Arsenic(III) and Antimony(III) Thionylimides

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thionylimides, 'Bu3_„As(NSO)„ and 'Bu3_„Sb(NSO)n, respectively, (n = 3, 2, 1). The tert-buty\- ..... From Me3SiNSO: Arsenic trifluoride, AsF3. (1.25 g, 9.5 mmol), ...
Arsenic(III) and Antimony(III) Thionylimides M ax Herberhold* and Thomas Triebner Laboratorium für Anorganische Chemie der Universität Bayreuth, Postfach 101251, D-8580 Bayreuth

Tristram Chivers* and Santhanathan S. Kumaravel Department o f Chemistry, The University o f Calgary, Calgary T 2 N 1 N 4 , Alberta, Canada Z. Naturforsch. 46b, 169-174(1991); received July 20, 1990 Thionylimide Compounds, Metal-Substituted Arsenic T hionylim ides+ The metathetical reactions o f potassium thionylimide, K N SO , with arsenic and antimony halides in acetonitrile solution have been used to prepare two series o f arsenic and antimony thionylimides, 'Bu3_„As(NSO)„ and 'Bu3_„Sb(NSO)n, respectively, (n = 3, 2, 1). The tert-buty\substituted compounds are moisture-sensitive oils. The half-sandwich hydrido-metal com plex­ es C pM (CO )3H react with 'BuAs(NSO)2 in T H F solution to give the metallo-arsanes [Cp(CO)3M]As('Bu)(NSO) (M = Cr, M o, W).

Introduction

Although thionylimide derivatives o f halogens and chalcogens, X -N S O (1) and E(NSO )2 (2), are well-known, no corresponding tris(thionylimide) com pounds of the main group V elements N, P, As, Sb and Bi have been described so far. We now report the synthesis and characterization of the homoleptic thionylimides As(NSO )3 and Sb(NSO)3, as well as some related organoarsenic and organoantim ony compounds containing thionylimide groups.

Hg(N SO )2 [21] and the silyl com pound M e3SiNSO [22-25]. F or example, arsenic tri(thionylimide), As(NSO )3 (3 a), is accessible by several routes starting from the trihalides AsX 3 (X = F, Cl, Br), according to the following equations: A sF 3 + 3 M e3SiNSO

(C H 3CN) (or THF)

As(NSO )3 + 3 M e3SiF 2 AsC13 + 3 Hg(NSO )2

(THF)

2 As(NSO )3 + 3 HgCl 2 0

0

w

//

AsBr 3 + 3 KNSO

(C H 3CN) (or TH F)

As(NSO )3 + 3 KBr X - N S O (1) X = F [1] Cl [1 -7 ] Br [ 1, 2] I [2]

3a

E(NSO)2 (2) E = S [8—15] Se [ 16] Te [17]

Results and Discussion

Several thionylimide sources can be used for the m etathetical displacement of halide by thionyl­ imide substituents, in particular the salts KNSO [18] and [(Me2N ) 3S]NSO [19, 20], the mercurial The IU PA C name “thionylimide' is favoured over the synonym s “sulfinylamide” and “thiazate” for the anionic N SO group. Reprint requests to Prof. Dr. M. Herberhold. Verlag der Zeitschrift für Naturforschung, D-7400 Tübingen 0932 - 0776/91 /0200 - 0169/$ 01.00/0

Whereas As(NSO )3 (3 a) is isolated as a pale-yel­ low solid, the ter/-butyl-substituted arsenic thionylimides, 'BuAs(NSO )2 (4 a) [cf 20] and ,Bu 2As(NSO) (5 a), are obtained as pale-yellow, very moisture-sensitive oils. The yields are in the range of 3 0 -4 0 % . (C H 3CN) Bu3_„AsC1„ + «KNSO (or THF) 'B u3_„A s(NSO)„ + «KC1 /! = 3 (3a) 2 (4 a) 1 (5 a)

The corresponding phenyl-substituted arsenic thionylimides, PhAs(NSO )2 (6a, m .p. 23 °C) and Ph 2As(NSO) (7 a, yellow oil), were described ear­ lier [20]:

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Ph 3_„AsCl„ + wM(NSO) (C H 3C N ) . > Ph 3_„As(NSO)„ + «MCI n = 2(M = (Me 2N ) 3S )( 6 a)

1 (M = K) (7a) An analogous thionylimide transfer reaction with KNSO was used to prepare the antimony thionylimides Sb(NSO )3 (3b), 'BuSb(NSO )2 (4b) and 'Bu 2Sb(NSO) (5b): 'Bu3_„SbCL + «KNSO

( C H 3C N ) >

(or TH F)

'Bu 3_„Sb(NSO)„ + «KC1 n = 3 (3b) 2 (4 b) 1 (5b)

Numerous attem pts to obtain phosphorus(III) thionylimides such as 'Bu 3_„P(NSO)„ (n = 1, 2, 3) in the free state were unsuccessful so far, although complexes of the type Cr(CO) 5[R-,P(NSO)] (R = Me [26], Ph [26,27]) and M o(CO) 5[R 2P(NSO)] (R Me [26], Ph [26-28]) can be synthesized by the

Compound

vas(NSO)

A s(N SO )3a 'BuAs(NSO)2b

(3 a) (4 a) [cf 20]

'Bu,A s(N SO )b PhÄ s(N SO ),3 Ph,A s(N SO )b

(5 a) (6 a) [20] (7 a) [20]

[Cp(CO)3M ]As('Bu)(NSO)e M = Cr (8 a) Mo (8 b) W (8c) Sb(N SO )3c 'BuSb(NSO)2a

(3 b) (4 b)

'Bu2Sb(NSO)

(5b)

HNSO (Gas) KNSO Hg(NSO)-,3 Cp2T i(N SO )2

[39] [18] [21] [40][32]e, [41] [32] [31] [22] [42] [22] [24] [25] [43] [12] [13]

m -[P t(M e,P ),(N SO ),]e c«-[Pt(Ph3P)2(NSO),] 'BuNSOb Me3SiN SO b

M e,Si(NSO ), S(N SO )2a

1209 1246, 1232 (1248, 1237)d 1245 1224, 1197 1234

reactions of the corresponding R 2PC1 complex­ es with KNSO. Phosphorus(V) thionylimides (R 0 ) 2P ( 0 ) - N S 0 (R = alkyl) are known [29], The infrared spectra of the new arsenic and anti­ mony thionylimides ( 3 a - 7 a and 3 b ~ 5 b , respec­ tively) are expected to contain 3 characteristic bands, corresponding to the asymmetric and sym­ metric stretching vibrations (vas(NSO) and vs(NSO)) and to the angle deform ation mode (J(NSO)) of the NSO substituents (Table I). The very intense vas band is easily recognised be­ tween 1300 and 1200 cm H, and the medium-tostrong vs absorption is, as a rule, observed between 1100 and 1000 cm "1. (An earlier discussion [20] has led to the conclusion that the higher-frequency band is more associated with the v(N=S) and the lower-frequency band more with the v(S = 0 ) vi­ bration; the two stretching modes are apparently not strongly coupled.) It is generally difficult to identify the weak deformation band,

8d

Transition metal-substituted arsanes o f the gen­ eral type [Cp(CO)3M]AsR 2 (e.g., M = Cr, Mo, W; R = Me [34]; M = W; R = 'Pr [33], 'Bu (8c) [35, 36]) were extensively studied by Malisch and co­ workers: Na[CpW (CO)3] + 'Bu 2AsC1

“ N aC 1

(THF)

[Cp(CO)3W]As'Bu 2 8e

In Table II the spectroscopic data of the new arsenic(III) thionylimides 8 a - c are compared with those reported for 8d,e.

Table II. Spectroscopic characterization. >mplex [Cp(CO)3Cr]AsR(NSO) [Cp(CO)3Mo]AsR(NSO) [Cp(CO)3W]AsR(NSO) 8b = fm-butyl) 8 a 8c

[Cp(CO)3W]AsR(Cl) [Cp(CO)3W]AsR, 8d [33] 8e [35]

L(Pentane) [cm '1]3 2002 vs CO) 1946 s, 1931 vs (NSO) 1234 m

2014 vs 1954 s, 1931 vs 1230 m

2012 vs 1945 s, 1920 vs 1231 m

2010 s 1951 s, 1923 vs -

1997 s 1923 vs, 1903 vs -

[ N M R (C6D f,) [PPm]b 4.40 Cp) 1.34 CM e3)

4.85 1.40

4.86 1.41

4.80 1.59

4.84 1.50

: n m r ( c 6d 6) [PPm3 243.3 CO) 239.5 236.1 91.6 Cp) 40.4 CM e,) 30.4 CMeQ

234.5 229.4 225.1 94.7 38.3 30.1

222.3 219.2 214.9 93.5 38.1 30.1

a Intensities: vs 9 (CM e3).

220.4 (cis) 214.4 (trans) 92.0 35.0 33.5

very strong, s = strong, m = medium; b the relative intensities o f the two singlets are 5 (Cp) to

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The addition of arsino-substituted sulfur diimides, S(NAs'Bu2)2, to hydrido-metal complexes CpM (CO)3H (M = Cr, Mo, W) leads to metallacycles [37], On the other hand, 2- and 4-tolyl thionylimide react with CpW (CO)3H to give tungsten sulfinamides, [C p(C 0) 3W ]S(0)N H R [38], Experimental

All m anipulations were carried out under an argon atm osphere using Schlenk techniques. The glass vessels were kept at 120 °C before use in o r­ der to remove traces of water. The solvents (hexane, diethyl ether, tetrahydrofuran and toluene) were heated under reflux over N a/K alloy and then distilled in a stream of argon. Acetonitrile (Fluka, puriss., p.a.) was saturated with argon and kept over molecular sieve. The trihalides AsX 3 (X = I, Cl, Br) and SbCl3 are commercially available; they were resublimed before use. Arsenic trifluoride (Alfa) was distilled before use. The organoarsenic and organoantimony com pounds PhAsCl2 [44], 'BuAsCU [45], 'BuSbCl 2 [46], 'Bu 2AsC1 [45] and 'Bu2SbCl [47] were prepared according to literature methods. Es­ tablished synthetic procedures are also available for the halfsandwich tricarbonyl metal-hydrides CpM (CO)3H (M = Cr, Mo, W [48]) and for the thionylimido compounds M e3SiNSO [23-25], KNSO [18, 20] and Hg(NSO )2 [21].

flux (65 °C) for 3 days. Cooling to - 2 0 °C gave 0.7 g (14%) As(NSO )3 (3a). b) From Hg(NSO)2: Arsenic trichloride, AsC13 (0.37 g, 2 mmol), in 10 ml T H F was added to a stirred solution of Hg(NSO )2 (1.0 g, 3 mmol) in 20 ml T H F at 0 °C. The solution was stirred at 25 °C for 24 h and then filtered, concentrated to 10 ml and cooled to - 2 0 °C. In the course of 1 week, pale-yellow crystals of 3 a precipitated which contained some Hg(NSO )2 according to the mass spectrum. The product was purified by washing with cold C H 3CN to give As(NSO)3. Yield 0.30 g (56%). c) From KNSO: A solution of AsBr 3 (0.32 g, 1 mmol) in 10 ml acetonitrile was added dropwise to a suspension of KNSO (0.31 g, 3 mmol) in ace­ tonitrile at -4 0 °C. The mixture was stirred for 6 h at room tem perature and then filtered to remove unreacted KNSO and newly-formed KBr. The fil­ trate was concentrated and kept in the refrigerator at - 2 0 °C to give a pale-yellow precipitate of As(NSO )3 (3a). Yield 0.08 g (32%). Antimony tri(thionylim ide), S b (N S O )3 (3 b)

A T H F solution (10 ml) of SbCl3 (0.23 g, 1 mmol) was added to a T H F suspension of excess KNSO (0.43 g, 4.2 mmol). The mixture was stirred for 6 h at 25 °C. Excess KNSO and KBr can be re­ moved by filtration, and cooling of the solution gave pale-yellow, hygroscopic 3 b, dec. above 87 °C. Yield 0.08 g (27%).

Arsenic tri(thionylim ide), A s(N S O ) 3 (3a) tert-Butyl-substituted arsine and stibine

a) From Me 3SiNSO: Arsenic trifluoride, A sF 3 thionylimides (1.25 g, 9.5 mmol), was added dropwise to a solu­ General procedure: A suspension of KNSO in tion of M e3SiNSO (3.85 g, 28.5 mmol) in 50 ml either acetonitrile or T H F is stirred with the equi­ acetonitrile at 25 °C. The mixture was stirred for valent am ount of the corresponding ter/-butyl24 h and filtered. The filtrate was concentrated to substituted arsine- and stibine chloride, respective­ 10 ml and cooled to -2 0 °C to precipitate ly, first at low tem perature (slightly above the As(NSO )3 (3 a) as an air- and very moisture-sensimelting point of the solvent), then at room temper­ tive pale-yellow solid, dec. above 148 °C. Yield ature for 4 - 6 h. After filtration over a G 4 frit, the 0.4 g (16%). Mass spectrum (El, 70 eV), m/e 261 (M +, 10%), 210 (As,SN„ 2%), 199 (As(NSO)2, filtrate is brought to dryness and the residue ex­ tracted with pentane. Evaporation of pentane 74%), 137 (AsNSO, 26%), 135 (AsNSN, 33%), leaves yellow to orange oils. Starting from 121 (AsNS, 16%) 107 (AsS, 6 %), 91 (AsO, 42%), 2 - 3 mmol of the chloride precursor, yields of 89 (AsN, 13%), 75 (As, 8 %), 64 (S 0 7, 34%), 62 230-260 mg (3 5 -4 0 % ) of the thionylimide can be (NSO, 28%), 48 (SO, 48%), 46 (NS, 100%). obtained. It is generally difficult to obtain satisfac­ A sN 30 3S 3 (261.14) tory analytical data for these moisture-sensitive Calcd N 16,1 S 36,8, compounds. Found N 15,6 S 36,0. The di(thionylimides), 'BuAs(NSO )2 (4a) and The reaction was also carried out in TH F solu­ 'BuSb(NSO )2 (4b), are less sensitive toward oxida­ tion. Colourless A sF 3 (2.6 g, 19.7 mmol) was ad ­ tion and hydrolysis than the corresponding ded to a solution of Me3SiNSO (8.02 g, 59.3 mmol) mono(thionylimides), 5a and 5b. Com pound 4b in 20 ml TH F. The mixture was heated under re­ solidifies below room temperature.

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173

rBuAs(NSO )2 (4a), yellow-orange oil, 'H N M R 0.95 ppm, ,3C{'H} N M R 43.7 and 25.8 ppm (