Structural and coordination properties of 1,2-bis(cyclopropyl)-3,4-bis(2,4, 6-tri-tert-butylphenyl)-3,4-diphosphinidenecyclobutene prepared by dehydrogenative homocoupling of 3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1- phosphaallene

Article abstract of DOI:10.1039/b510432g

According to a protocol for the synthesis of phosphaallenes we recently established, 3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1-phosphallene was obtained from (Z)-2-bromo-3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1- phosphapropene. A novel bidentat

Full text of DOI:10.1039/b510432g

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PAPER
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Structural and coordination properties of 1,2-bis(cyclopropyl)-3,4-bis(2,4,6-
tri-tert-butylphenyl)-3,4-diphosphinidenecyclobutene prepared by
dehydrogenative homocoupling of 3-cyclopropyl-1-(2,4,6-tri-tert-
butylphenyl)-1-phosphaallene
Shigekazu Ito,* Matthias Freytag and Masaaki Yoshifuji*
Received 21st July 2005, Accepted 28th September 2005
First published as an Advance Article on the web 31st October 2005
DOI: 10.1039/b510432g
According to a protocol for the synthesis of phosphaallenes we recently established, 3-cyclopropyl-
1-(2,4,6-tri-tert-butylphenyl)-1-phosphallene was obtained from (Z)-2-bromo-3-cyclopropyl-1-(2,4,6-
tri-tert-butylphenyl)-1-phosphapropene. A novel bidentate ligand, 1,2-bis(cyclopropyl)-3,4-bis(2,4,6-
tri-tert-butylphenyl)-3,4-diphosphinidenecyclobutene, was prepared by oxidative homocoupling of
3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaallene in the presence of butyllithium, together
with the generation of hydrogen gas. The 1,2-bis(cyclopropyl)-3,4-diphosphinidenecyclobutene was
allowed to react with (tht)AuCl (tht = tetrahydrothiophene) to afford the corresponding digold(I)
=
=
complex of a six-membered metallacycle containing the P C–C P skeleton. The molecular structures
of the 2-bromo-3-cyclopropyl-1-phosphapropene, 1,2-bis(cyclopropyl)-3,4-diphosphinidenecyclobutene
and the digold complex were unambiguously determined by X-ray crystallography and are discussed
from the point of view of the cyclopropyl conjugation.
Introduction
As cumulene compounds are widely employed for organic
synthesis,1 1-phosphaallenes [–P C C<] are expected to be
= =
promising materials for the synthesis of novel phosphorus
compounds.2 We previously reported topochemical head-to-tail
[2 + 2] dimerisation reactions in the solid state3 and a formal [3 +
2] dimerisation affording a 1,4-diphosphafulvene (1),4 suggesting
The synthesis of a 3-cyclopropyl-1-phosphaallene was successful,
the utility of 1-phosphaallenes in organic chemistry featuring
phosphorus. These findings motivated us to develop the chemistry
of phosphacumulene derivatives leading to material science.
In the study of the 1,4-diphosphafulvene 1, we found the
formation of 3,4-diphosphinidenecyclobutene 2 together with 1
from 3-phenyl-1-phosphaallene 3 in the presence of a base.4
The 3,4-diphosphinidenecyclobutenes (DPCB) have been utilised
as p-electron accepting ligands for synthetic catalysts,5 and
furthermore, attempts have been made to prepare DPCB deriva-
tives involving molecular functionality.6 Taking our previous
results into account,4 1-phosphaallenes are expected to be
versatile reagents for the synthesis of DPCB derivatives. We
have established some practical synthetic procedures of 1-(2,4,6-
tri-tert-butylphenyl)-1-phosphaallenes from 2-bromo-1-(2,4,6-tri-
tert-butylphenyl)-1-phosphapropenes,3,4,7 which encouraged us to
utilise 1-phosphaallenes for the preparation of novel organic
compounds containing phosphorus.
and therefore, we proceeded to investigate the chemistry of
phosphacumulenes bearing a cyclopropyl group. In the course
of our studies of 3-cyclopropyl-1-phosphaallenes, we found
an oxidative homocoupling affording a novel 3,4-diphosphin-
idenecyclobutene. In this paper we describe the generation, isola-
tion and molecular structure of a 1,2-bis(cyclopropyl)-3,4-diphos-
phinidenecyclobutene prepared simply by mixing a 3-cyclopropyl-
1-phosphaallene and butyllithium. Moreover, we report that the
two sp2-hybridised phosphorus atoms of the 3,4-diphosphinidene-
cyclobutene coordinate on two gold(I) atoms, respectively, afford-
ing a novel digold(I) complex, stabilised by an intramolecular
gold–gold contact. This observation is in contrast to the well-
established coordination chemistry of DPCB compounds, which
in most cases act as chelating ligands to one single metal centre,
forming a five-membered metallacycle. The effects of cyclopropyl
conjugation are discussed, based on the molecular structures.
=
On the other hand, we previously found that the P C double
bond conjugates with a cyclopropyl group on the basis of the
structures of 2-cyclopropyl-1-phosphaethenes,8 which prompted
us to investigate properties of 3-cyclopropyl-1-phosphaallenes.
Results and discussion
Preparation of 3-cyclopropyl-1-(2,4,6-tri-tert-butylphenyl)-
1-phosphaallene
Department of Chemistry, Graduate School of Science, Tohoku University,
Aoba, Sendai, 980-8578, Japan. E-mail: yoshifj@mail.tains.tohoku.ac.jp,
ito@synchem.chem.tohoku.ac.jp; Fax: +81-22-795-6562
2,2-Dibromo-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaethene
=
[Mes*P CBr2] was allowed to react successively with butyllithium,
710 | Dalton Trans., 2006, 710–713
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cyclopropanecarbaldehyde, and iodomethane4 to afford 2-bromo-
3-cyclopropyl-1-phosphapropene 4 in 63% yield (Scheme 1).
The structure of 4 was confirmed by X-ray crystallography as
displayed in Fig. 1. The cyclopropyl ring forms an equilateral
triangle, indicating almost no conjugative interaction with any
p-functional groups. On the other hand, the cyclopropyl triangle
of 2-cyclopropyl-1-phosphaethene is isosceles, indicating the
cyclopropyl conjugation.8 Compound 4 was allowed to react
with tert-butyllithium to afford 3-cyclopropyl-1-phosphaallene 5
diphosphinidenecyclobutene 6 was observed together with 5 by
31P NMR spectroscopy in a 2 : 1 ratio (Scheme 2). Compound
6 was recrystallised from hexane to obtain a suitable single
crystal for X-ray structure determination. In this reaction, no
1,4-diphosphafulvene derivative was observed in the reaction
mixture, which shows a sharp contrast to the reactions of 3-phenyl-
1-phosphaallene 3.4,11 Generation of hydrogen was observed
in the formation of 6, which is similar to the formation of
phenanthrenequinone from benzil in the presence of C8K.12 No
oxidative reagent is required in the preparation of 6 from 5, which
leads to the establishment of a concise method for the synthesis
of 3,4-diphosphinidenecyclobutene derivatives. We examined the
reaction of 5 with 1 equiv. of butyllithium, but the yield of 6 was
even lower than in the case using 0.5 equiv. of butyllithium, as men-
tioned above. The reaction mechanism of the formation of 6 from
5 in the presence of butyllithium might include a catalytic dehydro-
genation under basic conditions, and attempts to clarify the details
are underway. The melting point of 6 is considerably high, which is
similar to the property of hexacyclopropylbenzene (266–270 ◦C).13
The molecular structure of 6 was confirmed by X-ray crystallog-
raphy as shown in Fig. 2. The two cyclopropyl groups are perpen-
dicular to the nearly planar cyclobutene ring, which indicates the
cyclopropyl conjugation.4,10 However, the cyclopropyl groups of 6
do not take an exactly bisected conformation to the cyclobutene
ring, while the molecule shows a C2 symmetric structure. On the
other hand, the cyclopropyl groups in hexacyclopropylbenzene
are reported not to take a perpendicular alignment to the benzene
ring, probably due to minimisation of the steric congestion.13 The
in 63% yield. Although the X-ray structure determination of 5
9
= =
was incomplete, it indicated that the P C C skeleton and the
cyclopropyl group show a conformation of s-trans type and that
=
the cyclopropyl ring is almost perpendicular to the adjacent C C
p-system.10
Scheme
1
Reagents and conditions: (i) n-BuLi, THF, −100 ◦C;
(ii) c-PrCHO, −100 ◦C to rt; (iii) MeI; (iv) t-BuLi, THF, −100 ◦C to rt.
Scheme 2 Reagents and conditions: (i) n-BuLi, THF, −78 ◦C to rt;
(ii) (tht)AuCl, CH2Cl2, rt.
Fig. 1 Molecular structure of 4. Hydrogen atoms except for the CH
◦
˚
hydrogen are omitted for clarity. Selected bond lengths (A) and angles ( ):
Br–C1 1.901(3), P–C1 1.671(3), P–CMes* 1.841(3), C1–C2 1.533(4), C2–O
1.404(5), O–Me 1.411(5), C2–C3 1.488(5), C3–C4 1.495(5), C3–C5
1.492(5), C4–C5 1.493(6); C1–P–CMes* 105.0(1), Br–C1–P 125.5(2), Br–C1–
C2 114.6(2), P–C1–C2 120.0(2), C1–C2–C3 112.3(3), C2–C3–C4 118.8(3),
C2–C3–C5 119.5(3), C4–C3–C5 60.0(3), C3–C4–C5 59.9(3), C3–C5–C4
60.1(2).
Fig. 2 Molecular structure of 6. Hydrogen ato◦ms are omitted for
˚
clarity. Selected bond lengths (A) and angles ( ): P1–C1 1.674(6),
P1–CMes* 1.851(5), P2–C2 1.682(6), P2–CMes* 1.857(6), C1–C2 1.513(7),
C1–C3 1.472(8), C2–C4 1.487(8), C3–C4 1.393(8), C3–C5 1.484(8),
C5–C6 1.50(1), C5–C7 1.486(9), C6–C7 1.43(1), C4–C8 1.478(8), C8–C9
1.510(10), C8–C10 1.505(9), C9–C10 1.45(1); C1–P1–CMes* 100.2(2),
C2–P2–CMes* 100.5(3), C2–C1–C3 87.7(4), C1–C2–C4 87.6(4), C1–C3–C4
92.9(5), C2–C4–C3 91.7(5), C4–C3–C5 139.2(6), C1–C3–C5 127.8(5),
C3–C5–C6 120.7(7), C3–C5–C7 124.3(5), C6–C5–C7 57.4(5), C5–C6–C7
60.9(5), C5–C7–C6 61.7(5), C4–C8–C9 121.6(6), C4–C8–C10 123.8(5),
C9–C8–C10 57.7(5), C8–C9–C10 61.0(5), C8–C10–C9 61.3(5).
Preparation and structure of 1,2-bis(cyclopropyl)-3,4-bis(2,4,6-tri-
tert-butylphenyl)-3,4-diphosphinidenecyclobutene
3-Cyclopropyl-1-phosphaallene 5 was allowed to react with
0.5 equiv. of butyllithium in THF. In the reaction mixture, 3,4-
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proximal bonds of the cyclopropyl groups of 6 are longer than the
distal bonds, indicating the cyclopropyl conjugation.
generation of hydrogen gas. The molecular structure of 6 revealed
an effect of the cyclopropyl conjugation with the DPCB skeleton.
Two gold atoms can coordinate on the two phosphorus atoms of
6, indicating that the aurophilic interaction overcomes the steric
congestion caused by the bulky Mes* groups and the rigid DPCB
skeleton. Further investigation on properties of 4–7 is in progress
to develop novel functional phosphorus compounds.
Preparation and structure of the digold(I) complex of the
1,2-bis(cyclopropyl)-3,4-diphosphinidenecyclobutene
3,4-Diphosphinidenecyclobutene 6 is expected to function as a
P2-ligand for metal complex formation, and we chose the gold(I)
reagent (tht)AuCl (tht = tetrahydrothiophene) to obtain a novel
complex bearing 6 in this study. Compound 6 was allowed to react
with (tht)AuCl in dichloromethane at room temperature and, after
the workup procedure, the digold(I) complex 7 was obtained in
39% yield. Complex 7 is slightly unstable in solution as could be
observed by the formation of a gold mirror on the used glassware.
No monogold(I) complex was observed in the reaction mixture
of 6 and (tht)AuCl. The molecular structure of 7 was determined
by X-ray crystallography, and Fig. 3 displays its ORTEP drawing.
In spite of steric congestion and the rigid skeleton around the
phosphorus atoms, two gold atoms are included in the molecule.
The molecule shows C2 symmetry, and the cyclopropyl groups take
an “alternating” conformation, probably to minimise the steric
congestion. Indeed, the cyclopropyl groups of 7 turn up and down
probably due to the distortion caused by the coordination of two
gold atoms. The torsion angle of H(P1–C1–C2–P2) (26◦) is larger
than that of 6 (0.5◦). The six-membered metallacycle disturbs the
planar 3,4-diphosphinidenecyclobutene skeleton [H(Au2–Au1–
P1–C1) = 50.8◦; H(Au1–Au2–P2–C2) = 44.6◦]. The Au1–Au2
Experimental
Preparation of 4
To a solution of 2,2-dibromo-1-(2,4,6-tri-tert-butylphenyl)-1-
phosphaethene (1.00 g, 2.23 mmol) in THF (20 mL) was added
butyllithium (3.30 mmol, 1.6 M solution in hexane, 1 M =
1 mol dm−3) at −100 ◦C. After being stirred for 10 min, the mixture
was then treated with cyclopropanecarbaldehyde (2.23 mmol)
and allowed to warm to room temperature. An excess equiv. of
iodomethane (4.5 mmol) was added and the reaction mixture was
stirred for 15 min. The solvent and volatile materials were removed
in vacuo, and the residue was extracted with hexane. Silica-gel
column chromatography (hexane/EtOAc = 20 : 1) of the hexane
extracts gave 750 mg of 4 (yield: 63%), mp 76–78 ◦C; 31P{ H}
1
1
NMR (162 MHz, CDCl3) d 259.6; H NMR (400 MHz, CDCl3)
d 7.46 (2H, s, arom), 3.37 (3H, s, OMe), 3.31 (1H, m, CH–OMe),
1.55 (9H, s, o-tBu), 1.53 (9H, s, o-tBu), 1.38 (9H, s, p-tBu), 1.35
(1H, m, CH), 0.73 (1H, m, CHH), 0.59 (2H, m, CHH), 0.38
1
(1H, m, CHH); 13C{ H} NMR (101 MHz, CDCl3) d 166.4 (d,
distance is close to that of [Ph2P(CH2)2PPh2][AuCl]2 [8: 3.05(1)
1
2
=
JPC = 63.8 Hz, P C), 153.8 (d, JPC = 2.5 Hz, o-arom), 153.6
14
A], indicating an aurophilic attraction.15 The Au–P and Au–Cl
˚
2
1
(d, JPC = 2.5 Hz, o-arom), 151.3 (s, p-arom), 136.6 (d, JPC
=
distances are comparable to those of 8.14
54.3 Hz, ipso-arom), 122.8 (s, m-arom), 122.5 (s, m-arom), 91.4
2
(d, JPC = 40.0 Hz, CH), 57.3 (s, OMe), 38.3 (s, o-CMe3), 38.2
4
(s, o-CMe3), 35.5 (s, p-CMe3), 33.4 (d, JPC = 6.9 Hz, o-CMe3),
33.2 (d, 4JPC = 6.5 Hz, o-CMe3), 31.8 (s, p-CMe3), 16.9 (d, 3JPC
=
11.6 Hz, CH-cyclopropyl), 5.4 (s, CH2), 4.2 (s, CH2); HRMS: calc.
for C24H38BrOP + Na: 475.1736; found: 475.1738.
Preparation of 5
To a solution of 635 mg (1.4 mmol) of 4 in THF (30 mL) was
added tert-butyllithium (1.4 mmol) at −100 ◦C. After being stirred
for 10 min, the reaction mixture was allowed to warm to room
temperature and the volatile materials were removed in vacuo.
The residue was extracted with hexane and purified by column
chromatography (hexane) to give 300 mg of 5 (yield: 63%), mp
75–77 ◦C; 31P{ H} NMR (162 MHz, CDCl3) d 70.6; H NMR
1
1
Fig. 3 Molecular structure of 7. Hydrogen atoms are omitted for clarity.
Selected bond lengths (A) and angles ( ): Au1–Au2 3.0096(5), Au1–Cl1
◦
3
˚
(400 MHz, CDCl3) d 7.47 (2H, s, arom.), 5.33 (1H, dd, JPH
=
26.2 Hz, 3JHH = 5.6 Hz, C CH), 1.67 (18H, s, o-tBu), 1.49 (1H, m,
CH), 1.38 (9H, s, p-tBu), 0.80 (2H, m, CHH), 0.42 (2H, m, CHH);
2.293(3), Au2–Cl2 2.280(3), Au1–P1 2.223(3), Au2–P2 2.220(3), P1–C1
1.662(9), P1–CMes* 1.834(9), P2–C2 1.670(9), P2–CMes* 1.816(9), C1–C2
1.49(1), C1–C4 1.48(1), C2–C3 1.48(1), C3–C4 1.40(1); Au2–Au1–Cl1
89.64(7), Au2–Au1–P1 91.27(6), Cl1–Au1–P1 174.7(1), Au1–Au2–Cl2
94.58(9), Au1–Au2–P2 89.43(6), Cl2–Au2–P2 174.1(1), Au1–P1–C1
116.1(3), Au1–P1–CMes* 136.7(3), C1–P1–CMes* 107.0(4), Au2–P2–C2
119.3(3), Au2–P2–CMes* 133.7(3), C2–P2–CMes* 105.5(4), P1–C1–C2
131.7(3), P1–C1–P4 140.6(7), C2–C1–C4 87.7(3), P2–C2–C1 131.7(3),
P2–C2–C3 138.9(7), C1–C2–C3 88.1(7), C1–C4–C3 91.7(8).
=
1
1
13C{ H} NMR (101 MHz, CDCl3) d 239.1 (d, JPC = 24.0 Hz,
2
=
P C), 153.9 (d, JPC = 3.4 Hz, o-arom), 149.9 (s, p-arom), 133.1
(d, 1JPC = 64.3 Hz, ipso-arom), 122.4 (s, m-arom), 116.6 (d, 2JPC
=
=
15.2 Hz, C CH), 38.6 (s, o-CMe3), 35.4 (s, p-CMe3), 33.6 (d,
4JPC = 7.4 Hz, o-CMe3), 31.8 (s, p-CMe3), 10.5 (d, 3JPC = 15.1 Hz,
3
CH), 7.9 (d, JPC = 2.8 Hz, CH2), 7.5 (s, CH2); HRMS: calc. for
C23H35P + Na: 365.2369; found: 365.2366.
Conclusion
Preparation of 6
We have demonstrated the formation of 1,2-bis(cyclopropyl)-
3,4-diphosphinidenecyclobutene
6
from 3-cyclopropyl-1-
To a solution of 300 mg (0.88 mmol) of 5 in THF (12 mL)
phosphaallene 5 in the presence of a base, together with the
was added butyllithium (0.44 mmol, 1.6 M solution in hexane)
712 | Dalton Trans., 2006, 710–713
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at −78 ◦C. After being stirred for 10 min, the reaction mixture was
allowed to warm to room temperature and the volatile materials
were removed in vacuo. The residue was extracted with hexane and
evaporated in vacuo. Recrystallisation from hexane gave 48 mg of
unique reflections (Rint = 0.065), R1 = 0.031 (I > 2r(I)), Rw =
0.038 (all data).
CCDC reference numbers 272085–272087.
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b510432g
◦
1
6 (yield: 16%), mp 312–315 C; 31P{ H} NMR (162 MHz, CDCl3)
1
d 147.0; H NMR (400 MHz, CDCl3) d 7.33 (4H, s, arom), 1.57
(36H, s, o-tBu), 1.28 (18H, s, p-tBu), 0.22 (4H, m, CHH), 0.11
1
(4H, m, CHH), −0.31 (2H, m, CH); 13C{ H} NMR (101 MHz,
Acknowledgements
CDCl3) d 181.3 (dd, 1JPC = 19.8 Hz, 2JPC = 5.4 Hz, P C), 162.1
=
(dd, 2JPC = 7.8 Hz, 3JPC = 5.8 Hz, C C), 155.9 (s, o-arom), 149.9
This work was supported in part by Grants-in-Aid for Scientific
Research (No. 13303039 and 14044012) from the Ministry of Edu-
cation, Culture, Sports, Science andTechnologyof Japan. M. Frey-
tag is grateful to the Japan Society for the Promotion of Science
for Postdoctoral Fellowships for Foreign Researchers.
=
(s, p-arom), 136.5 (dd, 1JPC = 29.6 Hz, 4JPC = 25.4 Hz, ipso-arom),
121.3 (s, m-arom), 38.5 (s, o-CMe3), 35.3 (s, p-CMe3), 33.5 (pt,
(4JPC + 7JPC)/2 = 3.5 Hz, o-CMe3), 31.7 (s, p-CMe3), 9.8 (s, CH2),
8.4 (s, CH); HRMS: calc. for C46H68P2 + Na: 705.4688; found:
705.4690.
References
Preparation of 7
1 (a) S. Patai, The Chemistry of Ketenes, Allenes and Related Compounds,
Wiley, New York, 1980; (b) S. R. Landor, The Chemistry of the Allenes,
Academic Press, London, 1982; (c) H. F. Schuster and G. M. Coppola,
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2 (a) M. Regitz and O. J. Scherer, Multiple Bonds and Low Coordination in
Phosphorus Chemistry, Georg Thieme Verlag, Stuttgart, 1990; (b) K. B.
Dillon, F. Mathey and J. F. Nixon, Phosphorus: The Carbon Copy, John
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Trans., 1998, 3343.
3 S. Ito, S. Sekiguchi and M. Yoshifuji, Eur. J. Org. Chem., 2003, 4838.
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5 (a) F. Mathey, Angew. Chem., Int. Ed., 2003, 42, 1578; (b) L. Weber,
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Ozawa and M. Yoshifuji, C. R. Chim., 2004, 7, 747.
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Jpn., 2004, 77, 1377; (b) A. Nakamura, S. Kawasaki, K. Toyota and M.
Yoshifuji, Chem. Lett., 2004, 33, 1570; (c) R. Appel, V. Winkhaus and
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Murayama, H. Yoshimura, A. Okamoto, K. Hirotsu and S. Nagase,
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Polborn, Angew. Chem., Int. Ed. Engl., 1990, 29, 927.
A mixture of 25 mg (0.036 mmol) of 6 and 23.5 mg (0.073 mmol)
of (tht)AuCl in 8 mL of CH2Cl2 was stirred for 1 h, then the
volatile materials were removed in vacuo. Recrystallisation from a
mixture of CH2Cl2 and hexane gave 16 mg of 7 (yield: 39%). The
reaction and the recrystallisation were carried out in the dark, mp
◦
238–239 C; 31P{ H} NMR (162 MHz, CDCl3) d 113.7; 1H NMR
(400 MHz, CDCl3) d 7.48 (4H, s, arom), 1.71 (36H, s, o-tBu), 1.28
(18H, s, p-tBu), 0.39 (4H, m, CHH), 0.27 (4H, m, CHH), −0.37
1
1
(2H, m, CH); 13C{ H} NMR (101 MHz, CDCl3) d 170.3 (dd,
1
2
JPC = 38.2 Hz, 2JPC = 26.5 Hz, P C), 163.8 (d, JPC = 26.1 Hz,
=
3
=
C C), 158.7 (s, o-arom), 154.7 (s, p-arom), 123.2 (pt, ( JPC
+
6JPC)/2 = 4.9 Hz, m-arom), 39.3 (s, o-CMe3), 35.7 (s, p-CMe3), 34.6
(s, o-CMe3), 31.5 (s, p-CMe3), 10.8 (pt, (4JPC + 5JPC)/2 = 1.7 Hz,
CH2), 7.1 (s, CH) (ipso-arom could not be determined); HRMS:
calc. for C46H68Au2Cl2P2 + Na: 1169.3397; found: 1169.3403.
X-Ray crystallography
7 S. Ito, S. Sekiguchi, M. Freytag and M. Yoshifuji, Bull. Chem. Soc.
Jpn., 2005, 78, 1142.
8 S. Kimura, S. Ito, M. Yoshifuji and T. Veszpre´mi, J. Org. Chem., 2003,
68, 6820.
A Rigaku RAXIS-IV imaging plate detector with graphite-
˚
monochromated Mo-Ka radiation (k = 0.71070 A) was used.
The structure was solved by direct methods (SIR92),16 expanded
using Fourier techniques (DIRDIF94),17 and then refined by full-
matrix least squares method. The data were corrected for Lorentz
polarization effect. Structure solution, refinement, and graphical
representation were carried out using the teXsan package.18
9 Six independent molecules were found in the crystalline state: mono-
clinic, space group P21/n (no. 14), a = 28.672(3), b = 16.873(2), c =
◦
3
˚
˚
29.103(3) A, b = 109.763(8) , V = 13250(2) A . Diffraction data were
insufficient to determine the positions of all atoms.
10 T. Haumann, R. Boese, S. Kozhushkov, K. Rauch and A. de Meijere,
Liebigs Ann./Recueil, 1997, 2047.
=
=
11 Reaction of Mes*P
C CH–Ph with 0.5 equiv. of butyllithium gave
Crystal data. For 4: C24H38BrOP, M = 453.44, triclinic, space
2,6-diphenyl-1,4-bis(2,4,6-tri-tert-butylphenyl)-1,4-diphosphafulvene
(1) in a moderate yield: S. Ito, M. Freytag and M. Yoshifuji, Sci. Rep.
Tohoku Univ., Ser. I, 2004, 81, 17.
¯
˚
group P1 (no. 2), a = 9.9117(5), b = 13.2871(5), c = 9.7067(5) A,
◦
3
˚
a = 105.593(2), b = 96.440(4), c = 90.888(3) , V = 1222.1(1) A ,
12 (a) D. Tamarkin, D. Benny and M. Rabinovitz, Angew. Chem., Int. Ed.
Engl., 1984, 23, 642; (b) D. Tamarkin and M. Rabinovitz, J. Org. Chem.,
1987, 52, 3472.
13 (a) V. Usieli, R. Victor and S. Sarel, Tetrahedron Lett., 1976, 2705; (b) I.
Bar, J. Bernstein and A. Christensen, Tetrahedron, 1977, 33, 3177.
14 P. G. Jones, Acta Crystallogr., Sect. B, 1980, 36, 2775.
15 (a) F. Scherbaum, A. Grohmann, B. Huber, C. Kru¨ger and H.
Schmidbaur, Angew. Chem., Int. Ed. Engl., 1988, 27, 1544; (b) P.
Pyykko¨, Angew. Chem., Int. Ed., 2004, 43, 4412.
16 A. Altomare, M. C. Burla, M. Camalli, M. Cascarano, C. Giacovazzo,
A. Guagliardi and G. Polidori, J. Appl. Crystallogr., 1994, 27, 435.
17 P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman, R. de
Gelder, R. Israel and J. M. M. Smits, The DIRDIF94 program system,
Technical Report of the Crystallography Laboratory, University of
Nijmegen, The Netherlands, 1994.
Z = 2, Dc = 1.232 g cm−3, l(Mo-Ka) = 1.763 mm−1, T = 133 K,
9728 observed reflections, 5101 unique reflections (Rint = 0.024),
R1 = 0.051 (I > 2r(I)), Rw = 0.078 (all data).
For 6: C46H68P2, M = 682.99, monoclinic, space group P21/n
˚
(no. 14), a = 15.9000(4), b = 24.1687(7), c = 11.3333(5) A, b =
◦
3
−3
˚
89.711(1) , V = 4355.1(3) A , Z = 4, Dc = 1.042 g cm , l(Mo-
Ka) = 0.128 mm−1, T = 140 K, 35515 observed reflections, 9885
unique reflections (Rint = 0.084), R1 = 0.097 (I > 2r(I)), Rw
=
0.108 (all data).
For 7: C46H68Au2Cl2P2, M = 1147.83, orthorhombic, space
group Pna21 (no. 33), a = 19.4009(5), b = 15.0454(4), c =
3
−3
˚
˚
15.8448(7) A, V = 4625.0(3) A , Z = 4, Dc = 1.648 g cm , l(Mo-
18 Crystal Structure Analysis Package, Molecular Structure Corporation,
Ka) = 6.573 mm−1, T = 133 K, 36160 observed reflections, 5323
The Woodlands, TX, 1985 and 1999.
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The Royal Society of Chemistry 2006
Dalton Trans., 2006, 710–713 | 713
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