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An Arsinidene as a Cubane-Type Structural Unit Synthesis and Structure of [(CO)3FeЧAsCH3]4.

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By use of the Guinier-Simon technique, a phase transition
is shown to take place in Al(H2P04)3 at 60°C; the very
slight change of the powder diagram suggests that this change
is due to proton reorientation. Since the structure is acentric
and also contains a polar axis, ferroelectricity should be possible.
% r
Received: February 3, 1978 [Z 920 IE]
German version: Angew. Chem. 90,286 (1978)
CAS Registry numbers:
AI(H2POl)p. 13530-50-2
J . H . Morris, P . G . Perkins, A . E. A. Rose, W? E. Smith, Chem. SOC.
Rev. 6, 173 (1977).
P . B . Moore, 7: Araki, Am. Mineral. 59, 974 (1974); R . Kniep, D. Mootz,
A. Vegas, Acta Crystallogr. B 3 3 , 263 (1977); references cited therein.
J . C . Brosheer, F. A . Lenfesty, J . F . Anderson, J. Am. Chem. SOC.76,
5951 (1954); R. F . Jameson, J . E . Salmon, J. Chem. SOC.1954, 4013;
H . Guerin, R . Martin, C. R. Acad. Sci. 234, 1799 (1952).
E . Erlenmeyer, Justus Liebigs Ann. Chem. 194, 196 (1878).
C. F. Callis, J . R . Van Wazer, P . G . Arvan, Chem. Rev. 54, 771 (1954).
969 symmetry-independent reflections (MoKa, Syntex P2, four-circle
diffractometer); 937 reflections were significant (FO > 3 aF),The structure
was solved with the Syntex E-XTL program system: R=2.9 %; rhombohedral ( R ~ c ) , a=13.727(5), c=9.152(1)A, Z = 6 , d,,,,,=2.12,
d , , , . = 2 . 1 0 g ~ m ~ The
~ . positions of the protons could be established
in a difference Fourier synthesis.
An Arsinidene as a Cubane-Type Structural Unit:
Synthesis and Structure of [(CO)3Fe-AsCH3]4[**I
By Erika Rottinger and Heinrich Vahrenkamp~]
The phosphinidene and arsinidene groups RP and RAs
are isoelectranic with the sulfur and selenium atoms, respectively, suggesting that there should be some structural relationship between the transition metal complexes having RP and
RAs, on the one hand, and S and Se, on the other, as bridging
ligands. This is the case for some complexes with metal-metal
bonds"], but not for others. Thus there are still no chalcogen
analogs of the dinuclear p2-phosphinidene and p2-arsinidene
and the large number
complexes described by Huttner et a1.[2J,
of complexes having a cubane skeleton of four metal and
four sulfur atoms[31have no RP or RAs counterparts. We are
confident that expected analogies will be substantiated by
directed syntheses and now report the Fe4As4-cubane(1) as a
relevant example.
The thermolability of the As-H bond in complexes[41was
utilized in the production of complexed p3-methylarsinidene
in (1 ). The stoichiometric Fe : As ratio was already present
in the starting complex (C0)4Fe.CH3AsH2, which decomposes slowly at room temperature, and rapidly on heating,
to form (1). The appearance of only two IR bands in the
CO region (2025 (s) and 1985 (m) cm-') reveals the iron
atoms of product (1) to have C3" symmetry, and a singlet
in the 'H-NMR [6=1.32 rel. TMS internal (in benzene)]
shows the four arsenic atoms to be equivalent. The molecular
ion appears at very low intensity in the F D mass spectrum,
the principal fragment being [(C0)3Fe-AsCH3]:.
Compound (1), crystallizes from benzene/cyclohexane mixtures
as [(C0)3Fe-AsCH3]4.0.75C6H12,
which was used for a
structural determinationrs1.
[*] Prof. Dr. H. Vahrenkamp, DipLChem. E. Rottinger
Chemisches Laboratorium der Universitat
Albertstrasse 21, D-7800 Freiburg (Germany)
[**I This work was supported by the Fonds der Chemischen Industrie
and the Computing Center of Freiburg University. We are grateful t o Dr.
K . Steinbach, Marburg, for the mass spectrum.
Angew. Chem. Int. Ed. Engl. 17 (1978) No. 4
Fig. 1. Molecular structure of tetra-p3-methylarsanediyltetrakis(tricarbonyliron) ( I ) .
The molecules of ( I ) (cf. Fig. 1) are located on threefold
axes in the crystal. In contrast to the comparable complexes
[(C0)3Re-SCH3]4[61, [(CO)30s-O]4[71, and [(C0)3CoSbI4[", they thus have the maximum possible symmetry. Like
the other complexes, (1) also exhibits approximate non-crystallographic Td-43m symmetry and a distortion of the cubane
skeleton arising from the tendency of the M(CO)3 units to
adopt octahedral geometry and the main group element units
to assume tetrahedral geometry. The angles at iron and arsenic are accordingly 75.9k0.1" and 102.6+0.2", respectively.
The Fe-As bond lengths of 241.1f0.5pm are normal, no
metal-metal bonding occurring according to the 18-electron
rule.
The Fe4As4-cubane (1) warrants particular attention on
account of the analogy with Fe4S4 cubanes. It is our aim
to reproduce their varied chemistry[3] by preparative and
electrochemical reactions with (1 ).
Procedure
A solution of CH3AsH2in benzene (IOml, 1.5 M) is added
to a suspension of Fez(C0)9 (1.82g, 5.0mmol) in benzene
(70ml) and the mixture stirred until all the Fez(C0)9 has
dissolved and the formation of (C0)4Fe.CH3AsHz can be
detected by NMR spectroscopy (1 d). Complete conversion
into ( 1 ) is accomplished by refluxing for 4h. Removal of
solvent and recrystallization from n-hexane affords crude ( 1 )
(960mg, 83 %)containing varying amounts of solvent. Crystals
of homogeneous composition are obtained by column chromatography (4 x 50 cm) with cyclohexane on silica gel and subsequent recrystallization from cyclohexanefienzene.
Received: February 6, 1978 [Z 921 IE]
German version: Angew. Chem. 90,294 (1978)
CAS Registry numbers:
(I), 65815-63-6; Fe2(C0)9, 15321-51-4; CH3AsH2, 593-52-2
[I] L. Marko, B. Marko, Inorg. Chim. Acta 14, L39 (1975); R . C . Ryan,
L. F. Dahl, J. Am. Chem. SOC. 97, 6904 (1975); G . Huttner, G . Mohr,
A . Frank, U . Schubert, J. Organomet. Chem. 118, C73 (1976); M . Jacob,
E . Weiss, ibid. 131, 263 (1977).
123 G . Huttner, J . u. Seyerl, M . Marsili, H . 4 . Schmid, Angew. Chem. 87,
455 (1975); Angew. Chem. Int. Ed. Engl. 14, 434 (1975); G . Huttner,
H:D. Miiller, A . Frank, H . Lorenz, ibid. 87, 714 (1975) and 14, 705
(1975), respectively.
273
131 H . Vahrenkamp, Angew. Chem. 87, 363 (1975); Angew. Chem. Int. Ed.
Engl. 14, 322 (1975).
[4] P. Umland, H . Vahrenkamp, Chem. Ber. 110,2809 (1977).
[5] The cubic unit cell of these crystals contains eight heterocubane and
six cyclohexane molecules: P?3n, a = 1873(1)pm; 717 independent reflections, solution of structure with MULTAN program, R=0.051.
161 W Harrison, W C . Marsh, J . Trotter, J. Chem. SOC. Dalton Trans.
1972, 1009.
[7] D. Brighr, Chem. Commun. 1970, 1169.
183 A . S. Foust, L. F. Dahl, J. Am. Chem. SOC.92, 7337 (1970).
2,4,6-Tri-tert-butylphenoxyl(TBPO)as Sterically
Active Carbonyl-ProtectingGroup-A New
Nucleophilic DimethylaminomethylatingReagent
By Dieter Seebach and Tillmann Hassell']
Given adequate steric protection['] of the carbonyl group
of amides such as ( I ) , it proves possible to accomplish their
deprotonation at the a-N-CH3 and --CH2 groups with
strong bases such as sec-butyllithium". 'I. Organolithium derivatives accessible in this way can only be designated as nucleophilic aminoalkylating reagents if the products obtained with
electrophiles can be cleaved to give amines. We have now
found this condition to be fulfilled by the 2,4,6-tri-tert-butylphenoxyl group (TBPO) in the N,N-dimethylcarbamate (2 b)
in which the carbonyl C atom has been displaced from the
two protecting o,o'-tert-butyl groups by an oxygen in comparison with ( 1 ) .
plished with lithium tetrahydridoaluminate in boiling dioxane;
the reaction can be carried out with the crude products ( 4 )
[(4b) pure, gives (5aJr4], 51 % after 24h, 75 % conversion;
(4h) crude, gives (5b)['], 68 % based on (2b) after 6h].
Table 1. Carbamates ( 4 ) prepared by reaction of the lithium compound
(3) with electrophiles.
Electrophile
E in product
(4)
Yield [%]
M.p. r C ]
Iodometbane
I-Iodooctane
Benzyl bromide
2-Iodopropane
Hexanal
Cyclohexanone
Benzaldehyde
Benzophenone
CH3
n-C8HI7
CH2C6Hs
CH(CH3)2
CH(OH)-n-CsHI
C(OH)(CH&
CH(OH)C&
C(OH)(C~HS)~
(4a)
(4b)
( 4 ~ )
(4d)
(4 e )
71
87 [a]
35 [b]
32
80
63
50 [b]
61 [c]
78-79
Oil [a]
132
61-63
111-112
150
128
122
(4f)
(49)
(4h)
[a] See the conversion into the known CH31 adduct of ( 5 a ) . [b] Not
optimized. [c] Cf. higher yield of ( 5 b ) obtained without purification of
(4h).
The TBPO carbonyl group is a regenerablec61group for
acidification of aminesI'], and is readily accessible from
commercially available materials. The lithium compound ( 3 )
acts as a (CH3)'NCH? synthon on cleavage to tertiary amines
such as (5)[']. Other cleavage reactions are possible, and
other amines can be used.
Received: February 8, 1978 [Z 922 IE]
German version: Angew. Chem. 90.296 (1978)
CAS Registry numbers:
( 2 ~ )4511-21-1;
.
( 2 b ) , 65832-33-9; (3), 65832-34-0; ( 4 a ) . 65832-35-1; ( 4 b ) ,
65832-36-2; ( 4 c ) , 65832-37-3; ( 4 d ) , 65832-28-2; ( 4 e ) . 65832-29-3; ( 4f),
65832-30-6; ( 4 g ) , 65832-31-7; ( 4 h ) , 65832-32-8; ( 5 a ) , 17373-27-2; ( 5 b ) ,
5612-62-4; tri-t-butylphenol, 732-26-3; phosgene, 75-44-5; iodomethane, 7488-4; 1-iodooctane, 629-27-6;benzyl bromide, 100-39-0;2-iodopropane, 75-309 ; hexanal, 66-25-1 ; cyclohexanone, 108-94-1; benzaldehyde, 100-52-7; benzophenone, 119-61-9
[l] R . Schlecker, D . Seebach, Helv. Chim. Acta 60, 1459 (1977); R . Schlecker,
D. Seebach, W Lubosch, ibid. 61, 512 (1978); references cited therein.
[2] P. Beak, B. G. McKinnie, D. B. Reitz, Tetrahedron Lett. 1977, 1839;
P. Beak, B. G. McKinnie, J. Am. Chem. SOC.99, 5213 (1977).
Reaction of tri-tert-butylphenol and phosgener3' gives the
chlorocarbonate (2a) (ca. 50 %) which quantitatively affords
(2 b ) (m.p. 121 "C) on treatment with two mol. equiv. of dimeth~ l a m i n e [ ~On
] . stirring of a cooled (ice bath) solution of (2 b)
and tetramethylethylenediamine (TMEDA) (0.1 M in each reagent) in tetrahydrofuran for 90min with sec-butyllithium (10 %
excess) quantitative formation of a clear colorless solution
of the lithium compound takes place, according to 'H-NMR
analysis of a deuterolyzed sample. Compound ( 3 ) reacts with
alk yl halides and aldehydes or ketones to give the carbamates
(4) of the higher amines (4 a-d) and amino alcohols ( 4 e-h)
in the yields listed in Table 1 (recrystallized or chromatographed analytically pure products). The structures ( 4 ) are
confirmed by IR and 'H- and "C-NMR spectra. Cleavage
of the carbamates (4) to tertiary amines ( 5 ) can be accom-
[*] Prof. Dr. D. Seebach
Laboratorium fur Organische Chemie der Eidgenossischen Technischen
Hochschule
Universitatsstrasse 16, CH-8092 Zurich (Switzerland)
DipLChem. T. Hassel
Institut fur Organische Chemie der Universitat
Heinrich-Buff-Ring 58, D-6300 Lahn-Giessen (Germany)
214
[3] The phenol is first treated with NaH in tetrahydrofuran and then, in
the presence of a trace-of dimethylformamide, with 1.1 mol. equiv. of
phosgene (toluene solution). [Production of ( 2 a ) without base: C. W
Stephens, US-Pat. 3211 774; Chem. Abstr. 64,P655f (1966).] After filtration, concentration, dissolution in diethyl ether, and reaction with dimethylamine the product is worked up in aqueous medium and ( 2 b ) separated
from unreacted phenol by filtration over silica gel.
[4] As methiodide, m.p. 168°C [ H . King, 7: S. Work, J. Chem. SOC.1942,
402: 170°C].
[ S ] As hydrochloride, m. p. 235 "C [ E . Eidebenz, Arch. Pharm. 280,48 (1942):
234"CI.
[6] The phenol can he recovered quantitatively on LiAIHI cleavage
( 4 ) --t ( 5 ) .
[7] Cf. D. J . Peterson, Organomet. Chem. Rev. A 7 , 295 (1972); D. Seebach,
K.-H. Geiss, J. Organomet. Chem. Library 1, Elsevier, Amsterdam 1976,
pp. 1-92 and references cited therein.
Reactivity of a Sulfonium Ion in Layer Silicates of
Montmorillonite Type
By Jiirgen Gosselck and Ingfried Stahl"]
The intercalation of organic compounds in layer silicates
has been known for a long time. Both neutral molecules
and organic cations-including sulfonium ions[']-can be
intercalated['! We have now examined the reactivity of a
[*] Prof. Dr. J. Gosselck, Dr. I. Stahl
Bereich Organische Chemie (ONM) der Gesamthochschule
Heinrich-Plett-Strasse 40, D-3500 Kassel (Germany)
Angew. Chem. Int. Ed. Engl. I7 ( 1 978) N o . 4
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