[acs symposium series] inorganic fluorine chemistry volume 555 (toward the 21st century) ||...

Chapter 7

Influence of Fluorine and Parahalogen Substituents on the Chemistry

of Some Functional Groups

A. Haas and A. Brosius

Lehrstuhl für Anorganische Chemie II, Ruhr-Universität Bochum, D-44780 Bochum, Germany

The influence of fluorine, trifluoromethyl, trifluoromethylsulfenyl or trifluoromethylselenyl on the chemistry of selected functional groups such as carbene, nitrene, C=X (X = O, S, Se, Te), =CCO and -NSO will be presented. After describing evidence for the existence of (CF3S)2C: and CF3SN:, their stability and reactivity will be compared with those of F- and CF3-substituted carbenes and nitrenes. Tellurocarbonyl difluoride, (CF3S)2CCO, and CF3SNSO are other key compounds that will be treated in a similar manner. Their preparation, chemical and physical properties will be discussed in comparison with either their fluorine, CF3, CF3S or CT3Se analogues. An attempt will be made to offer rules for planning successful syntheses.

The aim of this chapter is to demonstrate the influence of the three important ligands F, CF 3, and CF3S on the stability and chemistry of some selected functional groups. First, it is informative to compare the constants for the three ligands as aromatic substituents (see Table I). Group electronegativity decreases regularly from a value of 4.00 for F to a value of 2.7 for CF3S, while π effects increase from 0.14 to 1.44, respectively. The other constants show substantial differences between fluorine and the other two ligands. For example, CF3 and CF3S have rather similar Hammett and Tail constants; however, overall there is no unique trend in the data shown in Table I.

On the other hand, little is known in terms of constants for these ligands as aliphatic substituents. No data could be found for the CF3S group, but its hydrophobicity should increase and its electron withdrawing effect decrease slightly with respect to F and CF3. Tentative extrapolations are given in Table I.

0097-6156/94/0555-0104$08.72/0 © 1994 American Chemical Society

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In Inorganic Fluorine Chemistry; Thrasher, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1994.

7. HAAS AND BROSIUS Influence of Fluorine & Parahalogen Substituents 105

The functional groups selected are carbenes and nitrenes and their derivatives with a chalcogen or parachalcogen (=CO, =SO) ligand. They are summarized in Scheme 1. These functional groups are incorporated into the periodic system as shown in Scheme 2. In particular the stability and chemistry of (CT^S^C:, CF3SN:, F2C=Te, (CF3S)2C=C=0, and CF3SN=S=0 shall be discussed.

Fluorine-Containing Carbenes

Fluorinated carbenes are a well known and thorougly investigated class of reactive intermediates. Their stability decreases in the order :CF 2 > :CFRf > :C(Rf)2 and :CF 2

> :CC12 > :CBr 2 > :CI 2. Since :CC12 is an important reagent in synthetic chemistry and the comparability of CI/CF3S (7) has been demonstrated in many cases, the preparation and characterization of (CF3S)2C: became important to us.

Almost all reactions providing carbenes were carried out when the corresponding CT^S-substituted derivative was available. But only the photolysis of (CF3S)2C=C=0, either neat or in C5F6 solution, provided low yields of (CF3S)2C=C(SCF3)2, thus indicating the formation of (CF3S)2C: as an intermediate. In protic solvents or in the presence of olefins such as cyclohexene, formation of either (CF3S)2C=C(SCF3)2 or 2+1 cycloadducts could not be detected. The reactions that were carried out are summarized in Scheme 3.

An explanation of these contradictory observations was found by investigating the photolysis of (CF3S)2C=C=0 by esr and matrix isolation IR spectroscopic methods. Irradiating a solution of (CF3S)2C=C=0 in w-hexane treated with argon in a flow cell provided an esr spectrum consisting of a doublet of septets as shown in Figure 1. This spectrum is assigned to the (CF3S)2CH radical formed by intermediate formation of (CF3S)2C: in the triplet state, which then abstracts a hydrogen atom from the solvent. This secondary reaction is probably one reason why the carbene was not detected in earlier experiments. The following data for (CF3S)2CH were measured and compared with literature values.

7\K\ a(lHa)[G] a(I9Fy)[G] g-Factor 283 13.9 2.2 2.00516 253* 17.5* 2.75* -

*(2)

When the ketene is irradiated in an argon matrix at 10 Κ (λ = 230 nm) the formation of CO, CS 2 and C 2F6 can be detected in addition to the bands of the ketene. These results prove the great instability of the carbene (CF 3S) 2C: which decomposes to the final products CS 2 and C 2 F G according to Scheme 4. As far as carbenes are concerned, a decrease in stability is observed going from F to CF3 to CF 3S (3).

Fluorine-Containing Nitrenes

A similar situation is observed with nitrenes. Representatives such as FN: and CF3N: are reactive intermediates, but they do not reach the importance of carbenes. In the

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106 INORGANIC FLUORINE CHEMISTRY: TOWARD THE 21ST CENTURY

Table I. Aromatic Substituent Constants EN σ

Ρ am α ~ σ Ώ τ Steric

h K Effects F CF 3

CF3S

4.00 0.06 3.3 0.54 2.7 0.50

0.34 0.43 0.40

0.43 -0.34 0.14 -0.46 0.38 0.19 0.88 -2.40 0.35 0.18 1.44 -1.07

Aliphatic Substituent Constants Hydrophobicity τ Electronic Effect σ

F CF CF3S

-0.61 0.06

-0.74?

3.08 2.85

-2.5?

Carbenes Nitrenes

Ϋ CF 3

•o / F

CF 3

CF 3

F-N-

F 3C-N-

F3C-S-N- ^ CF3S£N|

Fs C

F3CS

CF 3

F3CS

F3CS x c -

F3CS

CFS-N- ^ FS=N|

C1S-N- ^ ClSaNl

Chalcogenated Carbenes and Nitrenes F 2 C=Q (F 3 C) 2 C=Q (F 3 CS) 2 C=0 FNO

F 2 C=S (F 3C) 2C=S (F 3CS) 2C=S F 3 CNO

F2C=Ss (F3C)2C=Ss (F3CS)2C=Se F 3 CSNO

F 2 C = T i (F 3C) 2C=Te (F3CSe)2C=Se

(F 3CS) 2C=T£ (F3CTe)2C=Te

CO- and SO-substituted Carbenes and Nitrenes F2C=C=Q F2C=S=0 FN=C=Q FN=S=U (F3C)2C=C=Q (F 3 o 2c=?=a F3C-N=C=Q F3C-N=5"=U (F3CS)2C=C=Q (F3CS)2C=S=Q F3CS-N=C=Q F3CS-N=S=Q

Scheme 1

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Incorporation of the Substituted Functional Groups or Molecules in the Periodic System

A: With X=F,CF3,CF3S) as a Ligand to Carbon and Nitrogen C Ν 0

X-C XN X 2 C

B: With Chalcogens as Ligands to Χ-Ν and X2Ç Group 16 Group 17 Group 18

(Chalcogens) (Halogens) (Noble Gas) XN ΧΝΟ X 2 C

x2co x2cs X2CSe X2CTe

C: With =C=0 and =S=0 ai i ligands to Χ-Ν and X2Ç · Χ-Ν- XN=C=0

XN=S=0

x2c- x2c=c=o X2C=S=0

Scheme 2

h v i(CF3S)2C:] (CF3S)2C=C=0 • [(CF3S)2C:] • (CF3S)2C=C(SCF3)2

SCF3

Scheme 3

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INORGANIC FLUORINE CHEMISTRY: TOWARD THE 21ST CENTURY

Scheme 4

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case of CF3SN one must consider a thiazyl molecular structure in addition to that of a nitrene

CF 3 SN- CF3S=N|

One would expect CF3S=N| to be the thermodynamically more stable structure. In the literature CF 3 SN (4) was mentioned as an unstable intermediate which oligomerizes to (CF3SN)x. It is formed according to Scheme 5.

Decomposition of CF3S(Cl)=NSi(CH3)3 in the presence of dienes such as butadiene, cyclopentadiene, hexachlorocyclopentadiene and tetraphenyl cyclopentadienone affords no addition products, thereby proving that decomposition of the starting material proceeds via inter- instead of intramolecular condensation. The other synthetic method, which is based on CF 3 SN 3 as an intermediate (see Scheme 5), should be more promising since CF 3 SN (and N 2 ) will be formed through an intramolecular process. In the presence of hexachlorocyclopentadiene a 1:1 addition product is formed in rather low yield. Single crystal X-ray structure analysis of this material shows that CF 3 SN reacts as a nitrene and not as a thiazyl, giving hexachloro-3-cyclopentenylidene amino-trifluormethylsulflde according to Figure 2. A possible reaction pathway is provided in Scheme 6. This result raises the question of how C1SN or FSN would interact with C5CI6. The reaction with C1SN produces the corresponding sulfenyl chloride as proven by the X-ray crystallography. An almost identical structure is observed as is shown in the ORTEP plot in Figure 3. Again C1SN reacts as a nitrene. Additional proof for the presence of an -SCI group is provided by treating the product with Hg(SCF 3) 2 and SbCl5 in S 0 2 (see Scheme 7).

The reaction of C5CI6 with FSN is more complicated since the first reaction product, a sulfenyl fluoride, is unstable and undergoes metathetical reactions with C5CI6 as shown in Scheme 8 (5). With perfluoro olefins, however, FSN reacts differently. The reaction products formed depend on both the reaction conditions and the nature of the olefin. A [4+2] cycloaddition reaction is observed between FSN and perfluorobutadiene (6); however, a [2+1] cycloaddition cannot be excluded, since the six-membered ring is postulated only on the basis of NMR data. A Cl/F exchange was achieved with (CH 3) 3SiCl (<5) or by treating CF2=CFCF=CF2 with (C1SN)3 at 22°C (7) according to Scheme 9.

A low temperature X-ray crystal structure analysis proved unambigously the six-membered ring structure shown in Figure 4. The S-Cl bond of the 1,2-thiazine is converted by NaF or KF in good yields to the fluorinated derivative leaving no doubt that in both cases a [4+2] cycloaddition takes place. The reactions studied so far, at least with C5CI6 as a reaction partner, strongly suggest that the XSN (X = CF 3 , Cl, F) compounds react not only as thiazyls but also as nitrenes. Obviously the mesomeric structures shown in Scheme 10 explain their reactivity (7).

One can conclude that perfluorinated nitrenes are unstable, reactive intermediates. However, a stability trend caused by the ligands F, CF 3 , CF 3S cannot be demonstrated.

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Scheme 6

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HAAS AND BROSIUS Influence of Fluorine & Parahalogen Substituents

Figure 3. Molecular structure of hexachloro-3-cyclopentenylidene amino-sulfenyl chloride.

CI 0 ] ^ À c \ CISN

CI

c ^ / ^ > - s c i

oyW\ CI

CL

cr

-SCI

Hg(SCFJ 9

CI-

ci-

ISSCF3 + HgCI2

II +

SO, SbCL — ^

CI CI CI CI

cr ci cr ci ci-

cf CI

Scheme 7

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5 6 > II + C . C L F 5 6-n η

Scheme 8

1 a b

X F CI

Scheme 9

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Fluorine-Containing Carbonyls, Thiocarbonyls, Selenocarbonyls and Tellurocarbonyls

Carbenes coordinated with a chalcogen ligand are transformed to electronically saturated compounds with a C=E group such as X 2C=E (E = O, S, Se, Te). In this series the hitherto unknown substance is X2C=Te.

The preparations of F2C=Se can be expressed with one reaction as shown in Scheme 11. It is necessary to synthesize first of all a material containing an element-SeCF3 group which decomposes on heating in vacuo to an element-fluorine moiety and F2C=Se (8-10). This strategy was also applied to the first synthesis of F2C=Te. The reaction between Hg(TeCF3)2 and (C^Hs^AlI proceeds at 20 °C/10"4 torr as shown in Scheme 12 and provides a deep violet-colored, thermally very unstable substance in about 10% yield. The product already dimerizes during removal of the liquid nitrogen Dewar to its dark red-colored cyclic dimer. Cocondensation with excess F2CSe gives for the first time an orange-colored four-membered ring with two different chalcogen heteroatoms. X-ray crystal structure analysis of the dimer proved the postulated ring. An ORTEP projection and selected parameters are provided in Figure 5 (77).

An additional two step route to F2C=Te — preparation of the tin derivative and its thermal decomposition — is shown in Scheme 13 (72). This method gives better yields, and it was possible to demonstrate that F2C=Te undergoes a [4+2] cycloaddition with e.g. dimethylhexadiene. For the first time it was also possible to obtain an IR-spectrum in the gas phase. In the region 4000 to 400 cm~l the bands observed are shown in Figure 6a. Upon expansion of the range 1300 to 1100 cm~l one clearly recognizes band contours. At about 1240 cm~l, v\ shows a PQR splitting with APR = 12.2 cm' 1, and V4 a PR branch at 1206.7 and 1195.4 cm - 1, respectively. These bands are in complete agreement with the ones observed for F2C=Se as shown in Figure 6b. The other four bands are either too weak to be observed or appear below 400 cm'l. The mass spectrum of F2C=Te, shown in Figure 7, exhibits M + with the correct isotopic pattern and the fragments FCTe+, Te+, and CF2+. In addition, the fragments C2F44" and C2F3+ are observed.

The cyclic dimer is a good starting material for further reactions. Halogen exchange with BCI3 or BBr3 gives tetrahalogenated 1,3-ditelluraetanes according to Scheme 14. These compounds are soluble in DMF with adduct formation, but are not soluble in other common solvents. With ASF5 in SO2, only Te4[AsF6]2 can be detected (73).

The synthesis of a C=Te double bond for the first time encouraged us to search for other molecules with such a group. Some of these might even be more stable. From what we know thus far the stability of C-chalcogen double bonds decreases from Ο to Te and from F to CF3, but increases when F or CF3 is replaced by CF3E (E = S, Se). So the chances of synthesizing molecules of the type (CF3E)2C=Te or probably even (CF3Te)2C=Te should be reasonable.

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X2C: \

X 2 C=E (E = O, S, Se, Te)

Preparation of F2C=Se:

M(SeCF 3 ) n > M F n + nF2C=Se

M=B, n=3 (8); M=(CH 3 ) 3Sn, n=l (9); M=(CH 3) 2A1, n=l (10)

Scheme 11

20 °C/10~4 Torr Hg(TeCF ) + 2 (C Η )_AII

Hgl 2 + 2 (C 2H 5) 2AIF + F 2 C=Te

deep violet

10% yield

Te

2 F 2 C = T e . F 2 c / \ F 2

Te

dark red

Se

F 2C=Te + F 2C=Se >- ^ C F 2

Té

orange

Scheme 12

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Figure 5. The crystal structure of tetrafluoro-l,3-ditelluraetane. Averagebond lengths (in Â over two independent molecules in the unit cell): C-F 1.359 (10), Te-C 2.191 (11); angles (°): C-Te-C 78.9 (4), Te-C-Te 101.2 (4), F-C-F 105.3 (10), Te-C-F 112.7 (5).

C F 3 T e T e C F 3 + 2 (CH 3 ) 3 SnH 2 ( C H 3 ) 3 S n T e C F 3 + H 2

75% yield

yellow liquid

280 °C ( C H 3 ) 3 S n T e C F 3 ^ F 2 C=Te + (CH 3 ) 3 SnF

10 Torr 60%

C H 2 = Ç — Ç = C H 2 + F 2 C=Te

C H 3 C H 3 n X ^ F

low yield

Scheme 13

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100η

g 90-ε

80-

1500 1000 Wavenumber/crrT

400

Figure 6a. IR gas phase spectrum of F2C=Te.

100

= 60

40

20

1300 1250 1200 1150 1100

Wavenumbers/cm-1

T e C F 2

1300 1250 1200

Wave numbers/cm-1

1150

S e C F 2

Figure 6b. Comparison of IR band contours of F2C=Te with F2C=Se.

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ο Γ"

Intensity (%) ο ο I Γ"

8

-si

en ο

ο

8

Ν) CO Ο

Ν)

Ο

ω ο

ω αϊ ο

00 ο

ω CD ο

ÀHÎ11N33 ™ΙΖ 3ΗΙ OHVMOI vUIISIPVaHO ΒΝΙΗΟίΓΜ 3INVOHONI 8X1

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ν τ V . a . v T V

X = CI, Br

Soluble only In (CH 3 ) 2 NC(0)H (DMF) forming complexes

Te X = CI, η = 0.5

/ X / V D M F X - e r . . - ,

Te

Te

;CF 2 + A s F 5

-70 C / S O „ Te„

Te

+ products

Scheme 14. Dow

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Fluorine-Containing Ketenes and Thioketenes

A ketene results when the carbonyl function becomes a ligand to a carbene. Dihalogenated and perfluoralkyl-substituted ketenes exhibit characteristic and peculiar chemical properties. The stability of dihalogenoketenes can tentatively be arranged as follows: F2C=C=0 > C12C=C=0 > Br2C=C=0 » FC1C=C=0, and similarly the other fluorine-containing ketenes show the following scale of stability:

(F3C)2C=C=0 » F5S(FS02)C=C=0 > RfS02[C2H5OC(0)]C=C=0 > CF3[CH3OC(0)]C=C=0 > F5S(H)C=C=0 > CF3(FS02)C=C=0 > CF3[FC(0)]C=C=0

» CF3(F)C=C=0

The normally electrophilic character of the ketene group is increased by introducing two electronegative groups, making both (CF3)2C=C=0 and F2C=C=0 stable and pronounced electrophiles. What is going to happen if the less electronegative CF 3S group becomes a substituent? Will (CF3S)2C=C=0 become less stable and more reactive? To answer these questions the molecule had to be synthesized. This was achieved by three routes following known literature procedures as given in Scheme 15.

The starting materials for reactions a) and b) are synthesized as shown in Scheme 16. (CF3S)2C=C=0 is a colorless liquid which is stable up to at least 100°C. When the compound is heated at 200°C in a Carius tube, dimerization takes place, giving two isomers according to Scheme 17. Both isomers were separated by preparative gas chromatography. Photolysis of (CF3S)2C=C=0 in CCI4 for 72 h gave (CF 3S) 2C=C(SCF 3) 2 and CO in low yields only. This reaction has already been mentioned. When the ketene or its acetal was treated with ozone, oxidation took place according to Scheme 18 (14).

Attempts to prepare (CF3S)2C=C=S by treating (CF3S)2C=C=0 or its precursors with P4S10 in toluene at 145°C yielded ring compounds shown in Scheme 19(75).

Fluorine-Containing Sulfines, Isocyanates, and SulFinylamines

When =S=0 becomes a ligand to X 2 C , sulfines (thiocarbonyl-S-oxides) are formed. Their stability increases in the order F < CF 3 < CF 3Sj that means F2C—S—Ο is less stable than (CF3)2C=S=0 and (CF3S)2C=S=0. Stability and reactivity of perfluorinated ketenes and sulfines compare rather well. With CO as a ligand to XN, isocyanates are obtained. Their chemistry and stability is well known and shows that CF 3SNCO is more stable than CF 3NCO and FNCO (76).

Similarly, with S=0 as a ligand to XN, compounds of the type XNSO are obtained. Again the reactivity of FNSO (77-79) is higher than the reactivity of F 3CNSO (20-22) and F3CSNSO (23). In agreement with these facts, the reactions of F 3CNSO or FNSO with water gave no stable intermediates which could be isolated or fully characterized. Therefore hydrolysis of F3CSNSO was studied in detail to elucidate whether stable products result.

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P 4 Oio/80-100°C a) (CF 3S) 2CHC(0)OH (60-65 % )

CCI4

140°C b) (CF3S)2CHC(0)C1 > (CF 3S)2C=C=0 (46%)

CaO/Na2S04

-40°C/CCl4 c) Ag 2 C=C=0 + 2CF3SC1 > (50%)

-2AgCl

Scheme 15

CF 3 SCy20°C CH 2[C(0)OC 2H 5] 2+Na(K)—> (K)NaCH[C(0)OC 2H 5] 2 >

ether (12 h)

CF3SC1

CF 3SCH[C(0)OC 2H 5] 2+Na(K)—> (K)NaCF 3SCH[C(0)OC 2H 5] 2 >

62% HBr/reflux (CF 3 S) 2 C[C(0)OC 2 H 5 ] 2 > (CF 3S) 2CHCOOH (70%)

(85%) -(C0 2+C 2H4)

-60 to 20°C 62% HBr CH 3 C(OC 2 H 5 ) 3 +2CF 3 SCl > (CF 3 S) 2 CHC(OC 2 H 5 ) 3 >

ether (90%) reflux (CF 3S) 2CHC(0)OH (70%)

reflux (CF 3S) 2CHC(0)OH+S0C1 2 > (CF3S)2CHC(0)C1

3 to 5 h (90%)

Scheme 16

CF S S C F 3 W 3

>200 ° C y / \ C F 3 S ^ (CF3S)2C=C=0 —>- o=< >=o +

C F 3 S

CF3S^ B C F 3 CF 3 S SCF 3

Separation by gas chromotography [parameters:

3.0 m (i.d. = 6 mm) OV 101 10% on Chromosorb Ρ AW

45 - 60 mesh, 95 C, He flow: 80 mL/min

Scheme 17

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INORGANIC FLUORINE CHEMISTRY: TOWARD THE 21ST CENTURY

0°C/CCl4 (CF3S)2C=C=X + O3 > (CF3S)2C=0 + OC=X

X = O, (OC 2H 5) 2

Scheme 18

CH(SCF3)2COCI

CH(SCF 3) 2C0 2H

(CF 3S) 2CCO

F 3 CS

F 3 CS

F 3CS

F 3CS

P s 4 J 1 0

toluene, Δ Τ

SCF„

SCF„

S—S S C F 3

Scheme 19

(CF3S)2C=C=S

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Hydrolysis of F3CSNSO yielded colorless crystals which were characterized as the first representative of a perfluoroorganothiosulfonate RfSS02OR. In a stoichiometric reaction carried out in a sealed Carius tube, one mole of F3CSNSO reacted with two moles of water to form ammonium trifluoromethylthiosulfonate as the sole product, according to

Closed System: CF3SNSO + 2 H 2 0 > F3CSSO3NH4

The ammonium salt melts at 195°C and can be stored in a dry atmosphere for a few days at room temperature without decomposition. When the hydrolysis was carried out in an open system, the corresponding amine F3CSNH2 and sulfur dioxide were detected.

Open System: CF3SNSO + H 2 0 > F 3 CSNH 2 + S 0 2

In addition to the measurement of the 1 4 N - , 1 9 F- , 1 3 C - , 1 7 0-NMR (Table II), IR, and Raman spectra, which agree very well with the nature of the compound, CF3SSO3NH4 was also treated with a stoichiometric amount of chlorine. The expected cleavage of the characteristic sulphur-sulphur bond provided further evidence for the proposed thiosulfonate molecular structure, in full agreement with the behavior of the corresponding organothiosulfonates (24). Stoichiometric amounts of

F3CSSO3NH4 + C l 2 —> F3CSCI + CISO3NH4

the well known products were isolated and their identities confirmed by spectroscopic investigations and elemental analyses.

An alternative route to trifluoromethylthiosulfonate is the reaction between ammonium chlorosulfonate and Hg(SCF3)2 in acetonitrile according to

Hg(SCF 3) 2 + 2 CISO3M > M[CF 3SS0 3] + HgCl 2

M = NH4, Na,K

Separation of the salt-like compounds from HgCl 2 was laborious, as both products are soluble in polar solvents. However, covalent derivatives of the type F3CSS0 2R were prepared by reacting the mercurial with covalent derivatives of chlorosulfonic acid. These reactions were carried out in CCI4, a solvent in which the reactants and products, except HgCl 2, are soluble.

Hg(SCF 3) 2 + 2 C1S02R —> HgCl 2 + 2 F 3 CSS0 2 R R = N(CH 3 ) 2 , OSi(CH 3) 3

Thus, the N,N-dimethylamino and trimethylsiloxy derivatives of trifluoro-methylthiosulfonic acid were prepared and characterized by spectroscopic methods (Table II). The 2 9 Si-NMR shift of the trimethylsilylester allowed us to estimate the acidity of the corresponding acid by a known correlation (25) of 5(^9Si)-values of the various trimethylsilylesters with the acidity of their parent acids. The acidity of

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Tab

le Π

. NM

R s

pect

ra (s

olve

nt)

of T

riflu

orom

ethy

lthio

sulfo

nate

s F

3CSS

03N

H4

F3C

SS0 3

SiM

e 3

F3C

SSO

jH

F3C

SS0 2

N(C

H3) 2

Ή

δ =

5.9

(1:1

:1 t)

δ

= 0

.48(

s)

δ =

9.9

2(s)

δ

= 2

.99(

s)

stand

ard:

TM

S (D

3CC

N)

(CC

I4/C

DC

I3)

(CD

C1 3

) (C

DC

1 3)

^H

-^N

) =

51

Hz

14N

δ

= 3

52.6

(qui

ntet

t)

...

—

...

stand

ard:

H3C

NO

2 (D

3CC

N)

1J(1

4N-!H

) =

51

Hz

13C

δ

=127

.7(q

) Ô

(F3C

) =

127

.12(

q)

δ =

126

.95(

s)

Ô(C

F 3)

= 1

28.2

1(q)

sta

ndar

d: T

MS

(D3C

CN

) 1J(

13C

-19F

)=31

2.8H

z (C

DC

1 3)

^(^

C-^

F)

= 3

12.9

Hz

1J

(13C

-19F

)= 3

10.7

Hz

δ =

0.0

81(m

) 1 Ι

(13ο

.19ρ

) =

Ô

(CH

3) =

38.

49(q

) 1J(

13c-

1H) =

121

.43

Hz

312.

4 H

z ^

(^C

^H

) =

141

.1 H

z (C

DC

I3)

(DC

CI3

)

170

δ =

239

. l(s

) ô(

S=0)

= 4

08(s

) δ

= 2

09

δ =

203

.7(s

) sta

ndar

d: H

2O

(D3C

CN

) (C

DC

I3)

(D3C

CN

/ext

.) (D

CC

I3)

stand

ard:

H2O

ω

= 7

0 H

z ω

= 1

00 H

z ô(

S-O

-Si)

= 3

68(s

) ω

= 2

00 H

z 19

F

δ =

-38.

5(s)

δ

= -3

9.9(

s)

δ =

-39.

0(s)

δ

= -3

7.7(

s)

stand

ard:

FC

CI3

(D

3CC

N)

(D3C

CN

) (C

Cl4

/CD

Cl 3)

(D

CC

I3)

...

δ =

41.

9(m

) ..

. —

29

Si

(CD

CI3

)

stand

ard:

TM

S 2J(

29S

i-lH

) =

6.9

7 H

z

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trifluoromethylthiosulfonic acid is extrapolated to be similar to the acidities of trifluoromethylsulfonic and perchloric acid.

It is known that HSSO2OH is only the first member of a homologous series of polysulfane monosulfonic acids which can be generated by the reaction of H2SX with SO3, whereas CF3SSO3H should be the first member of a second homologous series as shown below:

HSS0 2OH, HSSS0 2OH, HSSSS02OH, HS x S0 2 OH CF3SSO2OH, C F 3 S S S 0 2 O H , C F 3 S x S 0 2 O H

In analogy to the insertion of SO3 into the S-H bond of H2S with formation of HSSO2OH (26), CF3SH reacts with SO3 forming a colorless liquid which was characterised (Table Π) as trifluoromethylthiosulfonic acid according to

CF3SH + SO3 —-> CF 3 SS0 2 OH

The free acid is extemely sensitive and decomposes at room temperature to F2C=S and fluorosulfonic acid.

It is noteworthy that all of the l^F-NMR resonances of the trifluoromethyl-thiosulfonates F3CS-SO2R are in a narrow region of -38.5 ± 1.5 ppm, without great influence from the inductive effect of different substituents R. It is possible to assign the characteristic, but coupled, S-S stretching frequencies in this type of compound by comparing the IR and Raman data (Table TV). The frequencies are very similar in the region of around 430 wavenumbers, and the S-S stretching vibration appears as a strong peak in the Raman and a weak peak in the infrared spectra.

Due to the oxidizing nature of SO3 and the reducing properties of CF3SSH, the second member of the homologous series F3CSXS020H, where χ = 2, cannot be obtained via insertion because side reactions are dominant. An alternative route to the first derivative of F3CSSSO2OH is hydrolysis of CF3SSNSO obtained from CF3SSCI and (CH3)3SiNSO (27). In analogy to the reaction of CF3SNSO, CF3SSNSO reacts stoichiometrically with two moles of water, forming the ammonium salt of trifluoromethylsulfenylthiosulfonic acid as the sole product with the characteristic NMR data as shown in Table IH. It may be possible to convert this salt to other ionic

F3CSSNSO + 2 H 2 0 —> F3CSSSO3NH4

and covalent derivatives of F3CSSSO2OH providing a new and interesting chemistry.

Conclusions

It has been shown that one can successfully plan and carry out syntheses by incorporating either fluorine or parahalogen substituent groups in the chemistry of certain functional groups including carbenes, nitrenes, carbonyls, thiocarbonyls, selenocarbonyls, tellurocarbonyls, ketenes, thioketenes, sulfines, isocyanates, and sulfinylamines. In certain cases a decrease in stability is observed upon going from F to CF3 and CF3S, while in other cases the instability of all derivatives precludes a

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Table ΠΙ. NMR spectra (solvent) of F3CSSSO3NH4 1H; 19P; 13C; 17q; standard: TMS standard: FCCI3 standard: TMS standard:

(D3CCN) (D3CCN) H3CN02

(D3CCN) 6=6.0(1:1:1 t) 5=-45.2(s) ô=130.21(q) ô=222.1(s)

Table IV. Assignments of S-S vibrations compound wa velength/cm'l F3CSSO3NH4 434 F3CSS03SiMe3 432 F3CSSO3H 430 F3CSS02N(CH3)2 430 F3CSSSO3NH4 381

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trend from being established. The chemistry describe herein will hopefully encourage the search for other molecules via the element displacement principle.

Acknowledgment

Dedicated to Prof. Jean'ne M. Shreeve on the occasion of her 60th birthday.

Literature Cited

(1) Haas, A. Pure Appl. Chem. 1991, 63, 1577. (2) Schlosser, K. J. Mol. Struct. 1982, 95, 221. (3) Dorra, M.; Haas, Α., J. Fluorine Chem., in press; Dorra, M. PhD

-Thesis, Ruhr-Universität Bochum 1992. (4) Bielefeld, D.; Haas, A. Chem. Ber. 1982, 116, 1257. (5) Haas, Α.; Mischo, Th. Can. J. Chem. 1989, 67, 1902. (6) Bludβuβ, W.; Mews, R. J. Chem. Soc., Chem. Commun. 1979, 35. (7) Boese, R.; Haas, Α.; Heβ, Th. Chem. Ber. 1992, 125, 581. (8) Haas, Α.; Koch, B.; Welcman, Ν. Ζ. Anorg. Allg. Chem. 1976, 427,

114. (9) Grobe, J.; Le Van, D.; Welzel, J. J. Organomet. Chem. 1988, 3, 153;

and references therein. (10) Darmady, Α.; Haas, Α.; Koch, Β. Z. Naturforsch. 1980, B35, 526. (11) Haas, Α.; Limberg, Ch. J. Chem. Soc., Chem. Commun. 1991, 1378. (12) Haas, Α.; Limberg, Ch. Chimia 1992, 46, 78. (13) Haas, Α.; Limberg, Ch., J. Chem. Soc., Dalton Trans., in press;

Limberg, Ch. PhD-Thesis, Ruhr-Universität Bochum 1992. (14) Haas, Α.; Praas, H.-W. Chem. Ber. 1992, 125, 571. (15) Haas, Α.; Praas, H.-W. J. Fluorine Chem., in press. (16) Haas, A. New Pathways in Inorganic Chemistry, Cambridge

University Press 1968, 87. (17) Veerbeck, W.; Sundermeyer, W. Angew. Chem. 1969, 81, 331. (18) Nachbaur, E.; Kosmus, W.; Krannich, H.; Sundermeyer, W.

Monatsh. Chem. 1978, 109, 1211. (19) Eysel, Η. H. J. Mol. Struct. 1970, 5, 275. (20) Lustig, M. Inorg. Chem. 1966, 5, 1317. (21) Leidinger, W.; Sundermeyer, W. Chem. Ber. 1982, 115, 2892. (22) De Marco, R. Α.; Shreeve, J. M. J. Fluorine Chem. 1971, 1, 269. (23) Haas, Α.; Schott, P. Chem. Ber. 1968, 101, 3407. (24) Bunte, H. Ber. Dtsch. Chem. Ges. 1874, 7, 646. (25) Marsmann, H. G.; Horn, H. G. Ζ. Naturforsch. 1972, 27, 1448. (26) Schmidt, M.; Bauer, Α.; Rampf, H. Angew. Chem. 1958, 70, 399. (27) Brosius, Α.; Haas, A. Chem. Ber., in press. RECEIVED November 25, 1993

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