close

Вход

Забыли?

вход по аккаунту

?

Tetrakis(methylmercurio)phosphonium Salts.

код для вставкиСкачать
C 0 M M U N I CATION S
Tetrakis(rnethy1mercurio)phosphonium Salts"*'
By Dietrich Breitinger, Klaus Geske, and
Walter Beitelschmidt"'
We have extended our studies of (methy1mercurio)ammonium complexes".
to compounds of elements of
Group VB. We have prepared tetrakis(methy1mercurio)phosphonium salts [P(HgCH,),]X, where X = BF,, PF,,
or SbF,, by the action of phosphane on methylmercury
compounds CH,HgXr3'.
The IR and Raman spectra indicate point group T, for
the cation [P(HgCH,),]+. Assignment of the vibrations
of the central PHg4 tetrahedron (corresponding values for
[N(HgCH3)4]i are given in parentheses) follows from the
selection rules, band intensities and band form, polarization state in the Raman effect (RE) and splitting in the
solid-state spectrum (site symmetry effects): v1 (al)
119cm- (RE, polarized : pz0)(141 cm- I), v3 (t,) 354 cm(IR; RE, depolarized) (584 cm-I), v4 (t2)54 cm-' (- ;RE)
(66 cm- I). The force constants for the P-Hg-(N-Hg)
bond are esti?ated from the y1 (al) vibrations as f i 3 f
=1.7, mdyn.A-' (2.5, mdyn.A-'). The P-Hg bond is
obviously weaker than the N-Hg bond.
'
'
X-ray analysis of single crystals of [P(HgCH,),]PF,
showed :pace group qz,-P 2,/c a9d the lattice parameters
a=8.28A, b=16.59A, c=12.15A, and p=92.3"; with
2=4, d,,,,=4.17g.~m-~ to be compared with dabs
=4.12g.cm-3. The compound was thus shown to be isotypic with the analogous ammonium salt[']. From the
number of formula units in the unit cell, from group-theoretical considerations, and from the IR spectrum of the
anion the cations and anions could be assigned to general
positions.
Experimental :
CH,HgX was prepared by metathesis of AgX with methylmercury bromide in diethyl ether or 2-propanol. Phosphane was led into the solution at room temperature with
exclusion of air, until the crystalline precipitate that was
rapidly formed no longer increased in amount. Recrystallization from 2-propanol gave, for example, analytically
pure [P(HgcR3),]PF6 in 10%yield (based on CH,HgBr).
Received: April 27,1971 [Z 426 IE]
German version: Angew. Chem. 83, 577 (1971)
[I]D. Breitinger and Nguyen Quy Dao, J. Organometal. Chem. 15.
P 21 (1968).
[2] Nguyen Quy Dao and D.Breitinger, Spectrochim. Acta, in press.
[3] Professor G. Schwarzenbach, Zurich, has informed us that
[P(HgCH,),]CIO, (explosive) was prepared in his School some time
ago but was not studied further.
[ 4 ] We thank Dr. K . Getbel, Institut fur Organische Chemie der Universitat Erlangen-Niirnberg, and Dr. D.Scheutzow, Institut fur Organische Chemie der Universitat Wurzburg, for measurement of the NMR
spectra.
[5] G. Beringer, unpublished work.
H[PO,CIF] and H[PO,BrF], Two New
Djhalooxophosphorus Acids["]
Fig. 1. 'H-NMR spectrum of [P(HgCH,),]PF, (saturated CD,CN
solution; 9 0 M H z ; CHD,CN at r=8.09ppm); left, main signal resolved.
In the 'H-NMR spectrum[41of [P(HgCH,),]PF, (Fig. 1)
the main signal is at T =9.28 ppm (9.27 ppm). This indicates
similar distribution of the cationic charge over the peripheral H atoms in the phosphonium and the ammonium
complex (Pauling electroneutrality principle). The constants for the short-range coupling between 'H and 199Hg
are found to be ' J = JmCH= 155 Hz (173 Hz), corresponding to the differing electronegativities of the central atoms.
Coupling between the peripheral protons and the central
P atom leads to a doublet splitting of main signal and
satellites with 3J =JPHgCH
= 4.8 Hz. Finally, long-range
coupling effects appear, due to the various nuclide compositions of the cations p(199HgCH3)n(200HgCH,)4-,]t
(Y = N, P ;O < n < 4 ; "'Hg represents all the non-coupling
Hg nuclides); the coupling constants 4J=JHgYmc,
= 2., Hz
(3.' Hz) are found.
[*] Priv.-Doz. Dr. D. Breitinger, Dipl.-Chem. K. Geske, and
Dip].-Chem. W. Beitelschmidt
Institut fur Anorganische Chernie der Universitat
852 Erlangen, Fahrstrasse 17 (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie.
Angew. Chem. internat. Edit. 1 Vol. 10 (1971)
No. 8
By Hans Falius and Klaus-Peter Giesen"'
Of the free dihalooxomonophosphorus(v) acids, only the
compounds H[PO,F,] and H[PO,Cl,] are as yet known,
while a dibromo acid could be obtained only in the form
of its salts"'. Of the mixed dihalooxo acids only a few
esters, alkylamides, and arylamides have been described"],
and the free mixed acids are all previously unknown ; they
cannot be prepared from organic derivatives as the phosphorus-halogen bond is cleaved by hydrolysis.
The flu(,1.ophosphorus(rrr) acid, H[PHO,F], obtained
recentl! ' I. appeared to be suitable as starting material for
preparation of mixed halofluorophosphorus acids. Its
reaction with chlorine or bromine in fact rapidly gave the
two mixed dihalo acids H[PO,ClF] ( I ) and H[PO,BrF]
(2),respectively.
H[PHOzF]+XZ
--*
H[POzXF]
(1) ; X = C l
(2); X=Br
+ HX
[*] Prof. Dr. H. Falius and DipLChem. K.-P. Giesen
Institut fur Anorganische Chemie der Technischen Universitat
33 Braunschweig, Postfach 7050 (Germany)
This work was supported by the Fonds der Chemischen Industrie
and the State of Niedersachsen.
[**I
555
Документ
Категория
Без категории
Просмотров
3
Размер файла
124 Кб
Теги
salt, phosphonium, methylmercury, tetrakis
1/--страниц
Пожаловаться на содержимое документа