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Crystal and Molecular Structure of 1 1-Dimethoxy-2 4 6-triphenylphosphorin.

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ranesC4J; the signals of the axial F atoms always appear at
lower field strengths than those of the equatorial atoms. The
same reasoning is used in the case of isomers of SF4 derivatives[sl. The relative positions of the multiplets are also in
accord with the rule that the axial positions are occupied by
the most electronegative ligands. As shown in Table 1, the
chemical shifts of each of the axial and equatorial fluorine
atoms agree very well even in the case of the two isomers of
HOIOF4; all these resonance lines lie between those of IF1 [61
and IF5171 and very close to the resonance lines of OIF516J.
Chemical shifts and coupling constants (56.4MHz)
2:1 in IF5
1 :2 in HSO3F
3:2 in HSO3F
' -189
- 146
[a] External standard CF3COOH.
[bl Measured against SiF4 as internal standard (SiF4: 83.8 ppm
against CF.KOOH) [61.
Ba3H4(106)2 (86 g) is added slowly with ice-cooling to HS03F
(200 g), and HOIOF4 (30 g) in admixture with HSO3F is
distilled from the reaction mixture (b.p. 46 'C/= 1 torr; yield
64%). For conversion into I02F3, 60% oleum is added in
small portions and the IOzF3 thus formed is immediately w b limed off at 30 "Cjw 1 torr. Yield of IOzF3 about 24 g (80%).
102F3 ignites on contact with inflammable organic substances,
is wetted only slowly by water, and hydrolyzed to H F and
H5106. On exposure to direct sunlight, it decomposes with
liberation of oxygen.
The compounds (Z), like phosphorins themselves, are characterized by their unusual stability. Since X-ray structure
analyses"W1 on two compounds of type ( I ) show that the
six TC electrons in the C5P rings are delocalized (planar form
of the ring, equal C-P bond distances of about 1.74A, aromatic C-C bond lengths), the molecular geometry of a compound of type (2) having tetracoordinate phosphorus seems
of interest.
Monoclinic prismatic crystals of 1,l-dimethoxy-2,4,6-triphenylphosphorin I(2): R1 = R2 = C&5; R3 = CH31,
which fluoresce yellow-green, were obtained by cooling a
benzene/ethanol solution 141.
Crystal data: space group P21/c; 2 = 4; a = 16.53, b = 7.01,
c = 20.98 A, p = 119.8'; dx-ray = 1.22, dexp= 1.22 g/cm3.
The intensities of the strong X-ray reflections were measured
with a n automatic two-circle diffractometer; those of the
weaker ones were estimated visually from Weissenberg photographs (all with C U Kradiation).
From a total of 4161 independent reflections, 953 were unobserved.
The structure determination was carried out by means of the
symbolic addition methodrsl using 333 reflections with E 2=
1.7. The positional and isotropic temperature parameters of
the atoms other than hydrogen were relined by the least
squares method. The conventional R value for the 3208 observed reflections is 15.5 %. Localization of the hydrogen
atoms was not performed. The molecular structure and main
bond lengths and angles are given in the figure.
+ '1202
partly in the form of ozone.
Received: July 14, 1969
[Z 60 IE]
German version: Angew. Chem. 81, 753 (1969)
[*I Prof. Dr. A. Engelbrecht and P. Peterfy [**I
Institut fur Anorganische und Analytische Chemie
der Universitat
A-6020 Innsbruck, Innrain 52a (Austria)
[**I We thank Dr. J . Miiller, Munchen, for the mass spectrometric measurements and Dr. W . Gretner and Dr. J . Schantl,
Innsbruck, for the N MR-spectrometric measurements.
[I] A . Engelbrerht and F. Sladky, Mh. Chem. 96, 159 (1965).
[2] A . Engelbrecht, W. Loreck, and W. Nehoda, Z. anorg. allg.
Chem. 360, 88 (1968).
[ 3 ] H . H . Willard, Inorg. Syntheses I , 171 (1939).
[4] E . L . Muetterties, W . Mahler, and R . Schmutzler, Inorg.
Chem. 2, 613 (1963).
[5] E . L . Muetterties, W. Mahler, K . J . Packer, and R. Schmutzler, Inorg. Chem. 3, 1298 (1964).
161 N . Bartlett, S . Beaton, L. W. Reeves, and E. J . Wells, Canad.
J . Chem. 42, 2531 (1964).
[7] E. L. Muetterties and W . D . Phillips, J. Amer. chem. SOC.81,
1084 (1959).
Crystal and Molecular Structure of 1,l-Dimethoxy2,4,6-triphenylphosphorin
By U. Thewalt[*I
Dimroth and Stiide['l have been able to obtain 1,l-dialkoxyand 1,I-diaryloxyphosphorins (2) by oxidation of 2.4.6-trisubstituted phosphorins (1) with mercury(1r) acetate in the
presence of alcohols or phenols.
Angew. Chem. internat. Edit.
1 Vol. 8 (19691 1 No. 10
+ C'-P-OZ
+ c~-P-o'
+ 1.E
+ 1.m
+ 1"
Projection along the b axis of a 1,l-dimethoxy-2,4,6-triphenylphosphorin
molecule. The estimated standard deviations of the bond lengths (A) and
angles ( ") are 0.01 -0.02 A and 1-2 resp.
The C-P bond lengths (1.72 and 1.72 A) lie between the
value for the C-P single bond and that for the C = P double
bond of tetracoordinate phosphorus (e.g. in (C6H5)3P=
CH2 [61, C-P distance = 1.82 A; C = P distance = 1.66 A);
similar distances (1.73-1.75 A) were also observed in com-
pounds ( I ) [2,31. The C-C bond lengths in the phosphorin
ring 0) agree, within experimental error, both mutually and
with the C-C bond lengths in benzene. The CsP ring deviates
slightly but significantly from planarity (deviations from t h e
C2PC4 plane: CI, -0.11; C3, 0.07; C5, --0.02 A).
The three bonds to the phenyl rings project out a little from
the C2PC4 plane ( 0 , -0.33; C14, 0.17; C20, -0.20 A). The
bond angle, like that in the phosphorins ( I ) f2.31, is
relatively small, having a value of 107 O ; the symmetrical
variation of the remaining inner angles of the central ring is
worthy of note.
The O'PO2 plane is perpendicular t o the ClPCs plane; the
OlPO* angle of 93 is surprisingly small. The P-OCH3 bond
lengths (1.57 and 1.59 A) are comparable with the P--OR
distances found in phosphoric esters.
The observed P-C bond distances suggest participation of
the d orbitals of phosphorus in these bonds. The aromaticity
of the central ring I can be deduced from its near planarity
and from the bond lengths. The three bonds between the rings
have a length corresponding to that of a C(sp2)-C(sp2) single
bond. The phenyl rings are twisted with respect to the plane
of the central ring; the configuration is not propeller-like.
The C-C distances in rings I1 and I11 are, within the limits of
error, the same as those of normal aromatic bond lengths.
In ring IV, on the other hand, unrealistic distances (1.28 t o
1.45 /i) - due t o extensive thermal motion of this ring are observed.
Received: July 25, 1969
12 68a IE]
German version: Angew. Chern. 81, 783 (1969)
[*] Dr. U. Thewalt
Mineralogisches Institut der Universitat
355 Marburg/Lahn, Deutschhausstr. 10 (Germany)
[l] K . Dimroth and W. Stude, Angew. Chem. 80, 966 (1968);
Angew. Chem. internat. Edit. 7, 881 (1968).
[2] J. C. J. Bart and J . J . Daly, Angew. Chern. 80, 843 (1968);
Angew. Chern. internat. Edit. 7, 811 (1968).
[3] W . Fischer, E. Hellner, A . Chatzidukis, and K . Dimroth,
Tetrahedron Letters 1968, 6227.
[41 Thanks are due to Dr. Stude for growing the crystals.
[5] J . Karle and I. L. Karle, Acta crystallogr. 21, 849 (1966).
161 J . C . J . Bart, Angew. Chem. 80, 697 (1968); Angew. Chern.
internat. Edit. 7, 730 (1968); J . C . J . Bart, J. chem. SOC.(London)
B 1969,350.
New Free-Radical Reactions with Phosphorins
By K. Dimroth, A . Hettche, W. Stade, and F. W. Steuberf*I
Oxidation of 2,4,6-trisubstituted phosphorins ( I ) with
mercury(I1) acetate in the presence of alcohols or phenols
leads to the formation of compounds containing tetravalent
phosphorus, i.e. to 1,l-dialkoxy- or 1,l-diaryloxyphosphorins
(21 respectively[lJ. In o u r opinion, this reaction proceeds in
the first step via the phosphorin radical cation[2,31.
We have now been able to prepare 1,l-diaryloxyphosphorins
using 2,4,64riphenyIphenoxyl as oxidizing agent and the
phenoxide from this reaction as reaction partner; thus, reaction of 2,4,6-triphenylphosphorinwith 2,4,6-triphenylphen-
oxyl in the molar ratio 1 : 2 leads t o formation of 1,l-bis(2,4,6-triphenylphenoxy)-2,4,6-triphenylphosphorin.
A further reaction of this type is that of phosphorins with
tetraphenylhydrazine. When 2,4,6-triphenylphosphorinwas
allowed to react with the diphenylaminyl radical formed on
heating the hydrazine the first representative of a new class
of compounds ( 3 ) was formed, namely 1,I-bis(dipheny1amino)-2,4,6-triphenylphosphorin(yellow fluorescing crystals, m.p. 179°C; 31P-NMR: 8 -29.5 ppm (8H3P04 = 0),
JpH3,S = 36 Hz in pyridine as solvent; UV:,,,A
(E): 439
(8.45 x 103) 330 nm (1.9 x 104) in cyclohexane as solvent).
The phosphorin radical cation can be detected by ESR
spectroscopy in this reaction too.
The compounds of type ( 2 ) and ( 3 ) must - as crystal structure analysis showsf41- contain an aromatic system with spd
hybridization at the tetravalent phosphorus.
Also in agreement with this assumption is the fact that compounds (2) and (3) can be readily oxidized both electrolytically and by lead(1v) benzoate to give a new class of stable
radical cations. The ESR spectrum of the 1,l-dimethoxy2,4,6-triphenylphosphorinradical cation (/up\= 18.4 gauss)
is shown in Figure 1. The radical cation of 1,l-bisttrideuteriomethoxy)-2,4,6-triphenylphosphoringives exactly the
same spectrum.
This indicates that the delocalization of the unpaired electrons
is mainly limited to the aromatic system.
I , l-Bis(2,4,6-triphenyIphenoxy)
A solution of 2,4,6-triphenylphenoxyl (2.2 g, 6.8 mmoles) in
benzene (20 ml) is added dropwise at room temperature t o a
solution of 2,4,6-triphenylphosphorin(1.1 g, 3.4 mmoles) in
benzene (20 ml). The mixture is stirred for 2 hours. Yield
1.6 g (48 %) of yellow crystals having m.p. 249--251 "C; UV:
Amax(&): 425 (1.32 x lO4), 323 ( 1 . 7 0 ~lO4), 251 n m (9.20 x 104)
in cyclohexane.
I , I-Bis(dipheny1amino)-2,4,6-triphenylphosphorin
A mixture of 2,4,64riphenylphosphorin (324 mg. 1 mmole)
and tetraphenylhydrazine (390 mg, 1.16 mmole) in 30 ml dry
benzene is heated for 2 hours. The benzene is then evaporated
and the dark green fluorescing, viscous residue is taken up in
a little benzenein-hexane and chromatographed on a n Si02
column. The product thus obtained can be recrystallized
from ethanol/acetone; m.p. 179 "C (decomp); yield: 340 mg
Received: July 28, 1969
[Z 68b IEI
German version: Angew. Chern. 81, 784 (1969)
Prof. Dr. K. Dimroth, A . Hettche, Dr. W. Stade, and
Dr. F. W. Steuber
Institut fur Organische Chemie der Universitat
355 Marburg/Lahn, Bahnhofstr. 7 (Germany)
Angew. Chem. internat. Edit. / Vol. 8 (1969)/ No. I0
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crystals, structure, molecular, triphenylphosphonium, dimethoxy
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