Direct syntheses of 1-phenylphosphetane and 1-phenylphosphirane. Crystal and molecular structures of neutral and cationic cyclotrimerization precursor complexes

Article abstract of DOI:10.1021/om9507336

Dilithium phenylphosphide reacts with 1,3-dichloropropane or 1,2-dichloroethane to give 1-phenylphosphetane (1) or 1-phenylphosphirane (2), respectively, both of which can be isolated by distillation in vacuo. The phosphetane rapidly polymerizes when neat but is stable in benzene wherefrom the polymer can be selectively and quantitatively separated from 1 by the addition of trans-dichlorobis(diethyl sulfide)palladium(II). Four-membered 1 has a remarkably low-field ³¹P NMR chemical shift (13.9 ppm), and 2, a remarkably high-field shift (-236 ppm). The crystal and molecular structures of the potential cyclotrimerization precursor complexes fac-[Mo(CO)₃(1)₃] (7), fac-[Mo(CO)₃(2)₃] (8), and [(η⁵-C₅H₅)Fe-(2)₃]PF₆ (9) have been determined. Both molybdenum complexes have C₃ symmetry in the solid state, and the iron complex has C₁ symmetry. An interesting feature of the three structures is that the phenyl groups of the small phosphorus heterocycles in each case are arranged in groups of three syn or anti to the auxiliary ligands.

Full text of DOI:10.1021/om9507336

Organometallics 1996, 15, 1301-1306
1301
Dir ect Syn th eses of 1-P h en ylp h osp h eta n e a n d
1-P h en ylp h osp h ir a n e. Cr ysta l a n d Molecu la r Str u ctu r es
of Neu tr a l a n d Ca tion ic Cyclotr im er iza tion P r ecu r sor
Com p lexes
David C. R. Hockless, Yew Beng Kang, Mark A. McDonald, Michael Pabel,
Anthony C. Willis, and S. Bruce Wild*
Research School of Chemistry, Institute of Advanced Studies, Australian National University,
Canberra, Australian Capital Territory 0200, Australia
Received September 14, 1995X
Dilithium phenylphosphide reacts with 1,3-dichloropropane or 1,2-dichloroethane to give
1-phenylphosphetane (1) or 1-phenylphosphirane (2), respectively, both of which can be
isolated by distillation in vacuo. The phosphetane rapidly polymerizes when neat but is
stable in benzene wherefrom the polymer can be selectively and quantitatively separated
from 1 by the addition of trans-dichlorobis(diethyl sulfide)palladium(II). Four-membered 1
has a remarkably low-field 31P NMR chemical shift (13.9 ppm), and 2, a remarkably high-
field shift (-236 ppm). The crystal and molecular structures of the potential cyclotrimer-
ization precursor complexes fac-[Mo(CO)3(1)3] (7), fac-[Mo(CO)3(2)3] (8), and [(η5-C5H5)Fe-
(2)3]PF6 (9) have been determined. Both molybdenum complexes have C3 symmetry in the
solid state, and the iron complex has C1 symmetry. An interesting feature of the three
structures is that the phenyl groups of the small phosphorus heterocycles in each case are
arranged in groups of three syn or anti to the auxiliary ligands.
In tr od u ction
ally characterized.6 A number of dimethyl- to penta-
methyl-substituted 1-phenylphosphetanes have been
isolated following reductions of the corresponding highly
substituted phosphine oxides,7 and 3-tert-butyl-1-
phenylphosphetane has been prepared by heteroatom
transfer between a 3-tert-butyltitanacyclobutane and
dichlorophenylphosphine.8 On the other hand, 2-meth-
yl-1-tert-butylphosphirane was prepared in low yield by
a direct synthesis involving dilithium tert-butylphos-
phide and 1,2-dichloropropane.9 We now report that
both 1 and 2 can be prepared by direct syntheses
between dilithium phenylphosphide and the respective
dichloroalkane and that the distilled products can be
used to prepare potential cyclotrimerization precursor
complexes. A preliminary account of part of this work
has been published.10
Strained three- and four-membered phosphorus
heterocycles are potential building blocks for macrocyclic
poly(tertiary phosphines) by cyclooligomerization on
metal templates. For such syntheses, which are known
for the conversion of oxirane into crown ethers,1
P-substituted phosphiranes and phosphetanes are
required with minimal substitution in the rings to
facilitate oligomerization and to reduce the number of
product diastereomers. Two ideal molecules for
attempted cyclooligomerization under metal template
conditions are 1-phenylphosphetane (1) and 1-phenyl-
phosphirane (2). Hitherto, however, there is no reported
synthesis of free 1 and the literature synthesis of 2
produces an equivalent of phenylphosphine as by-
product,2 which is difficult to remove without decom-
position of the otherwise stable heterocycle. In a
previous work, we reported the synthesis of 1 in the
Resu lts a n d Discu ssion
complex
(R*,R*)-(()-[(η5-C5H5){1,2-C6H4(PMePh)2}-
(a ) Dir ect Syn th esis of 1-P h en ylp h osp h eta n e (1)
a n d 1-P h en ylp h osp h ir a n e (2). Treatment of a sus-
pension of dilithium phenylphosphide, which was pre-
pared from phenylphosphine and 2.2 equiv of n-butyl-
lithium in tetrahydrofuran (THF), with 1,3-dichloro-
propane at -78 °C, followed by stirring of the reaction
mixture at room temperature for 18 h, gave a ca. 1:3
mixture of 1 and poly[(phenylphosphino)propane] (3)11
(Scheme 1). (It had been noted previously that this
Fe(1)]PF6‚0.5CH2Cl2.3 At the time no coordination
complex of 2 was known. In the meantime, however,
we have prepared (R*,R*)-(()-[(η5-C5H5){1,2-C6H4-
(PMePh)2}Fe(2)]PF63,4 and other workers have reported
the synthesis of [W(CO)5(2)].5 1-Methyl-1-phenylphos-
phiranium triflate has also been isolated and structur-
X Abstract published in Advance ACS Abstracts, J anuary 1, 1996.
(1) Dale, J .; Daasvatn, K. J . Chem. Soc., Chem. Commun. 1976, 295.
J ones, P. G.; Gries, T.; Gru¨tzmacher, H.; Roesky, H. W.; Schimkowiak,
J .; Sheldrick, G. M. Angew. Chem., Int. Ed. Engl. 1984, 23, 376. Meier,
K.; Rihs, G. Angew. Chem., Int. Ed. Engl. 1985, 24, 858.
(2) Chan, S.; Goldwhite, H.; Keyzer, H.; Rowsell, D. G.; Tang, R.
Tetrahedron 1969, 25, 1097. Gray, G. A.; Cremer, S. E.; Marsi, K. L.
J . Am. Chem. Soc. 1976, 98, 2109.
(3) Bader, A.; Pathak, D. D.; Wild, S. B.; Willis, A. C. J . Chem. Soc.,
Dalton Trans. 1992, 1751. Bader, A.; Kang, Y. B.; Pabel, M.; Pathak,
D. D.; Willis, A. C.; Wild, S. B. Organometallics 1995, 14, 1434.
(4) Pabel, M.; Willis, A. C.; Wild, S. B. Acta Crystallogr., Sect. C, in
press.
(5) Hung, J .-T.; Yang, S.-W.; Gray, G. M.; Lammertsma, K. J . Org.
Chem. 1993, 58, 6786.
(6) Hockless, D. C. R.; McDonald, M. A.; Pabel, M.; Wild, S. B. J .
Chem. Soc., Chem. Commun. 1995, 257.
(7) Cremer, S. E.; Chorvat, R. J . J . Org. Chem. 1967, 32, 4066.
(8) Tumas, W.; Huang, J . C.; Fanwick, P. E.; Kubiak, C. P.
Organometallics 1992, 11, 2944.
(9) Baudler, M.; Germeshausen, J . Chem. Ber. 1985, 118, 4285.
(10) Kang, Y. B.; Pabel, M.; Willis, A. C.; Wild, S. B. J . Chem. Soc.,
Chem. Commun. 1994, 475.
0276-7333/96/2315-1301$12.00/0 © 1996 American Chemical Society

1302 Organometallics, Vol. 15, No. 4, 1996
Hockless et al.
Sch em e 1
Ch a r t 1
F igu r e 1. ORTEP view of 7 showing the atom-labeling
scheme of selected non-hydrogen atoms. Thermal ellipsoids
enclose 50% probability levels.
Sch em e 2
enyl-1,2,3-triphospholane (6)13 (Scheme 2). 1-Phe-
nylphosphirane can be stored at 4 ˚C for 1 month
without sign of polymerization.
reaction gave 3 only, having δP -27 ppm.8) Removal of
solvent, followed by extraction of the residue with
petroleum ether (bp 40-60 °C) and subsequent distil-
lation, gave 1 as a colorless oil, bp 63 °C (0.05 mmHg).
Yield based on 1,3-dichloropropane: 13%. Pure 1 rear-
ranges rapidly into 3, but the rate of polymerization is
reduced substantially by quickly diluting the distillate
with benzene, whereupon a solution of ca. 4:1 1:3 of
considerable stability is obtained. The 31P NMR spec-
trum of the mixture in benzene-d6 contains a sharp
singlet at 13.9 ppm for the phosphetane and a singlet
at -27.2 ppm for the poly[(phenylphosphino)]propane.
This material was used for the synthesis of the tricar-
bonylmolybdenum(0) cyclotrimerization precursor com-
plex, although it was found subsequently that the
polymer can be selectively and quantitatively precipi-
tated from the ca. 4:1 1:3 mixture in benzene by
treatment with a small quantity of trans-[PdCl2(SEt2)2]
in the same solvent. The polymer-free solution of 1 in
benzene was used for the quantitative preparation of
cis-tetracarbonylbis(1-phenylphosphetane)molybdenum-
(0) (4) (see Chart 1) from the corresponding η4-norbor-
nadiene complex by titration with 1 and monitoring of
the reaction by 31P{1H} NMR spectroscopy.
It is noteworthy that the chemical shift values for the
phosphorus nuclei in the heterocycles PhP-(CH2)n
(quoted in ppm relative to 85% aqueous H3PO4) reach
a maximum for the phosphetane (n ) 3), viz. -236 (n
) 2), 13.9 (n ) 3), -15.3 (n ) 4),14 and -34.3 (n ) 5).14
We are intending to carry out ab initio calculations on
some of the interesting features of these phosphorus
heterocycles.
(b) Syn th esis a n d X-r a y Cr ysta l Str u ctu r es of
Cyclotr im er iza tion P r ecu r sor Com p lexes. Ben-
zene solutions of 1 and 2 react with tricarbonyl(η6-
mesitylene)molybdenum(0) to give high yields of fac-
[Mo(CO)3(1)3] (7) or fac-[Mo(CO)3(2)3] (8), respectively,
both of which were isolated as colorless crystals suitable
for X-ray crystallography. Complex [(η5-C5H5)Fe(2)3]-
PF6 (9) was prepared from [(η5-C5H5)Fe(η6-C6H5CH3)]-
PF6 by irradiation in acetonitrile at -40 °C followed by
the addition of 2. Complexes 7-9 are the first com-
pounds containing three three- or four-membered phos-
phorus heterocycles to be structurally characterized. In
recent works, the structures of (R*,R*)-(()-[(η5-C5H5)-
{1,2-C6H4(PMePh)2}Fe(2)]PF63,4 and [W(CO)5(2)]5 have
been reported. The molecular structures of 7-9 are
given in Figures 1-3, respectively. Crystal data for the
three complexes are provided in Table 1. Tables 2, 4,
and 6 give positional parameters for the compounds
A similar reaction between dilithium phenylphos-
phide and 1,2-dichloroethane afforded 2 in 21% yield
after distillation, bp 48 °C (1 mmHg), δP -236 ppm [lit.2
bp 44-48 °C (1.5 mmHg), δP -234 ppm], together with
1,4-diphenyl-1,4-diphosphorinane (5)12 and 1,2,3-triph-
(12) Brooks, P. J .; Gallagher, M. J .; Sarroff, A.; Bowyer, M.
Phosphorus, Sulfur, Silicon 1989, 44, 235.
(13) Baudler, M.; Vesper, J .; Sandmann, H. Z. Naturforsch. 1972,
27b, 1007.
(11) Kobayashi, S.; Suzuki, M.; Saegusa, T. Polym. Bull. (Berlin)
1982, 8, 417.
(14) Quin, L. D. The Heterocyclic Chemistry of Phosphorus;
Wiley-Interscience: New York, 1981; p 212.

1-Phenylphosphetane and 1-Phenylphosphirane
Organometallics, Vol. 15, No. 4, 1996 1303
Ta ble 1. Cr ysta llogr a p h ic Da ta for 7-9
7
8
9
formula
mol wt
C30H33MoO3P3
630.46
C27H27MoO3P3
588.37
C29H32F6FeP4
674.30
cryst system
space group
a, Å
cubic
I4h3d
22.966(2)
trigonal
P3h
orthorhombic
Pbca (No. 61)
20.797(6)
13.608(6)
21.231(5)
6008(5)
14.321(1)
b, Å
c, Å
7.506(1)
1333.2(2)
2
V, Å3
12 113(2)
16
Z
8
cryst dimens, mm
0.13 (radius) sphere
1.382
6.2
Mo KR (λ ) 0.710 73 Å)
Philips PW1100/20
20(1)
1377
1075
112
0.028
0.032
1.02
0.16 × 0.14 × 0.16
0.26 × 0.32 × 0.28
d
calcd, g cm-3
1.465
1.491
µ, cm-1
7.0
66.05
X-ray radiationa
diffractometer
T, °C
Mo KR (λ ) 0.710 73 Å)
Philips PW1100/20
Cu KR (λ ) 1.541 78 Å)
Rigaku AFC6R
-60(1)
4993
20(1)
2242
1831
132
0.024
0.031
1.05
no. of unique data
no. of data usedb
no. of variables
Rc
1945
234
0.070
0.075
c
Rw
GOFc
2.20
F(000)
5184
600
2768
a
b
Graphite monochromator. I > 3σ(I). c R ) ∑||Fo| - |Fc||/∑|Fo|; Rw ) {∑w(|Fo| - |Fc|)2/∑w(Fo)2}1/2; GOF ) {∑w(|Fo| - |Fc|)2/(Nreflcns
-
N
var)}1/2
.
F igu r e 3. ORTEP view of cation of 9 showing the atom-
labeling scheme of selected non-hydrogen atoms. Thermal
ellipsoids enclose 50% probability levels.
Ta ble 2. Atom ic Coor d in a tes a n d Equ iva len t
Isotr op ic Disp la cem en t P a r a m eter sa for
Non -Hyd r ogen Atom s in 7
F igu r e 2. ORTEP view of 8 showing the atom-labeling
scheme of selected non-hydrogen atoms. Thermal ellipsoids
enclose 50% probability levels.
a
x/a
y/b
z/c
Ueq
,
Å2
Mo
0.40202(1)
0.38098(5)
0.3938(2)
0.3897(2)
0.3211(2)
0.2957(3)
0.3301(2)
0.4372(2)
0.4652(2)
0.5099(3)
0.5266(2)
0.4998(3)
0.4551(2)
0.40202(1)
0.50827(5)
0.4103(2)
0.4133(2)
0.5339(2)
0.5678(4)
0.5433(2)
0.5638(2)
0.5888(2)
0.6286(2)
0.6433(3)
0.6191(3)
0.5789(2)
0.40202(1)
0.41340(5)
0.3169(2)
0.2670(2)
0.4609(2)
0.4124(4)
0.3612(2)
0.4238(2)
0.3768(2)
0.3855(3)
0.4409(3)
0.4877(2)
0.4796(2)
0.03257(8)
0.0371(3)
0.051(2)
0.092(2)
0.059(2)
0.120(4)
0.059(2)
0.041(1)
0.051(2)
0.067(2)
0.076(2)
0.072(2)
0.055(2)
P
employing the atom-labeling schemes given in Figures
1-3. The most important bond distances and angles
for 7-9 are listed in Tables 3, 5, and 7, respectively.
The two molybdenum complexes have C3 symmetry in
the solid state. The thermal ellipsoid for the central
carbon C(3) of each phosphetane ring in 7 is elongated
in the direction perpendicular to the C(2), P, C(4) plane,
consistent with conformational disorder over two or
C(1)
O
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
more sites. Calculations on phosphetane (HPCH2-
a
Ueq
)
1/3∑i∑jUijai*aj*a ia j.
CH2CH2) indicated a similarity in energies between two
conformers of Cs symmetry, with a pucker angle of
ligand in the related iron(II) complex.3 X-ray crystal
structure determinations have been performed also on
the complexes cis-dichlorobis(3-tert-butyl-1-phenylphos-
phetane)platinum(II)8 and tricarbonylbis(trans-2,2,3,4,4-
pentamethyl-1-phenylphosphetane)iron(0).16 An inter-
155.63° and a barrier to ring flipping of 5.81 kJ mol-1 15
.
The precision of the data for the phosphetane ligands
in 7 is greater than that obtained for the corresponding
(15) Bachrach, S. M. J . Phys. Chem. 1989, 93, 7780.

1304 Organometallics, Vol. 15, No. 4, 1996
Hockless et al.
Ta ble 3. Selected Bon d Dista n ces a n d An gles for 7
Ta ble 6. Atom ic Coor d in a tes a n d Equ iva len t
Isotr op ic Disp la cem en t P a r a m eter sa for
Non -Hyd r ogen Atom s in 9
Distances (Å)
Mo-P
2.501(1)
1.974(4)
1.851(5)
1.857(5)
1.831(4)
1.152(6)
1.480(10)
C(3)-C(4)
C(5)-C(6)
C(5)-C(10)
C(6)-C(7)
C(7)-C(8)
C(8)-C(9)
C(9)-C(10)
1.526(10)
1.382(6)
1.390(6)
1.388(7)
1.370(9)
1.357(9)
1.393(8)
a
x/a
y/b
z/c
Ueq,
Å2
Mo-C(1)
P-C(2)
P-C(4)
P-C(5)
C(1)-O
C(2)-C(3)
Fe
0.07748(5)
0.14739(9)
0.1134(1)
0.1376(1)
0.2167(4)
0.1598(4)
0.1613(4)
0.1195(5)
0.1809(5)
0.1055(4)
0.1523(5)
0.1089(5)
0.2071(4)
0.75368(10)
0.7691(1)
0.6103(2)
0.8327(2)
0.8485(6)
0.8817(6)
0.6714(6)
0.4993(7)
0.5397(7)
0.5706(6)
0.9646(7)
0.9290(7)
0.7814(6)
0.08534(5)
0.16228(10)
0.05398(10)
0.01776(9)
0.1682(4)
0.2060(4)
0.2197(3)
0.0986(4)
0.0844(4)
-0.0288(3)
0.0180(4)
-0.0333(4)
-0.0218(4)
2.82(2)
3.04(5)
3.32(5)
3.21(5)
4.8(2)
4.5(2)
3.1(2)
5.6(2)
6.2(3)
3.0(2)
5.7(2)
5.6(2)
3.3(2)
P(1)
P(2)
P(3)
C(11)
C(12)
C(13)
C(21)
C(22)
C(23)
C(31)
C(32)
C(33)
Angles (deg)
P-Mo-C(1)
P-Mo-P′
89.49(15)
P-C(2)-C(3)
91.0(4)
100.4(5)
89.3(4)
96.12(4)
83.81(13)
174.36(15)
90.54(19)
120.98(16)
118.49(17)
123.83(14)
77.1(2)
C(2)-C(3)-C(4)
P-C(4)-C(3)
P-M-C(1)′
P-Mo-C(1)′′
C(1)-Mo-C(1)′
Mo-P-C(2)
Mo-P-C(4)
Mo-P-C(5)
C(2)-P-C(4)
C(2)-P-C(5)
C(4)-P-C(5)
Mo-C(1)-O
P-C(5)-C(6)
121.1(3)
120.1(3)
118.6(4)
120.3(5)
120.2(5)
120.5(6)
120.0(5)
120.4(5)
P-C(5)-C(10)
C(6)-C(5)-C(10)
C(5)-C(6)-C(7)
C(6)-C(7)-C(8)
C(7)-C(8)-C(9)
C(8)-C(9)-C(10)
C(5)-C(10)-C(9)
a
Ueq
)
1/3∑i∑jUijai*aj*a ia j.
103.1(2)
103.1(2)
177.8(5)
Ta ble 7. Selected Bon d Dista n ces a n d An gles for 9
Distances (Å)
Fe-P(1)
2.197(3)
2.193(4)
2.186(4)
1.81(1)
1.81(1)
1.83(1)
1.79(1)
1.82(1)
P(2)-C(23)
P(3)-C(31)
P(3)-C(32)
P(3)-C(33)
C(11)-C(12)
C(21)-C(22)
C(31)-C(32)
1.85(1)
1.82(1)
1.80(1)
1.81(1)
1.50(2)
1.42(2)
1.50(2)
a
Primes (′) indicate atoms generated by the symmetry operation
(z, x, y); double primes (′′) indicate atoms generated by the
symmetry operation (y, z, x).
Fe-P(2)
Fe-P(3)
P(1)-C(11)
P(1)-C(12)
P(1)-C(13)
P(2)-C(21)
P(2)-C(22)
Ta ble 4. Atom ic Coor d in a tes a n d Equ iva len t
Isotr op ic Disp la cem en t P a r a m eter sa for
Non -Hyd r ogen Atom s in 8
a
x/a
y/b
z/c
Ueq
,
Å2
Angles (deg)
1
2
Mo
P
C(1)
O
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
/
/
0.28868(3)
0.47011(6)
0.1384(3)
0.0509(2)
0.6377(3)
0.7073(3)
0.3622(3)
0.2218(3)
0.1335(3)
0.1833(3)
0.3169(3)
0.4074(3)
0.03337(9)
0.0387(2)
0.0443(9)
0.0674(8)
0.061(1)
0.063(1)
0.0387(8)
0.0463(9)
0.053(1)
0.056(1)
0.059(1)
0.050(1)
P(1)-Fe-P(2)
94.9(1)
93.6(1)
92.5(1)
129.6(4)
123.8(4)
122.1(4)
65.7(7)
P(2)-C(21)-C(22)
P(2)-C(22)-C(21)
Fe-P(3)-C(31)
67.9(8)
3
3
0.30934(4)
0.2121(2)
0.1410(1)
0.3970(2)
0.2893(2)
0.2453(2)
0.2981(2)
0.2504(2)
0.1489(2)
0.0953(2)
0.1425(2)
0.51021(4)
0.5637(2)
0.5034(1)
0.5013(2)
0.4801(2)
0.3789(1)
0.3611(2)
0.2633(2)
0.1830(2)
0.2002(2)
0.2975(2)
P(1)-Fe-P(3)
65.6(8)
125.4(5)
124.3(5)
124.8(4)
65.0(8)
P(2)-Fe-P(3)
Fe-P(1)-C(11)
Fe-P(1)-C(12)
Fe-P(1)-C(13)
P(1)-C(11)-C(12)
P(1)-C(12)-C(11)
Fe-P(2)-C(21)
Fe-P(2)-C(22)
Fe-P(2)-C(23)
Fe-P(3)-C(32)
Fe-P(3)-C(33)
P(3)-C(31)-C(32)
P(3)-C(32)-C(31)
C(11)-P(1)-C(13)
C(21)-C(2)-C(23)
C(31)-C(3)-C(33)
66.2(8)
65.3(7)
105.3(6)
105.3(6)
104.3(6)
128.0(5)
128.7(5)
121.3(4)
a
the phenyl groups of the 1-phenylphosphirane ligands
form a belt around the middle of the molecule syn to
the carbonyls. In 9, however, the phenyl groups of the
1-phenylphosphirane adopt anti dispositions with re-
spect to the bulky cyclopentadienyl group, which is an
indication of the importance auxiliary ligands could
have on the attempted conversion of 1 and 2 into face-
capping tridentates by cyclotrimerization on metal
templates.
Ueq
)
1/3∑i∑jUijai*aj*a ia j.
Ta ble 5. Selected Bon d Dista n ces a n d An gles for 8
Distances (Å)
Mo-P
2.4945(6)
1.975(2)
1.826(3)
1.821(2)
1.818(2)
1.155(2)
1.508(5)
C(4)-C(5)
C(4)-C(9)
C(5)-C(6)
C(6)-C(7)
C(7)-C(8)
C(8)-C(9)
1.393(3)
1.388(2)
1.382(3)
1.379(3)
1.358(4)
1.385(3)
Mo-C(1)
P-C(2)
P-C(3)
P-C(4)
C(1)-O
C(2)-C(3)
Angles (deg)
Con clu sion
P-Mo-C(1)
P-Mo-P′
88.07(7)
93.04(3)
P-C(2)-C(3)
65.37(17)
65.77(15)
P-C(3)-C(2)
1-Phenylphosphetane (1) and 1-phenylphosphirane (2)
have been synthesized directly from dilithium phe-
nylphosphide and the appropriate terminal dichloroal-
kane in THF. The phosphetane polymerizes rapidly in
the neat state but has considerable stability in benzene.
The two heterocycles have extreme 31P NMR chemical
shifts, viz. 13.9 ppm for 1 and -236 ppm for 2 in
benzene. The phosphines react with tricarbonyl(η6-
mesitylene)molybdenum(0) to give high yields of the
potential cyclotrimerization precursor complexes fac-
[Mo(CO)3(1)3] and fac-[Mo(CO)3(2)3]. 1-Phenylphos-
phirane also reacts with the iron complex [(η5-C5H5)Fe(η6-
C6H5CH3)]PF6 in acetonitrile to give the cationic
cyclotrimerization precursor complex [(η5-C5H5)Fe(2)3]-
PF6. The phenyl groups of the three- and four- mem-
bered phosphorus heterocycles are arranged in groups
of three syn or anti to the auxiliary ligands in the three
P-Mo-C(1)′
P-Mo-C(1)′′
C(1)-Mo-C(1)′
Mo-P-C(2)
Mo-P-C(3)
Mo-P-C(4)
C(2)-P-C(3)
C(2)-P-C(4)
C(3)-P-C(4)
88.24(12)
178.27(7)
90.63(11)
130.39(8)
132.96(12)
117.22(7)
48.86(15)
104.08(13)
104.59(11)
P-C(4)-C(5)
P-C(4)-C(9)
119.17(13)
122.33(18)
118.38(18)
120.67(18)
119.73(25)
120.27(22)
120.59(20)
120.33(23)
179.85(24)
C(5)-C(4)-C(9)
C(4)-C(5)-C(6)
C(5)-C(6)-C(7)
C(6)-C(7)-C(8)
C(7)-C(8)-C(9)
C(4)-C(9)-C(8)
Mo-C(1)-O
a
Primes (′) indicate atoms generated by the symmetry operation
(1 - y, 1 + x - y, z); double primes (′′) indicate atoms generated
by the symmetry operation (-x + y, 1 - x, z).
esting feature of the structures of 7 and 8 is that the
phenyl groups of the 1-phenylphosphetane ligands in 7
are arranged anti to the carbonyl ligands, whereas in 8
(16) Bennett, D. W.; Grubisha, D. S.; Cremer, S. E.; Peterson, A. C.
J . Crystallogr. Spectrosc. Res. 1992, 22, 83.

1-Phenylphosphetane and 1-Phenylphosphirane
Organometallics, Vol. 15, No. 4, 1996 1305
27.90-28.90 (m, CH2CH2CH2), 128.74-128.95 (m, 3-ArC),
128.99 (s, 4-ArC), 129.24-129.54 (m, 2-ArC), 141.38-141.73
(m, 1-ArC), 209.62 (t, 2J (CP) ) 9.8 Hz, COcis), 216.02 (dd,
2J (CPcis) ) 2J (CPtrans) ) 7.9 Hz, COtrans). 31P{1H} NMR (CD2-
Cl2, 80.98 MHz): δ 60.49 (s). IR (n-hexane): 1912, 1933, 2022
cm-1 (νCO). MS: m/e 508 amu ([M]•+).
complexes, which could be an important factor in
determining the outcome of cyclotrimerization reactions.
Exp er im en ta l Section
All reactions were performed in an atmosphere of dry argon
using the Schlenk technique. Solvents were purified by
conventional literature methods; petroleum ether had a boiling
point of 40-60 °C. 1H and 31P{1H} NMR spectra were recorded
at 25 °C on a Varian XL 200E or VXR 300 S spectrometer
operating at 200.04 or 299.95 MHz and at 80.98 or 121.42
MHz, respectively. 13C{1H} NMR spectra were recorded at 25
°C on Varian XL 200E, VXR 300S, or VXR 500S spectrometer
operating at 50.31, 75.43, or 125.70 MHz. The chemical shifts
were referenced to Me4Si (1H, 13C) or external 85% aqueous
H3PO4 (31P) with downfield chemical shifts being positive. IR
spectra were recorded on a Model 683 Perkin-Elmer infrared
spectrophotometer. Mass spectra were recorded on a VG
Micromass 7070F double-focusing mass spectrometer. Fast
atom bombardment (FAB) mass spectra were recorded on a
VG Analytical ZAB-2SEQ mass spectrometer (ionization: 30
1-P h en ylp h osp h ir a n e (2). Dilithium phenylphosphide
(from phenylphosphine (9.54 g, 86.66 mmol) and 2.2 equiv of
n-butyllithium in THF) was suspended in THF (1 L), and 1,2-
dichloroethane (7.65 g, 77.3 mmol) was added with stirring at
-78 °C. After 30 min, the mixture was allowed to warm to
room temperature and stirring was continued for 18 h. The
solvent was removed from the reaction mixture in vacuo, and
the residue was extracted with petroleum ether (150 mL).
Filtration of the mixture, followed by removal of the solvent
under reduced pressure and distillation of the residue, gave
1-phenylphosphirane as a clear mobile oil: bp 48 °C (1 mmHg)
[lit.2 bp 44-48 °C (1.5 mmHg); yield 2.21 g (21%). 1H NMR
(C6D6, 200.04 MHz): δ 0.78-1.09 (m, 4 H, CH2), 6.90-7.27
(m, 5 H, aromatics). 13C{1H} NMR (C6D6, 50.30 MHz): δ 10.09
(d, 1J (CP) ) 40.3 Hz, CH2), 128.37 (s, 4-ArC), 128.50 (s, 3-ArC),
keV Cs+ ions) in
a matrix of 3-nitrobenzyl alcohol and
2
1
131.88 (d, J (CP) ) 19.6 Hz, 2-ArC), 139.81 (d, J (CP) ) 39.6
Hz, 1-ArC), 216.75-217.03 (m, CO). 31P{1H} NMR (CD2Cl2,
80.98 MHz): δ -236.60 (s).
methanol as solvent. Elemental analyses were performed by
staff within the Research School of Chemistry.
1-P h en ylp h osp h eta n e (1). Dilithium phenylphosphide
was prepared from phenylphosphine (10.65 g, 96.74 mmol) and
2.2 equiv of n-butyllithium in THF. The pyrophoric yellow
powder was suspended in THF (1 L), and 1,3-dichloropropane
(10.00 g, 88.5 mmol) was added with stirring at -78 °C. After
30 min, the mixture was allowed to warm to room temperature
and stirring was continued for 18 h. The solvent was removed
from the reaction mixture in vacuo, and the residue was
extracted with petroleum ether (150 mL). Filtration of the
mixture, followed by removal of the solvent under reduced
pressure and distillation of the residue, gave 1-phenylphos-
phetane as a clear mobile oil: bp 63 °C (0.05 mmHg); yield
1.71 g (13%, purity 80%). 1H NMR (C6D6, 200.04 MHz): δ
1.55-2.60 (m, 6 H, CH2), 6.90-7.45 (m, 5 H, aromatics). 13C-
{1H} NMR (C6D6, 50.30 MHz): δ 22.19 (d, 1J (CP) ) 6.0 Hz,
CH2CH2CH2), 24.63 (d, 2J (CP) ) 2.4 Hz, CH2CH2CH2), 127.77
(s, 4-ArC), 128.57 (d, 3J (CP) ) 4.9 Hz, 3-ArC), 130.58 (d, 2J (CP)
fa c-Tr ica r b on ylt r is(1-p h en ylp h osp h et a n e)m olyb d e-
n u m (0) (7). A solution of tricarbonyl(η6-mesitylene)molyb-
denum(0) (230 mg, 0.76 mmol) in dichloromethane (20 mL)
was slowly added to a solution of 1 (425 mg, 2.83 mmol, 80%
purity) in benzene (25 mL). After being stirred at room
temperature for 14 h, the reaction mixture was subjected to
flash chromatography on silica with dichloromethane. Re-
moval of the solvents from the eluate in vacuo afforded a
colorless solid that was dissolved in THF (5 mL) and crystal-
lized by the addition of petroleum ether (25 mL), giving the
pure product as colorless prisms: mp 189 °C; yield 390 mg
(81%). Anal. Calcd for C30H33MoO3P3: C, 57.2; H, 5.3; P, 14.9.
Found: C, 57.0; H, 5.3; P, 14.7. 1H NMR (CD2Cl2, 299.95
MHz): δ 1.89-2.50 (m, 18 H, CH2), 7.23-7.42 (m, 15 H,
aromatics). 13C{1H} NMR (CD2Cl2, 125.70 MHz): δ 24.46-
24.52 (m, CH2CH2CH2), 28.10-28.90 (m, CH2CH2CH2), 128.56-
128.64 (m, 4-ArC), 128.74-128.87 (m, 3-ArC), 129.88-130.04
(m, 2-ArC), 143.20-143.37 (m, 1-ArC), 219.86-220.06 (m, CO).
31P{1H} NMR (CD2Cl2, 121.42 MHz): δ 64.25 (s with satellites
(sextet), 1J (31P95Mo) ) 126.7 Hz). IR (CH2Cl2): 1848, 1941
cm-1 (νCO). FAB-MS: m/e 630 amu ([M]•+).
fa c-Tr ica r b on ylt r is(1-p h en ylp h osp h ir a n e)m olyb d e-
n u m (0) (8). A solution of tricarbonyl(η6-mesitylene)molyb-
denum(0) (279 mg, 0.93 mmol) in dichloromethane (16 mL)
was added to a solution of 2 (399 mg, 2.93 mmol) in benzene
(40 mL). After being stirred at room temperature for 20 h,
the mixture was heated under reflux for 150 min. Flash
chromatography on silica with benzene, followed by removal
of the solvents in vacuo and two recrystallizations of the
residue from hot toluene, afforded the desired complex as
almost colorless prisms: mp 141 °C; yield 380 mg (70%). Anal.
Calcd for C27H27MoO3P3: C, 55.1; H, 4.6; P, 15.8. Found: C,
55.7; H, 4.7; P, 15.5. 1H NMR (CD2Cl2, 200.04 MHz): δ 0.89-
1.48 (m, 12 H, CH2), 7.15-7.50 (m, 15 H, aromatics). 13C{1H}
NMR (CD2Cl2, 125.70 MHz): δ 10.20-10.40 (m, CH2), 128.73-
128.85 (m, 3-ArC), 129.54 (s, 4-ArC), 132.30-132.42 (m,
2-ArC), 138.14-138.35 (m, 1-ArC), 216.75-217.03 (m, CO).
31P{1H} NMR (CD2Cl2, 80.98 MHz): δ -164.60 (s with satel-
lites (sextet), 1J (31P95Mo) ) 143.5 Hz). IR (CH2Cl2): 1856, 1950
cm-1 (νCO). FAB-MS: m/e 588 amu ([M]•+).
1
) 16.5 Hz, 2-ArC), 143.54 (d, J (CP) ) 31.4 Hz, 1-ArC). 31P-
{1H} NMR (C6D6, 80.98 MHz): δ 13.90 (s, 80%, monomer),
-27.17 (s, 20%, polymer). MS: m/e 150.0 amu ([M]•+).
Selective P r ecip ita tion of P olym er fr om 1. A solution
of trans-[PdCl2(SEt2)2] in benzene (4 mL, 1.12% w/v) was added
to a solution of distilled 1 (380 mg, 2.02 mmol, 80% purity) in
benzene (50 mL). A voluminous yellow precipitate formed.
Filtration of the reaction mixture afforded a clear colorless
solution of pure 1, as indicated by 31P{1H} NMR spectroscopy.
cis-Tetr a ca r bon ylbis(1-p h en ylp h osp h eta n e)m olybd e-
n u m (0) (4). A solution of pure 1 in benzene (ca. 60 mL) was
treated at room temperature with a solution of tetracarbonyl-
(η4-norbornadiene)molybdenum(0) in benzene (0.053 M). The
progress of the reaction was monitored by 31P{1H} NMR
spectroscopy. After the addition of 9.0 mL of the solution of
the molybdenum complex (0.48 mmol) to the phosphine, the
singlet for the free ligand at δP 13.9 ppm had disappeared and
was replaced by the signal at δP 60.49 ppm for the product.
The solvent was removed from the reaction mixture under
reduced pressure, and the residue was chromatographed on a
short column of silica gel with benzene as eluant. The solvent
was removed from the eluate in vacuo, the residue was
dissolved in diethyl ether (1.5 mL), and n-hexane (8 mL) was
added. The solution was concentrated to ca. 8 mL in vacuo,
and then it was cooled to -28 °C. The colorless, crystalline
product was filtered off, washed twice with n-hexane at -78
°C, and dried in vacuo. Yield: 140 mg (58%); mp 91 °C. Anal.
Calcd for C22H22MoO4P2: C, 52.0; H, 4.4; P, 12.2. Found: C,
51.9; H, 4.4; P, 12.3. 1H NMR (CD2Cl2, 200.05 MHz): δ 2.10-
2.75 (m, 12 H, CH2), 7.30-7.60 (m, 10 H, aromatics). 13C{1H}
NMR (CD2Cl2, 75.43 MHz): δ 23.65-24.50 (m, CH2CH2CH2),
(η5-Cyclop en ta d ien yl)tr is(1-p h en ylp h osp h ir a n e)ir on -
(II) Hexa flu or op h osp h a te (9). The complex [(η5-C5H5)Fe(η6-
C6H5CH3)]PF6 (0.93 g, 2.60 mmol) was dissolved in acetonitrile
(10 mL), and the temperature of the solution was lowered to
-40 °C in a refrigerated cold bath. The stirred solution was
then irradiated with a 100 W mercury immersion lamp for ca.
15 h, whereupon the bright yellow solution became deep

1306 Organometallics, Vol. 15, No. 4, 1996
Hockless et al.
-
-
purple, consistent with the formation of [(η5-C5H5)Fe(NCCH3)3]-
PF6.17 A solution of 2 (1.18 g, 8.67 mmol) in toluene (5 mL)
was added to the cold acetonitrile solution of the intermediate,
and stirring was continued for 10 min at this temperature,
followed by 8 h stirring at room temperature. The acetonitrile
was removed under reduced pressure, and the orange oil was
dissolved in dichloromethane (ca. 3 mL) and transferred to a
2 mm silica gel Chromatotron plate. The product was eluted
as a deep orange band with use of an acetone-dichlo-
romethane (10/90) mixture. Removal of solvents from the
eluate afforded the crude product, which after recrystallization
from dichloromethane-diethyl ether formed orange prisms:
mp 182-185 °C; yield 0.36 g (21%). Anal. Calcd for C29H32F6-
FeP4: C, 51.7; H, 4.8; P, 18.4. Found: C, 51.8; H, 4.8; P, 18.2.
1H NMR (CD2Cl2, 299.95 MHz): δ 0.93-1.66 (m, 12 H, CH2),
4.49 (q, 2J (HP) ) 2.1 Hz, 5 H, C5H5), 7.36-7.47 (m, 15 H,
aromatics). 13C{1H} NMR (CD2Cl2, 75.43 MHz): δ 9.95-10.03
(m, CH2), 80.78 (s, C5H5), 129.38-129.51 (m, 3-ArC), 131.00
(s, 4-ArC), 131.87-132.02 (m, 2-ArC), 135.86-136.33 (m,
1-ArC). 31P{1H} NMR (CD2Cl2, 121.42 MHz): δ -121.62 (s).
FAB-MS: m/e 529 amu ([M-PF6]•+).
the major component of the PF6 ion. The PF6 ion in 9 was
refined over two positions, with bond and angle restraints
imposed on the ill-behaved minor component. The displace-
ment factor on C(3) in 7 was observed to be elongated at right
angles to the C(2), C(3), C(4) plane, suggesting that this atom
was disordered over two or more sites. A model was tested
with two isotropic sites, C(3A) and C(3B) of occupancy p and
1 - p, respectively, one above and one below the plane. This
model, however, was not significantly better than the ordered
representation at the corresponding stage of refinement,
suggesting that C(3) may be disordered over more than two
sites. Accordingly, the atom was described by using the
anisotropic displacement factors of the former (“ordered”)
model. Interpolated form factors were introduced, and refine-
ment was continued until all shift/error ratios were <0.02.
Refinement for 8 was also continued until all shift/error ratios
were <0.02. Least-squares refinement was performed for all
three structures using full-matrix methods. Maximum and
minimum heights in a final difference map were 0.31 and
-0.25 e Å-3 for 7, 0.30 and -0.21 e Å-3 for 8, and 0.71 and
-0.46 e Å-3 for 9. Data reduction and refinement computa-
tions for 7 and 8 were performed with XTAL3.2;19 data
reduction and refinement computations for 9 were performed
with teXsan.20 Atomic scattering factors for neutral atoms and
real and imaginary dispersion terms were taken from ref 21.
Cr ysta l Str u ctu r e An a lyses. Crystal data for 7-9 are
given in Table 1. Data sets for 7 and 8 were collected using
ω-2θ scans of width (1.0 + 0.3 tan θ)° with a scan speed in ω
of 0.5° min-1 for 7 and 1° min-1 for 8. Data for 9 were collected
at -60 ( 1 °C using ω-2θ scans of width (0.90 + 0.30 tan θ)°
with a scan speed of 8.0° min-1
. The intensities of three
representative reflections were measured periodically. Whereas
no significant decrease in intensities during data collection was
observed for 8 or 9, a decay correction of 4% was applied to 7.
Data were also corrected for absorption (transmission
ranges: 0.886-0.887 for 7, 0.890-0.895 for 8, and 0.86-1.00
for 9).18 The structures were solved by heavy-atom Patterson
methods and expanded using Fourier techniques. The hydro-
gen atoms were included in calculated positions (rC-H ) 0.95
Å). For 7 and 9 these parameters were not refined; for 8,
however, they were allowed to refine in the crystallographic
least-squares procedure but with one common isotropic dis-
placement factor for the methylene and the phenyl hydrogen
atoms. Individual anisotropic displacement factors were
employed for all non-hydrogen atoms in compounds 7 and 8
and for all non-carbon and non-hydrogen atoms in 9, including
Su p p or tin g In for m a tion Ava ila ble: For 7-9, text de-
scribing X-ray procedures, tables of data collection parameters,
bond distances and angles, thermal parameters for non-
hydrogen atoms, calculated hydrogen atom parameters, least-
squares planes, and selected torsion angles, and ORTEP
diagrams (52 pages). Ordering information is given on any
current masthead page.
OM9507336
(19) Hall, S. R., Flack, H. D., Stewart, J . M., Eds. XTAL3.2 Reference
Manual. Universities of Western Australia, Geneva, and Maryland,
1992.
(20) teXsan: Crystal Structure Analysis Package. Molecular Struc-
ture Corp. 1985, 1992.
(21) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, England, 1974; Vol. IV, pp 99-101, 149-150. (Present
distributor: Kluwer Academic Publishers, Dordrecht, The Nether-
lands.)
(17) Gill, T. P.; Mann, K. R. Inorg. Chem. 1983, 22, 1986.
(18) Churchill, M. R.; Kalra, K. L. Inorg. Chem. 1974, 13, 1427.