close

Вход

Забыли?

вход по аккаунту

?

Oligo(difluorophosphoranes) by Direct Fluorination of Tertiary Phosphanes.

код для вставкиСкачать
ceric ammonium nitrate in acetone at room temperature
affords benzene as the sole organic product, thus proving
the ease of decomposition of the primarily liberated o,p'-dibenzene.
The greater stability of ( 8 ) compared to that of the rhodium
complex (6) and of norbornadienonetricarbonyliron" 'I can be
explained as follows: In the latter-mentioned complexes the
metal fixes the bent bicyclo[2.2.n]diene moiety, which must
be flattened in the transition state with scission of the bond
to the metal. In (8), on the other hand, the metal remains
bound to the cyclohexadiene ring, with the result that the
double bond that is formed does not gain the resonance
energy of benzene[12!
Received: July 27, 1977 [Z 801 IE]
German version: Angew. Chem 89.754 (1977)
CAS Registry numbers:
( I ) , 21604-76-2;( 2 a ) , 63784-75-8;( 2 b ) , 63784-74-7;(Zc), 63784-73-6;( Z d ) ,
63784-72-5;(3), 63784-71-4;(S), 63797-21-7;
(71,63797-20-6;(8), 63797-193; dichloroketene, 4591-28-0;dicarhonyl(hexafluoropentane-2,4-dionato)rhodium, 18517-12-9:Fe2(CO)9, 15321-51-4;
Fe(CO)5,13463-40-6
compete successfully with cleavage of the PC and/or C H
bondrz1.However, our preliminary experiments with triphenylphosphane showed quantitative conversion into the difluorophosphorane.
The general validity of direct fluorination will now be illustrated for the example of tertiary oligophosphanes whose
difluorides were formerly accessible in isolated cases only
by the action of SF4r3alor hydrofluorination of phosphoric
i m i d e ~ ~Passage
~ ~ ' . of a current of fluorine (max. 20ml/min)
diluted with an inert gas (Nz,
He, Ar; ca. 100ml/min) through
a suspension of perphenylated polymethylenebisphosphane
( 1 ) in CFCl3 furnishes the bis(difluorophosphorane) (2) as
reaction product in good yield, independently of the length
of the methylene bridge.
+ 2
PhzP-(CHz),-PPh,
already decompose at 25°C: a) W G . Dauben, G . 7: Rivers, R. J . Twieg,
W 7: Zimmerman, J. Org. Chem. 41, 887 (1976); h) A . R . R y e , D .
Wege, Aust. J. Chem. 27, 1943 (1974).
131 a) J. A . Berson, R . F. Daois, J. Am. Chem. SOC. 94, 3658 (1972);b)
H . Rotfele, W Martin. J . F . M . Oth, G . Schroder, Chem. Ber. 102,
3985 (1969).
[4] a) G.F. Emerson, L . Watts, R . Prttit, J. Am. Chem. SOC.87, 131 (1965);
b) W Grimme, K . Seel, Angew. Chem. 85, 514 (1973);Angew. Chem.
Int. Ed. Engl. 12, 507 (1973);C. R . Graham, G . Scholes, M . Brookhart,
J. Am. Chem. SOC.99, 1180 (1977).
[5] a) L. Ghosez, R . Montaigne, A . Roussel, H . Vanlierde, P . Mollet, Tetrahedron 27, 615 (1971):b) M . Atram, €. Sliarn, C. D . Nenitzescu, Justus
Liebigs Ann. Chem. 636,184 (1960);cf. also ref. [Za].
I
h
(2)
(1)
n = 1 (a). 2 (b). 3
[l] Cf. H . Kwart, K . King, Chem. Rev. 68, 415 (1968)
[2] E.g. the compounds
F
7
k
CFC13
F Z -Ph,P-(CHz),-PPh2
(c),
4
(d)
The concentration of fluorine given is an upper limit. If
it is exceeded local ignition occurs at the gas inlet tube and
decomposition of the substrate ensues. However, under the
mild conditions chosen the methylene protons are not attacked
even in the presence of an excess of fluorine. Phosphanes
bearing terminal methyl groups such as (3 a) and (3 b ) are
likewise fluorinated mainly at the phosphorus[4],i. e. the procedure is not restricted to resistant phenyl substituents.
F
/
I
F
F
F
( C H ~ ) Z ~ - ( C H Z )I ~ - $ ~ C H , ) Z
[6] Assignment of signals and configuration was made from the
(CH~)ZP-(CHZ),-P(CH~)Z
shifts A8 by tris(l,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionaF
F
to)europium as a function of [Eu(FOD),]/[(Za)].
t g a is the slope
(3b)
(46)
of this linear relationship.
[7] cic-Mesyloxychlorocyclobutanes eliminate under the same conditions
The synthesis of the oligo(difluorophosphoranes)(6a) and
as the dichloro analogs: E. L . Allred, B. R . Beck, K . J . Voorhees,
(66) constitutes a further impressive demonstration of the
J. Org. Chem. 39, 1426 (1974).
scope of oxidative direct fluorination[51.
[S] M . J . Goldstern, R . S . Leigh, M . S. Lipfon, J . Am. Chem. SOC. 98,
5717 (1976).
[9] F . Bonari, G. Wilkinson, J . Chem. Soc. 1964, 5517.
[lo] W Slegeir, R. Case, .
I
.
S . McKennis, R. Pettit, J. Am. Chem. SOC.
96,287 (1974).
[ I l l J . M. Londesberg, J . Sirzkowski, J. Am. Chem. SOC. 90, 1655 (1968).
[12] The same effect stabilizes the ketone tautomer of phenol in its tricarbonyliron complex: A. J . Birch. P. E. Cross. J . Lewis, D. A . Whire, S .
8.Wild, J. Chem. Soc. A 1968, 332.
Oligo(difluorophosphoranes)by Direct Fluorination of
Tertiary Phosphanes
By Ingo Ruppert and Volker Bastian[*]
Although the first gas-phase chlorination of tertiary phosphanes was described as long ago as 1876f11,no such halogenation with fluorine has yet been reported. The reason may
lie in the suspected failure of regioselective fluorination to
[*]Dr.1.
Ruppert. Dr.V. Bastian
Anorganisch-chemisches Institut der Universitlt
Max-Planck-Strasse I. D-5300 Bonn
718
The modest yields obtained in these cases are due less
to side reactions during the actual fluorination than to greater
sensitivity of the products to hydrolysis which interferes with
their isolation and purification.
The constitution of the difluorophosphoranes is confirmed
by correct elemental analysis and characteristic fragment
and above all by NMR studies. The 31P{1H)spectra
exhibit an overall triplet pattern['], showing that two fluorine
atoms coordinate each h5-phosphorus atom and thereby ruling
Anyew. Chem. Int. Ed. Engl. 16 (1977) No. 10
Table 1. Preparative and NMR spectroscopic data [a] of the compounds prepared.
19F-NMR
Yield
M.p. [h]
["/.I
c"c1
118
132
63
114
65
60
55
82
6 [c]
'J(PF)
31P(1H}-NMR
6
J(PF)
[CI
CHZI
-27.8 (dm)
-40.8 (dm)
- 40.0 (dm)
- 39.9 (dm)
-40.1 (dm)
- 18.0 (dm)
- 17.4 (dm) [d]
-40.3 (dm)
- 39.0 (dm)
-42.7 (dm)
-41.8 (dm)
Ph2PFz
Me2PFz [d]
Ph2PF2
PhPF2
Ph2PF2
PF2
656
648
644
645
640
550
550
650
635
650
620
-45.2 (tm)
-42.4 (tm)
- 42.0 (t)
-41.3 (t)
-45.7 (td)
-14.1 (td)
- 12.8 (t) [d]
-44.0 (td)
-31.1 (tt)
- 46.8 (td)
- 18.8 (tq)
PhzPFz
Me2PFz [dl
Ph2PF2
PhPF2
Ph2PF2
PF2
650
640
642
642
643
546
543
650
632
650
630
'J(PP)
[Hzl
103
100
89
[a] The I9F- (Varian A 56/60. 56.4 MHz, CFC13 int.) and 31P(1H)-NMRspectra (Jeol C 60/HL, 24 MHz, H,PO4 ext.) were recorded in conc. CHCI, solution.
Owing to pronounced multiplicity arising by PP coupling, "P{'H}-PFT spectra with a more favorable signal to noise ratio were also recorded for ( 4 a ) , (6a), and
(66) (Varian CFT 20, phosphorus head, 32 MHz).
[h] In sealed capillary with partial decomposition.
[c] Signal multiplicities in the usual notation, e.g. (Id) = triplet with doublet fine structure.
[d] In alkyl-substituted difluorophosphoranes. HF-exchange (result of partial hydrolysis) leads, in some cases, to diffuse signal summits. However, this
exchange phenomenon can be suppressed by low-temperature measurement.
out phosphonium structures; if nonequivalent phosphorus
centers are present in the molecule then a significant fine
structure of the individual triplet peaks is observed II3J(PPj,
cf. Table I]. The 19F-NMR spectra show the complementary
signal multiplicity: a quasi-doublet (dmj due to the h5-phosphorus atom with unresolved fine structure arising from longrange coupling with 'H, 31P,
as well as I9F oia the methylene
bridge.
Procedure
A current of diluted fluorine (max. 20ml F2 to 100ml of
Ar per minute, amount of fluorine determined by a rotameter
system[']) is passed into a magnetically stirred suspension
or solution [ ( 3 a ) , (3b)l of oligophosphaner8] (25 mmol) in
CFC13(150 ml, dried over P40,),, (Solidex glass f l a k with gas
tube and low temperature cooler, - 90°C circulatory cooling
with cryostat). Depending upon the solubility of the phosphane,
reaction is complete after passage of 60-80 mmol of F2
(excess). as checked by "P-NMR spectroscopy. In the case
of ( 2 a ) and ( 2 b ) the product is recrystallized from boiling
CH3CN after filtration. Otherwise, the solids (oxide and/or
H F adduct) are removed from the solution, CFC13 distilled
off, and the residue recrystallized from hot n-heptane [f2d)],
sublimed in oucuo [ ( 4 b)], or repeatedly frozen out of n-pentane/ether ( 5 : 1) [(2c), ( 4 u ) , ( 6 u ) , and (6b)].
Received: August 3, 1977 [Z 810 IE]
German version: Angew. Chem. 89, 763 (1977)
CAS Registry numbers:
( I n ) . 2071-20-7; ( 1 b ) , 1663-45-2; ( I c), 15383-58-1; ( I d J , 7688-25-7;
( 2 a ) , 26040-41-5; ( Z b j , 55339-52-1; (Zc), 63883-61-4; ( 2 d ) . 63883-60-3;
(-la). 42495-77-2; ( 3 b ) , 39564-18-6; ( ~ L z 63883-59-0;
),
( 4 6 ) . 55339-53-2;
(So), 23582-02-7; ( j b ) , 23582-03-8; ( 6 a ) , 63883-58-9; (6b), 63883-57-8;
F2, 7782-41-4
[l] A . Michaelis, Justus Liebigs Ann. Chem. 181, 351 (1876).
[2] Only recently was the remarkable stability of element-carbon bonds
toward molecular fluorine mentioned in the literature E . K . S . Liu,
R . J . Lagow, J. Am. Chem. SOC. 98, 8270 (1976).
[3] a) 7: A. Blazer, J . K . Gregor, R. Sckmutzler, 2. Naturforsch. B24, 1081
(1969); R . Srhmutzfer,Inorg. Chem. 3, 421 (1964); b) R . Appel, I . Ruppert,
Chem. Ber. 108, 919 (1975); R . Appel, R. Milker, I . Ruppert, 2. Anorg.
Allg. Chem. 429, 69 (1977).
[4] In contrast, we detected the expected side-chain fluorination in experiments performed with (CH3)3P at a maximum concentration of 40ml
F2 and 100 ml He per minute. In addition to varying amounts of
(CH3)3PF2, dealkylation to form hexafluorophosphate can also be
observed.
Angew. Ckem. Int. Ed. EngI. 16 (1977) N o . 10
[5] Although more involved, the method appears to be not only of phenomenological interest in view of the price of SF4.
[6] Molecular ions recorded with only weak intensity, if at all. in the mass
spectrum.
[7] The symmetrically substituted bis(difluorophosphoranes) ( 2 a ) and (2 b)
having a short (CH,), bridge show the substructure of a XX'AA'X"X"'
31P/19Fspin system of four chemically hut not magnetically equivalent
fluorine (X) and two phosphorus atoms (A).
[8] Preparation: ( 1 a-d): K . Sommer, Z. Anorg. Allg. Chem. 376, 37 ( 1 970);
(3a): R. B. King, J . C. Cloyd, P. K . Hendrick, J. Am. Chem. SOC.
95, 5083 (1973); ( 3 6 ) : A . Wold, J . K . RuK Inorg. Synth. 14, 17 (1973);
( 5 a , b): R . B. King, P. N . Kapoor, J. Am. Chem. Soc. 93, 4158 (1971).
[9] P! Bustian, Dissertation, Universitat Bonn 1976.
Dependence of the Calcium Isotope Effect upon the
ElectrolyteConcentrationin Ion-Exchange Chromatography[**l
By Klaus G . Heumann, Ferdinand Gindner, and Helmut
Kloppel
Enriched stable calcium isotopes are of topical interest"]
primarily for labeling experiments in medical research. With
the set aim of chemical pre-enrichment of calcium isotopes and
elucidation of the origins of separation effects we have studied
the dependence of the calcium isotope effect upon several
parameters during ion exchange in inorganic electrolyte systems. Our previous findings suggested that the behavior of
isotopes in electrolyte systems is comparable with that of a
homologous series of elements-such as the alkaline earth
All experiments were performed in a column packed with
the strongly acidic sulfonic acid exchanger resin Dowex 50 WXI2 (H' form, 200-400 mesh, Bio-Radj at 20°C. In each
case a 60-mg sample of calcium of natural isotope abundance
was applied in the form of CaClz or Ca(C104)2and eluted
with HCI or HC104 of various concentrations (HCI: 3. 6,
9 M ; HCIOQ:3, 5,6 M) at a rate of about 15ml/h. The calcium
content of the eluate collected fractionwise was established
[*] Prof. Dr. K. G. Heumann, F. Gindner, Dip1.-Ing. H. Kloppel
Institut fur Chemie der Universitat
Universitatsstrasse 3 1, D-8400 Regensburg (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Industrie.
719
Документ
Категория
Без категории
Просмотров
0
Размер файла
231 Кб
Теги
oligo, phosphane, direct, fluorination, difluorophosphoranes, tertiary
1/--страниц
Пожаловаться на содержимое документа