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Isolation of Crystalline Acylsulfenyl IodidesЧ Intermediates in the I2- Oxidation of Thiocarboxylic Acids.

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The red-brown tricobalt compound 2d (43e) can be
conveniently prepared by reaction of protonated 3 qs-cyclopentadienyl(q5-1,3-diborolene)cobalt151- with
(C,H,)Co(CO), in mesitylene at 170°C [74% yield, m.p.
209°C; S'H(C6D6): 14.6, 9.3, - 10.0, - 12.9, -38.1;
m/z=601 ( M + , 100°/o rel. int.)]. Silver ions oxidize 2d to
the dark-red, diamagnetic 42e cation 2 d + [78% yield;
G'H(CDzC12): 1.32 (s, 6), 1.27 (t, 6), 2.19 (s, I), 2.8 and 2.1
(m, 4), 4.65 (s, 5 ) ; 6"B: 18.31.
These results reveal the unusual ligand properties of 1,3diborolene for the construction of tetradecker complexes
containing 42 to 46 valence electrons. With exception of
the paramagnetic 2c, with "high-spin" d6 Fe, the new trinuclear complexes are electronically closely related to the
corresponding mono- and dinuclear complexes : Formal
insertion of the 12e-fragment 1,3-diborolenylcobalt
[(CzB2C)Co]between CsHS and Ni in nickelocene affords
1, and then 2a. Since the 17e-sandwich .radical
[(C,H,)CO(C~B,C)]~
corresponds to the 5e-ligand C,HF, a
nickelocene-like chemistry is to be expected, at least in the
case of the triple-decker 1.
Received: June 29, 1981 [Z 2b IE]
revised: November 16, 1981
German version: Angew. Chem. 94 (1982) 148
[I] W. Siebert, C. Bohle, C. Kriiger, Angew. Chem. 92 (1980) 759; Angew.
Chem. Int. Ed. Engl. 19 (1980) 746.
[2] K. Jonas, C. Kriiger, Angew. Chem. 92 (1980) 513; Angew. Chem. Int. Ed.
Engl. 19 (1980) 520.
131 W. Siebert, Ado. Orgunornet. Chem. 18 (1980) 301.
[4] Crystallographic data ofa 2a: monoclinic, P2,/?, a=8.875(2),
b = 15.261(7), C = 10.492(4) A, 8=91.50(2), V = 1420.6 A', Z = 2 ; 3195
unique observed reflections, R =0.037, R, =0.049.
[S] W. Siebert, J. Edwin, H. Pritzkow, Angew. Chem. 94 (1982) 147: Angew.
Chem. Int. Ed. Eng1. 21 (1982) No. 2.
We now report the first successful isolation of the crystalline acylsulfenyl iodides 2 (Table I), which were obtained by reaction of phenylmercury thiocarboxylates 1
with iodine. The PhHgI, which is also formed, is readily
reconverted into the educt by reaction with piperidiniumor potassium-thiocarboxylates.
The acylsulfenyl iodides 2 were characterized by spectral data and by elemental analyses. For example, in the
mass spectrum, 2b shows a molecular ion at m/z 278.
The 1R spectrum shows a characteristic absorption band at
1650 c m - ' due to the v(C=O) vibration; its position differs distinctly from that of the corresponding band of the
educt 1 (1625 cm - ') and from that of bis(4-methylbenzoyl)
disulfide (1692 cm-I), the possible decomposition product. 2b reacts with dithiobenzoic acid to give the unsymmetrical 4-methylbenzoyl(thiobenzoyl)di~ulfide[~"]
in almost quantitative yield.
The acylsulfenyl iodides 2 obtained are stable for several hours at room temperature, both in the solid state and
in solution (methanol or n-hexane); however, they decompose below SO'C, or on irradiation with sunlight, liberating free iodine.
Experimental
2b: To a suspension of lb'Sbl(0.21 g, 0.5 mmol) in methanol (30 ml) was added 5 mL of 0.1 N 12/CHC13 solution.
The purple colored solution immediately turned yellow.
The mixture was stirred at room temperature for 1 h and
then allowed to stand at ca. -60°C for 1 h. After removal
of the white precipitate (PhHgI) by filtration, the solvent
was evaporated off in uacuo. Recrystallization of the solid
residue from n-hexane (ca. 40 mL) at -60°C gave 0.11 g
(79%) of 2b as a yellow microcrystalline solid.
Received: May 6, 1981 [ Z 982 IEj
German version: Angew. Chem. 94 (1982) 148
Isolation of Crystalline Acylsulfenyl IodidesIntermediates in the 12-Oxidation of Thiocarboxylic
Acids
CAS Registry numbers:
la 79293-05-3; l b 79293-02-0; lc 79293-00-8; Id 79292-97-0; 2a 80461-741;
2b 80461-75-2; 2~ 80461-76-3; 2d 80461-77-4; I?, 7553-56-2.
By Shinzi Kato*, Eiji Hattori, Masareru Mizuta, and
Masaru lshida
Sulfenyl iodides (RSI) probably play a decisive role as
reactive intermediates, both in the iodation reaction in the
thyroid gland"] and in the 1,-oxidation of thiolslzl. However, because of their instability, such compounds have
rarely been in~estigated[~l
since the first attempts were
made by Rheinboldt and M o t ~ k u s [to
~ ]isolate tert-butylsulfenyl iodide.
(?
I
A
RCSHgPh
1
?
RCSI + PhHgI
From a Formyl to a Methyl Complex
2
Table I.Acylsulfenyl iodides 2 by reaction of the phenylmercury derivative
1 with iodine.
Cpd.
21
R
Yield
CoH,
4-CH&H4
4-CH,OC,H,
4-CIChH4
2b
2c
2d
IW
M.p.
I"Cl la1
IR [cm-'1
v(C-0) [bl
72
79
73
64
45-46
40 (dec)
32 (dec)
48 (dec)
1667
1650
1648
1678
[a] Decomposition. [b] KBr
[*I
Prof. Dr. S. Kato, E. Hattori, M. Mizuta, M. lshida
Department of Chemistry, Faculty of Engineering
Gifu University
Yanagido, Gifu 50 I 1 1 (Japan)
150
[ I ] a) H. FrankeCConrat, J. Eio1. Chem. 217(1955) 373: b) J. P. Danehy in A.
Senning: Su&r in Organic and Inorganic Chemisfry, Marcel Dekker, New
York 1971, p. 327.
[2] J. P. Danehy, B. T. Doherty, C. P. Egan, J. Org. Chem. 36 (1971) 2525.
131 The isolation of a penicillin derivative containing an SI moiety was reported in 1973: L. Field, J. E. White, Proc. Nuf. Acad. Sci. USA 70 (1973)
328; Int. J. Sutfur Chem. 8 (1976) 539, and references cited therein.
[4] H. Rheinboldt, E. Motzkus, Chem. Ber. 7 2 8 (1939) 657.
[5] a ) S . Kato, H. Watarai, T. Katada, M. Mizuta, K. Miyagawa, M. Ishida,
Synthesis. 1981, 370; b) S . Kato, E. Hattori, H. Sato, M. Ishida, M. Mizula, Z. Nufurforsch.. B36 (1981) 783.
0 Vertag Chernie GmbH. 6940 Weinheim. 1982
By Heinz Berke* and Gertrud Weiier
Neutral formyl complexes are assumed to be important
intermediates in homogeneous carbon monoxide hydrogenation processed']. However, their thermodynamic instability relative to the products, metal-hydride complex and
carbon monoxide, has, with few e x c e p t i o n ~ [ ~so
, ~ far
] , hindered isolation or investigation of secondary reactions. According to theoretical considerations a formyl moiety in
pseudooctahedral environment should be additionally stabilized by a meridional arrangement of phosphite ligands.
[*I Dr. H. Berke, G. Weiler
Fakultat fur Chemie der Universitat
Postfach 5560, D-7750 Konstanz (Germany)
0570-0833/82/0202-0150 $02.50/0
Angew. Chern. Int. Ed. Engl. 21 (1982) No. 2
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acid, oxidation, acylsulfenyl, crystalline, isolation, iodidesч, thiocarboxylic, intermediate
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