and Reduction

of X-ray Data. X-ray diffraction data were collected using a P4

Siemens diffractometer equipped with a Siemens SMART 1K

charge-coupled device (CCD) area detector (using the program

SMART)⁴⁷and a rotating anode using graphite-monochromated Mo

KR radiation (λ ) 0.710 73 Å). The crystal-to-detector distances

for [OsO₃F][AsF₆], [OsO₃F][SbF₆], [OsO₃F][HF]₂[AsF₆], [OsO₃F]-

[HF][SbF₆], and [OsO₃F][Sb₃F₁₆] were 4.9870, 4.9870, 5.000,

4.9870, and 5.0140 cm, respectively, and the data collections were

carried out in 512 × 512 pixel mode using 2 × 2 pixel binning.

Complete spheres of data were collected to better than 0.8 Å

resolution. Processing was carried out by using the program

SAINT,⁴⁷which applied Lorentz and polarization corrections to

three-dimensionally integrated diffraction spots. The program

SADABS⁴⁸was used for the scaling of diffraction data, the

application of a decay correction, and an empirical absorption

correction based on redundant reflections.

macrochamber of the instrument with a resolution of 1 cm^-1and

a total of 10 reads each having 30 s integration times using laser

powers of 100 mW. The low temperatures were achieved as

previously described.⁴²

The low-temperature Raman spectra of [OsO₃F][Sb₃F₁₆] (-165

°C) and [OsO₃F][HF][SbF₆] (-165 °C) were recorded on a Bruker

RFS 100 FT Raman spectrometer using 1064-nm excitation as

previously described.⁴The low-temperature spectra of [OsO₃F]-

[Sb₃F₁₆] and [OsO₃F][HF][SbF₆] were recorded on powdered

1

samples in a melting point capillary and in a /₄-in. FEP sample

tube, respectively, using laser powers of 200 mW and a total of

1000 and 500 scans, respectively.

Nuclear Magnetic Resonance Spectroscopy. The ¹⁹F NMR

spectra (470.539 MHz) of [OsO₃F][Sb₃F₁₆] in SbF₅(SO₂ClF)

solvent were recorded unlocked (field drift < 0.1 Hz h^-1) on a

Bruker DRX-500 (11.7438 T) spectrometer using a 10-mm (5-mm)

broad-band probe. The spectra of the SbF₅(SO₂ClF) solutions were

acquired in 64/16 (64) K memories with spectral width settings of

100/25 (50) kHz, yielding acquisition times of 0.328 (0.655) s and

data point resolutions of 1.526 (0.763) Hz/data point; a pulse width

of 2.5 µs was used. The ¹⁹F NMR spectrum (282.409 MHz) of

OsO₃F₂with excess AsF₅in HF solvent was recorded unlocked

(field drift < 0.1 Hz h^-1) on a Bruker AC-300 (7.046 T)

spectrometer using a 5-mm ¹H/¹³C/¹⁹F/³¹P combination probe. The

spectrum was acquired in a 64 K memory with a spectral width

setting of 100 kHz, yielding an acquisition time of 0.328 s and

data point resolution of 3.052 Hz/data point; a pulse width of 3 µs

was used.

(b) Solution and Refinement of the Structures. All calculations

were performed using the SHELXTL Plus package⁴⁹for structure

determination, refinement, and molecular graphics.

The XPREP program⁴⁹was used to confirm the unit cell

dimensions and the crystal lattices. Solutions were obtained using

direct methods which located the positions of the heavy atoms.

(47) SMART and SAINT, release 4.05; Siemens Energy and Automation

Inc.: Madison, WI, 1996.

(48) Sheldrick, G. M. SADABS (Siemens Area Detector Absorption

Corrections), personal communication, 1996.

(49) Sheldrick, G. M. SHELXTL-Plus, release 5.03; Siemens Analytical

X-ray Instruments, Inc.: Madison, WI, 1994.

276 Inorganic Chemistry, Vol. 41, No. 2, 2002

+

The OsO₃F⁺and µ-F(OsO₃F)₂Cations

Calculations. The electron structure calculations were done at

the DFT level.^50-54The DFT geometry optimizations and frequency

calculations were done with the program DGauss^55-58on SGI

computers. The calculations were carried out at the local level with

the potential fit of Vosko, Wilk, and Nusair⁵⁹for correlation and

Slater exchange⁶⁰and with the following basis sets: For H, O, F,

Sb, and As, the DZVP polarized double-ú basis set⁶¹was used (no

polarization functions on H) with the A1 fitting set. For Os, the

ECP and basis set of Hay and Wadt was used with the A1 fitting

set derived for pseudopotentials within DGauss.^63,64The geometries

were optimized by using analytic gradient methods, and second

derivatives were also calculated analytically. Atomic valencies

following Mayer were calculated.^65-68No scaling of the calculated

vibrational frequencies was applied.

Acknowledgment. We thank the donors of the Petroleum

Research Fund, administered by the American Chemical

Society, for support of this work under Grant ACS-PRF No.

28284-AC3. This research was performed, in part, using the

Molecular Science Computing Facility (MSCF) in the

William R. Wiley Environmental Molecular Sciences Labo-

ratory at the Pacific Northwest National Laboratory. The

MSCF is funded by the Office of Biological and Environ-

mental Research in the U.S. Department of Energy. The

Pacific Northwest Laboratory is operated by Battelle for the

U.S. Department of Energy under Contract DE-AC06-

76RLO 1830. We also thank the Ontario Ministry of

Education and the Richard Fuller and James A. Morrison

Memorial Funds for the award of graduate scholarships to

M.G. and the Canada Council for the award of a Killam

Research Fellowship (1998 and 1999) to G.J.S. We also

thank Dr. William J. Casteel for his help with some of the

exploratory experiments and Dr. He´le`ne P. A. Mercier for

her help with the solution of the crystal structure of [OsO₃F]-

[SbF₆].

(50) Parr, R. G.; Yang, W. Density-Functional Theory of Atoms and

Molecules; Oxford University Press: New York, 1989.

(51) Labanowski, J. K., Andzelm, J. W., Eds. Density Functional Methods

in Chemistry; Springer-Verlag: New York, 1991.

(52) Ziegler, T. Chem. ReV. 1991, 91, 651.

(53) Salahub, D. R. In Ab Initio Methods in Quantum Chemistry-II; Lawley,

K. P., Ed.; J. Wiley and Sons: New York, 1987; pp 447-520.

(54) Jones, R. O.; Gunnarsson, O. ReV. Mod. Phys. 1989, 61, 689.

(55) Andzelm, J.; Wimmer, E.; Salahub, D. R. In The Challenge of d and

f Electrons: Theory and Computation; Salahub, D. R., Zerner, M.

C., Eds.; ACS Symposium Series 394; American Chemical Society:

Washington, DC, 1989; p 228.

Supporting Information Available: Unit cell diagrams for

[OsO₃F][AsF₆] (Figure S9), [OsO₃F][HF]₂[AsF₆] (Figure S10),

[OsO₃F][HF][SbF₆] (Figure S11), and [OsO₃F][Sb₃F₁₆] (Figure

S12), X-ray crystallographic files, in CIF format, for the structure

determinations of [OsO₃F][AsF₆], [OsO₃F][SbF₆], [OsO₃F][HF]₂-

[AsF₆], [OsO₃F][HF][SbF₆], and [OsO₃F][Sb₃F₁₆], calculated di-

hedral angles for (FO₃Os--(HF)₂--FPnF₅)₂(Pn ) As, Sb) (Table

S11), and Mulliken charges and Mayer valencies for (FO₃Os--

FPnF₅)₂and (FO₃Os--(HF)₂--FPnF₅)₂(Table S12). This material is

available free of charge via the Internet at http://pubs.acs.org.

(56) Andzelm, J. In Density Functional Theory in Chemistry; Labanowski,

J., Andzelm, J., Eds.; Springer-Verlag: New York, 1991; p 155.

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(58) DGauss is a density functional program which is part of Unichem

and is available from Oxford Molecular.

(59) Vosko, S. H.; Wilk, L.; Nusair, M. Can. J. Phys. 1980, 58, 1200.

(60) Slater, J. C. Phys. ReV. 1951, 81, 385.

(61) Godbout, N.; Salahub, D. R.; Andzelm, J.; Wimmer, E. Can. J. Chem.

1992, 70, 560.

(62) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 299.

(63) Chen, H.; Krasowski, M.; Fitzgerald, G. J. Chem. Phys. 1993, 98,

8710.

(64) Lee, C.; Chen, H. Unpublished results. See: UniChem Manual Version

3.0-5.0.

(65) Mayer, I. Chem. Phys. Lett. 1983, 97, 270.

IC0107680

(67) Mayer, I. Int. J. Quantum Chem. 1986, 29, 73.

(68) Mayer, I. Int. J. Quantum Chem. 1986, 29, 477.

(66) Mayer, I. Theor. Chim. Acta 1985, 67, 315.

Inorganic Chemistry, Vol. 41, No. 2, 2002 277

Article Doi

The OsO3F+ and μ-F(OsO3F)2+ cations

DOI: 10.1021/ic0107680

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Article abstract of DOI:10.1021/ic0107680

Full text of DOI:10.1021/ic0107680

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