NOTIZEN
1432
New Polyphosphines Containing Various
Combinations of Primary, Secondary, and
Tertiary Phosphorus Atoms
R . B . K I N G a n d J . C . C L O Y D , JR.
Department of Chemistry, University of Georgia, Athens,
Georgia, 30601, U.S.A.
(Z. Naturforsch. 27 b, 1432—1433 [1972] ; received September 11, 1972)
Tertiary-secondary diphosphine, Secondary-primary Diphosphine, Tertiary-diprimary Triphosphine, Tertiary-triprimary
Tetraphosphine, Ditertiary-diprimary Linear Tetraphoshine
Recently the first tertiary-primary diphosphine
(C6H5) 2PCH2CH2PH2 was reported l . This Communication reports the preparation of other diphosphines,
triphosphines, and tetraphosphines containing novel
combinations of primary, secondary, and tertiary phosphorus atoms. Such compounds are of interest as ligands
in coordination chemistry and as precursors to other
unusual organophosphorus compounds including polytertiary phosphines with up to ten phosphorus atoms.
Most of the reaction sequences used for the preparations of the new polyphosphines employ the additions
of phosphorus-hydrogen bonds across the vinyl bond of
a vinylphosphonate followed by lithium aluminum hydride reduction. In the previously reported 1 synthesis
of (C6H5)2PCH2CH2PH2 a reaction sequence of this
type was used for converting a PH group into a
PCH2CH2PH2 group.
Using these preparative methods the first known tertiary-secondary diphosphine was prepared. Thus the
Arbusov reaction of C 6 H 5 P[ (OCH (CHS) 2 ] 2 with 1,2dibromoethane at 1 4 0 - 1 5 0 ° gave BrCH 2 CH 2 P(0)
[OCH (CH3) 2 ] C6H5 which underwent dehydrobromination with a 50% excess of triethylamine overnight in
boiling benzene to give a 70% yield of the isopropyl
phenylvinylphosphinate CH2 = CHP (O) [OCH (CH,) 2 ]
C6H3 (1), b.p. 97 — 100°/0.10 — 0.15 mm. Reaction of
equimolar quantities of diphenylphosphine and 1 in
tetrahydrofuran solution in the presence of potassium
tert-butoxide catalyst gave the expected adduct which
was reduced with LiAlH4 in diethyl ether at room temperature for 4 days. Product isolation after hydrolysis
with aqueous base gave a 57% yield of the white crystalline tertiary-secondary diphosphine (C6H5)2PCH2CH2P
(H)C 6 H 5 (2), m.p. - 3 0 ° . The 31P NMR spectrum of
this product in CH2C12 solution exhibited a singlet at
14.1 p.p.m. and a doublet ( / = 212Hz) at 44.5 p.p.m.
corresponding to the tertiary and secondary phosphorus
atoms, respectively, in structure 2.
CH,=CH—P—C
6
OCH<
H
C 6 H 55
^ D;T
C„H
5
XH
>PCH,CH
'
2
P<
H
C„H-
3
T H ,
H
C«HS
H
>PCH.,CH,P<
H
The first known secondary-primary diphosphine has
also been prepared. Thus the A r b u s o v reaction of
C 6 H 5 P[OCH(CH 3 ) 2 ] 2 with
[(CHS)2CH0]2P(0)CH,
CH2Br at 170° followed by LiAlH4 reduction in boiling
tetrahydrofuran of the residue non-volatile at 70°/
1 mm gave after hydrolysis with aqueous base a 34%
yield of the colorless malodorous liquid air-sensitive
secondary-primary diphosphine C 6 H 5 P(H) CH2CH2PH2
(3), b.p. 87 —88°/0.1 mm. The 31P NMR spectrum of
this product (neat liquid) exhibited a doublet (7 = 208
Hz) at 48.1 p.p.m. and a triplet (7=191 Hz) at 129.1
p.p.m. corresponding to the secondary and primary
phosphorus atoms, respectively, in structure 3.
The diphosphines (C 6 H 5 ) 2 PCH 2 CH 2 P(H)C 6 H 5 (2)
and C 6 H 5 P (H) CH2CH2PH2 (3) are the final members of
the series of six diphosphinoethanes RnR'2-nPCH2CH2
RnR'ä-n containing only phenyl and hydrogen groups
on the phosphorus atoms. The remaining four possible
compounds of this type (i.e.,
(C6H5)2PCH2CH2P
(C6H5);
C6H5P (H) CH2CH2P (H) C6H5 3 , (C6H5)
PCH2CH2PH2 \ and H2CH2CH2PH2 4 ) have already
been prepared and characterized.
A similar synthetic procedure can be used to prepare the tertiary-diprimary triphosphine C6H5P(CH2CH2
PH2) 2 (4). Reaction of phenylphosphine with two equivalents of CH2 = CHP(0) (OC 2 H 5 ) 2 in tetrahydrofuran
solution in the presence of a potassium tert-butoxide
catalyst followed by removal of materials volatile at
210°/0.1 mm gave a waxy adduct. Reduction of this
adduct with LiAlH4 in boiling tetrahydrofuran (7 hrs)
followed by hydrolysis with aqueous base gave a 54%
yield of C 6 H 5 P(CH 2 CH 2 PH 2 ) 2 (4) as an air-sensitive
colorless malodorous liquid, b.p. 106 —109°/0.1 mm.
The 31P NMR spectrum of this product (neat liquid) exhibited a singlet at 20.7 p.p.m. and a triplet (7 = 192
Hz) at 126.7 p.p.m. corresponding to the single tertiary phosphorus atom and the two primary phosphorus
atoms, respectively, in structure 4.
/ C H X H O P
^H
^ ^
/CHOCH2P
C„H,P
\CH,CH.,P
H
P
:
CH.,CH,P
CH,CH,P
/-H
^H
^H
\I1
Two novel tetraphosphines have been prepared by
similar synthetic procedures. Reaction of a saturated
tetrahydrofuran solution of phosphine with CH2 = CHP
(O) [OCH(CH 3 ) 2 ] 2 in the presence of a potassium tertbutoxide catalyst and excess gaseous phosphine followed by removal of the tetrahydrofuran at ~25°/35
mm and reduction of the non-volatile residue with
LiAlH4 in diethyl ether for 68 hr gave after aqueous
base hydrolysis a 28% yield of the tertiary-triprimary
tripod tetraphosphine P(CH 2 CH 2 PH 2 ) 3 (5) as an airRequests for reprints should be sent to Prof. R. B. KING.
University of Georgia, Department of Chemistry, Athens,
Georgia, 30601, U.S.A.
Unauthenticated
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NOTIZEN
sensitive colorless malodorous liquid, b.p. 104 — 105°/
0.2 mm. The 31P NMR spectrum of this product (neat
liquid) exhibited a singlet at 23.0 p.p.m. and a triplet
( / = 191 Hz) at 125.3 p.p.m. corresponding to the single
tertiary phosphorus atom and the three primary phosphorus atoms, respectively, in structure 5. Reaction of
C 6 H 5 P(H)CH 2 CH,P(H)C 6 H 5 3 with two equivalents
of CH2 = CHP(0) [OCH(CH 3 ) 2 ] 2 in tetrahydrofuran
solution in the presence of a potassium tert-butoxide
catalyst followed by LiAlH4 reduction of the syrupy adduct in diethyl ether solution gave after hydrolysis with
aqueous base a 36% yield of the ditertiary-diprimary
linear tetraphosphine H 2 PCH 2 CH 2 P(C 6 H 5 )CH 2 CH 2 P
(C6H5) CH2CH2PH2 (6) as an air-sensitive colorless
malodorous liquid, b.p. 2 0 0 - 2 0 5 ° / 0 . 3 5 - 0 . 4 5 mm.
The 31P NMR spectrum of this product (neat liquid)
exhibited a singlet at 19.2 p.p.m. and a triplet (7 = 191
Hz) at 126.7 p.p.m. corresponding to the two tertiary
phosphorus atoms and the two primary phosphorus
atoms, respectively, in structure 6.
c6H3
C6H5
H\
I
I
PCH 2 CH,PCH 2 CH, PCHoCHOP
"
- ^H
H^
6
Base-catalyzed additions5 of the phosphorus-hydrogen bonds in these new polyphosphines to the vinyl
1
2
3
R . B. KING and P . N. KAPOOR, A n g e w . C h e m . 8 3 ,
[1971].
J. C H A T T a n d F . A . H A R T , J . c b e m . S o c . 1 9 6 0 , 1 3 7 8 .
K . ISSLEIB
and
H . WEICHMANN,
Chem. Ber. 101,
766
1433
double bond in (C6H5) 2PCH = CH2 and related compounds provide routes to polytertiary phosphines with
more complex structures than can be obtained by similar reactions on previously available phosphorus-hydrogen compounds. Thus the base-catalyzed addition of
two equivalents of (C 6 H 5 ),PCH 2 CH 2 P(H)C 6 H 5 (2) to
C 6 H 5 P ( C H = C H , ) 2 and the addition of C 6 H 5 P ( H ) C H 2
CH2PH2 (3) to three equivalents of (C 6 H 5 ) 2 PCH =
CH, gave the crystalline linear pentatertiary phosphine
( C 6 H 5 ) 2 P C H 2 C H 2 P (C 6 H 5 ) C H 2 C H 2 P (C 6 H 5 ) CH 2
CH 2 P(C 6 H 5 )CH 2 CH 2 P(C 6 H 5 ) 2 and the viscous liquid
branched pentatertiary phosphine [(C 6 H 5 ) 9 PCH.,CH 2 ]»
PCH 2 CH 2 P(C 6 H 5 )CH 2 CH 2 P(C 6 H 5 ) 2 , respectively. Similar base-catalyzed additions of the phosphorus-hydrogen bonds in C 6 H 5 P(CH 2 CH,PH 2 ), (4), H2PCH2CH2P
(C 6 H 5 )CH 2 CH 2 P(C 6 H S )CH 2 CH 2 PH 2 (6), and P(CH,
CH 2 PH 2 ) 3 (5) to excess (C 6 H 5 ) 2 PCH = CH2 gave the
expected polytertiary phosphines with seven, eight, and
ten phosphorus atoms, respectively. Work on the polytertiary phosphines prepared from the new compounds
described in this Communication is continuing and will
be described in detail in future publications.
We are indebted to their Air Force Office of Scientific
Research for partial support of this work under Grant AFAFOSR-71-2000.
4
L. MAIER, Helv. Chim. Acta 49, 842 [1966].
5
R . B . KING a n d P . N . KAPOOR, J. A m e r . c h e m . S o c . 9 1 , 5 1 9 1
[1969] ; 93, 4158 [1971].
2197
[1968].
Unauthenticated
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