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Organometal-Substituted Phosphines having a Cage-Like Structure.

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Organometal-Substituted Phosphines having a
Cage-Like Structure[**]
By H. Schumunn and H . Bendu [*I
Di- and trifunctional organometal halides react with phosphine, alkali-metal phosphides, or alkali-metal organophosphides to give not only polymeric but also oligomeric organometallophosphines having a cage-like structure. Thus we
recently reported on the synthesis of cho-tetrakis(pheny1stannylphosphine) [XJ.
If a benzene solution of phenyltrichlorosilane or phenyltrichlorogermane and a suspension of dipotassium phenylphosphide in monoglyme/ether are simultaneously added
under argon to a 2 : 1 mixture of diethyl ether,'monogIyme,
a cu. 60 % yield of colorless doso-tetrakis(phenylsily1)hexakis(pheny1phosphine) ( I ) or pale-yellow rho-tetrakis(phenylgermyl)hexakis(phenylphosphine) (2) is obtained
alongside potassiumIchloride and small amounts of insoluble
polymers.
R
benzene; one third of the solution is transferred, together
with ether (60 ml) and monoglyme (30 ml), to a three-necked
flask that has been flushed out with dry argon. The remaining
two thirds of the solution is then added dropwise and simultaneously with a suspension of dipotassium phenylphosphide
(0.03 mole) in monoglyme (50 ml), over a period of 4h with
stirring. After six hours' stirring, half of the solvent is removed under reduced pressure, the solution is filtered, and the
filtrate is concentrated until it becomes oily. Repeated extraction with petroleum ether and methylcyclohexane, dissolution in benzene, and fractional precipitation with pentane/
methylcyclohexane affords almost pure crystals, which can
be recrystallized from toluene/methylcyclohexane.
(3) and ( 4 ) : Solutions of butyltrichlorostannane (5.7 g,
0.02 mole) or phenyltrichlorostannane (6.0 g, 0.02 mole),
phenylphosphine (3.3 g, 0.03 mole), and triethylamine (6.1 g,
0.06 mole) in benzene are simultaneously added dropwise at
the same rate to benzene (150 ml) under dry argon. The resulting precipitate is removed after six hours' stirring. On fractional precipitation with pentane/methylcycloliexane, the
clear concentrated benzene solution yields a product that
proves pure on thin-layer chromatography.
Receiyed: October 15, 1969
[Z 113 IEI
German version: Angew. Chem. 81, 1049 (1969)
-~~
[*I
( I ) , It
(2). I?
= C6H5, M = Si
= C,H5, M =
Ge
The crystals of ( I ) and (2) are soluble in benzene, sensitive
to oxygen, and decompose, without melting, above 125°C
with blistering; their homogeneity was established by thinlayer chromatography [21. Complete elemental analyses, the
cryoscopically determined molecular weight, and the IR
spectra [ ( I ) : vSi-P at 406, 348, and 326 cm-1; (2): vGe-P
at 390, 334, and 309cm-11 confirm the adamantane-type
structure, which has also been found for the corresponding
organosilyl[31, organogermyl[41, and organostannyl[51 sulfides.
By contrast, the reaction of butyl- or phenyl-trichlorostannane with phenylphosphine in the presence of triethylamine affords a cu. 25 % yield of benzene-soluble closo-bis(butylstannyl)tris(phenylphosphine) (3) or cbso-bis(pheny1stannyl)tris(phenylphosphine) ( 4 ) , together with polymeric
products.
Doz. Dr. H. Schumann and Dr. H. Benda
Institut fur Anorganische Chernie der Universitat
87 Wurzburg, Rontgenring 11 (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chernischen Industrie. We are
grateful to Dr. G. Engelhardt, Berlin-Adlershof, for recording
the 31P-NMR spectra.
[l] H . Schumann and H. Bendu, Angew. Chem. 80, 846 (1968);
Angew. Chem. internat. Edit. 7, 813 (1968).
[2] MN-Polygram Cel 300/UV 254, Macherey-Nagel and C o . ;
methylcyclohexane/dioxaneas mobile phase.
[3] J. A. Forsfner and E . L. Muetterties, Inorg. Chem. 5 , 552
(1966).
[4] K. Moedritzer, Inorg. Chem. 6, 1248 (1967).
[51 M . Komura and R . Okawaru, Inorg. nuclear Chem. Letters
2, 93 (1966); C . Dorfelt, A . Juneck, D . Kobelt, E . F. Puulus, and
H. Scherer, J. organometallic Chem. 14,P 22 (1968).
[6] 10% solution in benzene, 85;" H3P04 as external reference.
[ 7 ] Nujol mull, capillary.
Rotational Isomerism of
N2-Methyl-N2-phenylthioformohydrazide111
By W . Wulter and H. Weiss"*l
P
The colorless compounds (3)and ( 4 ) are sensitive to air and
melt at 89-91 OC (decomp.) and 133-135 "C, respectively.
The trigonal-bipyramidal structure is in accord with the
cryoscopically determined molecular weights, the results of
elemental analyses, the 31P-NMR spectra[61 [(3) shows a
singlet at +5.2 ppm], as well as the I R spectraC71 [vSn-P at
375, 328, 305 ((3)), and 362, 320, 296 cm-1 ( ( 4 ) ) ] .
Procedure:
( 1 ) and (2): Phenyltrichlorosilane (4.2 g, 0.02 mole) or
phenyltrichlorogermane (5.1 g, 0.02 mole) is dissolved in
Angew. Chem. internat. Edit. 1 Vol. 8 (1969)/ N o . I 2
A number of Nz,N2-dialkylthioformohydrazides exhibit betaine-thioacyl tautomerism 12931. In the case of N2,Nz-diethylthioformohydrazide it was assumed 131 that a n additional
rotational isomerism (E-Z isomerism) occurs in solutions of
thioacyl tautomers, as is generally observed in thioamides [I].
We report here on N2-methyLN2-phenylthioforrnohydrazide
( I ) , which does not form a betaine and permits direct observation of the rotational isomerism. The compound crystallizes in two forms having different melting points and exhibiting different IR- and UV spectra.
In carbon tetrachloride a n equilibrium is rapidly set up between ( l a ) and (Ib) [about 10% ( l a ) : 90% ( I b ) ] . Nevertheless, the bands could be assigned to the two isomers by
comparison with those of the rotational isomers of thioamides [41.
Since rapid isomerization occurs in solution the signals of
both forms, i.e. of ( I u ) and ( l b ) , appears in the 1H-NMR
spectrum. In CDC13 the formyl proton of the E form ( I b )
couples with the N-H proton to give a n AB system. The
coupling constant is of the same order of magnitude as in
N2,N2-diethylthioformohydrazide[31 and in thioamides [51,
989
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