Synthesis of New Heterocycles by Halogenation

of Tetrasulfur Tetranitride S4N4*

Y. MONTEIL and H. VINCENT Universite Claude Bernard, Lyon I, Laboratoire de Physico-Chimie minerale, Associe au C.N.R.S. N° 116, Service du Pr. Cueilleron, 43, Bd. du 11 novembre 1918, 69621 Villeurbanne, France

(Z. Naturforsch. 31 b, 673-676 [1976]: received October 7, 1975)

Inorganic Heterocycles, Thiazyl Compounds, Tetrasulfur Tetranitride Reactions, P-S-N Compounds

Bromine reacts with tetrasulfur tetranitride S4N4 in solution in different solvents to give thiodithiazyl dibromide S3N2Br2. Iodine reacts under the same conditions with S4N4 to give trithiazyl iodide (SN)3l. The addition of chlorine, bromine or iodine to a mixture of tetrasulfur tetranitride and

white phosphorus leads to compounds with the general formula P2S3NsXw, with n — 1 or 3 depending on the nature of X.

Introduction Moreover, we obtained also new combinations The thiazyl SN radical, the analogue of nitric containing the pattern P2S3N3 by reaction of oxide NO, polymerizes easily owing to the halogens on a mixture of white phosphorus with d-orbitals. The better known of these polymers, tetrasulfur tetranitride. tetrasulfur tetranitride S4N4 can give SN radicals in the course of reactions, but it is at present impos- A. Starting Compounds sible to predict how and where SN bond rupture Very pure compounds are required to study the occurs during a given reaction. reaction of the halogens with tetrasulfur tetranitride. The S4N4 structure is known1. This heterocycle We have been obliged to synthetize some thiazyl can lead to other cycles with very different shapes. chlorides which have been used either as reference Examples are the structures of the compounds or as starting materials for the bromination and 3 4 2 5 iodination reactions. S4N4F4 , S3N3CI3 , S3N2CI2 , S4N3NO3 , S5N5A1C14 e and S6N4X2 7. A.l. Tetrasulfur tetranitride S4N4 The large variety of the compounds produced Numerous authors studied the preparation of from S4N4 shows that it is a good starting material S4N4. We used the method which has been perfected for the synthesis of new combinations. by BECKE-GOEHRING and revised by VILLENA- The action of fluorine on S4N4 leads to the BLANCO and JOLLY14. In this method S4N4 is compound S4N4F48. The chlorination reaction obtained by ammonolysis of yields S3N3CI39, via the intermediate step of according to the overall reaction: S4N4CI410. We studied the bromination and the iodination of S4N4. While the bromination of S4N4 6 S2CI2 + 16 NH3 S4N4 + 12 NH4C1 + 8 S. has been studied by several workers11-13, it is the S4N4 is little sensitive to moisture. Consequently, first time that the iodination reaction is reported. it is easy to remove ammonium chloride by water treatment of the product at 0 °C. On the other hand, the separation from sulfur is much more delicate * Paper, presented at the 1. International Symposium on Inorganic Heterocycles, Besan^on (France), June because it is soluble in the same solvents as S4N4. 16-19, 1975. After several recrystallisations of the S-S4N4 mix- ture from dioxane and benzene, it is possible to Requests for reprints should be sent to Prof. Dr. Y. MONTEIL, Universite Claude Bernard Lyon I, Lab. obtain a product enriched in S4N4. This is then de Physico-Chimie Minerale I, Associe au C.N.R.S., chromatographed on a column of acid alumina to Service du Pr. Cueilleron, 43, Boulevard du II No- 15 vembre 1918, F-69621 Villeurbanne, France. exclude the residual sulfur .

Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung This work has been digitalized and published in 2013 by Verlag Zeitschrift in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der für Naturforschung in cooperation with the Max Planck Society for the Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Advancement of Science under a Creative Commons Attribution Creative Commons Namensnennung 4.0 Lizenz. 4.0 International License. 674 Y. MONTEIL-H. VINCENT • SYNTHESIS OF NEW HETEROCYCLES

IR (KBr pellet) absorptions occurred (cm-1) at: IR (CsBr pellet) absorptions occurred (cm-1) at: 925 s, 800 w, 768 w, 760 w, 728 s, 698 vs, 620 m, 1160 vs, 1125 m, 998 vs, 682 s, 608 m, 565 s, 465 vs, 550 vs, 528 m, 519 w. 450 s, 325 s. Powder diffraction data (copper radiation) at: Powder diffraction data (copper radiation) at: 6.33 m, 6.04 m, 4.75 vs, 4.60 vs, 4.37 m, 3.11m, 5.31 s, 4.56 m, 4.06 s, 3.21 m, 3.06 vs, 2.93 m, 2.78 s Ä. 2.71 s, 2.56 ml.

A.2. Thiodithiazyl dichloride S3N2CI2 A 5. Thiotrithiazyl bromide SiN3Br Thiazyl chlorides can be prepared from tetra- The ionic character of the thiotrithiazyl chloride

sulfur tetranitride9. Ammonium chloride and di- and the stability of the S4N3+ ion enables the are the preferred starting materials. bromide to be obtained by methatesis with potas- They react easily according to the scheme17: sium bromide17:

2 NH4CI + 4 S2CI2 -> S3N2CI2 + 8 HCl + 5 S. S4N3+C1- + K+Br- -> S4N3Br + K+Cl-. The reaction is carried out in presence of sulfur The reaction has been carried out either in water at to restrict the disproportionation of disulfur di- 0 °C or in formic acid. The thiotrithiazyl bromide chloride in sulfur dichloride SCI2. The compound precipitates from the solution: S3N2CI2 segregates easily from the reaction mixture IR (CsBr pellet) absorptions occurred (cm-1) at: by sublimation. Since it is easily obtained, it is used 1155 s, 992 vs, 670 m, 558 m, 462 vs, 315 s. as a starting material for the preparation of the Powder diffraction data (copper radiation) at: 5.41 s, 5.23 s, 4.79 s, 4.24 m, 4.08 s, 3.45 m, 3.17 m, thiazyl chlorides S4N3CI and S3N3CI3 instead of 3.10 vs, 2.96 m, 2.75 s, 2.64 s, 2.60 m Ä. S4N4 17.

IR (nujol mull) absorptions occurred (cm-1) at: B. Study of the Bromination of S4N4 1015 m, 940 s, 582 m, 548 w, 460 w, 398 w. The first study11 on the bromination of tetra- Powder diffraction data (copper radiation) at: 4.57 vs, 4.28 m, 4.07 s, 3.73 m, 3.42 m, 3.34 m, sulfur tetranitride reported the formation of 2.70 s, 2.68 vs, 2.60 s, 2.51 m, 2.27 m Ä. (SNBr)^. More recently, HEAL12 and ZBORILOVA13 concluded that a mixture of products is formed with A.3. Trithiazyl trichloride S3N3CI3 a composition close to the formula S3N2Br2- Trithiazyl trichloride is obtained by chlorination We studied the reaction between S4N4 and of thiodithiazyl dichloride: bromine in carbon or carbon tetrachloride.

3 S3N2CI2 + Cl2 -> 2 S3N3CI3 + 3 SC12. It is very important to use moisture free conditions, i.e. strictly anhydrous solvents. Moreover, tetra- It can be separated from S3N2CI2 due to its solubility sulfur tetranitride must be free from sulfur. All in carbon tetrachloride and benzene. The compound manipulations must be carried out in an inert S3N3CI3 is very sensitive to moisture and must atmosphere and the reaction products are therefore therefore be handled in a glove-box. handled in a glove-box. The reaction between S4N4 IR (CS2 or CCI4 solution) absorption occurred and bromine has been studied at different tem- (cm-1) at: 1017 vs, 701s, 621 w, 514 s, 390 m, peratures. 260 w. Powder diffraction data (copper radiation) at: 5.56 s, 5.40 s, 4.08 s, 3.15 vs, 3.11 m, 3.06 m, 2.90 s, B.l. Preparations of SsN^Brz 2.64 vs, 1.90 m, 1.79 m, 1.61 m, 1.52 m Ä. A solution of S4N4 and bromine in CS2 is refluxed for one hour. The precipitate found is thiodithiazyl A.4. Thiotrithiazyl chloride S4N3CI dibromide. This new compound is a yellow-orange Thiotrithiazyl chloride is obtained by reaction coloured crystalline product. between thiodithiazyl dichloride and disulfur di- S2N2Br2 has been obtained also by brominating chloride : S2N2CI2 with HBr. The solid-gas phase reaction 3 S3N2CI2 + S2CI2 -> 2 S4N3CI + 3 SC12. proceeds according to the equation: The compound is ionic, S4N3+C1-, and the struc- S3N2CI2 + 2 HBr -> S3N2Br2 + 2 HCl. ture of the S4N3+ ion has been determined using a The formation of HCl is evidenced by IR ab- single crystal of thiotrithiazyl nitrate5. Further sorption spectroscopy. Yet, the product is less pure data are: than the SßNoBro obtained by bromination of S4N4. 675 Y. MONTEIL-H. VINCENT • SYNTHESIS OF NEW HETEROCYCLES

Experimental B.3. Transformation of SsN%Br2 into S^NsBr

A 250 ml flask was equipped a reflux condenser Thiotrithiazyl bromide S4N3Br has been found and the top of the condenser was fitted with a as an impurity in thiodithiazyl dibromide in the drying tube filled with calcium chloride. The bromination of S4N4. It can result either from the reaction temperature was controlled with an electric heating mantle. hydrolysis of S3N2Br2 or from the presence of sulfur The reaction flask was charged with 200 ml of CS2 formed in the reaction of bromine on S4N4. The or CCI4 dried with molecular sieves, and 1.84 g thermal decomposition of SsN2Br2 leads likewise to (0.01 mol) of S4N4 recrystallised in CßHe just prior the formation of S4N3Br. to use. After dissolution of S4N4, 3 ml of Br2 was SsN2Br2 is very sensible to moisture. It decom- added. The reaction mixture was allowed to reflux for two hours. Then the SsN2Br2 was collected by poses in the atmosphere giving mainly thiotri- filtration in a glove-box, desiccated with P2O5, and thiazyl bromide and ammonium bromide. subsenquently washed with dry CS2 • S3N2Br2 was The same thiotrithiazyl bromide has been found dried in vacuo. as an impurity in SsN2Br2 when bromine reacts Analysis for S3N2.Br 2, with a sulfur containing sample of S4N4. In this Calcd S 33.80 N 9.86 Br 56.34, case, bromine reacts both with S4N4 and S, the Found S 34.1 N 9.94 Br 56.4. latter forming disulfur dibromide. The formation of S4NsBr can then be explained by the reaction of Bromine is titrated by potentiometry, nitrogen S2Br2 with S3N2Br2. In the same way, S2C12 trans- by the Kjeldahl's method and sulfur as barium forms S3N2C12 into 1«. S4N3Br and S3N2Br2 mlfate. S4N3CI IR (CsBr pellet) absorptions occurred (cm-1) at: are separated by selective dissolution of S4NsBr in 1160 s, 1010 vs, 1000 s, 675 m, 562 m, 470 vs, 320 s. liquid S0213. Powder diffraction data (copper radiation) at: At 90 °C and 10-1 torr, S3N2Br2 decomposes 5.14 m, 4.84 m, 4.52 m, 3.89 m, 3.48 vs, 3.30 s, according to: 3.09 m, 2.85 m, 2.51 m, 2.42 w A. 6 S3N2Br2 -> 4 S4N3Br + S2Br2 + 3 Br2. B.2. Study of the reaction of bromination of S4N4 C. Study of the Iodination of S4N4 We will recall that chlorine and fluorine react The reaction between iodine and S4N4 has been vvith S4N4 to give S3N3CI3 and S4N4F4, and the studied in an inert solvent at different temperatures. compound S4N4CI4 is obtained as an intermediate. In any case, a precipitate is formed which cor- On an other hand, bromine does not lead to sym- responds to the formula (SN)3l. netrical compounds such as S4N4Br4 or SsNsBrs The iodination of S4N4: but yields SsN2Br2 instead. In order to obtain information on the possible 2 S4N4 + 2 I2 4 (SN)sI existence of the compound S3N3Br3, S3N3CI3 was is slow at room temperature but is appreciably reated with HBr. The reaction takes place with accelerated when carried out in boiling solvents.

EtCl and Br2 evolution. The yellow S3N3Cl3 turns Experiments in progress show that hydrogen ed rapidly to finally give a yellow-orange coloured iodide displaces the chlorine atoms from the thio- product. The X-ray diagram of this latter product dithiazyl dichloride. The new compound (SN^I s analogous to S3N2Br2. This result can be explained which is sensible to moisture is dark red. Its X-ray oy the formation of SsNsBrs as an intermediate diagram is that of a nearly amorphous compound. compound with decomposes at once in SsN2Br2. Analysis for (SN In boiling CS2 (or CCI4) S3N2Br2 is obtained in a Calcd S 36.22 N 15.85 147.92. Dure state; at room temperature, the bromination Found S 35.5 N 15.9 147.8. >f S4N4 leads to a mixture of products: SsN2Br2 is IR (Csl pellet) absorptions occurred (cm-1) at: >btained admixed with another compound, the 962 vs, 755 s, 665 w, 638 m, 590 w, 465 w, 425 m Ä. iementary analysis of which corresponds to the

ormula (SN^Br. S3N2Br2 is separated from (SN^Br D. Study of the Halogenation

)y dissolving the latter selectively in liquid S02. of the Mixture S4N4-White Phosphorus The compound (SN^Br is orange coloured and The halogens (chlorine, bromine and iodine) react •rystallized. with a mixture of white phosphorus and tetrasulfur 676 Y. MONTEIL-H. VINCENT • SYNTHESIS OF NEW HETEROCYCLES tetranitride. The reactions are carried out in carbon Experimental disulfide which is a solvent of both S4N4 and white 4.96 g (0.16 mol) of white phosphorus, 7.36 g phosphorus. (0.04 mol) of finely ground tetrasulfur tetranitride The reactions are rapid and can be represented and 300 ml of inert solvent (CCI4, CS2) were placed in a 500 ml round-bottomed three necked flask. as follows: This flask was equipped with a mechanical stirrer, 3 S4N4 + 8 P + 6 Cl2 -> 4 P2S3N3CI3 with a nitrogen inlet tube which was used to prevent moisture during the reaction, and with a reflux 3 S4N4 + 8 P + 6 Br2 -> 4 PaSsNgBrg condenser. The top of the condenser was connected 3 S4N4 + 8P + 2I2 4 P2S3N3I with a drying tube containing calcium chloride, The products precipitate from the reaction which was replaced with an inlet tube for the adding bromine and iodine solution in The medium. They are characterized by elementary CCI4. chlorine was passed directly through the solution. analysis and mass spectrometry. They are amor- The mixture of phosphorus and S4N4 was allowed phous to X-rays. to reflux for 4 hours and cooled to room temperature. Their stability decreases when passing from the The solution was brown red. Soon after the start of iodinated to the chlorinated compound. the halogen adding, the colour turned into yellow. The halogens were added in excess. The compounds They decompose below 100 °C. A polymer (PSN)n precipitated slowly. After 24 hours, the solid was is obtained as residue in the decomposition of the collected by filtration in a glove-box, washed with iodinated derivate at 95 °C. ether and dried in vacuo.

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