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B8S16ЧAn УInorganic PorphineФ.

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be stabilized by coordination to a metal. Unfortunately,
the precursor for the synthesis of
Cr(CO),CNNH2121is not easily acce~sible~~l.
In search of a suitable "form of storage" of isodiazomethane we have now been able to prepare N-isocyanoiminotriphenylphosphane
according to
+ 2PPh, + 2CC14 + 2NEtx +
+ 2HCCI, + 2[NEt3H]C1+ OPPh,
The surprising stability (dec. pt. 159-160°C) of this functional N-isocyanide is apparently due to the masking of the
primary amine function.
Apart from synthetic route and IR spectrum [(KBr): 2067
w (u(CN)), 1117 s, 1009 sh (u(P=N)) cm-'1 it is particularly
its strong tendency to form complexes, which proves (1) to be
an isocyanide. Thus, the stablef5]complexes (2a-c) and (3)
are formed smoothly from tetrahydrofuran or bromo derivatives and (I), respectively. No more problems arise in the
syntheses of (4) and (5) by, respectively, addition of (I) to
(2a-c), M = Cr. Ma, W
PdIz and cleavage of the bridge in [PtCl(PPh3)2]2[BF4]2.
Complex formation is accompanied by an increase Au(CN)
in the u(CN) frequency, which in the case of N-isocyanides
reaches values up to 130 cm-' (Pt" complexes)[']. In view of
the high Au(CN) values found here, and the low-lying CO
bands of the pentacarbonylmetal moiety [(2a): KBr: 2055 s
[A,], 1924 vs [El cm-'1 (I) is primarily a donor ligand, i.e.
bonding in metal complexes of (1) is perhaps best described
by the resonance formula
As expected, the iminophosphorane bond in (2) can be
cleaved hydrolytically under conditions leaving the rest of
the molecule untouched. The isodiazomethane complexes
(6)121formed in >70% yield according to
(2) + H2O _ _ M(CO)SC_N--NH2
+ OPPh,
are stable enough to be sublimed after chromatographic separation from phosphane oxide.
(2) reacts with aldehydes and ketones in a Wittig-type
reaction to give complexes (7) with N-isocyanoiminoalkane
(2) + R R ' C - - 0
+ OPPh,
_ j
All solvents and reagents must be anhydrous and, where
necessary, saturated with NZ.
(1): A suspension of PPh3 (157.4 g, 0.6 mol) in CHzClz
(600 ml) is treated with 50.6 g (0.5 mol) of NEt, and 15.3 g
(0.25 mol) of formylhydrazine and heated to 50-60 "C.CCl,
(77.0 g, 0.5 mol) is added dropwise to the mixture, which is
kept at 50-60°C for 4-5 h. After removal of the volatile
components at room temperature, the residue is dried in a
high vacuum, pulverized, stirred in 200 ml ethanol/water
(1 : 1.5), filtered, and recrystallized from hot ethanol; yield
31.7 g (42%) ( 1 ) as orange-brown crystals.
(2c): A solution of W(CO), (1.76 g, 5 mmol) in tetrahydrofuran (100 ml) is irradiated until -110 ml of CO have
evolved. The solution is then cooled to - 30 "C, mixed with
1.39 g (4.6 mmol) of (I), stirred for 2 h at -30 "C, and for 1 h
at 0 "C. After removal of the solvent (0 "C, high vacuum) and
sublimation of W(CO)6, the residue is extracted with 6 x 50
ml boiling petroleum ether (40-60 "C), the extract filtered
rapidly through filter-cellulose, concentrated to ca. 1/3 of its
volume and transferred to a refrigerator. Pale yellow (2c)
crystallizes out; yield 2.91 g (93%).
(7), M = W, R = R'= CH,: Dry HCI gas is passed into a solution of (2c) (0.63 g, l mmol) in acetone (30 ml) for ca. 1/2
min. The solution is stirred for 2 h, the solvent removed, and
the mixture chromatographed on silica gel with CH2C12/nhexane (4:l). After evaporation of the solvent 0.20 g of a
pale yellow solid (50%, m.p. 86.5 "C) are left behind.
Received: January 2. 1980 [ Z 484 IE]
German version: Angew. Chem. Y2, 478 (1980)
[ I ] E. Muller, P. Kadner, R. Beutler, W Rundel, H. Suhr, B. Zeeh, Justus Liebigs
Ann. Chem. 713, 87 (1968).
121 W. P. Fehlhammer, P. BuraEas, K. Bartel, Angew. Chem. BY, 752 (1977); Angew. Chem. Int. Ed. Engl. 16, 707 (1977)
(31 N Wiherg. G Huhler. Z Naturforcch R 31. 1317 (1976)
[4] Similar results have been obtained with Br2PPhl/NEt, [L. Horner. H . Oediger, Justus Liebigs Ann. Chem. 627, 142 (1959); H. J. Besrmann. J. Lienert, L.
Moll, ibid. 718.24 (1968)j in the place of the Appel three-component reagent
[R. Appel, Angew. Chem. 87, 863 (1975); Angew. Chem. In! Ed. Engl. 14.
801 (1975)J.
151 In contrast. PhrPN-NCO and Ph-PN-NCS which, according to the "6electron chalcogen atom/ 16-electron metal fragment" analogy should be
comparable with metal complexes of / I ) . were formulated only as lahile intermediates: R. Appel. G.Siegemund. Z. Anorg. Allg. Chem. 363, 183 (1968).
161 W. P. Fehlhammer. Habililationsschrift. Universitat Munchen 1976.
171 I. Hagedorn, U. Eholzer, Angew. Chern. 74. 499 (1962); Angew. Chem. In!.
Ed. Engl. 1.75 (1962).
[S] Cr(CO)sNCNPPh, had been synthesized previously (by photolysis of
Cr(CO)* in the presence of NCNPPL,) and studied IR spectroscopically: H.
Bock, H. fom Dieck, Z. Anorg. Allg. Chem. 345, 9 (1966).
BsSl6-An "Inorganic Porphine"[**l
By Bernt Krebs and Hans- Ulrich Hurter"]
e.g. R=R'=CH3; R=ChHS,R ' = H
In this way, a class of compounds becomes readily accessible in metal complexes, of which only one representativeCNN= -C(CH3)C,H4-p-OCH3-has so far been characterized
in free forml'l.
There is definitely more synthetic potential in pentacarbonylmetal(6A) complexes of (I) as shown by the acid-catalyzed isomerization to the complex cyanamide (8), which is
complete in 2-3 d at room temperature1*lI.
This reaction proceeds particularly smoothly and quantitatively in the presence of palladium(I1) compounds in a CO atmosphere.
Angew Chem. 1111. Ed. Engl. 19 (1980) No. 6
The preparation and characterization of boron sulfides is
difficult. The only compound to have been unequivocally
identified in the solid state is B2S3, which has a polymeric
structure made up of B3S3 six-membered rings and B2S2
four-membered rings[']. The existence of BI2S,B4S, BS, and
B2S5121 as defined phases has not yet been confirmed. The
Prof. Dr. B. Krebs. Dip1.-Chem. H.-U. Hurter
Anorganisch-chemisches lnslitut der Universitat
Gievenbecker Weg 9, D-4400 Miinster (Germany)
["I This work was supported by the Minister fur Wissenschaft und Forschung
des Landes Nordrhein-Westfalen and the Fonds der Chemischen Industrie.
0 Verlag Chemie, GmbH. 6940 Weinherm, 1980
$ 02.50/0
48 1
only evidence for a species of composition BS2 has so far
come from mass spectrometry and thermal analysi~[~.'~.
During our studies on binary and ternary boron sulf i d e ~ ~ ' . ~we
' have now obtained a new boron disulfide of
molecular formula B8Sibby two different routes. Rapid heating of a B2S,/S mixture (molar ratio 1:1.5) to ca. 300 "C at
bar in a sealed quartz glass
which has been
graphitized or protected by a boron nitride coating, in a twozone furnace with a sharp temperature profile (300/1OO "C)
leads to deposition of a crystalline product within a narrow
region in the colder zone of the reaction tube. The colorless
needles are up to 2 mm long, extremely sensitive to hydrolysis, and decompose above 115 " C in a sealed vessel under
normal pressure (Nz).
The compound [elemental analysis B :S = 1:2.01(2)] forms
monoclinic crystals (space- group P2,/c), a = 12.158(3),
b=4.089(1), ~=21.961(4) A, @ = 107.65(3)", Z = 16 BS2,
V = 1040.4 A3, pLalL=1.913,pexp=1.90(2) g cm-'. As shown
by the complete X-ray structure analysis (1349 diffractometer data, R = 5.5%), solid boron disulfide is made up of discrete exactly planar BsSi6 molecules whose porphine type
skeleton contains four 1,2,4,3,5-trithiadiborolanerings linked
by sulfur bridges. Figure 1 shows the molecular structure
with distances and angles averaged over chemically equivalent bonding parameters. Within the limits of experimental
accuracy the molecule has Dlh symmetry (exact symmetry in
the crystal is C,). The average B-S bond length (1.811 A)
affords the porphine-like B8Si6in ca. 6% yield along with polymeric (B2S& chains made up of S-linked B2S3 five-membered rings['l. Cyclization can be promoted in the reaction
mixture by addition of d Xor d9-transition metal compounds;
the geometry of the BXSi6molecule permits formation of interesting transition metal complexes having square-planar
coordination of the tetradentate ligand (transannular S . .. S
distance in B,S,,,: 4.667 A).
In addition to other fragmentation products, the mass
spectrum shows B2S; as fragment of maximum intensity. The
Raman spectrum contains bands at 942, 935, 883, 861, 835,
590, 530, 518, 462, 439 (vs), 344, 328 c m - ' in the region of
stretching vibrations.
Received January 8, 1980 [Z 485 IE]
German version: Angew. Chem. 92. 479 (1980)
CAS Registry numbers:
BxS,,. 73825-17-9; 3.5-dibromo-l.2.4,3,S-trithiadiborolane,13863-77-9; SC(SH)2,
H. Diercks, B. Krebs, Angew. Chem. 89. 327 (1977): Angew. Chem. Int. Ed.
Engl. 16, 313 (1977).
Cf. Gmelin Handbuch der Anorganischen Chemie, Erganzungswerk zur 8.
Aufl., Bd. 19. Borverbindungen Teil 3. pp. 6ff. Springer-Verlag. Berlin 1975;
and further references cited therein.
F. T. Greene, P. W. Gilles. J. Am. Chem. Soc. 86. 3964 (1964): H. Chen. P. W.
Gilles. ibid. 92, 2309 (1970).
a) B. Krebs, H. Diercks. Acta Crystallogr. A 31, S66 (1975); b) Inorg. Chem..
in press; c) B. Krebs, H - U . Hiirfer. Z. Naturforsch. B. in press.
0.Gropen, P. Vussborn. Acta Chem. Scand. 27. 3079 (1973).
H. M . Serp, R. Seip, W. Sieberf, Acta Chem. Scand. 27, 15 (1973); A. Almenningen, H . M . Seip, P. Vussborn, ibid. 27, 21 (1973).
M. Schmidt, W. Sieberr, Angew. Chem. 76. 687 (1964); Angew. Chem. In!.
Ed. Engl. 3. 637 (1964); Chem. Ber. 102, 2752 (1969): and further references
cited therein.
B. Krebs, G. Guttow, Z. Anorg. Allg. Chem. 338, 225 (1965).
Under milder conditions, this condensation reaction of (XB)2S, with
SC(SH)>can be used to prepare new boron-carbon-sulfur compounds.
Hexakis(dimethylamino)cyclohexaborane, a Boron(1)
Compound without Electron Deficiency
By Heinrich Noth and Hans Pommereningl']
Dedicated to Professor Rolf Huisgen on the occasion of
his 60th birthday
Fig. I.BXSlhmolecule with bond lengths [A] and bond angles (u=0.003
A and
0.1', respectively).
The molecular structures of boron@) compounds in the
solid state are characterized by B,-polyhedral frameworks:
B4C14 a tetrahedron ( 1 u f f a 1BRCIR
a square antiprismlib],
(BCl)lo(CH)zand BlzH:; an
however, in solution B4CL shows a "B-NMR signal at 6 = 85
relative to BF3.OEt212"1,which would contradict a closo
structure, yet support presence of threefold coordinated boron (the same applies for B4Br4fZbl).According to
B4C14 could therefore adopt the four-membered ring structure (16) in solution. If this assumption is supported by further findings, then a polyhedral ring rearrangement
corresponds approximately to that in B& (1.808 il")
once again, in agreement with the planarity of the molecule,
is indicative of strong ( p - p ) ~interactions. The significant
difference between the two types of B-S bond lengths in the
five-membered rings (Fig. 1) provides the first confirmation
of the differing T bond orders estimated by C N D O calculations on trithiadiborolane~l~~.
The similarity of the structural
characteristics to those of dimethyl- and dichloro-1,2,4,3,5trithiadiborolane in the gas phase161 demonstrates the remarkable, substituent-independent constancy of the bonding
in the stable five-membered ring.
A second synthetic route leading to BsSlbwas found in the
thioIysis of the halogenated trithiadiborolanes described by
would be demonstrated for the first time in the realm of borSchmidt and SiebertI7]. Thus reaction of 3,5-dibromoon chemistryf41.Apparently, neither the energy difference be1,2,4,3,5-trithiadiborolane with trithiocarbonic acid as a n
tween the two structural isomers is particularly large, nor the
HZSgeneratorl'l in dilute CS, solution according to
0 Verlag Chemie, GmbH, 6940 Weinheim, 1980
Prof. Dr. H. Noth, Dr. H. Pommerening
lnstitut fur Anorganische Chemie der Universitat
Meiserstr. I , D-8000 Mhnchen 2 (Germany)
0570-0833/80/0606-482 $ 02.50/0
Angew. Chem. Int. Ed. Engl. 19 (1980) No. 6
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