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Reactions of the Hexafluorothioacetone Dimer with Cyanides of Phosphorus, Arsenic and Germanium

Herbert W. Roesky*, Kaveripatnam S. Dhathathreyan, Mathias Noltemeyer, and George M. Sheldrick* Institut für Anorganische Chemie der Universität Göttingen, Tammannstraße 4, D-3400 Göttingen, F R G

Herrn Dr. Karl Damaschke zum 60. Geburtstag gewidmet

Z. Naturforsch. 40b, 240 -246 (1985); received September 19/October 25, 1984

Crystal Structure, Hexafluorothioacetone, Nitriles, Heterocyclics

Cyanides such as P(CN)3 , As(CN)3 , PhP(CN)2 , Bu'As(CN)2 and Ge(CN)4 react with [(CF3)2CS]2 (1) by insertion of the carbon atom of the /so-nitrile isomer into the four-mem-bered [CS]2 ring to give compounds PR 3 (2), AsR3 (3), FP(S)R2 (4), PhP(S)R^ (5), Bu'AsR^ (6) and GeR 4 (7) respectively, where R ' is the novel heterocyclic ligand —N=C—S—C(CF3)2—S —C(CF3)2. The crystal structures of 3 and 7 are reported.

The dimer of hexafluorothioacetone, 2,2,4,4-tet-rakis(trifluoromethyl)-l,3-dithietane (1) reacts with nucleophilic reagents such as amines [1], alcohols [2] and dienes in the presence of fluoride ion catalyst [3], but in each case the products contain only the mono-mer unit. The same applies to the reactions of (Ph3P)3Pt [4] or Ni(COD)2 [5] with 1. In a recent preliminary report [6] we showed that 1 undergoes a different type of reaction with phosphorus and arsenic tricyanides, the four-membered [CS]2 ring of the dimer being enlarged by the insertion of the car-bon atom of the z'so-nitrile isomer. In this paper we describe the details of these reactions, together with the reactions of 1 with other cyanides and the crystal structures of two of the resulting products.

Results and Discussion

In our earlier communication [6] we showed that compound 1 reacted with P(CN)3 and As(CN)3 to yield the products 2 and 3, respectively, the struc-tures of which were assigned on the basis of spectro-scopic data:

E(CN) 3

[R = C F 3 J

ROC — S 2 | I

s — C R 2 1

E = P(2) and As

-N = C S — CR 2

I C R 2 - S

(3)]

However it was not possible to rule out the structures in which N and S atoms are interchanged. We there-fore determined the structure of 3 by single-crystal X-ray diffraction, confirming that proposed from the spectroscopic data.

In the reaction of 1 with P(CN)3 in the presence of triethylamine as a catalyst, a second product 4 was isolated in low yield, for which the following struc-ture is suggested by the spectroscopic data:

- N = C

CR2

C R 2 - S

It should be mentioned that the reaction Bu"P with 1 yields Bu3'!PF2 in 60% yield [7], In our hands Ph3P=CH2 also yields Ph3PF2 as one of the products when reacted with 1 [8]. An arsenic analogue of 4 could not be isolated from the reaction of 1 with AS(CN)3. With Sb(CN)3, 1 yielded a complex mix-ture of products which could not be separated.

Whereas 1 and Bu'As(CN)2 yielded the expected 6, the corresponding reaction of 1 with PhP(CN)2 gave the phosphorane 5:

R2C — S PHP(CN)2 • | |

S — CR2

1

S ii Ph-P - N = C

S CR2

C R 2 — S

* Reprint requests to Prof. Dr. H. W. Roesky or Prof. G. M. Sheldrick.

0340- 5087/85/0200 - 0240/$ 01.00/0

. R2C — S BU AS(CN)2 I | -

S — CR2

t

BIAÄS • -N = C. S CR 2

C R 2 — S

241 H. W. Roesky et al. • Reactions of Hexafluorothioacetone Dimer

Although CH3Si(CN)3 and 1 yielded a complex mixture of products which was difficult to separate, Ge(CN)4 and 1 gave the expected 7, the structure of which was confirmed by X-ray diffraction.

considerable changes in the signals for the ring car-bon atoms, indicating ring opening by attack on one of them. When this mixture is allowed to stand for a few hours, sulfur is precipitated.

R 2 C — S Ge(CN)^ • | | Ge

S — CR2 1

The role of triethylamine in these reactions is probably twofold. NMR studies (e.g. [9]) have shown that Lewis bases form weak adducts with tri-valent phosphorus compounds, which might activate the nitrile-isonitrile isomerisation. In addition, the 13C NMR spectrum recorded immediately after the addition of a few drops of triethylamine to 1 shows

Interpretation of Spectra

The 70 eV mass spectra show a molecular ion peak for all the compounds reported. Loss of one com-plete ligand [NC3S2(CF3)4 = 390 mass units] is fre-quently observed. v(CF) is observed between 1200 and 1300 cm - 1 in the IR spectra, with v(C=N) in the range 1600-1640 cm - 1 . An analysis of the NMR spectra is presented in Table I. The 13C spectra show the expected couplings to P and F. The 13C resonance at lowest field is not split by F; the small value of

-N = C S CR2

CR2—S

Table I. Mass and NMR (31P, 19F, 13C) spectral data, d is in ppm, / in Hz, solvent CFC13, atoms labelled as indicated in the formula (q = quartet , s = septet, d = doublet).

•C2(C3F3)2

- N =C

V -(C5F3)2

Compound mle (calc/obs)

242 H . W. Roesky et al. • Reactions of Hexaf luoroth ioacetone D i m e r

7(P—C) is consistent with P—N=C rather than P—C=N, as observed in the crystal structures.

Crystal structure analyses

Crystal data and details of the structure determina-tion for 3 and 7 are summarised in Table II. In both cases the heavy atoms were located by direct methods and the remaining atoms from difference syntheses, with some difficulties caused by the large anisotropic thermal motion of the trifluoromethyl groups. The structures were refined anisotropically

Table III. (continued).

Table II. and 7.

Crystal data and structure determinat ion for 3

Compound 3 7

Molecular formula C21ASF36N3S6 C28F48GeN4S8 M 1245.5 1633.3

Space group P I C2/c a [A] 7.103(8) 53.650(10) b [A] 11.587(8) 12.647(4) c [A] 23.815(17) 24.864(8) a [»] 94.42(7) 90 ß [°] 96.28(8) 103.43(3) y [°J 93.30(8) 90 V [A ] 1938.1 16005.6 Z 2 12 d c [gcm" 3 ] 2.134 2.033 H [cm '] 13.8 10.6 crystal size [mm] 0 . 3 x 0 . 2 x 0 . 6 0 . 2 x 0 . 2 x 0 . 3

Number of reflections collected 5383 8067 unique 5057 7466 observed [ F > p a ( F ) ] 4415 4635 P 3 4 maximum 20 [°] 45 45 R 0.047 0.072 Rw 0.049 0.065 g [weight" 1 = o 2 ( F ) + g F : 2] 0.0007 0.0003

Table III. Atomic coordinates (x lO 4 ) and isotropic ther-mal parameters ( Ä 2 x l 0 3 ) for 3.

X y z U

As 4919(1) 8502(1) 2624(1) 38(1)* N(11) 4877(5) 9718(3) 2163(1) 41(1)* C(12) 5277(6) 10768(4) 2314(2) 38(1)* S(13) 5524(2) 11404(1) 3019(1) 53(1)* C(14) 6663(7) 12785(4) 2913(2) 45(2)* C(15) 5649(9) 13745(4) 3222(2) 68(2)* C(16) 8788(8) 12828(5) 3156(2) 65(2)* F ( l l ) 5765(6) 13647(3) 3765(1) 101(2)* F(12) 6383(7) 14790(3) 3139(2) 103(2)* F(13) 3851(5) 13703(4) 3022(2) 104(2)*

X y 2 U

F(14) 8965(5) 12662(3) 3703(1) 97(2 * F(15) 9656(5) 12003(3) 2894(2) 94(2 * F(16) 9666(5) 13840(3) 3097(2) 101(2 * S(17) 6549(2) 13034(1) 2169(1) 60(1 * C(18) 5506(7) 11623(4) 1856(2) 48(2 * C(19) 6867(9) 11168(5) 1451(2) 72(2 * C ( l a ) 3524(10) 11827(5) 1551(2) 72(2 * F(17) 6079(6) 10286(3) 1093(1) 102(2 * F(18) 8386(5) 10793(3) 1736(2) 98(2 * F(19) 7450(7) 11981(3) 1135(1) 112(2 * F ( l a ) 2421(5) 12236(3) 1913(2) 94(2 * F ( l b ) 2669(6) 10867(3) 1286(2) 104(2 * F ( l c ) 3699(7) 12591(3) 1164(1) 104(2 * N(21) 3468(5) 9126(3) 3167(1) 38(1 * C(22) 2828(6) 8512(4) 3524(2) 38(1 * S(23) 2888(2) 6979(1) 3527(1) 47(1 * C(24) 2868(7) 6922(4) 4285(2) 41(1 *

C(25) 4916(7) 6901(4) 4569(2) 55(2 * C(26) 1649(8) 5844(4) 4398(2) 61(2 * F(21) 5004(5) 6939(3) 5126(1) 79(1 * F(22) 5961(4) 7816(3) 4448(1) 74(1 * F(23) 5741(5) 5968(3) 4387(1) 84(1 * F(24) - 100(5) 5856(3) 4159(1) 81(1 * F(25) 2343(5) 4877(3) 4193(2) 88(1 * F(26) 1608(6) 5786(3) 4950(1) 92(1 * S(27) 1822(2) 8195(1) 4592(1) 51(1 * C(28) 1710(6) 9060(4) 3986(2) 40(1 * C(29) - 379(7) 9106(4) 3733(2) 56(2 * C(2a) 2568(7) 10285(4) 4202(2) 50(2 * F(27) 1886(5) 10646(3) 4677(1) 74(1 * F(28) 4440(4) 10282(2) 4321(1) 63(1 * F(29) 2230(5) 11065(2) 3835(1) 64(1 * F(2a) - 1 3 8 2 ( 4 ) 9655(3) 4097(1) 83(1 * F(2b) - 513(4) 9628(3) 3257(1) 73(1 * F(2c) - 1 1 9 3 ( 4 ) 8045(3) 3610(1) 74(1 * N(31) 2914(5) 7561(3) 2255(1) 43(1 * C(32) 2353(6) 7384(3) 1735(2) 39(1 * S(33) 3221(3) 8115(1) 1192(1) 73(1 * C(34) 1893(9) 7319(5) 583(2) 67(2 * C(35) 3263(11) 6731(6) 227(3) 94(3 * C(36) 789(13) 8182(6) 236(3) 96(3 * F(31) 4235(8) 5981(4) 537(2) 135(2 * F(32) 4530(7) 7476(4) 69(2) 127(2 * F(33) 2398(8) 6159(4) - 234(2) 142(2 * F(34) - 199(8) 7654(5) - 220(2) 159(3 * F(35) 1900(9) 8991(4) 70(2) 140(2 * F(36) - 392(9) 8716(5) 549(2) 154(3 * S(37) 207(2) 6237(1) 787(1) 76(1 * C(38) 729(7) 6442(4) 1553(2) 51(2 * C(39) 1361(9) 5260(4) 1756(3) 73(2 * C(3a) - 1 0 4 1 ( 9 ) 6777(7) 1805(3) 88(3 * F(37) - 2 5 1 8 ( 6 ) 6022(5) 1614(2) 126(2 * F(38) - 884(5) 6817(4) 2365(2) 115(2 * F(39) - 1 4 9 9 ( 6 ) 7814(4) 1663(2) 128(2 * F(3a ) 167(6) 4393(3) 1523(2) 106(2 * F(3b) 1490(7) 5228(3) 2301(2) 110(2 * F(3c) 3046(6) 5068(3) 1587(2) 109(2 *

Equivalent isotropic U defined as one third of the trace of the orthogonalised U,j tensor.

243 H. W. Roesky et al. • React ions of Hexaf luoroth ioacetone Dimer

except for the C and N atoms in 7, which were iso-tropic. In 3 the asymmetric unit consists of one molecule; in 7 one molecule lies in a general posi-tion, and a further molecule lies on a crystallographic twofold axis. The structures of 3 and of the general molecule of 7 are shown in the two Figures; atomic coordinates are given in Tables III and IV, and the

S(17)

Table IV. Atomic coordinates (x lO 4 ) and isotropic ther-mal parameters ( Ä 2 x l 0 3 ) for 7.

S(37) Fig. 1. The molecule of 3, with fluorine a toms and the names of the tr if luoromethyl carbons omit ted for clarity.

S(11)

S(31)

Fig. 2. The general molecule of 7, with fluorine atoms and the names of the tr if luoromethyl carbons omit ted for clarity.

X y 2 U

G e ( l ) -1651(1 ) 6090(1) - 914(1) 50(1)* N ( l ) -1713(1 ) 4847(6) - 614(3) 50(2) C ( l ) -1877(2 ) 4696(8) - 359(4) 51(3) C ( l l ) -1927(2 ) 3570(8) - 173(5) 65(3) S ( l l ) - 2205(1 ) 3526(3) 75(2) 96(2)* C(12) -2288(2 ) 4910(9) 31(5) 73(4) S(12) -2047(1 ) 5702(3) - 123(2) 96(2)* C(13) -1988(2 ) 2835(10) - 673(5) 91(4) F(13a) -1780(1 ) 2613(5) - 847(3) 115(4)* F(13b) -2158(2 ) 3249(6) - 1136 (3 ) 117(4)* F(13c) -2081(2 ) 1895(5) - 592(3) 122(4)* C(14) -1677(2 ) 3208(11) 305(6) 88(4) F(14a) -1471(1 ) 3134(7) 137(4) 132(4)* F(14b) -1723(2 ) 2255(6) 493(4) 138(5)* F(14c) -1632(2 ) 3874(7) 726(3) 136(4)* C(15) -2562(3 ) 5054(12) - 420(6) 121(5) F(15a) -2637(2 ) 6038(7) - 482(4) 160(5)* F(15b) -2741(2 ) 4444(8) - 362(5) 185(6)* F(15c) -2531(2 ) 4812(8) - 942(4) 155(5)* C(16) -2322(3 ) 5283(11) 611(6) 117(5) F(16a) -2380(2 ) 6298(7) 585(5) 185(7)* F(16b) -2100(2 ) 5099(8) 1008(3) 163(5)* F(16c) -2505(2 ) 4699(8) 722(4) 187(7)* N(2) -1350(1 ) 5890(6) - 1107 (3 ) 52(2) C(2) -1328(2 ) 5202(8) - 1451 (4 ) 55(3) C(21) -1058(2 ) 5053(8) - 1546 (4 ) 58(3) S(21) -1067(1 ) 4023(3) - 2047 (2 ) 88(2)* C(22) -1408(2 ) 3621(9) - 2 2 1 8 ( 5 ) 75(4) S(22) -1573(1 ) 4376(3) - 1 8 4 4 ( 2 ) 123(2)* C(23) - 980(2) 6077(10) - 1 7 7 3 ( 5 ) 85(4) F(23 a) - 934(2) 6862(6) - 1 4 1 6 ( 4 ) 168(6)* F(23b) -1167(2 ) 6377(6) - 2234 (4 ) 138(5)* F(23c) - 763(1) 5971(6) - 1927 (3 ) 109(4)* C(24) - 845(3) 4739(11) - 981(6) 114(5) F(24a) - 803(2) 5523(10) - 615(4) 175(6)* F(24b) - 619(1) 4511(7) -1056(4 ) 138(5)* F(24c) - 928(2) 3966(9) - 752(4) 172(6)* C(25) -1538(4 ) 3815(16) - 2876 (9 ) 160(8) F(25 a) -1792(2 ) 3449(11) - 2 9 9 8 ( 4 ) 239(8)* F(25b) -1413(4 ) 3205(21) -3090(7 ) 461(18) F(25c) -1537(3 ) 4752(14) -2964(5 ) 357(11) C(26) -1416(3 ) 2467(14) -2033(7 ) 148(6) F(26a) -1661(2 ) 2155(7) - 2163 (6 ) 214(8)* F(26b) -1307(2 ) 2340(10) - 1542 (7 ) 337(10) F(26c) -1314(3 ) 1948(8) -2375(10) 422(19) N(3) -1609(1 ) 7161(6) - 400(3) 49(2) C(3) -1445(2 ) 7872(7) - 266(4) 47(3) C(31) -1477(2 ) 8732(8) 155(4) 51(3) S(31) -1225(1 ) 9735(3) 294(2) 82(2)* C(32) -1042(2 ) 9272(8) - 163(5) 65(3) S(32) — 1171(1) 8045(3) - 500(2) 91(2)* C(33) -1738(3 ) 9281(11) - 71(7) 94(5) F(33a) -1942(1 ) 8636(6) - 132(4) 130(4)* F(33b) -1770(2 ) 9608(7) - 594(4) 139(5)* F(33c) -1766(2 ) 10093(6) 228(4) 145(5)* C(34) -1451(2 ) 8211(9) 728(5) 78(4) F(34a) -1646(2 ) 7540(7) 694(3) 140(5)* F(34b) -1452(2 ) 8912(6) 1125(3) 118(4)* F(34c) -1235(1 ) 7671(6) 910(3) 112(4)*

244 H. W. Roesky et al. • React ions of Hexaf luorothioacetone Dimer

Table IV. (continued).

X z U

C(35) - 1071 (3 ) 10117(12) - 623(6) 126(5) F(35a) - 936(2) 9840(8) - 971(4) 174(6)* F(35b) - 975(2) 11023(7) - 401(4) 191(7)* F(35c) - 1310 (2 ) 10250(8) - 936(4) 180(6)* C(36) - 762(3) 9105(12) 183(6) 107(5) F(36a) - 618(2) 8769(8) - 128(4) 163(5)* F(36b) - 739(1) 8422(7) 585(4) 141(5)* F(36c) - 648(2) 9997(8) 441(4) 160(5)* N(4) - 1954 (2 ) 6396(6) -1495(3 ) 58(3) C(4) - 1 9 8 0 ( 2 ) 7028(7) -1885(4 ) 50(3) C(41) - 2255 (2 ) 7232(8) -2325(4 ) 65(3) S(41) - 2238 (1 ) 8162(3) -2865(1 ) 80(2)* C(42) - 1891 (2 ) 8426(8) -2641(5 ) 64(3) S(42) - 1718 (1 ) 7724(3) -2005(2 ) 99(2)* C(43) - 2358 (2 ) 6169(10) -2611(5 ) 92(4) F(43a) - 2412 (2 ) 5487(6) -2262(3 ) 131(4)* F(43b) - 2 1 9 3 ( 2 ) 5732(5) -2821(3 ) 119(4)* F(43c) - 2582 (2 ) 6332(6) -3041(4 ) 141(4)* C(44) - 2 4 3 3 ( 2 ) 7690(10) -2021(5 ) 85(4) F(44 a) - 2481 (2 ) 7055(7) -1647(4 ) 151(5)* F(44b) - 2662 (1 ) 8002(7) -2385(4 ) 141(5)* F(44c) - 2 3 2 5 ( 2 ) 8548(6) -1733(3 ) 127(4)* C(45) - 1771 (3 ) 8092(11) -3104(6 ) 96(4) F(45 a) - 1520 (2 ) 8266(7) -2968(4 ) 149(5)* F(45b) - 1890 (2 ) 8583(9) -3575(4 ) 179(6)* F(45 c) - 1 8 1 1 ( 2 ) 7078(7) -3210(4 ) 171(6)* C(46) - 1844 (2 ) 9635(10) - 2520 (5 ) 92(4) F(46 a) - 1 5 8 9 ( 1 ) 9856(6) -2360(4 ) 133(5)* F(46b) - 1 9 3 4 ( 2 ) 9914(6) -2114(4 ) 148(5)* F(46c) - 1968 (2 ) 10163(6) -2964(4 ) 164(5)* Ge(2) 0 1886(1) 2500 51(1)* N(5) - 48(1) 2642(6) 1844(3) 57(2) C(5) - 226(2) 3278(8) 1627(4) 57(3) C(51) - 236(2) 3792(8) 1051(4) 64(3) S(51) - 465(1) 4874(3) 871(2) 89(2)* C(52) - 607(2) 4776(9) 1437(5) 72(4) S(52) - 475(1) 3662(3) 1888(2) 116(2)* C(53) 33(3) 4250(10) 1089(6) 87(4) F(53a) 208(1) 3497(6) 1095(3) 123(4)* F(53b) 128(1) 4815(6) 1539(4) 121(4)* F(53c) 24(2) 4859(7) 648(3) 129(4)* C(54) - 321(3) 2951(11) 592(6) 113(5) F(54a) - 163(2) 2142(6) 654(3) 141(5)* F(54b) - 341(2) 3372(7) 79(3) 155(5)* F(54c) - 549(2) 2578(7) 560(4) 147(5)* C(55) - 544(4) 5788(14) 1792(7) 116(6) F(55a) - 639(2) 5777(7) 2229(4) 160(6)* F(55b) - 638(2) 6605(7) 1464(5) 189(8)* F(55c) - 289(2) 5867(9) 2023(4) 180(6)* C(56) - 911(3) 4636(13) 1174(7) 130(6) F(56a) - 1012 (2 ) 4580(8) 1604(5) 181(7)* F(56b) - 957(2) 3764(8) 907(5) 218(7)* F(56c) - 1 0 1 1 ( 2 ) 5415(9) 847(4) 199(6)* N(6) - 303(1) 1134(6) 2412(3) 51(2) C(6) - 325(2) 426(7) 2736(4) 46(3) C(61) - 600(2) - 79(8) 2657(4) 55(3) S(61) - 591(1) - 1 0 8 8 ( 3 ) 3165(2) 82(2)* C(62) - 242(2) - 1 0 7 5 ( 8 ) 3571(4) 65(3) S(62) - 71(1) - 132(3) 3288(2) 98(2)* C(63) - 791(3) 773(11) 2702(6) 96(5)

Table IV. (continued).

x y z U

F(63a) - 840(2) 1508(7) 2302(4) 168(6)* F(63b) - 691(2) 1268(6) 3179(4) 131(5)* F(63c) - 1 0 2 0 ( 1 ) 372(7) 2706(4) 143(5)* C(64) - 700(3) - 587(11) 2060(6) 122(5) F(64a) - 747(2) 118(8) 1643(3) 174(5)* F(64b) - 913(2) -1147(9 ) 1993(4) 182(6)* F(64c) - 518(2) -1234(7 ) 1994(4) 167(6)* C(65) - 212(3) - 783(11) 4193(6) 102(5) F(65a) 36(2) - 767(8) 4502(3) 160(5)* F(65b) - 354(2) -1335(11) 4394(4) 205(7)* F(65c) - 297(2) 216(8) 4189(4) 172(6)* C(66) - 127(3) -2216(12) 3517(6) 127(5) F(66a) - 255(2) -2807(7 ) 3827(7) 251(9)* F(66b) 126(2) -2181(7 ) 3841(4) 170(6)* F(66c) - 161(2) -2455(9 ) 3043(5) 238(7)*

* Equivalent isotropic U defined as one third of the trace of the orthogonalised U^ tensor.

Table V. Selected mean bond lengths (Ä) and angles (°) for 3 and 7. Es t imated standard deviations in individual bond lengths and angles were in the ranges 0.004 to 0.010 Ä and 0.2 to 0.5° for 3, and about double these values for 7. E = As (3) or G e (7). The atoms are labelled as for Table I.

3 7

E - N 1.853 1.833 N = C(1) 1.254 1.238 C ( 1 ) " S ( 1 ) 1.765 1.747 S ( l ) - C ( 2 ) 1.805 1.783 C ( 2 ) - C ( 3 ) 1.537 1.552 C ( 2 ) - S ( 2 ) 1.817 1.810 S ( 2 ) - C ( 4 ) 1.818 1.796 C ( 4 ) - C ( 5 ) 1.539 1.529 C ( 4 ) - C ( l ) 1.544 1.555 C - F 1.322 1.312

E — N = C 126.0 126.5 N = C ( 1 ) - S ( 1 ) 126.0 126.0 C ( l ) - S ( l ) - C ( 2 ) 98.7 100.9 S ( l ) - C ( 2 ) - S ( 2 ) 111.4 111.5 C ( 2 ) - S ( 2 ) - C ( 4 ) 99.7 100.0 S ( 2 ) - C ( 4 ) - C ( l ) 111.0 112.2 C ( 4 ) - C ( l ) - N 118.9 119.4 C ( 4 ) - C ( l ) - S ( l ) 115.0 114.6 N - E - N 97.1 109.5

molecular dimensions are summarised in Table V. The heterocyclic rings are effectively planar, with mean deviations of 0.08 Ä (3) and 0.03 Ä (7) from the least-squares planes through the five ring atoms. Most of the sulphur atoms exhibit relatively aniso-tropic thermal motion, with the greatest amplitude perpendicular to the ring plane; this suggests that the

245 H. W. Roesky et al. • Reactions of Hexaf luorothioacetone Dimer

rings undergo a low-frequency puckering vibration or pseudorotation. The planar conformation ob-served in the crystal may be an average of several slightly puckered conformations, and does not neces-sarily itself represent a potential energy minimum.

Experimental 1H, 19F NMR spectra: Bruker 60-E (60 MHz), TMS

and CFCI3 as internal standard. 13C NMR spectra: Bruker AM-250 (250 MHz), TMS as internal stand-ard. 31P NMR spectra: Bruker WP80SY (32.442 MHz), 85% H3PO4 as external standard. IR spectra: Perkin Elmer spectrograph 735 B (in Nu-jol). Mass spectra: Finnigan MAT 8230. Elemental analysis: Mikroanalytisches Laboratorium Beller, Göttingen.

All the experiments were carried out in glass ves-sels which had been previously dried and then filled with dry N2 gas. All the solvents were dried before use by conventional methods. The nitriles were pre-pared by previously reported procedures either using Me3SiCN [10] or AgCN [11]. The starting materials are dissolved in CH3CN and cooled to —78 °C. 1 is then injected in one stroke followed by few drops of Et3N. The reaction mixture is allowed to warm to room temperature slowly and then stirred for 12 h.

Tris[2,2,4,4-tetrakis (trifluoromethyl)-1,3-dithio-cyclopent-5-ylidene-amino]phosphine (2)

0.55 g (5 mmol) P(CN)3, 0.1 g (1 mmol) NEt3 and 5.46 g (15 mmol) 1 are reacted in 60 ml CH3CN. Af-ter 12 h, the precipitate is filtered and recrystallised from 1,1,2-trichlorotrifluoro-ethane/hexane to yield colourless crystals of 2; m.p. 136-138 °C, 3.21 g (53% yield).

IR: 1620 vst (C=N), 1295-1200 br. vst, 1100 m, 980 m, 940 st, 920 st, 850 st, 800 m, 745 st, 720 st, 700 cm"1 m.

C21F36N3PS6 (1201) Calcd C 21.05 F 57.1 P 2.58 S 16.04, Found C 19.72 F 56.8 P 2.52 S 16.04.

Bis [2,2,4,4-tetrakis(trifluoromethyl)-l,3-dithio-eyelo-pent-5-ylidene-amino]fluoro(thio)phosphorane (4)

The filtrate from the previous experiment is evaporated under reduced pressure to get a viscous oil. Double sublimation of this residue at 55—60 °C/ 10 -2 torr, followed by recrystallisation from 1,1,2-trichlorotrifluoroethane/CH2Cl2 yields colourless cry-stals of 4; m.p. 72 °C, 0.52 g (12% yield).

IR: 1640 st (C=N), 1610 st (C=N), 1295-1190 br. vst, 1100 st, 995 st, 920 vst, 970 vst, 795 st, 740 st, 720 st, 700 st, 660 cm - 1 m.

C14F25N2PS5 (862) Calcd C 19.48 F 55.1 S 18.56 P 3.6, Found C 20.00 F 55.0 S 18.58 P 3.7.

Tris[2,2,4,4-tetrakis (trifluoromethyl)-1,3-dithio-eyelopent-5-ylidene-aminoJarsine (3)

0.77 g (5 mmol) As(CN)3, 0.1 g (1 mmol) Et3N and 5.46 g (15 mmol) 1 are reacted in 60 ml CH3CN. After 12 h, the precipitate is filtered and recrystal-lised from 1,1,2-trichlorotrifluoroethane/hexane to yield colourless crystals of 3; m.p. 113—114 °C, 3.63 g (58% yield).

IR: 1605 st (C=N), 1280-1200 br. vst, 1080 m, 960 m, 940 st, 920 st, 905 m, 830 st, 760 st, 735 st, 715 st, 695 cm - 1 st.

C21F36N3AsS6 (1246) Calcd C 20.22 F 54.89 S 15.40 As 6.08, Found C 20.72 F 52.90 S 15.32 As 6.29.

Bis [2,2,4,4-tetrakis(trifluoromethyl)-l,3-dithio-eyelo-pent-5-ylidene-amino]phenyl(thio)phosphorane (5)

0.8 g (5 mmol) PhP(CN)2, 0.1 g (1 mmol) Et3N and 3.64 g (10 mmol) 1 are reacted and worked up as in (1). 5 is obtained as colourless crystals; m.p. 89-90 °C, 2.76 (60% yield).

IR: 1640 st (C=N), 1620 st (C=N), 1270-1200 br. vst, 1100 m, 980 m, 950 st, 930 st, 860 m, 800 w, 780 m, 750 st, 730 st, 720 st, 700 cm - 1 st.

C20H5F24N2PS5 (920) Calcd C26.08 H0.54 N3.04 F49.56 S 17.39 P3.37, Found C26.16 H0.59 N2.98 F49.60 S 17.41 P3.36.

Bis [2,2,4,4-tetrakis (trifluoromethy l)-l, 3-dithio-eyclopent-5-ylidene-aminoJ-tert-butylarsine (6)

0.92 g (5 mmol) BufAs(CN)2, 0.1 g (1 mmol) Et3N, 3.64 g (10 mmol) 1 are reacted and worked up as in (1). 6 is obtained as colourless crystals; m.p. 76 -78 °C, 2.05 g (46% yield).

IR: 1620 st (C=N), 1280-1200 br. vst, 1080 m, 970 m, 940 st, 920 st, 905 m, 820 st, 740 st, 720 st, 680 cm - 1 st.

C18H9F24N2AsS4 (912) Calcd C23.68 H0.98 N3.07 F50.00 S 14.04 As8.22, Found C23.49 HO.92 N3.03 F49.86 S 14.00 As7.82.

Tetrakis[2,2,4,4-tetrakis (trifluoromethyl)-1,3-dithio-eyclopent-5-ylidene-amino]germane (7)

0.88 g (5 mmol) Ge(CN)4, 0.1 g (1 mmol) NEt3 and 7.28 g (20 mmol) 1 are reacted in 60 ml CH3CN.

246 H. W. Roesky et al. • Reactions of Hexaf luoroth ioacetone Dimer

After 12 h, the liquid which had separated was dis-solved in 1,1,2-trichlorotrifluoroethane and CH2C12 was added. On cooling to 0 °C, colourless crystals of 7 are obtained. M.p. 131-133 °C, 2.61 g (32% yield). The crystals are sensitive to oxygen and mois-ture.

IR: 1615 vst (C=N) , 1280-1200 br. vst, 1080 m, 970 m, 940 m, 940 st, 915 st, 835 st, 800 w, 740 st, 735 st, 710 st, 690 st, 670 cm"1 m.

C28F48GeN4S8 (1633) Calcd C 20.58 F 55.86 S 15.65 Ge 4.45, Found C 20.83 F 52.18 S 15.12 Ge 4.20.

using graphite monochromated Mo—Ka radiation (A = 0.71069 Ä). An empirical absorption cor-rection was applied. Further details are given in Table II. All calculation were performed using pro-grams written by author G. M. S., from whom tables of bond lengths, angles, anisotropic tempera-ture factors and structure factors may be obtained.

X-ray data collection Data were collected on a Stoe-Siemens four-circle

diffractometer by a profile-fitting procedure [12]

We thank the Alexander von Humboldt Founda-tion for a fellowship (to K. S. D.) and the Deutsche Forschungsgemeinschaft, the Fonds der Chemischen Industrie and Hoechst AG for support.

[1] N. Ishikawa and T. Kitazume, Bull. Chem. Soc. Jpn. 46, 3260 (1973).

[2] T. Kitazume and N. Ishikawa, Bull. Chem. Soc. Jpn. 46, 3285 (1973).

[3] T. Kitazume and N. Ishikawa, Chem. Lett . 1973, 267. [4] M. C. Baird and G. Wilkinson, J. Chem. Soc. A 1967,

865. [5] a) J. Browning, D. J. Cook , , C. S. Cundy, M. Green ,

and F. G. A. Stone, Chem. Commun. 1968, 929; b) J. Browning, C. S. Cundy, M. Green , and F. G. A. Stone, J. Chem. Soc. A 1969, 20.

[6] H . W. Roesky and K. S. Dhatha threyan , Chem. Com-mun. 1984, 1053.

[7] W. J. Middleton and W. H . Sharkey, J. Org. Chem. 30, 1384 (1965).

[8] H. W. Roesky and K. S. Dha tha th reyan , unpublished results.

[9] a) C. A. Wilkie and R. W. Parry, Inorg. Chem. 19, 1499 (1980); b) P. G. Kirk and T. D. Smith, J. Chem. Soc. A 1969, 2190.

[10] T. A. Bither, W. H. Knoth , R. V. Lindsay (Jr . ) , and W. H. Sharkey, J. Am. Chem. Soc. 80, 4151 (1958).

[11] C. E . Jones and K. J. Coskran , Inorg. Chem. 10, 1536 (1971).

[12] W. Clegg, Acta Crystallogr. A 37, 22 (1981).