Reaction of tetrasulphur tetranitride with chlorine

INORG.

NUCL.

CHEM.

LETTERS

Vol. 6,

PP.

429-433,

1970.

REACTION OF TETRASULPHURTETRANITRIDE

Pergamon

Press.

Printed in Great Britain.

WITH CHLORINE

Jane Nelson and Henry G. Heal Department of Chemistry, Queen's University of Belfast, Northern Ireland ~ e c e i v e d 6 February I ~ 0 )

When chlorine is passed into a suspension of tetrasulphur tetranitride, tri-(thiazylchloride),

(NSCI)3, eventually crystallises out (1,2).

The

contraction from an eight-membered to a six-membered S-N ring in this reaction is surprising, especially as mild fluorination of the tetranitride gives not (NSF) 3 but (NSF) 4 (3).

We now report infrared evidence of a

moderately stable intermediate in the chlorination process, probably (NSCI)4; and we find that most of the (NSCI) 3 end-product is formed directly from this intermediate and not, as has previously been suggested (4) ~rom a monomeric NSCI intermediate. The main features of our results on the chlorination in carbon disulphide solution at about 30 ° can be explained by the following reaction sequence: [i]

84N4 + 2C12

[23

"A"

[3]

3NSCl

~minutes> intermediate "A", probably (NSCI) 4.

-hours ~ (NSCI) 3 + NSCI -days

, CNSCl) 3

Reaction [i] was marked by disappearance of the infrared bands of S4N 4 and simultaneous growth of those of the intermediate"A"

(see Figure and'

Table i). It was nearly complete in a few minutes.

Two moles of chlorine were needed

to convert one mole of S4N 4 to "A", which indicates the formula (NSCI)x for "A".

On this evidence x might be 2 or 4, but could not be I or 3, because

the spectrum of "A" differs from the known spectra of NSCI and (NSCI)3.

429

TETRASULPHUR TETRANITRIDE WITH CHLORINE

SolventCS2

0.4

Tcmp3 0 °

Vol. 6, No. 4

Initial molarlties

s, N, O.0263 CI2

0"0526

"A"

0-3

"i 0-2 0.1 /

~

1322era-, N S CI ..~--......~

0

2

4

I 6

I

i

I

8

IO

12

~I 14

698 cm-'

I

I

I

I

I

16

18

20

22

24

i,

~ ..

26

28

30

TImG since mixing (mln)

TABLE

i

Infrared Bands~ cm -I (solutions in carbon disulphide) S4N 4 NSCI

940m

698s

550m

1322m

(NSCI) 3

lO14s

70Ow

513ms

Intermediate "A" P

I083m

983w

956s

548w

464m

probably (NSCl)4

Starting with solutions containing 2 moles chlorine to I mole $4N4, the S4N 4 disappeared with a reactionorder

of about 1.5 (Table 2).

Reaction

[i] is probably a multistage radical chain process and kinetically complicated. Reaction [2] was much slower, being nearly complete in a day.

It was mani-

fested by the simultaneous growth of the bands of NSCI and (NSCI) 3 (Figure), while the spectrum of "A" faded away with first-order kinetics.

(Table 3).

Vol. 6, No. 4

TETRASULPHUR TETRANITRIDE WITH CHLORINE

TABLE

431

2

Rate Constants for Disappearance of S4N 4 in Reaction LI] (four runs:

S4N 4 concentrations from optical density at 698 cm-I)

T°C

Initial [$4N4] mole

k(l~ order) mole _i~ 1½ rnin-I

34

0,00658

0.42

30

0.00965

0.46

34

0.0132

0.38

34

0.00405

0.48

-i

TABLE

3

Rate Constants for Disappearance of Intermediate "A" in Reaction [~2] (two runs:

concentrations of "A" from optical density at 956 cm -I) Time interval (min from mixing S4N 4 with C12)

k(first order) min-i

/26 - 36

0.0215

32°C, initial [S4N 4]

36 - 46

0.0247

0.026 mole 1-I

46 - 56

0.0255

50-

60

0.0255

12 - 22

0.0166

I

29°C, initial [84N4] 0.039 mole I-I

22

3~

0.0166

32

42

0.0166

42

52

0.0166

This order is consistent with (NSCI) 4

- (NSCI) 3

+

NSCI

~(NSCI) 3

÷

NSCI

but seems to rule out 2(NSCI) 2

We therefore believe that "A" is (NSCI) 4. Reaction [3] revealed itself by a still slower decline of the NSCI band at 1322 cm

-I

, which had not disappeared after a week at room temperature.

At

432

TETRA~.JL,PHUR TETRANITRIDE WITH CHLORINE

Vol. 6, No. 4

the same time, the (NSCl) 3 bands intensified. These results point to formation of the previously unknown (NSCI) 4 as the first reasonably stable chlorination product of $4N4;

it lasts for hours

at room temperature and might be crystallised out by strong cooling. quarters of the end-product mixing;

Three-

(NSCI) 3 form slowly during the first day after

this explains why "standing for 20 hr" (I) is necessary~in the

preparation of (NSCI)3, and why yields do not exceed 65% (2).

It is not

difficult to imagine the (NSCI) 4 ring eliminating one NSCI unit through a twisted or puckered transition state.

Experimental Carbon disulphide was freshly distilled from phosphorus pentoxide. Tetrasulphur tetranitride was made by a published method (5). added in the form of fresh, iodimetrically-standardised gas in CS 2.

Chlorine was

solutions of the dry

Spectra were taken with a Perkin-Elmer Model 457 infrared

instrument, using 0.2 m

or i m

solution cells.

All kinetic runs were

done with non-leaking sodium chloride cells, the wavelength scan being set at band maximum and the optical density mechanically recorded over a period. The temperature in the cell-compartm~nt remained within I ° of the stated value during any run. The infrared spectrum of S4N 4 has been published was obtained from an authentic sample. the gas phase (7) but not for solutions;

(6).

That of (NSCI) 3

That of NSCI has been published for we have attributed our single solution

peak at 1322 cm -I to NSCI because it coincides with the origin of the vibrationrotation band in the gas phase.

The other peaks in the gas spectrum of NSCI

(bracketed in Table i) were obliterated in our work by solvent absorptions.

Acknowled~nents We are grateful to Prof. O. Glemser, and Drs. A. Banister and M.G. Burnett, for helpful discussions and correspondence, for a grant to J.N.

and to the Science Research Council

Vol. 6, No. 4

TET~LPHUR

TETRANITRIDE WITH CHLORINE

433

References i

i. M. C~EHRING, Ergebnisse und Probleme der Chemie der Schwefelstickstoffver bindugen p. 155. Akademie-Verlag, Berlin (1957). 2.

H. SC}{ROEDER and O. GLEMSER, Z. Anorg. AIJqem. Chem., 298, 78 (1959).

3. O. GLEMSER, H. SCHROEDER and H. HAESELER, Z. Anorg. Allgem. Chem., 279, 28(1955). 4. M. BECKE-GOEHRING and E. FLUCK, Developments in Inorganic Nitrogen Chemistry, vol. i, p. 194. Elsevier, Amsterdam (1966). 5.

M. VILLENA-BLANCO and W.L. JOLLY, Inorg. Syn., 9, 98 (1967).

6. H.G. HEAL, Inorganic Sulphur Chemistry, ed. by G. NICKLESS, p. 464. Elsevier, Amsterdam (1968). 7. O. GLEMSER and H. RICHERT, Z. Anorg. Allgem. Chem. 307, 313 (1961); A. MULLER, G. NAGARAJAN, S.F. CYVIN and J. WEGENER, Speetrochim. Acta 23A, 2683 (1967).