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Hexakis(trifluorophosphane)vanadium Hydride.

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if the electron in the C4-O antibonding orbital (b2 changes
to the C4-O bonding orbital @3. If this internal conversion
(“o-coupled”[*] transition from H to D) occurs sufficiently
+,.
Fig. 3. Energy sequences of the orbitals
x*, and
isomer of cyclobutanone for ! k c a . 190 and p>cu. 190
of the “stretch
rapidly to preclude thermal equilibration at H then the mobile
molecule continues its initial motion after reaching D and
thus arrives at Erg].
Just as an electron in (b2 favors bending of the three-center
system O-C1-Cz,
an electron in the x* orbital of the CO
group of the x*,n-excited cyclobutanone will cause the oxygen
to become twisted out of the molecular planer”]. In order
to discover the effect of this tendency on our unrealistic,
but transparent model, we have calculated a second energy
surface for the lowest EH excited state with the 0 atom
twisted out of the molecular plane by 30‘. The new energy
curve A’*-H’ corresponds qualitatively to that one characterized by A*-H. The lower energy of the former curve is a
consequence of o*x*admixture in the nonplanar system. In
this way crossing of the energy surfaces of the “x*,n”- and
“o*,n”-excited stretch isomers is avoided : the crossing point
G of the energy surfaces of the n*,n- and o*,n-excited stretch
isomers becomes a true maximum G’.
According to our simple model, the light-induced cyclobutanone-tetrahydrofurylidene isomerization is a diabatic rearrangement in which the oxacarbene is formed in the photochemical primary process[’’!
Hexakis(trifluorophosphane)vanadium Hydride“]
By Thomas Kruck and Hans-Ulrich hemp el['^
Although trifluorophosphanemetal hydrides are characterized
by a considerably greater thermal stability than the carbonylmetal hydrides, which have comparable compositions and
structures, corresponding derivatives have so far only been
obtained for metals of Groups 7A and 8 (type HM(PF3)s:
M = M n , Re; type H,M(PF,),: M = F e , Ru, 0 s with n = 2 ;
M = Co, Rh, Ir with n = l)r21. However, the stabilization of
transition metal-H bonds by PF3 ligands provided an early
indication that the first hydrido complex (3) to be isolated
would be a stable vanadium compound HVL, in which the
central atom could assume the true coordination number
7. Our successful synthesis is based on complete CO/PF3
exchange on a carbonylmetalate( - I). This preparative finding
itself appears remarkable since complete substitution of CO
by PF3 ligands has hitherto only been accomplished with
carbonylmetal(0) complexes.
UV irradiation of a solution of bis(dig1yme)sodium hexacarbonylvanadate(1) ( 1 )I3’ in di(2-methoxyethyl) ether (diglyme)
saturated with trifluorophosphane afforded an almost quantitative yield of hexakis(trifluorophosphane)vanadate(- I),
which is isoelectronic with Cr(PF3)6and likewise has an octahedral configuration, in the form of its colorless bis(dig1yme)sodium salt (2).
[ I I] D C.. Moirlr. Pan. J. Phys. 47. 1235 (1969).
The composition of (2) was established by elemental analysisE41and by its IR spectrum [vp- (cm- I ) in KBr :867 S, 833 VS,
778 s].
The hydrido complex (3) can be obtained in almost 70%
yield from (2) by the action of 90% phosphoric acid and
subsequent sublimation at 60 C/10-2 torr. Further sublimation of the product over P4010 furnishes (3) as pale yellow
crystals which d o not decompose below 135 C when heated
in a sealed tube. The compound is sparingly soluble in saturated hydrocarbons and owing to its strongly acidic character
it reacts with oxygen- and nitrogen-containing donor solvents
with spontaneous formation of onium salts.
The IR spectrum of gaseous (3) contains two bands in the
V P - F region at 911 vs and 846 s cm-‘ and is thus almost
identical with that of hexakis(trifluorophosphane)chromium(o)
[ V P - F (gas): 916 vs, 851 s cm-’1. This indicates that hexakis(trifluorophosphane)vanadiumhydride has a structure deviating only insignificantly from a regular octahedron.
Further evidence for the presence of a true complex metal
hydride comes from the following findings:
I ) The substance is diamagnetic[“’ having xrn = -236x lo-’
cm mol I.
2) The mass spectrum‘“’ (20eV) displays the molecular ion
at m/e 580 and fragments derived by successive loss of PF3
from the ions HV(PF3): (m/r 492) and V(PF3): ( m / r 491).
The absence of V(PF3)hf (m/e 579) is remarkable.
3) The ‘H Fourier NMR spectrum[‘’ of a solution of (3)
in Ni(PFj)4 contains a five-line multiplet centered at 18.4~:
the remaining two of the theoretically predicted seven lines
[ I21 For the possible consequences of explicitly accounting for clectron-electron interaction see ref. [13].
[*] Prof. Dr. Th. Kruck and DipILChem. H.-U. Hempel
Received: September 4. 1973:
revised: November 2. 1973 [Z 919d I t ]
German version: Angew. Chem. 86. 200 i 1974)
[ I ] 18th Communication on Light-Induced Reactions. This work was supported by Farbwerke Hoechst AG, the Deutsche Forschungsgcmeinschaft,
and the Fonds der Chernischcn Industrie. The calculations were performed
at the Computing Center of Frankfurt University.-- 17th Communication:
ref. 1-11.
[2] D. R. Morron and N J . Xrrro, J. Amer. Chem. Soc. 95. 3947 11973):
and further literature cited therein.
[ 3 ] W - D . Srohrer, G. Wiivh, and G. QirinLvrt, Angew. C‘hem. 86, 199 i 1974):
Angew. Chcm. internat. Edit. IJ. 199 (1974). the designation “oxacarbenes“
has become accepted for cyclic organooxycarbenes.
[4] W - D . Srohriv and R. Hofmunn. J. Amer. Chem. Soc. 94, 1661 (1972).
R. Hufinunn, J. Chem. I’hys. 39. 1397 11963): 40, 2745 (1964).
151
[6] R Hoffniunn, Accounts Chem Rcs. 4, I (1971): and further literature
cited therein.
[7] R . GI&c++, W-D. Srohrc~r,and R . Hoffnzunn, Hclv. Chim. Acta j g . X93
(1972): P. Bud, R. Glrirur, and G . Kdhrich, Chem. Ber. 103, 1431 11970).
[ X I A . W J . D . D c i l r r s , J . W V w h o r c m . and W N . S p d u m p . Tetrahedron
29, 1691 11973). and further literature cited therein.
[9] Our stereochemical findings rule out that molecules that have arrived at
D by internal conversion partition themselves between reaction paths leading
to E or C respectively [lo]
[lo] G. Quinkcrr. 1’. Ju<oh,>,and W - D . Srohrvr. Angew. Chem. 86, 197 11974):
Angcw. Chem. internat. Edit. 13. 197 (1974).
[ 131 W - D . Srohrw, P. Jo<oh.s, K. H. Kaiser, G. Wirch, and G. Qi,inli,rr,
Fortschr. Chem. Forsch. 46, 181 (1974).
Angrw. Chrm. inremar. Edit.
Vul. 13 ( 1974) J No. 3
~
-
~
lnstitut fur Anorganische Chemie dcr Univcrsitat
5 Koln 41. Hacdcnkampstrassc 2 (Germany)
201
are apparently not registered owing to the low solubility of
(3).
In addition to HV(C0)3(n-C6H3(CH3)3)151
we now have
another defined hydrido complex of vanadium in HV(PF,),.
Whether the above synthetic route is suitable for the preparation of hexakis(trifluorophosphane)metal hydrides of higher
homologs of vanadium which may also be capable of existence
is currently under study.
Experimental:
All operations are performed under nitrogen; the solvents
are purified in the usual way and saturated with nitrogen.
Bis (diglyme) sodium hexakis (trifluorophosphane) vanadate(1)
(2)
A solution of ( 1 ) (7.00 g, 13.7 mmol) in diglyme (150 ml) is
cooled to -45°C and saturated with PF, in an irradiation
apparatus (Duran 50) with internal cooling and an external
vacuum jacket. The vigorously stirred reaction mixture is
irradiated for 24 h with an external high-pressure mercury
arc lamp (Q 600 Hanau) until evolution of CO is no longer
observed. The solution must be resaturated several times with
PF3 during the reaction. The solvent is then removed in
a high vacuum and the residue washed twice with light petroleum. The product thus obtained is sufficiently pure for the
synthesis of (3). Analytically pure samples are obtained by
recrystallizing from diglyme with light petroleum. Yield :
11.64g (98%).
Dianions of this kind have hitherto been generated exclusively
by reaction of carbonyl derivatives with alkali metals"]. We
.I
I
I/
131
14)
now report the first preparation of such a reagent with X = S
by double metalation of the corresponding hydrogenated precursor.
Reaction of a solution of lithium benzyl sulfide (3) with
n-butyllithium, in the presence (2.5 h) or absence (4.0h) of
tetramethylethylenediamine (TMEDA), at - 5 "C in THF/pentane (1 : 1) leads to an orange-colored suspension of the dilithium salt ( 4 ) . The presence of the dianion is deduced from
its reactions with various electrophiles, which we generally
add at - 78 "C. The products listed in Table 1 can be divided
into three different types ( 5 ) , ( 6 ) , and (7).
Hexakis(trifluorophosphane)vanadiwn hydride ( 3 )
Compound (2) (5.00g, 5.7 mmol) and crystalline orthophosphoric acid (50g, 510mmol) are heated to 60°C in a flask
fitted with a cold trap. The resulting hydrido complex is
immediately drawn off into the cold trap (- 196°C) by a
high vacuum and then sublimed at 50"C/10-z torr over P4010
in order to remove residual traces of water. Yield 2.26 g (68 YO)
of ( 3 ) .
Received: October 23, 1973 [Z 957 IE]
German version: Angew. Chem. 86, 233 (1974)
Publication delayed at authors' request
[11 Trifluorophosphanemetal Complexes, Part 46. This work was supported
by the Deutsche Forschungsgemeinschaft.-Part 45: Th. Kruck, H. Jung,
M. Hofler, and H . Blume, Chem. Ber., in press.
[2] Tk.Kruck, Angew. Chem. 79, 27 (1967); Angew. Chem. internat. Edit.
6, 53 ( I 967).
[ 3 ] R. P. M. Werner and H. E . Podall, Chem. Ind. [London) 1961, 144.
[4] We are grateful to Dr. G.SyIuesterand Mrs. C. Breitkopffor the magnetic
measurements, Dip1.-Chem. W Molls, for recording the mass spectra, Prof.
Dr. H. Gunrher and DipLChem. H. Schmickler, for recording the NMR
spectra, and to BASF, Ludwigshafen, for the C, H analyses.
[ 5 ] A. Dauison and D. L. Reger, J. Organometal. Chem. 23,491 (1970).
Doubly Metalated Thiobenzyl AlcoholThiobenzaldehyde Dianion[**l
By Dieter Seebach and Karl-Heinz Geiss"]
Carbonyl compounds and their analogs always react with
nucleophiles ( N ) ( 1 ) at the C atom. The polarity of this
reaction can be reversed in favor of electrophiles (E) in the
case of dianions (2).
[*] Prof. Dr. D. Seebach and Dip].-Chem. K.-H. Geiss
Institut fur Organische Chemie, Fachbereich 14 der Universitat
63 Giessen, Ludwigstrasse 21 [Germany)
[**I This work was supported by the Fonds der Chemischen Industrie
and the Deutsche Forschungsgemeinschaft. We thank G. Protschuk for his
assistance in a number of experiments.
202
1) Thiols of type (5) are formed with an aldehyde, a ketone,
or trimethylchlorosilane (molar ratio 1 : I).
2) Derivatives of type (6) are produced with halides, epoxides,
or trimethylchlorosilane (molar ratio 1 :2).
3) Compounds of type (7) formed by addition of two different
electrophiles to C and S are obtained by consecutive treatment
with (i) aldehyde, ketone, or trimethylchlorosilane and (ii)
methyl iodide (molar ratio 1 : 1 in each case).
Special mention should also be made of the tetrahydrothiophenes (8) and (9) obtainable with 1,3-dibromopropane and
epichlorohydrin, respectively, and the mixed dithioacetal ( 1 1)
resulting on benzylation of the primary adduct ( 1 0 ) generated
with dimethyl disulfide, which is apparently stable under the
reaction conditions. Yields (not optimized) and physical data
of the derivatives ( 5 ) - ( 9 ) and (11) are given in Table 1.
All the IR and NMR spectra and the results of elemental
analysis are in accordance with the structures given. Products
having more than one center of asymmetry were isolated
as mixtures of diastereoisomers.
Doubly metalated thiobenzyl alcohol is remarkably
After storage for two weeks at +S"C about 30% of the
dianion remains undecomposed. The decomposition products
have not yet been studied in detail.
Angew. Chem. internal. Edit. 1 Vol. 13 (1974) 1 No. 3
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