Synthesis and crystal structure of a bis(phosphiren-1-yl)-iron complex

Article abstract of DOI:10.1039/a709127c

1-Chloro-1H-phosphirenes 5 react with disodium tetracarbonylferrate to furnish the novel mono-complexed bis(phosphirenyl)s 7 which, in turn, are converted to the doubly-complexed species 8 by treatment with nonacarbonyldiiron.

Full text of DOI:10.1039/a709127c

View Article Online / Journal Homepage / Table of Contents for this issue
Synthesis and crystal structure of a bis(phosphiren-1-yl)–iron complex1
J. Simon, U. Bergstr a¨ ßer and M. Regitz*†
Fachbereich Chemie der Universit a¨ t Kaiserslautern, Erwin-Schr o¨ dinger-Straße, D-67663 Kaiserslautern, Germany
1
-Chloro-1H-phosphirenes 5 react with disodium tetracar-
compared to 2132). Complexation with the tetracarbonyliron
13
bonylferrate to furnish the novel mono-complexed
bis(phosphirenyl)s 7 which, in turn, are converted to the
doubly-complexed species 8 by treatment with nonacarbo-
nyldiiron.
fragment is also apparent in the C NMR spectra from a drastic
reduction in the intracyclic 1
C,P coupling constant of the
J
complexed phosphirene to 22–27 Hz, in comparison to 50–57
Hz for the uncomplexed ring. A similar phenonemon has also
been reported for complexation reactions of other
3
9c
Investigations on the synthesis and reactivity of l -phosphi-
1H-phosphirenes. The signals for the ring carbon atoms of
9
nines 1 in the 1960s played a major role in the development of
7a,b occur in the typical region for 1H- phosphirenes.
The initial reductive substitution of the chlorine atom of 5 by
the tetracarbonyliron fragment results in the anionic phosphir-
ene complex 6 which participates in an immediate nucleophilic
substitution with a second molecule of 5 to afford 7.
R
R
R
R
P
P
P
P
1
2
3
4
Treatment of the compounds 7a,b with nonacarbonyldiiron
results in the formation of the symmetrical, doubly-complexed
bis(phosphirenyl)s 8a,b in yields of 63% (8a) and 54% (8b).§
As a consequence of the high symmetry of compounds 8 their
the chemistry of low-coordinated phosphorus.2,3 Somewhat
3
2
later, their classical valence isomers such as, for example, l ,s -
31
4
5
3
3
P NMR spectra each contain only one singlet signal.
Dewar-benzenes 2, phosphaprismanes 3 and l ,s -benzva-
5
Complexation of the additional tetracarbonyliron fragments
effects further shifts to lower field [d 269.3 (8a) and 270.5
(8b)].
lenes 4 were also prepared.
The Dewar-benzene derived from 2,4,6-tri-tert-butyl-
,3,5-triphosphinine was recently added to this list. In contrast,
very little information about the diphosphinines is available,
and the valence isomers derived from them are still unknown.
We now report the first synthesis of a complexed bis(phosp-
hirenyl), representing a new type of phosphinine valence
isomer.
The starting materials for the syntheses of the bis(phosp-
hirenyl)s 7a,b were the 1-chloro-1H-phosphirenes 5a,b
Scheme 1). Reactions of the latter with disodium tetracar-
bonylferrate (0.5 equiv.) furnished the mono-complexed bis-
phosphirenyl)s 7a,b in good yields (60%). The composition
6
1
The 13C NMR spectra of 8 do not show any significant
changes in chemical shifts due to the additional complex
fragments in comparison to those of 7.
7
An X-ray crystallographic analysis of the complex 8a
confirmed the proposed structure (Fig. 1).¶ In the crystal the two
tetracarbonyliron fragments and, respectively, the two phos-
phirene rings have syn orientations to each other. Because of the
extreme steric situation, the two phosphirene rings are some-
what twisted, as reflected in torsional angles of 39.4° [Fe(1)–
8
(
(
and constitution of the products were elucidated with the help of
NMR and mass spectroscopy.‡ Because of the presence of
centres of chirality at the two phosphorus atoms and their
configurational stability, these reactions give rise to two
diastereomers which, however, cannot be separated by column
chromatography. One of the diastereomers in each case can be
enriched up to a ratio of 8:1 (7a) or 4:1 (7b) (as determined
O(64)
O(61)
O(63)
C(4)
O(51)
P(2)
Fe(2)
1
from their H NMR spectra) by crystallization.
The formation of 7 is reflected in the 31P NMR spectra by a
C(3)
1
significant JP,P coupling constant of 427 Hz. The complexed
ring phosphorus atom gives rise to a signal at considerably
lower field than that of the uncomplexed ring (d 288, as
O(62)
O(52)
O(54)
C(1)
–
P(1)
R
R
Fe(1)
Fe(CO)4
+
P
Cl + Na2Fe(CO)4
P
Na
C(2)
–NaCl
Ph
Ph
5
6
O(53)
+
5 (–NaCl)
(
OC)4Fe
Fe(CO)4
(OC)4Fe
R
P
P
Fe2(CO)9
n-pentane
P
P
Fig. 1 Crystal structure of 8a. Selected bond lengths (Å) and angles (°):
Fe(1)–P(1) 2.2311(7), Fe(2)–P(2) 2.2185(7), P(1)–P(2) 2.2516(10),
P(1)–C(1) 1.793(2), P(1)–C(2) 1.796(2), P(2)–C(3) 1.793(2), P(2)–C(4)
1.797(2), C(1)–C(2) 1.317(3), C(3)–C(4) 1.319(3); C(1)–P(1)–C(2)
43.05(11), C(1)–P(1)–P(2) 108.23(8), C(2)–P(1)–P(2) 108.97(8),
C(3)–P(2)–C(4) 43.11(11), C(3)–P(2)–P(1) 108.55(8), C(4)–P(2)–P(1)
R
Ph
Ph
Ph
R
Ph
R
8
a R = But
b R = EtMe2C
7
1
09.05(8), C(2)–C(1)–P(1) 68.60(14), C(1)–C(2)–P(1) 68.3(2), C(3)–C(4)–
Scheme 1
P(2) 68.3(2), C(4)–C(3)–P(2) 68.58(14).
Chem. Commun., 1998
867

View Article Online
P(1)–P(2)–Fe(2)] and 33.9° [C(1)–P(1)–P(2)–C(4)]. The
P(1)–P(2) bond length amounts to 2.2516(10) Å and is thus
somewhat lengthened as a result of the spatially demanding
substitution pattern. The intracyclic P–C bond lengths of 1.793
to 1.797 Å, as well as the carbon–carbon double bond length of
(400 MHz, CDCl
s, 6 H, C(CH Et], 1.80 (q, 4 H, CH
.67–7.73 (m, 4 H, o-Ph); d (100 MHz, CDCl
Et], 26.21 [s, C(CH Et], 34.24 (d, JC,P 10.4,
), 38.28 [d, JC,P 14.5, C(CH Et], 126.32 (d, JC,P 20.0, C-2/C-
3
) 0.90 (t, 6 H, CH
2
CH
3
), 1.42 [s, 6 H, C(CH
3 2
) Et], 1.45
[
7
CH
CH
3
)
2
2
CH
3
), 7.34–7.46 (m, 6 H, m/p-Ph),
4
C
3
) 8.79 (d, JC,P 8.8,
3
2
CH
3
), 26.00 [s, C(CH
3
)
2
3 2
)
2
1
2
CH
3
3 2
)
2
3
2
J
A), 128.93 (s, m-Ph), 129.87 (pseudo t, JC,P + JC,P 7.2, i-Ph), 130.38 (d,
1
.317 Å, are of the expected sizes for a complexed 1H-
3
5
1
2
C,P 6.4, o-Ph), 130.54 (d, JC,P 3.2, p-Ph), 141.61 (pseudo t, JC,P + JC,P
9c
phosphirene. Similary, the C–P–C bond angles of 43.05(11)
2
1
2.0, C-3/C-3A), 213.74 [d, JC,P 4.8, Fe(CO)
[M ], 143 (100) [C11 ]. (Calc. for C32H28Fe P O : C, 55.02; H, 4.35.
Found: C, 53.95; H, 4.10%).
¶ Crystal data for 8a: C32 28Fe
space group P2
b = 99.86(3)°, V = 3414.7(12) Å , Z = 4, D
4
]; m/z (EI, 70 eV) 742 (0.04)
and 43.11(11)° are comparable with those of other
+
H
11
+
2 2 8
9
1H-phosphirenes.
2 8 2
O P
, M = 714.18 g mol21, monoclinic,
We thank the Landesregierung von Rheinland-Pfalz for a
graduate grant (to J. S.) and the Fonds der Chemischen Industrie
for generous financial support.
H
1
/n, a = 10.102(2), b = 18.273(4), c = 18.775(4) Å,
3
23
c
= 1.389 Mg m , m = 0.989
2
1
3
mm , F(000) = 1464. Crystal dimensions 0.35 3 0.20 3 0.15 mm ,
2
6734 reflections collected, 6321 independent reflections (Rint = 0.0382),
511 reflections with I > 2s(I), goodness-of-fit on F2 = 1.205, R [I >
Notes and References
4
†
‡
E-mail: regitz@rhrk.uni-kl.de
Selected data for 7a (only values for the major diastereomer are given):
2 2
2s(I)] = 0.0370, wR = 0.0896; R (all data) = 0.0534, wR = 0.0945;
2
3
maximum residual density 0.420 e Å . Data were collected on a STOE
Imaging Plate Diffraction System at room temperature with Mo-Ka
radiation (l = 0.71073 Å). The structure was solved with SHELXS-86 [ref.
10(a)] and refined with SHELXL-93 [ref. 10(b)]. CCDC 182/787.
1
mp 97–99 °C; d
P
(81 MHz, CDCl
(200 MHz, CDCl
.40–7.51 (m, 6 H, m/p-Ph), 7.57–7.65 (m, 4 H, o-Ph); d
9.22 [d, JC,P 1.7, C(CH ) ], 29.53 [s, C(CH ) ], 33.86 [dd, JC,P 6.4, JC,P
3 3 3 3
.0, C(CH
3
) 288.1 (d, JP,P 427.3, P-1), 2134.2 (d,
) 1.44 [br s, 18 H, C(CH ],
3
(50 MHz, CDCl )
1
J
P,P 427.3 P-2); d
H
3
3 3
)
7
2
3
1
C
3
2
3
2
1
3
)
3
1
], 34.24 [d, JC,P 6.8, C(CH
3
)
3
], 120.33 (d, JC,P 50.8, C-5),
2
24.80 (dd, JC,P 22.0, JC,P 4.2, C-3), 127.30 (d, JC,P 7.6, Ph), 128.62 (s,
1 Part 128 of the series of papers on Organophosphorus Compounds. For
part 127, see: T. W. Mackewitz and M. Regitz, Synthesis, 1998, in the
press.
2 O. J. Scherer and M. Regitz, in Multiple Bonds and Low Coordination
in Phosphorus Chemistry, ed. M. Regitz and O. J. Scherer, Thieme,
Stuttgart, 1990, p. 1.
3 G. M a¨ rkl, in Multiple Bonds and Low Coordination in Phosphorus
Chemistry, ed. M. Regitz and O. J. Scherer, Thieme, Stuttgart, 1990,
p. 220.
4 J. Fink, W. R o¨ sch, U.-J. Vogelbacher and M. Regitz, Angew. Chem.,
1986, 98, 265; Angew. Chem., Int. Ed. Engl., 1986, 25, 280.
5 K. Blatter, W. R o¨ sch, U.-J. Vogelbacher, J. Fink and M. Regitz, Angew.
Chem., 1987, 99, 67; Angew. Chem., Int. Ed. Engl., 1987, 26, 85.
6 P. Binger, S. Leininger, J. Stannek, B. Gaber, R. Mynott, J. Bruckmann
and C. Kr u¨ ger, Angew. Chem., 1995, 107, 2411; Angew. Chem., Int. Ed.
Engl., 1995, 34, 2227
Ph), 128.87 (s, Ph), 129.73 (d, JC,P 5.1, Ph), 130.41 (d, JC,P 4.2, Ph), 131.33
s, Ph), 138.50 (d, JC,P 57.7, C-6), 140.51 (dd, JC,P 27.1, 2JC,P 5.1, C-4),
1
1
(
2
+
2
13.94 [d, JC,P 19.5, Fe(CO)
4
]; m/z (EI, 70 eV) 546 (8) [M ], 276 (100)
28FeP : C, 61.56; H, 5.17. Found:
+
[M 2 4CO 2 C12
H14] (Calc. for C28
H
2 4
O
+
C, 60.90; H, 5.07%) (HR-MS: calc. for M : 546.0813. Found: 546.0813).
1
1
For 7b: d
P
(81 MHz, CDCl
(200 MHz, CDCl
t, 3 H, JH,H 7.0, CH CH ), 1.42 [s, 3 H, C(CH
.46 [s, 3 H, C(CH ], 1.47 [s, 3 H, C(CH
CH CH ), 7.37–7.53 (m, 6 H, Ph), 7.57–7.77 (m, 4 H, Ph); d
CDCl ) 8.67 (d, JC,P 6.3, CH
3
) 290.6 (d, JP,P 427.6, P-1), 2132.2 (d, JP,P
3
427.6, P-2); d
H
3
) 0.96 (t, 3 H, JH,H 7.6, CH
], 1.43 [s, 3 H, C(CH
], 1.63–1.92 (m, 4 H,
2
CH
3
), 1.12
3
(
1
2
3
3
)
2
3 2
) ],
3
)
2
3
)
2
2
3
C
(100 MHz,
4
4
3
2
CH
3
), 9.13 (d, JC,P 4.5, CH
2
CH
3
), 25.66 [s,
3
C(CH
C(CH
C(CH
3
3
3
)
)
)
2
2
2
], 26.28 [d,
], 34.36 (d, 3JC,P 5.4, CH
Et], 37.65 [d, JC,P 5.4, C(CH
J
C,P 5.4, C(CH
3
)
2
], 26.45 [s, C(CH
), 34.39 (s, CH CH
3
3 2
) ], 26.88 [s,
2
CH
3
2
1
), 37.01 [s,
Et], 120.89 (d, JC,P 51.2, C-5),
2
3
)
2
1
3
3
125.12 (d, JC,P 22.4, C-3), 127.03 (d, JC,P 8.3, o-Ph), 127.16 (d, JC,P 7.2,
2
o-Ph), 128.32 (s, Ph), 128.58 (s, Ph), 129.41 (d, JC,P 16.2, i-Ph), 129.48 (d,
7 D. B o¨ hm, F. Knoch, S. Kummer, U. Schmidt and U. Zenneck, Angew.
Chem., 1995, 107, 251.
2
1
J
C,P 14.4, i-Ph), 130.12 (s, Ph), 131.18 (s, Ph), 138.25 (d, JC,P 57.5, C-6),
1
2
2
1
41.38 (dd, JC,P 28.3, JC,P 4.0, C-4), 213.73 [d, JC,P 18.0, Fe(CO)
4
]; m/z
8 O. Wagner, M. Ehle and M. Regitz, Angew. Chem., 1989, 101, 227;
Angew. Chem., Int. Ed. Engl., 1989, 28, 225; O. Wagner, M. Ehle,
M. Birkel, J. Hoffmann and M. Regitz, Chem. Ber., 1991, 124, 1207.
9 (a) F. Mathey and M. Regitz, in Comprehensive Heterocyclic Chemistry
II, ed. A. R. Katritzky, C. W. Rees and E. F. V. Scriven, Pergamon,
Oxford, 1996, p. 277; (b) H. Memmesheimer and M. Regitz, Rev.
Heteroatom Chem., 1994, 10, 61; (c) F. Mathey, Chem. Rev., 1990, 90,
997.
+
+
+
(EI, 70 eV): 574 (1) [M ], 143 (100) [C11H11 ] (HR-MS: calc. for M :
5
§
74.1135. Found 574.1130).
Selected data for 8a (only values for the major diastereomer are given):
mp 135 °C (decomp.); d
CDCl ) 1.52 [s, 18 H, C(CH
H, o-Ph); d (50 MHz, CDCl
C(CH
P
(81 MHz, CDCl
3
) 269.3 (s); d
H
(200 MHz,
3
3
)
3
], 7.41–7.54 (m, 6 H, m/p-Ph), 7.55–7.61 (m,
3
4
4
C
3
) 29.27 [pseudo t,
J
C,P
+
J
C,P 4.2,
)
+
3
4
], 34.82 [pseudo t, JC,P + 3JC,P 3.4, C(CH
J
2
3
)
J
3
], 126.07 (pseudo t,
3
3
1
C,P + 2
J
C,P
C,P 3.4, o-Ph), 128.52 (pseudo t,
J
C,P 15.2, C-2/C-2A),
10 (a) G. M. Sheldrick, SHELXS-86, a program for the solution of crystal
structures, G o¨ ttingen, Germany 1986; (b) G. M. Sheldrick, SHELXL-
93, a program for structure refinement, G o¨ ttingen, Germany 1993.
2
3
5
128.93 (s, m-Ph), 130.38 (pseudo t, JC,P + JC,P 5.9, i-Ph), 130.55 (d, JC,P
1
2
1
.7, p-Ph), 142.20 (pseudo t, JC,P + JC,P 22.0, C-3/C-3A), 213.11 [pseudo
2
3
+
t, JC,P + JC,P 17.0, Fe(CO)
4
]; m/z (EI, 70 eV): 714 (0.02) [M ], 332 (100)
14] (Calc. for C32 28Fe : C, 53.82; H, 3.95.
Found: C, 53.12; H, 4.20%). For 8b: d (81 MHz, CDCl ) 270.5 (s); d
+
[M
2 8CO 2 C12
H
H
2 2 8
P O
P
3
H
Received in Liverpool, UK, 22nd December 1997; 7/09127C
868
Chem. Commun., 1998