Synthesis, structure, and coordination chemistry of P-Acyl-, P-Thiocarbamoyl-, and P-Dithiocarboxyl-substituted phosphaalkenes R(X)C-P=C(NMe2)2 (R = Ph, tBu, SSiMe3, N(Ph)SiMe3; X = O, S)

Article abstract of DOI:10.1021/om980264i

Reaction of Me₃SiP=C(NMe₂)₂ (1) with pivaloyl chloride and benzoyl chloride afforded the acylated phosphaalkenes RC(O)P=C(NMe₂)₂ 2a (R = tBu) and 2b (R = Ph). Carbon disulfide and phenyl isothiocyanate were inserted into the P-Si bond of 1 to give the functionalized phosphaalkenes R(X)C-P=C(NMe₂)₂ 2c [R(X)C - Me₃Si-S(S)C] and 2d [R(X)C = Ph(Me₃Si)N(S)C]. Heating 2c and 2d with (CO)₅MBr (M = Mn, Re) in toluene at 50-80°C led to complexes [X = CSM(CO)₃-μ-PC(NMe₂)₂]₂ 3c (M = Mn, X = S), 3d (M = Mn, X = NPh), 4c (M = Re, X = S), and 4d (M = Re, X = NPh). The X-ray structure analysis of 2c showed extensive π-delocalization of electron density from phosphorus into the C=S group The structure determination of 4d revealed the molecule as a tricyclic system with an anti orientation of the peripheric four-membered rings. The organophosphorus fragment serves as η²(P,S)-μ(P) bridging ligand, a coordination mode without precedence in phosphaalkene chemistry.

Full text of DOI:10.1021/om980264i

Organometallics 1998, 17, 3593-3598
3593
Syn th esis, Str u ctu r e, a n d Coor d in a tion Ch em istr y of
P -Acyl-, P -Th ioca r ba m oyl-, a n d
P -Dith ioca r boxyl-Su bstitu ted P h osp h a a lk en es
R(X)C-P dC(NMe2)2 (R ) P h , tBu , SSiMe3, N(P h )SiMe3; X
) O, S)†
Lothar Weber,* Stefan Uthmann, Hartmut Bo¨gge, Achim Mu¨ller,
Hans-Georg Stammler, and Beate Neumann
Fakulta¨t fu¨r Chemie der Universita¨t Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
Received April 7, 1998
Reaction of Me3SiPdC(NMe2)2 (1) with pivaloyl chloride and benzoyl chloride afforded
the acylated phosphaalkenes RC(O)PdC(NMe2)2 2a (R ) tBu) and 2b (R ) Ph). Carbon
disulfide and phenyl isothiocyanate were inserted into the P-Si bond of 1 to give the
functionalized phosphaalkenes R(X)C-PdC(NMe2)2 2c [R(X)C ) Me3Si-S(S)C] and 2d
[R(X)C ) Ph(Me3Si)N(S)C]. Heating 2c and 2d with (CO)5MBr (M ) Mn, Re) in toluene at
50-80 °C led to complexes [X ) CSM(CO)3-µ-PC(NMe2)2]2 3c (M ) Mn, X ) S), 3d (M )
Mn, X ) NPh), 4c (M ) Re, X ) S), and 4d (M ) Re, X ) NPh). The X-ray structure analysis
of 2c showed extensive π-delocalization of electron density from phosphorus into the CdS
group. The structure determination of 4d revealed the molecule as a tricyclic system with
an anti orientation of the peripheric four-membered rings. The organophosphorus fragment
serves as η2(P,S)-µ(P) bridging ligand, a coordination mode without precedence in phos-
phaalkene chemistry.
Sch em e 1
In tr od u ction
The vast majority of phosphaalkenes show a polarity
Pδ+ Cδ- of the PC double bond as anticipated by the
different electronegativities of carbon and phosphorus.2,3
There are, however, a number of phosphaalkenes com-
prising RPdC(NMe2)2 [R ) H,4 SiMe3,5,6 (η5-C5Me5)(CO)2-
Fe7], CF3PdC(NR2)F (R ) Me, Et),8 and the phospha-
triafulvenes RPdC-C(tBu)dC(tBu) (R ) SiMe3, 2,4,6-
Me3C6H2)9 where an inverse polarity Pδ- Cδ+ of the
multiple bond is encountered.
During the course of our continuing studies on P-
metallophosphaalkenes of the type (η5-C5Me5)(CO)2M-
† Dedicated to Professor Peter J utzi on the occasion of his 60th
birthday.
(1) Part 36: Weber, L.; Dembeck, G.; Stammler, H.-G.; Neumann,
B. Eur. J . Inorg. Chem. 1998, 579.
(2) Review: Schoeller, W. W. In Multiple Bonds and Low Coordina-
tion in Phosphorus Chemistry; Regitz, M., Scherer, O. J ., Eds.;
Thieme: Stuttgart 1990; pp 5-31.
(3) Reviews: (a) Appel, R. In Multiple Bonds and Low Coordination
in Phosphorus Chemistry; Regitz, M., Scherer, O. J ., Eds.; Thieme:
Stuttgart 1990; pp 157-219. (b) Appel, R.; Knoll, F. Adv. Inorg. Chem.
1989, 33, 259-361. (c) Markovskii, L. N.; Romanenko, V. D. Tetrahe-
dron 1989, 45, 6019-6090. (d) Dillon, K. B.; Mathey, F.; Nixon, J . F.
Phosphorus: The Carbon Copy; Wiley: Chichester, 1998; pp 88-127.
(4) Chernega, A. N.; Ruban, A. V.; Romanenko, V. D.; Markovskii,
L. N.; Korkin, A. A.; Antipin, M. Y.; Struchkov, Y. T. Heteroat. Chem.
1991, 2, 229.
(5) Markovskii, L. N.; Romanenko, V. D.; Pidvarko, T. I. Zh. Obshch.
Khim. 1982, 52, 1925; Chem. Abstr. 1982, 97, 216330h.
(6) Weber, L.; Kaminski, O. Synthesis 1995, 158.
(7) Weber, L.; Kaminski, O.; Stammler, H.-G.; Neumann, B.; Ro-
manenko, V. D. Z. Naturforsch. 1993, 48B, 1784.
PdC(NR2)2 (M ) Fe, Ru; R ) Me, Et), we observed a
marked elongation of the PC bond upon η1-coordination
to 16 VE complex fragments such as [Ni(CO)3] or [Cr-
(CO)5].10 This finding suggests a description of the
bonding situation in metallophosphaalkenes by two
canonical formulas A and B, the zwitterion of which is
stabilized by η1-ligation of the molecule to a metal center
(C) (Scheme 1).
(8) Grobe, J .; Le Van, D.; Nienstedt, J .; Krebs, B.; Dartmann, M.
Chem. Ber. 1988, 121, 655.
(9) Fuchs, E. P. O.; Heydt, H.; Regitz, M.; Schoeller, W. W.; Busch,
T. Tetrahedron Lett. 1989, 30, 5111.
(10) (a) Weber, L.; Quasdorff, B.; Stammler, H.-G.; Neumann, B.
Chem. Eur. J . 1998, 4, 465. (b) Quasdorff, B. Ph.D. Thesis, Universita¨t
Bielefeld, 1997.
S0276-7333(98)00264-7 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 07/18/1998

3594 Organometallics, Vol. 17, No. 16, 1998
Weber et al.
1088 s, 1058 sh, 925 m, 899 s, 876 m, 771 m, 733 w, 696 m,
653 w, 632 m, 544 w. MS/EI m/z: 236 (M+), 131 [PC(NMe2)2+],
44 (NMe2+). Anal. Calcd for C12H17N2OP (236.25): C, 61.01;
H, 7.25; N, 11.86. Found: C, 60.46; H, 7.83; N, 11.76.
Me3SiSC(S)P dC(NMe2)2 (2c). A solution of carbon di-
sulfide (0.07 mL, 82.3 mg, 1.08 mmol) in 10 mL of n-pentane
was added dropwise to a cold solution (-50 °C) of Me3Si-
Moreover protonation, alkylation, and silylation occur
at the phosphorus atom to give R-phosphanyl carbenium
ions (D).11
We are interested in the polarity and chemical
behavior of nonmetalated phosphaalkenes of the type
RC(O)-PdC(NMe2)2. If in these molecules a significant
accumulation of electron density at phosphorus occurs,
delocalization of negative charge into the organic car-
bonyl substituents should be possible.
This paper focuses on the synthesis, structure, bond-
ing, and coordination chemistry of P-acyl-, P-dithiocar-
boxyl-, and P-thiocarbamoyl derivatives of inversely
polarized phosphaalkenes.
PdC(NMe2)2 (0.22 g, 1.08 mmol) in 30 mL of n-pentane.
A
yellow precipitate occurred immediately, which was filtered
and washed with 50 mL of cold n-pentane (-30 °C). Yield:
0.26 g (86.1%) of pure yellow powderous 2c. 1H NMR (C6D6,
22 °C) δ: 0.59 (s, 9H, SiMe3), 2.65 (s, 12H, NMe2). 13C{1H}
NMR (C6D6, 22 °C) δ: 2.2 [s, Si(CH3)3], 43.3 [s, N(CH3)2], 193.7
1
[d, J PC ) 87.2 Hz, PdC(NMe2)2], 234.5 (br, PCS2). 31P{1H}
NMR (C6D6, 22 °C) δ ) 145 br. IR (Nujol, cm-1) ν: 1624 m,
1589 m, 1553 s, 1510 sh, 1488 s, 1402 w, 1366 s, 1300 m, 1265
s, 1258 s, 1249 s [δ(SiMe3)], 1183 s, 1162 w, 1140 w, 1106 m,
1085 s [ν(CdS)], 1072 sh, 957 w, 906 w, 879 w, 845 s [F(SiMe3)],
755 m, 696 m, 621 w, 566 w, 508 w. MS/EI m/z: 280 (M+),
149 (Me3SiSCS+). Anal. Calcd for C9H21N2P2S2Si (280.46): C,
38.54; H, 7.55; N, 9.99. Found: C, 38.21; H, 7.35; N, 10.46.
P h (Me3Si)N-C(S)P dC(NMe2)2 (2d ). A solution of phenyl
isothiocyanate (0.17 g, 1.26 mmol) in 10 mL of n-pentane was
dropped into a cold solution (-30 °C) of Me3SiPdC(NMe2)2
(0.26 g, 1.26 mmol) in 30 mL of n-pentane to afford pure 2d
as an orange powder (0.31 g, 72%). 1H NMR (C6D6, 22 °C) δ:
0.57 (s, 9H, SiMe3), 2.61 (s, 12H, NMe2), 6.9-7.2 (m, 5H,
phenyl-H). 13C{1H} NMR (C6D6, 22 °C) δ: 3.5 [s, Si(CH3)3],
43.2 [s, N(CH3)2], 127.0 s, 128.0 s, 129.3 s, 148.2 (s, phenyl-
Exp er im en ta l Section
All operations were performed with standard Schlenk
techniques in an oxygen-free Ar atmosphere. Solvents were
dried by standard methods and freshly distilled under argon.
Infrared spectra were recorded on a Bruker FT-IR IFS66
spectrometer, and the 1H, 13C, and 31P NMR spectra were
taken on Bruker AM Avance DRX 500, Bruker AC 250P, and
Bruker AC 100 instruments; standards: SiMe4 (1H, 13C) and
external 85% H3PO4 (31P). Elemental analyses were performed
in the microanalytical laboratory of the University of Bielefeld.
Mass spectra were obtained with a VG Autospec sector-field
mass spectrometer (micromass).
6
Phosphaalkene Me3SiPdC(NMe2)2 and the complexes
1
1
C), 198.1 (d, J PC ) 72.1 Hz, PdC(NMe2)2], 231.5 [d, J PC
)
Mn(CO)5Br,12 Re(CO)5Br,13 and Re2(CO)6Br2thf2 were syn-
13
72.3 Hz, N(CdS)P]. 31P{1H} NMR (C6D6, 22 °C) δ: 82.8 s. IR
(KBr, cm-1) ν: 2946 w, 2930 w, 2893 w, 1589 w, 1519 m, 1482
m, 1462 w, 1448 w, 1404 w, 1265 vs, 1250 sh [δ(SiMe3)], 1193
s, 1139 w, 1114 m, 1094 w, 1037 vs [ν(CdS)], 999 w, 940 w,
912 w, 873 w, 847 s [F(SiMe3)], 712 w, 698 w, 622 m, 567 w,
520 w. MS/EI m/z: 339 (M+), 131 [PdC(NMe2)2+]. 44 (NMe2+).
Anal. Calcd for C15H26N3PSSi (339.52): C, 53.06; H, 7.72; N,
12.38. Found: C, 53.06; H, 7.60; N, 12.41.
thesized according to the literature. Carbon disulfide, phenyl
isothiocyanate, pivaloyl chloride, and benzoyl chloride were
purchased commercially.
P r epar ation of Com pou n ds. tBu C(O)P dC(NMe2)2 (2a).
A solution of pivaloyl chloride (0.14 g, 1,13 mmol) in 10 mL of
n-pentane was added dropwise to a chilled solution (-30 °C)-
of Me3SiPdC(NMe2)2 (0.23 g, 1.13 mmol) in 40 mL of n-
pentane, whereupon a light yellow precipitate separated. The
chilled slurry was filtered, and the filter cake was washed with
50 mL of cold n-pentane (-30 °C). After drying in vacuo, 2a
was obtained as a light yellow analytically pure powder (0.17
g, 70%). 1H NMR (C6D6, 22 °C) δ: 1.43 (s, 9H, tBu), 2.60 (s,
12H, NMe2). 13C{1H} NMR (C6D6, 22 °C) δ: 28.4 [s, C(CH3)3],
[SdC-S-Mn (CO)3-µ-P C(NMe2)2]2 (3c). A solution of 1.23
mmol of 2c in 40 mL of toluene was prepared from 0.25 g of
Me3SiPdC(NMe2)2 and 0.09 g of carbon disulfide at -50 °C.
After warmup to 20 °C, solid (CO)5MnBr (0.34 g, 1.23 mmol)
was added and the suspension was heated to 50 °C, whereupon
a color change from light red to dark red and the separation
of a deep-red precipitate occurred. After 1 h of stirring it was
cooled to 20 °C, and the slurry was filtered. The filter cake
was washed with cold CH2Cl2 (5 × 10 mL, 0 °C) to afford pure
3c as a red-violet powder (0.32 g, 73.4%). 1H NMR (CD2Cl2,
22 °C) δ: 3.23 (s, NMe2). 31P{1H} NMR (CD2Cl2, 22 °C) δ: 121
s. IR (KBr, cm-1) ν: 1994 [s, ν(CO)], 1908 [s, ν(CO)], 1700 w,
1653 w, 1550 m, 1507 w, 1496 w, 1458 w, 1387 m, 1262 w,
2
42.7 [s, N(CH3)2], 47.6 [d, J PC ) 41.0 Hz, C(CH3)3], 201.4 [d,
1J PC ) 80.5 Hz, PdC(NMe2)2], 231.4 [d, J PC ) 90.8 Hz,
1
tBuC(O)]. 31P{1H} NMR (C6D6, 22 °C) δ: 26.4 s. IR (KBr,
cm-1) ν: 2946 m, 2927 sh, 2857 w, 1563 vs [ν(CO)], 1527 s,
1467 m, 1443 m, 1414 w, 1380 sh, 1367 s, 1351 m, 1267 m,
1209 w, 1148 m, 1135 w, 1111 w, 1092 m, 1057 w, 1026 m,
941 s, 921 s, 876 w, 804 w, 679 w, 646 w, 614 w, 516 w, 449 w.
MS/EI m/z: 216 (M+), 131 [PdC(NMe2)2+], 100 [C(NMe2)2+],
85 (tBuCO+), 57 (tBu+), 44 (NMe2+). Anal. Calcd for C10H21N2-
OP (216.26): C, 55.54; H, 9.79; N, 12.95. Found: C, 53.74; H,
9.76; N, 12.62.
1090 w, 941 m, 668 m, 630 m, 517 w. Anal. Calcd for C18H24
-
Mn2N4O6P2S4 (692.50): C, 31.22; H, 3.49; N, 8.09. Found: C,
31.56; H, 3.54; N, 7.50.
P h C(O)P dC(NMe2)2 (2b). Analogously, 0.24 g (77%) of
pure yellow powderous 2b was synthesized by combination of
0.19 g (1.32 mmol) of benzoyl chloride and 0.27 g (1.32 mmol)
of Me3SiPdC(NMe2)2 in 40 mL of n-pentane. 1H NMR (C6D6,
22 °C) δ: 2.68 (s, 12H, NMe2), 7.18 (m, 3H, m- and p-phenyl-
H), 8.35 (m, 2H, o-phenyl-H). 13C{1H} NMR (C6D6) δ: 42.9 [s,
N(CH3)2], 126.4 (s, phenyl-C), 126.5 (s, phenyl-C), 130.7 (s,
[P h NdC-S-Mn (CO)3-µ-P C(NMe2)2]2 (3d ). A sample of
solid (CO)5MnBr (0.34 g, 1.23 mmol) was added at 20 °C to
the solution of 1.23 mmol of 2d (prepared from 0.25 g of Me3-
SiPdC(NMe2)2 and 0.17 g of phenyl isothiocyanate) in 40 mL
of toluene. The slurry was stirred at 70 °C until all (CO)5MnBr
went into solution. Stirring was continued for 2 h, whereupon
an orange precipitate separated. After being cooled to 20 °C,
it was filtered and the filter cake was washed with cold CH2-
Cl2 (3 × 10 mL, 0 °C). The orange powder was crystallized
from hot CH2Cl2 to give 0.28 g (56.2%) of 3d . The product is
insoluble in arenes, ethers, and saturated hydrocarbons and
only slightly soluble in CH2Cl2. 1H NMR (CD2Cl2, 22 °C) δ:
3.38 (s, 12H, NMe2), 7.07 (m, 3H, m- and p-phenyl-H), 7.37
(m, 2H, o-phenyl-H). 31P{1H} NMR (CD2Cl2, 22 °C) δ: -17
(s, br). IR (KBr, cm-1) ν: 2000 [w, ν(CO)], 1982 [s, ν(CO)],
1903 [s, ν(CO)], 1894 [s, ν(CO)], 1889 sh, 1559 [s, ν(CdN)],
2
o-phenyl-C), 145.0 (d, J PC ) 49.3 Hz, i-phenyl-C), 199.3 [d,
1
1J PC ) 78.5 Hz, PdC(NMe2)2], 215.6 [d, J PC ) 78.7 Hz,
PhC(dO)]. 31P{1H} NMR (C6D6) δ: 31.3 s. IR (film, CsI, cm-1
)
ν: 2926 m, 1583 w, 1546 s [ν(CO)], 1492 m, 1464 m, 1441 m,
1404 w, 1369 s, 1268 m, 1193 m, 1166 m, 1147 m, 1108 m,
(11) Weber, L.; Scheffer, M.; Stammler, H.-G.; Neumann, B.,
manuscript in preparation.
(12) Abel, E. W.; Wilkinson, G. J . Chem. Soc. (London) 1959, 1501.
(13) Vitali, D.; Calderazzo, F. Gazz. Chim. Ital. 1972, 102, 586.

Acyl Phosphanes and Phosphaalkenes
Organometallics, Vol. 17, No. 16, 1998 3595
1499 w, 1484 w, 1464 w, 1446 w, 1387 m, 1260 w, 1113 w, 913
w, 868 w, 763 w, 696 w, 663 m, 633 m, 516 w. MS/LSIMS,
nitrobenzyl alcohol matrix m/z: 810 (M+). Anal. Calcd for
Sch em e 2
C
30H34Mn2N6O6P2S2‚CH2Cl2 (895.47): C, 41.58; H, 4.05; N,
9.39. Found: C, 41.83; H, 4.14; N, 9.57.
[SdC-S-Re(CO)3-µ-P C(NMe2)2]2 (4c). P ath 1. A sample
of solid (CO)5ReBr (0.54 g, 1.32 mmol) was added to a solution
of 1.32 mmol of 2c (prepared from 0.27 g of Me3SiPdC(NMe2)2
and 0.10 g of CS2 in 40 mL of toluene. The slurry was stirred
at 70 °C until all (CO)5ReBr went into solution. After 30 min,
a red precipitate occurred, and the slurry was stirred for
another 60 min. Cooling the deep-red slurry to 20 °C and
filtration afforded dark red 4c, which was washed with cold
CH2Cl2 (5 × 10 mL, 0 °C). Yield: 0.52 g (82.5%).
P a th 2. A yellow slurry of 0.98 mmol of 2c in 40 mL of
n-pentane was produced by combination of 0.20 g of Me3Si-
PdC(NMe2)2 and 0.075 g of carbon disulfide. At -20 °C, a
solution of Re2(CO)6Br2(thf)2 (0.41 g, 0.49 mmol) in 10 mL of
THF was added dropwise. Warming to room temperature led
to the formation of a red precipitate. After 60 min of stirring
it was filtered, and the filter cake was washed with cold CH2-
Cl2 (4 × 20 mL, 0 °C) to give 0.32 g (68%) of 4c as a red powder.
The product is insoluble in common organic solvents and only
slightly soluble in CH2Cl2. 1H NMR (CD2Cl2, 22 °C) δ: 3.29
(s, br, NMe2). 31P{1H} NMR (CD2Cl2, 22 °C) δ: 60 (s, br). IR
(KBr, cm-1) ν: 1998 [s, ν(CO)], 1889 [s, ν(CO)], 1696 w, 1653
w, 1550 m, 1495 w, 1458 w, 1384 m, 1261 w, 1154 w, 1107 m,
945 m, 923 m, 865 w, 637 w, 621 w, 517 w. Anal. Calcd for
w-1 ) σ2(Fo2) + (0.0357P)2 + 0.35P, where P ) [max(Fo2, 0) +
2Fc2]/3, maximum/minimum residual electron densities 0.293
and -0.240 eÅ-3
.
X-r a y Cr ysta l Str u ctu r e Deter m in a tion of 4d . Single
crystals of 4d were grown by slow cooling a saturated boiling
CH2Cl2 solution to ambient temperature. A yellow crystal with
the approximate dimensions of 0.22 × 0.22 × 0.16 mm3 was
measured on a Bruker AXS SMART CCD area detector system
with a three-axis goniometer and with Mo KR radiation at 183
K. Crystal data and refinement details: cell dimensions a )
9.3004(4) Å, b ) 10.0027(4) Å, c ) 12.8497(5) Å, R ) 106.112-
(1)°, â ) 104.544(1)°, γ ) 98.936(1)°, V ) 1078.6(1) Å3 (refined
from all reflections >20σ(F)), Z ) 1, dcalcd ) 1.914 g cm-3, µ )
6.07 mm-1, space group P1h, hemisphere data collection in ω
at 0.3° scan width in three runs with 606, 435, and 230 frames
(φ ) 0, 88, and 180°) at a detector distance of 4.019 cm (2 θmax
) 60°), data reduction with SAINT program (V4.050 Bruker-
AXS), empirical absorption correction with redundant data
(SADABS program) max/min transmission 0.695/0.524, and
R(merg) before/after correction 0.075/0.018; structure solution
and refinement on F2 with SHELXS-96 and SHELXL-93; 8671
intensities read, 6049 unique (Rint ) 0.0179), and 5676
observed [I > 2σ(I)], 248 parameters, hydrogen atoms treated
as riding groups with a 1.2-fold (1.5-fold for methyl groups)
isotropic U value of the equivalent U value of the correspond-
ing C atom. R1 ) 0.023; wR2 ) 0.072, GooF (F2) ) 0.628, w-1
) σ2(Fo2) + (0.1P)2 + 0.0P, where P ) [max(Fo2, 0) + 2Fc2]/3,
C
18H24N4O6P2Re2S4 (955.04): C, 22.64; H, 2.53; N, 5.87.
Found: C, 22.13; H, 2.77; N, 5.66.
[P h NdC-S-Re(CO)3-µ-P C(NMe2)2]2 (4d ). A sample of
solid (CO)5ReBr (0.40 g, 0.98 mmol) was added to a solution
of 0.98 mmol of 2d (prepared in situ from 0.20 g of Me3SiPd
C(NMe2)2 and 0.13 g of phenyl isothiocyanate) in 40 mL of
toluene. The slurry was stirred at 80 °C, whereupon the color
changed to deep-red and an orange precipitate separated. After
2 h, the slurry was cooled to 20 °C and filtered. The filter
cake was washed with cold CH2Cl2 (3 × 10 mL, 0 °C) to afford
0.25 g (47.5%) of pure orange 4d . Single crystals were grown
from hot CH2Cl2 upon slow cooling to ambient temperature.
1H NMR (CD2Cl2, 22 °C) δ: 3.42 (s, 12H, NMe2), 7.03 (m, 2H,
phenyl-H), 7.06 (m, 1H, phenyl-H), 7.35 (m, 2H, phenyl-H).
31P{1H} NMR (CD2Cl2, 22 °C) δ: -116 s. IR (KBr, cm-1) ν:
1995 [s, ν(CO)], 1909 [s, ν(CO)], 1890 [s, ν(CO)], 1564 [m,
ν(NdC)], 1550 [m, ν(NdC)], 1484 w, 1463 w, 1446 w, 1388 w,
1260 w, 1158 w, 1114 w, 915 w, 868 w, 767 w, 694 w, 663 w,
517 w. MS/LSIMS, nitrobenzyl alcohol matrix m/z: 1073 (M+).
Anal. Calcd for C30H34N6O6P2Re2S2 (1073.10): C, 33.58; H,
3.19; N, 7.83. Found: C, 33.41; H, 2.92; N, 7.43.
max/min residual electron densities 1.54 and -1.61 eÅ-3
.
Resu lts a n d Discu ssion
Reaction of phosphaalkene Me3SiPdC(NMe2)2 (1)
with an equimolar amount of pivaloyl chloride or
benzoyl chloride in n-pentane at -30 °C produced the
P-acyl phosphaalkenes 2a ,b as yellow solids in good
yields. Combination of 1 with carbon disulfide or phenyl
isothiocyanate under similar conditions afforded the
yellow orange P-functionalized phosphaalkenes 2c and
2d (Scheme 2).
Several years ago, Markovskii et al. described the
reaction between 1 and phenyl isocyanate, which led to
an isomeric mixture of insertion products.14 Replace-
ment of the P-silyl group in 1 (δ31P ) -47.1)15 by acyl,
dithiocarboxy, and thiocarbamoyl functions leads to a
significant deshielding of the 31P NMR resonances in
2a -d (δ 31P ) 26.4-145). In comparison to this, the
X-r a y Cr ysta l Str u ctu r e Deter m in a tion of 2c. Single
crystals of 2c were grown from toluene at -30 °C. A red
needlelike crystal with the approximate dimensions of 0.2 ×
0.2 × 0.45 mm3 was measured on a Siemens SMART CCD area
detector system with three-axis geometry with Mo KR radia-
tion at 173 K. Crystal data and refinement details: Crystal
system monoclinic, cell dimensions a ) 9.4986(6) Å, b )
11.8038(7) Å, c ) 13.4494(8) Å, â ) 98.3100(10)°, V ) 1492.11-
(16) Å3 (refined from 5356 reflections) Z ) 4, dcalcd ) 1.248 g
cm-3, µ ) 0.520 mm-1, space group P21/n, hemisphere data
collection in ω at 0.3° scan width in three runs with 606, 435
and 230 frames (φ ) 0, 88, and 180°) at a detector distance of
5 cm (2 θmax ) 54°), data reduction with the SAINT program
(V4.028 Siemens)by which more than 93.5% of the data are
covered, empirical absorption correction with redundant data
(SADABS program, Siemens) max/min transmission 1.000/
0.770; 8294 intensities collected, 3194 unique (Rint ) 0.0218);
structure solution and refinement on F2 with SHELX97, 143
parameters, hydrogen atoms treated as riding groups with a
1.5-fold isotropic U value of the equivalent U value of the
corresponding C atom. R1 ) 0.0397; wR2 ) 0.0724 for all data,
(14) Markovskii, L. N.; Romanenko, V. D.; Pidvarko, T. V. Zh.
Obshch. Khim. 1983, 53, 1672; Chem. Abstr. 1983, 99, 195100g.
(15) Povolotskii, M. I.; Negrebetskii, V. V.; Romanenko, V. D.;
Ivanchenko, V. I.; Sarina, T. V.; Markovskii, L. N. Zh. Obshch. Khim.
1990, 60, 2238; Chem. Abstr. 1991, 115, 8934w.

3596 Organometallics, Vol. 17, No. 16, 1998
Weber et al.
Sch em e 3
substitution of the silyl group in Me3SiPdC(OSiMe3)-
(tBu) (δ 31P ) 120)16 by the pivaloyl unit to give tBuC-
(O)PdC(OSiMe3)(tBu) (δ 31P ) 131) has much less
influence on the 31P NMR resonances.16 Obviously the
electronic structure of the inverse phosphaalkene 1 is
much more perturbed by acylation than is observed in
the more “classically polarized” phosphaalkenes. This
idea is supported by IR evidence. In tBuC(O)Pd
C(OSiMe3)(tBu), an intense band at v ) 1664 cm-1 is
assigned to the ν(CO) stretching mode. This value falls
in the range of 1630-1690 cm-1 usually encountered
in acyl phosphanes.17 In the IR spectra of 2a and 2b,
strong bands at v 1563 and 1546 cm-1, respectively,
indicated a pronounced π-delocalization of electron
density onto the carbonyl group. This electronic situ-
ation may be described by canonical formulas E-G
similar to the bond description of carbonyl-stabilized
ylides (E′-G′) (Scheme 3).
F igu r e 1. Molecular structure of 2c in the crystal with
ellipsoids drawn in at 50% probability.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 2c
S(1)-C(4)
S(2)-C(4)
P(1)-C(5)
N(1)-C(6)
N(2)-C(5)
N(2)-C(9)
1.8007(15) S(1)-Si(1)
1.6731(16) P(1)-C(4)
1.8264(16) N(1)-C(5)
1.458(2)
1.338(2)
1.466(2)
2.1732(6)
1.7483(16)
1.341(2)
1.464(2)
1.462(2)
N(1)-C(7)
N(2)-C(8)
C(4)-S(1)-Si(1)
C(5)-N(1)-C(6)
C(6)-N(1)-C(7)
C(5)-N(2)-C(9)
S(2)-C(4)-P(1)
P(1)-C(4)-S(1)
N(2)-C(5)-P(1)
106.08(5) C(4)-P(1)-C(5) 101.89(7)
122.61(15) C(5)-N(1)-C(7) 122.24(15)
113.96(16) C(5)-N(2)-C(8) 122.36(14)
123.29(14) C(8)-N(2)-C(9) 113.53(14)
130.92(9) S(2)-C(4)-S(1) 121.43(9)
107.53(8) N(2)-C(5)-N(1) 118.03(14)
118.87(12) N(1)-C(5)-P(1) 122.68(12)
Si(1)-S(1)-C(4)-S(2) 29.8
Si(1)-S(1)-C(4)-P(1) -153.7
C(5)-P(1)-C(4)-S(1) 175.9
C(5)-P(1)-C(4)-S(2) -8.0
C(4)-P(1)-C(5)-N(1) -58.8
C(4)-P(1)-C(5)-N(2) 128.9
Consistently, the IR spectra of the ylides Me(O)CCHd
PPh3 and Ph(O)CHdPPh3 display strong carbonyl bands
at v 1540 and 1500 cm-1, respectively.18
In the 13C{1H} NMR spectra of 2a and 2b, doublets
at δ 201.4 (1J PC ) 80.5 Hz) and 199.3 (1J PC ) 78.5 Hz),
respectively, are attributed to the tricoodinate carbon
atom of the PdC bond. The respective 13C nucleus in 1
gives rise to a doublet at δ 204.0 (1J PC ) 85.0 Hz).15 The
carbon atoms of the carbonyl groups in 2a ,b resonate
as doublets at δ 231.4 (1J PC ) 90.8 Hz) and 215.6 (1J PC
) 78.7 Hz), respectively. The 13C NMR resonances due
to the PdC and the CdS units in 2c are registered at δ
1.740(1) Å6]. Delocalization of negative charge into the
CdS bond is obvious by the bond length P(1)-C(4) of
1.7483(16) Å, which is amid the PdC double bond length
in nonconjugated phosphaalkenes (1.65-1.67 Å 3) and
the standard value for P-C single bond (1.85 Å). The
trigonal-planar carbon atom C(4) (sum of angles 359.88°)
is linked to atom S(1) by a single bond of 1.8007(15) Å
(sum of single bond covalence radii 1.81 Å) and to S(2)
by a double bond of 1.6731(16) Å, which is elongated in
comparison to the calculated value for a CdS double
1
193.7 (d, J PC ) 87.2 Hz) and 234.5 (s, br). In keeping
with this, the doublet at δ 231.5 (1J PC ) 72.3 Hz) in 2d
was assigned to a CdS function and thus may serve as
evidence for the presence of a carbamoyl function at the
phosphorus atom and disfavor the isomeric thioimidate
C(dNPh)SSiMe3 structure.
bond (1.62 Å 19
)
Such a situation is well-known from the structural
data of many â-ketoylides having CdO lengths ranging
from 1.22 to 1.30 Å, with most being near 1.25 Å,
compared to a determined length of 1.217 Å in a
corresponding phosphonium salt. Likewise the C-CO
lengths range from 1.35 to 1.48 Å, with most being near
1.40 Å, compared to a determined length of 1.51 Å in a
phosphonium salt.20
The bond angle C(4)-P(1)-C(5) [101.89(7) Å] is close
to the respective value in HPdC(NMe2)2 [103(1)°].4 In
good agreement with the VSEPR concept, the angle
P(1)-C(4)-S(2) of 130.92(9)° clearly exceeds those
between the bonds of a lower degree of π-bonding [S(1)-
C(4)-S(2) ) 121.43(9)°, S(1)-C(4)-P(1) ) 107.53(8)°].
The atoms S(1), C(4), S(2), P(1), and C(5) slightly deviate
from a planar arrangement as evident from the torsion
angles C(5)-P(1)-C(4)-S(1) ) 175.9° and C(5)-P(1)-
C(4)-S(2) ) -8.0°.
To substantiate the spectroscopic evidence for a
delocalization of negative charge by π-accepting sub-
stituents at the phosphorus center, an X-ray structure
analysis of 2c was performed. Single crystals of 2c were
grown from toluene at -30 °C. The results of the
structural determination are shown in Figure 1. Se-
lected bond lengths and angles for the molecule are
given in Table 1. The analysis confirms the presence
of a P-dithiocarboxy-stabilized carbenium phosphanide
in which the planar carbenium center C(5) shows
multiple bonding to the planarly configurated nitrogen
atoms [C(5)-N(1) ) 1.341(2) Å; C(5)-N(2) ) 1.338(2)
Å]. The former PC double bond of the precursor 1 is
elongated to a single bond since the P(1)-C(5) distance
in 2c is 1.8264(16) Å [cf. in HPdC(NMe2)2; d(PdC) )
(16) Becker, G. Z. Anorg. Allg. Chem. 1977, 430, 66.
(17) (a) Osaki, T.; Otera, J .; Kawasaki, Y. Bull. Chem. Soc. J pn.
1973, 46, 1803. (b) Issleib, K.; Priebe, E. Chem. Ber. 1959, 92, 3183.
(18) Vicente, J .; Chicote, M. T.; Saura-Llames, I.; Turpin, J .;
Fernandez-Baeza, J . J . Organomet. Chem. 1987, 333, 129.
(19) Shriver, D. F.; Atkins, P. W.; Langford, C. H. Inorganic
Chemistry, 2 ed.; Oxford University Press: Oxford, 1994; p 58.
(20) Ylides and Imines of Phosphorus; J ohnson, A. W., Ed.; Wiley:
New York, 1993.

Acyl Phosphanes and Phosphaalkenes
Organometallics, Vol. 17, No. 16, 1998 3597
Sch em e 4
Molecules of the type 2 exhibit a number of donor sites
and therefore may act as multidentate ligands in
transition metal coordination chemistry.
F igu r e 2. Molecular structure of 4d in the crystal with
ellipsoids drawn in at 50% probability.
The phosphaalkenes 2c and 2d smoothly reacted with
(CO)5MBr (M ) Mn, Re) in toluene (50-80 °C) to afford
red (3c, 4c) and orange (3d , 4d ) tricyclic complexes in
good yield (42.5-82.5%) (Scheme 4).
Complex 4c was also prepared by the treatment of
complex Re2(CO)6Br2(thf)2 with 2 molar equiv of 2c in
a pentane/tetrahydrofuran mixture at ambient temper-
ature (68% yield). The compounds 3c,d and 4c,d are
air-stable solids which are insoluble in THF, ether, and
toluene. They are only slightly soluble in dichlo-
romethane, which hampers the registration of meaning-
ful 13C NMR spectra.
The ν(CO) region in the IR spectra (KBr) of 3c,d is
dominated by two intense bands at v 1994 and 1908
cm-1 (3c) and 1998 and 1889 cm-1 (3d ), which points
to a facial assembly of three carbonyl ligands in an
octahedrally configurated complex. In 4c and 4d , more
than two ν(CO)bands were observed. The absence of
the typical absorptions of the SiMe3 group in the IR and
NMR spectra agree with the release of Me3SiBr during
the reaction. Bands of medium intensity at v 1550 (4c)
and 1564 and 1550 cm-1 (4d ) are assigned to CdN
stretching vibrations. Mass spectra of 4c,d (LSIMS in
a nitrobenzyl alcohol matrix) show the peaks of the
molecular ions at m/z 810 (3d ) and 1073 (4d ). The 31P-
{1H} NMR spectra of 3c and 4c display singlets at δ
121 and 60, which in comparison to the 31P NMR
resonance in 2c (δ 145) are markedly shielded. Simi-
larly, the 31P NMR signals of 3d (δ -17) and 4d (δ -116)
appear at higher field than in precursor 2d (δ 82.8).
Constitution and configuration of the novel complexes
3c,d and 4c,d were unambiguously manifested by an
X-ray diffraction study of 4d . Crystals of the complex
were grown from a saturated solution in hot CH2Cl2,
which was slowly cooled to ambient temperature. The
results of the structural determination are shown in
Figure 2. Selected bond lengths and angles for the
compound are given in Table 2.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4d
Re(1)-C(9)
Re(1)-C(8)
Re(1)-P(1A)
P(1)-C(2)
P(1)-Re(1A)
O(1)-C(7)
O(3)-C(9)
N(1)-C(6)
N(2)-C(1)
N(2)-C(4)
N(3)-C(10)
1.920(3)
1.932(3)
2.5215(7) Re(1)-P(1)
1.833(3)
Re(1)-C(7)
Re(1)-S(1)
1.931(3)
2.5198(7)
2.5292(7)
1.852(3)
1.775(3)
1.155(4)
1.338(4)
1.470(4)
1.463(4)
1.275(3)
P(1)-C(1)
2.5215(7) S(1)-C(2)
1.140(4)
1.155(4)
1.465(4)
1.336(4)
1.478(4)
1.416(4)
O(2)-C(8)
N(1)-C(1)
N(1)-C(5)
N(2)-C(3)
N(3)-C(2)
C(9)-Re(1)-C(7)
C(7)-Re(1)-C(8)
C(7)-Re(1)-S(1)
93.63(12) C(9)-Re(1)-C(8) 92.60(13)
88.87(13) C(9)-Re(1)-S(1)
92.98(9) C(8)-Re(1)-S(1)
173.19(9)
89.15(10)
C(9)-Re(1)-P(1A) 89.92(9)
C(7)-Re(1)-P(1A) 96.44(9)
C(8)-Re(1)-P(1A) 173.97(9) S(1)-Re(1)-P(1A) 87.73(2)
C(9)-Re(1)-P(1)
C(8)-Re(1)-P(1)
P(1A)-Re(1)-P(1) 75.02(2)
105.27(9) C(7)-Re(1)-P(1)
99.02(10) S(1)-Re(1)-P(1)
159.05(9)
67.94(2)
108.40(12)
C(2)-P(1)-C(1)
C(2)-P(1)-Re(1A) 115.02(9) C(1)-P(1)-Re(1A) 106.87(8)
C(2)-P(1)-Re(1)
87.85(8)
C(1)-P(1)-Re(1)
132.98(9)
89.42(9)
121.3(3)
123.9(3)
113.7(3)
118.4(3)
122.4(2)
127.0(2)
Re(1A)-P(1)-Re(1) 104.98(2) C(2)-S(1)-Re(1)
C(1)-N(1)-C(6)
C(6)-N(1)-C(5)
C(1)-N(2)-C(4)
C(2)-N(3)-C(10)
N(2)-C(1)-P(1)
N(3)-C(2)-S(1)
S(1)-C(2)-P(1)
O(2)-C(8)-Re(1)
125.0(3)
113.6(3)
121.1(3)
119.6(3)
118.8(2)
129.9(2)
C(1)-N(1)-C(5)
C(1)-N(2)-C(3)
C(3)-N(2)-C(4)
N(2)-C(1)-N(1)
N(1)-C(1)-P(1)
N(3)-C(2)-P(1)
102.86(13) O(1)-C(7)-Re(1) 177.2(3)
176.8(3) O(3)-C(9)-Re(1) 179.5(3)
central planar ring by their carbon and sulfur atoms.
The central ring is a trapezium with Re-P bond lengths
of 2.5292(7) Å [Re(1)-P(1)] and 2.5215(7) Å [Re(1)-
P(1A)]. These values compare well with the Re-P
distances in Re2Br2(CO)6(P2Ph4) [2.508(5) Å].21 A sum-
mary of 10 independent Re-P bond lengths in univalent
rhenium complexes range from 2.413(4) to 2.538(5) Å
(av ) 2.461 Å).21 The endocyclic angle at phosphorus
in central ring Re(1)-P(1)-Re(1A) [104.98(2)°] is more
The analysis of 4d reveals a centrosymmetrical
tricyclic molecule with an anti orientation of the two
phenyl isothiocyanate units, which are connected to the
(21) Atwood, J . L.; Newell, J . K.; Hunter W. E.; Bernal, I.; Calder-
azzo, F.; Mavani, I. P.; Vitali, D. J . Chem. Soc., Dalton Trans. 1978,
1189.

3598 Organometallics, Vol. 17, No. 16, 1998
Weber et al.
obtuse than that at the rhenium atoms [P(1)-Re(1)-
P(1A) ) 72.02(2)°]. The four-membered ring defined by
the atoms Re(1), P(1), C(2), and S(1) is puckered with
an interplanar angle of 37.0° between the triangular
planes Re(1), P(1), S(1) and P(1), C(2), S(1). The plane
defined by the heavy atoms S(1), Re(1), and P(1) and
the central ring enclose a dihedral angle of 86.3°. The
trigonal planar carbon atom C(2) is linked to the
exocyclic phenylimino group by a CN double bond of
1.275(3) Å. The remaining atoms S(1) and P(1) are
ligated to C(2) by single bonds of 1.775(3) Å [S(1)-C(2)]
and 1.833(3) Å [P(1)-C(2)]. The interatomic distance
Re(1)-S(1) [2.5198(7) Å] exceeds that of the rhenium-
sulfur single bonds in Re2Br2(CO)6(S2Ph2) (2.487 Å)22
and Re2Br2(CO)6(S2Me2) (2.486 Å).23 The phosphorus
atoms are tetracoordinate featuring exocyclic PC single
bonds of 1.852(3) Å to the planar carbon atom C(1) of a
bis(dimethylamino)carbenium unit. The plane defined
by the atoms N(1), C(1), and N(2) is orientated nearly
orthogonally to the central Re2P2 ring, featuring a
dihedral angle of 100.3°. The rhenium atoms are
centered in a distorded octahedron with a facial ar-
rangement of the three carbonyl ligands. The rhenium
carbon bond lengths range from 1.920(3) to 1.932(3) Å
and thus within experimental error are comparable to
the respective data in Re2Br2(CO)6(E2R2) [E2R2 ) S2-
Ph2 (1.89 Å),22 S2Me2 (1.87 Å),23 and P2Ph4 (1.90 Å).21
The 12 bond angles about the rhenium atom range from
67.94(2)° [S(1)-Re(1)-P(1)] to 105.27(9)° [C(9)-Re(1)-
P(1)]. The organophosphorus building block in the
complex can be characterized as an η2(P,S)-µ(P) ligand,
thus constituting a novel mode of coordination in
phosphaalkene chemistry.
Ack n ow led gm en t. This work was generally sup-
ported by the Fonds der Chemischen Industrie, Frank-
furt/M., Germany, and BASF AG, Ludwigshafen, which
are gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Tables of X-ray
data, atomic coordinates, thermal parameters, and complete
bond distances and angles and thermal ellipsoid plots for
1
compounds 2c and 4d as well as H and 13C{1H}NMR spectra
of 2a and 2b (19 pages). Ordering information is given on any
current masthead page.
(22) Bernal, I.; Atwood, J . L.; Calderazzo, F.; Vitali, D. Gazz. Chem.
Ital. 1976, 106, 971.
(23) Bernal, I.; Atwood, J . L.; Calderazzo, F.; Vitali, D. Isr. J . Chem.
1976/77, 15, 153.
OM980264I